B xy dng

Chng trnh bi dng k s

t vn gim st xy dngBi ging

Mn Hc

Gim st thi cng v nghim thu lp t Thit b

Trong cng trnh dn dng

Ngi son :

PGs L KIu

Trng i hc Kin trc H ni

H ni, 11-2004

Chng I

Nhng vn chung

1. Trang b tin nghi trong cng trnh dn dng ngy cng chim vai tr quan trng trong vic u t v xy dng cng trnh.

1.1 S pht trin cng ngh v nhng ng dng cng ngh phc v i sng con ngi.

Trc y chng hn mt th k , hu ht dn c nc ta u thp n du , cha bit in l g . Ngay cch y hai mi nhm nm c cu chuyn chng ta m c c tht ln Ngh Tnh ct trong t lnh Nam H v ngy nay , tht ln ca chng ta tiu dng phi l tht nc. Hu nh mi nh thnh ph u c TV. Vido dn dn khng c chung na m phi dng u a compact ,VCD, SVCD, DVD . S pht trin cng ngh v ng dng cng ngh mi phc v con ngi lm cho kin trc s v k s xy dng phi c thi nghim tc khi thit k v trang b nh v nh dn dng.

1.2 Ngi nh thng minh , phn nh xu th thi i.

u nhng nm 1980 trn th gii bt u ni n khi nim " ngi nh thng minh ". Nhiu nh l lun kin trc a ra nhng nh ngha v " ngi nh thng minh " t ch cha tho ng n ng dn . Lc u c ngi nu rng " ngi nh thng minh l ngi nh m mi th u thu ht". Hi tho quc t v " ngi nh thng minh " t chc vo hai ngy 28 v 29 thng Nm nm 1985 Toronto ( Canaa ) a ra khi nim " ngi nh thng minh kt hp s i mi theo cng ngh vi s qun l kho lo khin cho thu hi n ti a c vn u t b ra". Ngi nh khng ch l ni ngh ngi sau gi lao ng ti sn xut sc lao ng m ngi hin i phi lun lun tip cn c vi mi ngi , vi cng vic , vi th gii vo bt k lc no v bt k v tr no trong ngi nh. Ngi nh l s kt hp ti u ho 4 nhn t c bn l : kt cu ti u , h thng ti u , dch v ti u , v qun l c ti u v quan h cht ch gia cc nhn t ny. Ngi nh thng minh phi l ni h tr c cho ch doanh nghip , nh qun l ti sn , nhng ngi s dng nh thc hin c mc tiu ca h trong lnh vc chi ph , tin nghi , thch hp , an ton , mm do lu di v c tnh cht th trng .

Ngi nh thng minh l ngi nh gn lin vi cng ngh hin i. Yu t th hin s hin i l in t. Quan nim theo in t v s vt th hin qua 4 nhm : (i) s dng nng lng hiu qu , (ii) h thng an ton cho con ngi , (iii) h thng lin lc vin thng v (iv) t ng ho ni lm vic. C th ho trn 4 nhm ny thnh 2 l nhm ln l phng tin iu hnh ( nng lng v an ton ) v h thng thng tin ( thng tin v t ng ho ni lm vic ). Phng tin iu hnh ni chung l vn kt cu vt cht v cch iu hnh kt cu vt cht ra sao. H thng thng tin lin quan n s iu khin c th bn trong ngi nh . Ngi Nht khi nhn nhn v ngi nh thng minh cho rng c 5 vn chnh l : (i) mng li khng gian ti ch , ( ii) s tng nh nng cao dn , (iii) phng ngang co li phng ng tng ln , (iv) h thng nghe nhn v (v) th thng minh .

Vi s s dng trang thit b trong nh ngy mt nhiu khin cho cc kin trc s v k s xy dng phi c nhng nhn thc v vai tr trang thit b trong ngi nh khc xa nhiu.

Lu nay ta hiu rng trang thit b l th cng c gii tr hoc tng tin nghi trong gia nh. Vi s chuyn i nn kinh t sang th trng, vi ng li hi nhp khu vc v th gii, gi gic lao ng khng b hp trong 8 gi hnh chnh m nhiu khi l 24/24 gi trong mt ngy. Khi chng ta sp i ng th c chung in thoi. in thoi bo nhng thng tin v cng vic. Lnh sn xut c ban hnh khi ta sp i ng v nu khng bt my tnh, ni mng v vo th in t giao dch ngay, nhiu khi nh vic, thit hi kinh t kh tnh ton c.

c ln, na m, ting chung in thoi bo t ni sn xut xa ch trn 1500 km l ang sn xut th b ri gu khi khoan cc nhi. Cn thit ng gp ngay kin v phng thc ly gu. Ni sn xut thc hin theo nhng kin t vn t xa y. Ch sau mt gi gu c ly ln khi h khoan. Nu khng c phng tin lin lc t xa, nu cu n rng na m khng phi l lc bn chuyn cng vic th thit hi s l con s ng k.

My fax l phng tin giao dch bng vn bn. Qu trnh kinh doanh, qu trnh lin h ca thi i mi th vic trao i vn bn t xa thng s dng my fax. Nhiu khi khng nhn c vn bn tc thi s l cng vic. Cho nn my fax phi lun ni vi mch in . Nu cch qun l vn theo kiu ngy xa, c ht gi hnh chnh , nhn vin bo v ngt cu dao trc khi kho cng c quan th my fax lm sao nhn c tn hiu v vn bn gi n vo lc ngoi gi hnh chnh. By gi s giao dch u ch trong ni th, ni m m rng ra c nc v c lin lc vi nhiu nc. Ni ny trn tri t l ban ngy, ni khc li l ban m. Ch ny l ang gi hnh chnh m lin lc th ch khc li l gi ang ngh ngi. Khng l g v mi gi m li ngt mi lin h.

Tm li vn y l cuc sng cng ln cao, s phc v con ngi bng nhng thnh qu cng ngh hin i cng c gn b vi cng trnh. iu na l thi hin i , gi gic lao ng khng ch b hp trong khun gi hnh chnh v hnh thi lao ng kiu mi cng thay i v a im lao ng khng b gn trong c quan m nh , ni i chi gii tr cng l ni lao ng v nhng phng tin lin lc , phng tin ct cha thng tin khng hn ch ch trong c quan.

2. Vai tr ca ngi k s t vn gim st xy dng trong vic lp t trang thit b tin nghi s dng cng trnh.

2.1 Nhim v ca gim st bo m cht lng ni chung :

T vn gim st xy dng c ch u t giao cho , thng qua hp ng kinh t , thay mt ch u t chu trch nhim v cht lng cng trnh. Nhim v ca gim st thi cng ca ch u t :

(1) V cng tc gim st thi cng phi chp hnh cc qui nh ca thit k cng trnh c cp c thm quyn ph duyt , cc tiu chun k thut , cc cam kt v cht lng theo hp ng giao nhn thu. Nu cc c quan t vn v thit k lm tt khu h s mi thu th cc iu kin k thut trong b h s mi thu l c s gim st k thut.

(2) Trong giai on chun b thi cng : cc b t vn gim st phi kim tra vt t , vt liu em v cng trng . Mi vt t , vt liu khng ng tnh nng s dng , phi a khi phm vi cng trng m khng c php lu gi trn cng trng . Nhng thit b khng ph hp vi cng ngh v cha qua kim nh khng c a vo s dng hay lp t. Khi thy cn thit , c th yu cu ly mu kim tra li cht lng vt liu , cu kin v ch phm xy dng .

(3) Trong giai on xy lp : theo di , gim st thng xuyn cng tc thi cng xy lp v lp t thit b . Kim tra h thng m bo cht lng , k hoch cht lng ca nh thu nhm m bo vic thi cng xy lp theo ng h s thit k c duyt.

Kim tra bin php thi cng , tin thi cng , bin php an ton lao ng m nh thu xut . Kim tra xc nhn khi lng hon thnh , cht lng cng tc t c v tin thc hin cc cng tc . Lp bo co tnh hnh cht lng v tin phc v giao ban thng k ca ch u t . Phi hp cc bn thi cng v cc bn lin quan gii quyt nhng pht sinh trong qu trnh thi cng . Thc hin nghim thu cc cng tc xy lp . Lp bin bn nghim thu theo bng biu qui nh .

Nhng hng mc , b phn cng trnh m khi thi cng c nhng du hiu cht lng khng ph hp vi yu cu k thut nh trong tiu ch cht lng ca b h s mi thu hoc nhng tiu ch mi pht sinh ngoi d kin nh ln qu qui nh , trc khi nghim thu phi lp vn bn nh gi tng th v s c xut ca n v thit k v ca cc c quan chuyn mn c php .

(4) Giai on hon thnh xy dng cng trnh : T chc gim st ca ch u t phi kim tra , tp hp ton b h s php l v ti liu v qun l cht lng . Lp danh mc h s , ti liu hon thnh cng trnh xy dng. Khi kim tra thy cng trnh hon thnh m bo cht lng , ph hp vi yu cu ca thit k v tiu chun v nghim thu cng trnh , ch u t t chc tng nghim thu lp thnh bin bn . Bin bn tng nghim thu l c s php l lm bn giao a cng trnh vo khai thc s dng v l c s quyt ton cng trnh.

S t chc mt cng trng v mi quan h gia cc bn c th hnh dung nh sau:

S t chc v quan h in hnh mt cng trng

* * * * * * *

2.2 Nhim v ca gim st bo m cht lng trong cng tc lp t trang b tin nghi v an ton :

(i) Quan h gia cc bn trong cng trng : Gim st bo m cht lng trong cng tc lp t trang b tin nghi v an ton cho cng trnh nm trong nhim v chung ca gim st bo m cht lng cng trnh l nhim v ca bn ch u t. Di s ch o trc tip ca ch nhim d n i din cho ch u t c cc cn b gim st bo m cht lng cng trnh . Nhng ngi ny l cn b ca Cng ty T vn v Thit k k hp ng vi ch u t , gip ch u t thc hin nhim v ny. Thng thng ch c ngi chu trch nhim m bo cht lng xy lp ni chung , cn khi cn n chuyn mn no th Cng ty t vn iu ng ngi c chuyn mn theo ngnh hp n tham gia h tr cho ngi chu trch nhim chung .

Trn cng trng, bn cnh nh u t l ch nhm d n, b phn t vn bo m cht lng v n c tin , nhn vin kim sot khi lng hon thnh.Sau khi bn nghin cu kh thi ca d n u t v xy dng c duyt, ch u t phi lp h s mi thu la chn nh thu. Quy nh ca Nh nc l ch u t l ngi chu trch nhim lp h s mi thu, trong c cc yu cu k thut ca cng trnh c u t. Nu nh u t khng lp c h s mi thu, c quyn thu chuyn gia. Nu thu chuyn gia m ch t yu cu th nh u t c quyn thu mt c quan t vn gip mnh lp h s mi thu hoc c th ch thu t vn lp ring cc yu cu k thut trong b h s mi thu.

Cc yu cu k thut trong b h s mi thu ht sc quan trng. Yu cu k thut ca h s mi thu l cc tiu ch nh thu cn c vo y lp gi cho thu. K s t vn bn cnh ch u t cn c vo y kim tra v nghim thu trong sut qu trnh thc hin d n.Lp c cc yu cu k thut cng k bao nhiu, cng st vi tnh hnh thc tin bao nhiu th qu trnh thc hin d n cng thun li by nhiu.

(ii) Phi hp tin l nhim v trc ht ca ch nhim d n m ngi xut chnh l gim st bo m cht lng . Trc khi bt u tin hnh cc cng tc xy lp cn lp tng tin . Tng tin ch cn vch ra nhng vic thuc bn thi cng no vo thi im no m mc chi tit c th tnh theo tng nh . Tng tin cho bit vo thi gian no cng tc no phi bt u cc thnh vin tham gia xy dng ton b cng trnh bit v phi hp . T tng tin m cc thnh vin tham gia xy lp v cung ng lp ra bng tin thi cng cho n v mnh trong ht sc ch n s phi hp ng b to din thi cng cho n v bn .

(iii) Ch tr thng qua bin php thi cng v bin php m bo cht lng.

Trc khi khi cng , Ch nhim d n v t vn m bo cht lng cn thng qua bin php xy dng tng th ca cng trnh nh phng php o t ni chung , phng php xy dng phn thn ni chung , gii php chung v vn chuyn theo phng ng , gii php an ton lao ng chung , cc yu cu phi hp v iu kin phi hp chung . Nu n v thi cng thc hin cng tc theo ISO 9000 th cn b t vn s gip Ch nhim d n tham gia xt duyt chnh sch m bo cht lng ca Nh thu v duyt s tay cht lng ca Nh thu v ca cc n v thi cng n cp i .

(iv) Ch tr kim tra cht lng , xem xt cc cng vic xy lp lm tng ngy . Trc khi thi cng bt k cng tc no , nh thu cn thng bo t vn m bo cht lng kim tra vic chun b . Qu trnh thi cng phi c s chng kin ca t vn m bo cht lng trong tt c cc khu, tt c cc cng vic t nh n ln. Khi thi cng xong cn tin hnh nghim thu cht lng v s lng cng tc xy lp hon thnh.

phn bit r nhim v ca k s t vn bo m cht lng bn cnh ch u t, ta xem nhim v ca k s ca nh thu.

K s ca nh thu l ngi c trch nhim hng dn cng nhn lm theo cc yu cu k thut ca ch u t to ra sn phm giao cho ch u t.

Nh vy nhim v hng dn cng nhn khng phi l nhim v ca k s t vn bn cnh ch u t. Ngi ny ch phi v ch nn thc hin cc nhim v nu trn.

3. Phng php kim tra cht lng trn cng trng :

Thc cht th ngi t vn kim tra cht lng l ngi thay mt ch u t chp nhn hay khng chp nhn sn phm xy lp thc hin trn cng trng m kim tra cht lng l mt bin php gip cho s khng nh chp nhn hay t chi .

Mt quan im ht sc cn lu tm trong kinh t th trng l : ngi c tin b ra mua sn phm phi mua c chnh phm , c sn phm p ng yu cu ca mnh. Do tnh cht ca cng tc xy dng kh khn , phc tp nn ch u t phi thu t vn m bo cht lng.

C s nhn bit v kim tra cht lng sn phm l s p ng cc Yu cu cht lng ghi trong b H s mi thu . Hin nay chng ta vit cc yu cu cht lng trong b H s mi thu cn chung chung v cc c quan t vn cha quen vi cch lm mi ny ca kinh t th trng .

Nhng nguyn tc v phng php ch yu ca kim tra cht lng trn cng trng l :

3.1 Ngi cung ng hng ho l ngi phi chu trch nhim v cht lng sn phm trc ht .

y l iu kin c ghi trong hp ng kinh t gia ch u t v nh thu . T iu ny m mi hng ho cung ng a vo cng trnh phi c cc ch tiu cht lng p ng vi yu cu ca cng tc. Trc khi a vt t , thit b vo to nn sn phm xy dng nh thu phi a mu v cc ch tiu cho Ch nhim d n duyt v mu cng nh cc ch tiu phi c lu tr ti ni lm vic ca Ch u t cng trng. Ch tiu k thut (tnh nng ) cn c in thnh vn bn nh l chng ch xut xng ca nh cung ng v thng yu cu l bn in chnh thc ca nh cung ng . Khi dng bn sao th i din nh cung ng phi k xc nhn v c du ng xc nhn mu v c s chp thun ca Ch u t bng vn bn. Mi s thay i trong qu trnh thi cng cn c Ch u t duyt li trn c s xem xt ca t vn bo m cht lng nghin cu xut ng . Nh cung ng v nh thu phi chu trch nhim trc php lut v s tng thch ca hng ho m mnh cung cp vi cc ch tiu yu cu v phi chu trch nhim trc php lut v cht lng v s ph hp ca sn phm ny.

Cn b t vn m bo cht lng l ngi c trch nhim duy nht gip Ch nhim d n kt lun rng sn phm do nh thu cung ng l ph hp vi cc ch tiu cht lng ca cng trnh . Cn b t vn gim st bo m cht lng c Ch u t u nhim cho nhim v m bo cht lng cng trnh v thay mt Ch u t trong vic xut chp nhn ny .

3.2 Kim tra ca t vn k thut ch yu bng mt v dng c n gin c ngay ti hin trng :

Mt phng php lun hin i l mi cng tc c tin hnh th ng vi n c mt ( hay nhiu ) phng php kim tra tng ng. Nh thu tin hnh thc hin mt cng tc th yu cu gii trnh ng thi l dng phng php no bit c ch tiu cht lng v dng dng c hay phng tin g cho bit ch tiu y . Bin php thi cng cng nh bin php kim tra cht lng y c t vn trnh Ch nhim d n duyt trc khi thi cng . Qu trnh thi cng , k s ca nh thu phi kim tra cht lng ca sn phm m cng nhn lm ra . Vy trn cng trng phi c cc dng c kim tra bit cc ch tiu thc hin. Th d : ngi cung cp b tng thng phm phi chu trch nhim kim tra cng chu nn mu khi mu t 7 ngy tui . Nu kt qu bnh thng th nh thu kim tra nn mu 14 ngy . Nu kt qu ca 7 ngy v 14 ngy. Nh thu phi th cng nn 28 ngy xc nh cht lng b tng . Nu ba loi mu 7 , 14 , 28 c kt qu gy ra nghi vn th t vn kim tra yu cu lm cc th nghim b sung khng nh cht lng cui cng. Khi thi cng cc nhi, nht thit ti ni lm vic phi c t trng k bit dung trng ca bentonite , phi c phu March v ng h bm giy kim tra nht ca dung dch khoan , phi c ng nghim o tc phn tch nc ca dung dch . . .

Ni chung th t vn m bo cht lng phi chng kin qu trnh thi cng v qu trnh kim tra ca ngi thi cng v nhn nh qua hiu bit ca mnh thng qua quan st bng mt vi sn phm lm ra . Khi no qui trnh bt buc hay c nghi ng th t vn yu cu nh thu thu phng th nghim kim tra v phng th nghim c ngha v bo s liu t c qua kim tra cho t vn t vn kt lun vic t hay khng t yu cu cht lng. trnh tranh chp , t vn khng nn trc tip kim tra m ch nn chng kin s kim tra ca nh thu v tip nhn s liu quyt nh chp nhn hay khng chp nhn cht lng sn phm . Khi c nghi ng , t vn s ch nh ngi kim tra cng nh phng php kim tra v nh thu phi thc hin yu cu ny .

3.3 Kim tra bng dng c ti ch :

Trong qu trnh thi cng , cn b , k s ca nh thu phi thng xuyn kim tra cht lng sn phm ca cng nhn lm ra sau mi cng on hay gia cng on khi thy cn thit . Nhng ln kim tra ny cn c s chng kin ca t vn m bo cht lng. Mi vic kim tra v thi cng khng c s bo trc v yu cu t vn m bo cht lng chng kin , ngi t vn c quyn t chi vic thanh ton khi lng hon thnh ny . Kim tra kch thc cng trnh thng dng cc loi thc nh thc tm , thc cun 5 mt v thc cun di hn . Kim tra cao , thng ng thng s dng my o c nh my thu bnh , my kinh v .

Ngoi ra , trn cng trng cn nn c sng bt ny kim tra s b cng b tng . Nhng dng c nh qu di chun , di laze , ng nghim , t trng k , cn tiu ly , l xy , vin bi thp , l thp chun kim tra khe h, . . . cn c trang b . Ni chung trn cng trng phi c y cc dng c kim tra cc vic thng thng .

Nhng dng c kim tra trn cng trng phi c kim chun theo ng nh k . Vic kim chun nh k l cch lm tin tin trnh nhng sai s v nghi ng xy ra qua qu trnh nh gi cht lng.

Trong vic kim tra th ni b nh thu kim tra l chnh v t vn bo m cht lng ch chng kin nhng php kim tra ca nh thu . Khi no nghi ng kt qu kim tra th nh thu c quyn yu cu nh thu thu n v kim tra khc . Khi tht cn thit , t vn bo m cht lng c quyn ch nh n v kim tra v nh thu phi p ng yu cu ny .

3.4 Kim tra nh cc phng th nghim :

Vic thu cc phng th nghim tin hnh kim tra mt s ch tiu nh gi cht lng trn cng trng c thc hin theo qui nh ca tiu chun k thut v khi ti cng trng c s khng nht tr v s nh gi ch tiu cht lng m bn thn nh thu tin hnh .

Ni chung vic la chn n v th nghim , nh thu ch cn m bo rng n v th nghim y c t cch php nhn tin hnh th cc ch tiu c th c ch nh. Nhng phng th nghim phi c B Xy dng chng nhn c php hot ng theo h cc phng trong s cc phng LAS . Cn khi nghi ng hay cn m bo tin cy cn thit th t vn m bo cht lng dnh quyn ch nh n v th nghim .

Nh thu l bn t ra cc yu cu th nghim v nhng yu cu ny phi c Ch nhim d n da vo tham mu ca t vn m bo cht lng kim tra v ngh thng qua bng vn bn . n v th nghim phi m bo tnh b mt ca cc s liu th nghim v ngi cng b chp nhn hay khng chp nhn cht lng sn phm lm ra phi l ch nhim d n qua tham mu ca t vn m bo cht lng .

Cn lu v t cch php nhn ca n v th nghim v tnh hp php ca cng c th nghim . trnh s cung cp s liu sai lch do dng c th nghim cha c kim chun , yu cu mi cng c th nghim s dng phi nm trong phm vi cho php ca vn bn xc nhn kim chun .

n v th nghim ch c nhim v cung cp s liu ca cc ch tiu c yu cu kim nh cn vic nhng ch tiu y c t yu cu hay c ph hp vi cht lng sn phm yu cu phi do t vn m bo cht lng pht biu v ghi thnh vn bn trong t nghim thu khi lng v cht lng hon thnh.

3.5 Kt lun v lp h s cht lng

(i) Nhim v ca t vn m bo cht lng l phi kt lun tng cng tc , tng kt cu , tng b phn hon thnh c thc hin l c cht lng ph hp vi yu cu hay cha ph hp vi yu cu .

nh km vi vn bn kt lun cui cng v cht lng sn phm cho tng kt cu , tng tng nh , tng hng mc l cc vn bn xc nhn tng chi tit , tng vt liu cu thnh sn phm v h s kim tra cht lng cc qu trnh thi cng. Lu nay cc vn bn xc nhn cht lng vt liu , cht lng thi cng ghi rt chung chung . Cn lu rng mi bn xc nhn phi c a ch kt cu s dng , khng th ghi cht lng m bo chung chung.

Tt c nhng h s ny ng thnh tp theo trnh t thi cng khi tra cu thun tin.

(ii) i i vi cc vn bn nghim thu , vn bn chp nhn cht lng kt cu l nht k thi cng . Nht k thi cng ghi chp nhng d kin c bn xy ra trong tng ngy nh thi tit , din bin cng tc tng v tr, nhn xt qua s chng kin cng tc v tnh hnh cht lng cng trnh. kin ca nhng ngi lin quan n cng tc thi cng khi h chng kin vic thi cng , nhng kin ngh , xut qua qu trnh thi cng v kin gii quyt ca t vn m bo cht lng v kin ca gim st ca nh thu . . .

(iii) Bn v hon cng cho tng kt cu v b phn cng trnh c lp theo ng qui nh. Quyt nh 18/2003/Q-BXD ngy 27 thng 6 nm 2003 ca B trng B Xy dng v qun l cht lng cng trnh xy dng c ph lc 26 hng daqn lp bn v hon cng.

Tt c nhng h s ny dng lm c s cho vic thanh ton khi lng hon thnh v c s lp bin bn tng nghim thu , bn giao cng trnh cho s dng.

Chng II

Gim st thi cng v nghim thu

Cng tc lp t in

1. Nhng vn chung v h thng in trong cng trnh dn dng :

H thng in trong nh v nh dn dng bao gm cc thnh t sau y:

- Ngun cung cp in

- Cc thit b qun l v iu hnh h thng in

- Mng li dy dn in

- Cc dng ph ti tiu th in ngoi nh , trong nh

- Mng tip a

Hin nay cc n v t vn thit k thng thit k in theo cc tiu chun sau y:

+ Chiu sng nhn to cho cc cng trnh dn dng ( TCXD 16-1986)

+ t ng dy dn in trong nh v cng trnh dn dng ( TCXD 25-1991 )

+ Chng st cho cc cng trnh dn dng ( TCXD 46-1984)

+ Thit k ng dy h p trn khng n 1000V ( Quy phm trang b in 11 TCN-84 B in lc )

+ Quy phm ni t v ni khng cc thit b in (TCVN 4756-89 ).

Hu ht nhng tiu chun ny dch t tiu chun ca Lin X c.

Nay theo thng t s 12/ BXD KHCN ngy 24 thng 4 nm 1995, v iu 1.6 ca phn 1 chng 1 trong b Quy chun xy dng Vit Nam, B Xy dng cho php s dng tiu chun khng nhng ca Vit nam m cn ca cc t chc tiu chun ho quc t ISO, ca Anh, c, M, Nht, Php , c .

Ti cuc hi tho quc t v tiu chun thit k v lp t in IEC 60364 ngy 2-12-2003 , B Xy dng khuyn khch cc n v t vn nn thit k in theo IEC 60364 c hu nh cc nc trn th gii s dng.

Tiu chun IEC 60364 do Hi ng K thut Quc t ( International Electrotecnical Commission ) ban hnh theo tinh thn chung l mng in s dng trong cng trnh phi p ng cc quy nh v an ton cho con ngi v trang thit b.

y l tiu chun mi i vi th trng nc ta m rt nhiu d n u t , nht l cc d n ca nc ngoi v lin doanh yu cu thc hin.

Sau y l khi qut v s dng tiu chun ny:

Cn xc nh r mc ch ca h thng in l:

Phi bo m an ton

Phi m bo cc tnh nng s dng theo yu cu

Mun bo m an ton th h thng in phi p ng cc yu cu :

+ Bo v chng in git

+ Bo v chng cc tc ng nhit

+ Bo v chng qu dng

+ Bo v chng r in

+ Bo v chng nhiu lon in p.

Khi xy dng in cn la chn v lp t cc thit b:+ Dy dn

+ Thit b ng ct v iu chnh

+ Thit b bo v

Trong h thng in c th la chn dy v cp in: mt , hai, ba, bn, nm li .

Nhng thit b c th c s dng trong h thng in:

Thit b ng ct v iu khin nh loi khng c bo v gm cu dao, cng tc, cm, loi c bo v nh ptmt, khi ng t.

Thit b bo v c s dng gm cu chy, r le bo v, dng c theo di, pht hin, ch th, bo hiu.

Nhng thit b khc nh thit b ni dy, thit b lun dy, thit b ni t.

Khi thit k v lp t mng in hin nay ang s dng cc tiu chun sau y m khng nh hng ti vic s dng tiu chun IEC 60364 l:

TCVN v sn phm dy v cp in:

TCVN 5064:1994 Dy trn dng cho ng dy ti in trn khng bao gm cc loi dy ng, dy nhm, dy nhm li thp.TCVN 6483: 1999 ( tng ng vi IEC 1089) Dy trn si trn xon thnh cc lp ng tm , tiu chun ny thay th cc phn dy nhm v dy nhm li thp trong TCVN 5064: 1994.

TCVN 6610:2000 ( tng ng vi IEC 227 ) cp cch in bng PVC in p danh nh 400/750 VTCVN 6614: 2000 ( IEC 811 ) v phng php th vi vt liu cch in v v bc

TCVN 6447:1998 Cp vn xon cch in bng XLPE in p 0,6/1 KV

V nhm thit b ng ct v iu khin:

TCVN 6188:1996 ( IEC 884-1:1994 ) cm v phch in

TCVN 6190:1991 ( IEC 83) cm v phch in. Kch thc v kiu dng

V thit b ng ct v bo v :

TCVN 6480:1999 ( IEC 669-1: 1993) Thit b ng ct cho h thng in c nh trong gia nh v cc h thng tng t dng in n 63A in p n 440V.

TCVN 6592-1:2000 ( IEC 947-1:1999) Thit b ng ct v iu khin h p.

TCVN 6592-2:2000 ( IEC 947-2:1999) Thit b ng ct v iu khin h p.

TCVN 6434-1:1998 ( IEC 898 :1995) Kh c in. ptmt bo v qu dng

TCVN 6592-4-1:2001 ( IEC 947-4-1:1990) Thit b ng ct v iu khin h p.

TCVN 6615-1:2000 ( IEC 1058-1:1996) Thit b ng ct dng cho thit b.TCVN 6950-1:2001 ( IEC 1008-1:1996) Aptmt tc ng bng dng d khng c bo v qu dng (RCCB) dng trong gia nh

TCVN 6951-1:2001 ( IEC 1009-1:1996) Aptmt tc ng bng dng d c bo v qu dng (RCBO) dng trong gia nh

TCVN 5926:1995 ( IEC 269/1 :1986 Cu chy h p, yu cu chung

TCVN 5927:1995 ( IEC 269/3 :1987 Cu chy h p, yu cu b sung

Tiu chun IEC 60364 l tiu chun tin tin c rt nhiu nc trn th gii p dng. Trin vng tiu chun ny s c chp nhn thnh tiu chun Vit Nam. Tuy nhin nu p dng ngay t by gi vn c, khng sai vi tinh thn ca theo thng t s 12/ BXD KHCN ngy 24 thng 4 nm 1995, v iu 1.6 ca phn 1 chng 1 trong b Quy chun xy dng Vit Nam.Theo quan im nhn vn v tit kim, trong vic phi hp tin cn tin hnh ng b ngay t khi xy dng mng cn c mt ca nhng ngi xy lp in. Trong qu trnh lm cp pha mng , c nhng ng cp xuyn qua mng cn c b tr nhng ng qua dm mng. Nhng ng lun cp phi c t vo mng trc khi b tng . Trc khi lp t vo mng , nhng ng cp, ng dy tip a phi t xong trong lng nh.

Cn n c nhng ngi tin hnh xy lp in thc hin cc cng vic v in nm trong phn ngm cng trnh . Khi cha kim tra v k bin bn nghim thu cng trnh khut bao gm c cng tc xy dng in, li chng st th cha lp t mng .

Trnh t hp l vi h thng in l cng trnh , hng mc xa cn thi cng trc . Th d nh h cung cp ngun thng c cp im u xa cng trng, cn phi xy dng tuyn ti ngun n cng trng. Tip l xy dng trm bin p cung cp . Mng dn in vo tng hng mc xy dng s thi cng sau khi o t lm phn ngm xong v trc khi b tng mng v lp t mng . S phi hp trong trnh t thi cng nhm trnh c o sau khi lm phn ngm v trnh o bi sau khi lp t.

Nhng tiu ch cn lu tm khi kim tra cht lng phn xy v lp h thng in cho cng trnh dn dng nh sau :

* Kim tra v thm nh cc tiu ch ca vt liu v thit b da vo yu cu k thut trong thit k v catalogues .

* Kim tra v tr lp t

* Kim tra s gn kt ca vt liu v thit b vo v tr v cc dng c neo gi.

* Kim tra mc cch in v dn in v nhy vn hnh ca thit b in.

* Kim tra cc yu cu ca phn xy i km phn lp.

* Vn hnh th nghim v cc tiu ch , ch cn t khi vn hnh.

2. Mng li dy dn in :

C s kim tra v nghim thu mng li dy in trong xy dng dn dng v nh l cc yu c ghi trong iu kin k thut thi cng h thng in trong b H s mi thu v TCXD 25 : 1991 : t ng dn in trong nh v nh cng cng . Tiu chun thit k.

Qu trnh xy lp in , t vn bo m cht lng phi chng kin vic thi cng ca nh thu lp in . Phi i chiu vi thit k kim tra vt liu in v sau ny nhng vt liu in ny phn ln b chn lp di t hay nm bn trong lp va.

Dy dn in c la chn theo dng in m dy phi ti , mc an ton m li phi tho mn , vt ti kh d c th xy ra , cch in phi m bo , s chu lc c hc m dy phi chu trong qu trnh lp t v s dng . Quan h gia nhit v cng dng in ti c phn nh qua tit din dy.

C quan t vn thit k in gip ch u t lp bn thit k cung cp in bao gm cung cp ngun in , mng li dy , cc trang thit b in n tng ph ti . Nhng iu lu khi kim tra l s m bo tun theo ng thit k hoc khi thay i ti ch phi m bo cc tiu ch s dng c ra khi thit k. Thng thng cn i chiu gia s la chn ca thit k ban u v khi thay th . Mun vy , cn d liu so snh . Sau u l nhng d liu c bn quyt nh khi la chn :

Dng in lin tc cho php ln nht ca dy dn rut ng c cch in bng v cao su , nha tng hp khi nhit khng kh l 25oC.

Tit din rut dy dn ( mm2)

Dng in lin tc ln nht cho php (A)Dng in nh mc ca dy chy cu ch ( A )

Dy chiu sng,dy chnh , dy nhnh trong nh

0,5

0,75

1

1,5

2,5

4

6

10

16

25

35

50

70

95

1206

6

6

10

15

25

35

60

90

125

150

190

240

290

340

-

-

6

10

15

25

35

60

80

100

125

160

200

225

260

Dng in lin tc cho php ln nht ca dy dn rut nhm cch in bng v cao su t trong nh nhit khng kh mi trng 25oC.

Tit din rut dy dn ( mm2)

Dng in lin tc ln nht cho php (A)

Dng in nh mc ca dy chy cu ch ( A )

Dy chiu sng,dy chnh , dy nhnh trong nh

4

6

10

16

25

35

50

70

95

120

150

19

27

45

70

95

115

145

185

225

260

30020

25

35

60

80

100

125

160

200

225

260

Dng in lin tc cho php ln nht ca dy dn rut ng c cch in bng v cao su , nha tng hp t trong ng khi nhit khng kh l 25oC.

Tit din rut dy dn ( mm2)Dng in lin tc cho php ln nht (A)Dng in nh mc ca dy chy cu ch (A)

Trong ng c 2 dy dn Trong ng c 3 dy dnTrong ng c 4 dy dnDng trong nh

1

1,5

2,5

4

6

10

16

22,5

35

50

70

95

1206

10

15

25

35

60

75

100

120

165

200

245

2806

10

15

25

35

55

70

90

110

150

185

225

2556

10

15

25

35

45

65

80

100

135

165

200

2306

10

15

20

25

35

60

80

100

125

160

200

230

Dng in lin tc cho php ln nht ca dy dn rut nhm cch in bng v cao su t trong ng nhit khng kh mi trng 25oC.

Tit din rut dy dn ( mm2)Dng in lin tc cho php ln nht (A)Dng in nh mc ca dy chy cu ch (A)

Trong ng c 2 dy dn Trong ng c 3 dy dnTrong ng c 4 dy dnDng trong nh

4

6

10

16

25

35

60

70

90

120

15019

27

46

57

75

90

125

155

190

215

24519

28

42

54

70

85

115

145

175

195

22520

27

35

50

60

75

105

125

155

175

20020

25

35

35

60

60

100

125

160

160

200

Khi s lng dy ti in nhiu hn s qui nh trn cc bng nu trn th iu chnh bng cc h s gim cng dng in theo cc h s:

* Nu 5~6 dy trong mt ng , h s gim cng l 0,68

* Nu 7~9 dy trong mt ng th h s gim cng l 0,63

* Nu 10 ~12 dy trong mt ng th h s gim cng l 0,60.

bo m bn c hc tit din ca dy dn v dy cp khng c chn nh hn s liu trong bng sau y:

Chn dy c tit din cho php nh nht theo iu kin bn c hc

Loi dy dn

Tit din nh nht ( mm2)

ngNhm

1. Dy dn chung cp in n chiu sng c nh trong nh

2. Dy dn n chiu sng ngoi nh

3. Dy mm cp in cc thit b trong nh, n treo, n bn , n di ng

4. Dy mm c cch in t trn cc vt cch in, khong cch vt nh hn 1 mt khi :

* t trn kp s

* t trn tr s

5. Dy dn hai rut xon, mi rut c nhiu si t trn cc vt cch in t cch nhau khng qu 0,80 mt.

6. Dy dn cch in trn vt cch in trong nh m khong cch vt nh sau:

* t 1 ~ 2 mt

* t 2 ~ 6 mt

* t 6 ~ 12 mt

* t 12 mt tr ln

7. Dy dn c cch in c bo v v dy dn c cch in t theo b mt ngoi cng trnh

- Cc trng hp khc

8. Dy dn c cch in t trong ng

9. Dy dn cch in c bo v t trong ng0,5

1,0

0,75

1

1,5

0,75

1,5

2,5

4

6

2,5

4

1

1,5-

-

-

2,5

2,5

-

4

4

10

16

4

10

2,5

2,5

ng lun dy in phi trn . V l do g m ng thnh bu dc th ng knh nh khng b hn ng knh ln 10% th cn c s dng . Nu chnh m ln hn 10% th phi loi b. Ch lun dy vo ng khi lp va trt kh . Khng c c ch ni dy hay phn nhnh dy bn trong rut ng.

Dy cp in i trn v trong tng phi c gn cht vo tng ti cc im c nh cp m khong cch nh sau :

V tr t cpKhong cch gia cc im c nh cp

1. Mt phng ngang

2. Mt ng

3. Mt ng

4. Mt ngang

5. Ch un cong

6. V tr t cp gn hp ni cp

7. Hp ni cp v u cp dn vo thit b hoc ch bt u cpLp trn gi cp : 1 mt

2 mt

Kp gia nh cp 0,8 ~ 1 mt

Tt c cc im cn phng khng cho lp v ch ca cp b bin dng, ng thi khng lm cho li trong hp u dy lin tip b tc ng bi trng lng bn thn ca cp gy nn

u cui mi on cp

u cui ca on cp un cong, nu cp ln th cn t kp gia on cong.

Khong cch gia cc im gi c nh dy cp hai bn hp ni cp.

Cch hp ni , u cp hoc ch bt u khng qu 100 mm.

Cp t h trong nh khng dng cp c v bc ngoi bng lp ay tm nha. Trong cc phng khng chy, kh chy m m t v khng c vt nguy him khi chy th c th dng cp c bc ngoi l si ay tm nha. Cp i vo nh , ng hm hoc cp chuyn t thng sang ngang cn t d tr mt on di hn 1 mt. Cp t trong nh khng cn c on d tr nhng khng c cp cng qu.

Khi t ngm cp di nn nh th khong cch gia dy cp v ng ng nc giao nhau di t khng nh hn 0,5 mt. Khi khng khng gian m bo khong cch nh vy , phi c bin php bo v ch giao nhau nh t tm chn , tm chn ny phi ko di v mi bn ca dy cp l 0,5 mt phng m t hay h hng do nguyn nhn c l.

Khi cn treo dy cp bng si dy thp th sc lm t dy cp phi ln gp 4 ln sc chu khi treo dy cp. u cui ca cp khng u vo u cn hn bt kn . Gia cp v gi cn cch in. Chiu dy lp cch in phi ln hn 2 mm . Khi cp c v bc bn ngoi l cht hu c v kim loi cp khng c cnh sc c th khng cn dng lp lt cch in, nhng nu c th th nn lm .

t dy dn trong tng gip mi rt hay c ngi thit k s dng nhng bin php ny cng l u mi ho hon nn phi tun theo nhng iu sau y :

Lun dy dn trong ng thp , t kn trong tng , trn v mi vi nh s dng vt liu khng chy . Nu dng puli s ng dy trong tng ny th khong cch gia cc s khng c xa qu 0,6 mt. Khi i hai dy song song th khong cch gia hai si phi xa hn 0,5 mt. Khi bt dy i thp hn 2 mt k t mt sn ln phi c bin php chng h hng do cc tc nhn c l. Dy dn s dng trn tng mi l dy ng . Dy dn nhm ch dng trong mi nh m vt liu xy dng l loi khng chy. Hp ni v hp phn nhnh phi bng kim loi. Cc thit b ng mch , thit b iu khin v thit b bo v khng c t tng gip mi.

t dy in ngoi nh phi ch n qui hoch. Mi ni , nht l nhng ni c ngi qua li , phi m bo an ton , khng con ngi ng chm vo dy in.

Dy dn v dy cp khng i trong ng phi m bo tun theo cc qui nh v khong cch an ton sau y:

* Theo phng ngang:

+ trn bc tam cp, ban cng cng nh mi nh : 2,5 mt.

+ trn ca s : 0,5 mt.

+ di ban cng: 1 mt.

+ di ca s ( tnh t khung ca ): 1mt.

* Theo phng ng : khong cch t dy dn n :

+ ca s : 0,75 mt.

+ ban cng : 1 mt.

* Dy dn cch mt t : 2,75 mt.

Dy dn t trn ct in , phi m bo khong cch t dy n ban cng v ca s khng gn hn 1,5 mt. Khng cho t dy dn in ngoi nh trn mi nh. Khi chm vo dy c cch in ngoi tri coi nh chm vo dy trn v phi tun theo cc iu kin ca dy trn.

Dy in vt qua ng , khi dy i trn khng th phi cao hn :

+ ng xe qua : 6 mt.

+ ng khng c xe qua : 3,50 mt.

Khi dy in xuyn qua tng phi t ng cho dy i qua v m bo ng khng tch t nc .

Sau khi lp xong ng dy, cn tin hnh kim tra :

* thng ca tng si dy theo tng mch . Cn tho tng l kim tra c lp tng l .

* cch in ca tng dy vi v , vi cc dy khc trong ng v vi mi trng cha ng dy.

3. Lp t trang thit b in trong nh dn dng v nh :

Vic lp t v nghim thu trang thit b in trong nh dn dng v nh phi tun theo cc yu cu ca b H s mi thu , iu kin k thut trong Hp ng giao nhn thu lp t in v TCXD 27 : 1991 , Tiu chun thit k : t thit b in trong nh v nh cng cng.

Thit b dn in vo ngi nh c th kt hp vi bng phn phi , bng in , t in ca ngi nh.

u dn vo ngi nh ca mng in phi t thit b bo v v iu khin nhng nu thit b dn vo nh c dng in nh hn 20 A c th khng cn t thit b iu khin.

Mng in phi c thit b bo v khi ngn mch. Phi m bo ngt c mch khi c s c:

+ mt v nhiu pha ca mng in c trung tnh vi t

+ hai v ba pha ca mch trung tnh cch ly.

Thit b bo v t ni d kim tra v khng b cc tc nhn c hc ph hng. Vic vn hnh ca cc thit b bo v phi m bo bnh thng trong mi tnh hung , khng gy nguy him cho ngi phc v v cc vt chung quanh.

Cc thit b bo v c b phn mng in h ch c php lp t khi khai thc cng trnh c b tr th chuyn mn v in vn hnh v qun l. Khi dng cu ch bo v mng in th t cu ch ti :

+ cc pha bnh thng khng ni t,

+ dy trung tnh ca mng in hai dy trong cc cng trnh c dy dn m t , ni khng c th in chuyn mn vn hnh v qun l v in v c nguy c n.

Khng c t cu ch dy trung tnh ca mng 3 pha 4 dy v ca mng 2 pha, 1 dy trung tnh.

Khi t cc thit b dn vo bng phn phi in chnh, bng in v t in trong nh phi p ng cc yu cu sau y:

(i) V tr t phi ni thun tin cho vic s dng , d kim tra v theo di nh gm cu thang, tng hm ni kh ro.

(ii) Bng phn phi chnh , bng in, t in phi t trong cc t , hp bng kim loi hay bng g hoc t trong cc hc ca tng chu lc chnh v phi c ca kho. Tay iu khin ca cc thit b khng c nh ra ngoi. Nu b tr mt phng ring bng iu khin , bng phn phi th nhng qui nh trn khng nht thit phi chp hnh.

(iii) Thit b dn vo t in, bng in, hp in phi t cch xa ng dn nc, rnh nc vi khong cch ti thiu l 0,5 mt.

Vi cc nh quan trng , t bng phn phi in chnh ca ngi nh t vo phng ring c ca kho v ch nhn vin chuyn trch mi c vo. Nhng ni c kh nng ngp nc th mi thit b dn vo , bng phn phi in , bng in, t in v cc thit b khc phi t cao hn mc nc ngp. Lu phng t t in , bng in khng t di cc phng dng nc nhiu nh bp, x , tm , git . Khi c ng nc dn qua phng t cc thit b iu khin in th khng c m vi , khng c c cc ming kim tra hay bt k trang b g m c kh nng phun bn nc phng ny.

i vi nh th tit din dy dn in khng c nh hn cc ch s nh bng di y:

Tn ng dy Tit din nh nht ( mm2)

ng Nhm

1. ng dy nhm mng in chiu sng khng c cm in

2. ng dy nhm mng in chiu sng c cm in v dy dn n cm in

3. Dy dn in vo thit b m in nng

4. Dy dn in thng ng ca mng cung cp in cho cc h dng in1

1,5

2,5

2,52,5

2,5

4

4

Khi dng in ba pha nu tit din dy ng nh hn 16 mm2 v dy nhm nh hn 25 mm2 th dy trung tnh ly bng dy pha. Nu tit din ln hn th dy trung tnh ly nh bng 50% dy pha . Thit b in t trong nh yu cu c cch in tt. Cht cch in phi kh chy , chu m , khng ht nc , khng h hng v bin dng do cc tc ng lin tc ca nhit cao hn 25% so vi nhit cho php ca thit b trong iu kin lm vic bnh thng.

Trong mi trng hp trn v thit b phi ghi cc ch s k thut cn thit ca dng in i qua thit b nh : cng , in p , cng sut. . . Nu thit b c nhiu b phn th tng b phn phi ghi cc ch s cn thit.

Mi cm in phi t cao hn mt nn , mt sn ti thiu l 1,50 mt. Nu cm trong hc tng c th tho phch cm ra , hc tng c np ng li c th t cao 0,4 mt tr ln so vi mt sn. Mi cm u phi t xa cc b phn kim loi c tip xc vi t nh ng dn nc, chu tm, cc ming kim loi t nht l 0,50 mt.

Yu cu i vi cm v phch cm nh sau:

+ Phch v phi thch hp v in th v la chn chng loi sao cho nu c nhm cng khng th nhm c , th d in p 110 V dng thanh cm dt , in p 220 V dng thanh cm trn hay l loi ba chn chng hn.

+ Hp b v s cc . Phch mt cc khng th cm vo nhiu cc. Phch hai cc khng th cm vo ba cc . . .

in p li 127~220 V , mi cm phi c mt cu ch bo v.

Thit b tt dng n phi t cao trn 1,5 mt tnh t mt sn tr ln. an ton trong s dng in , khng t thit b ng , tt n bung tm, phng git , phng v sinh. Mch in chnh hay nhnh u phi t mt cu dao . Nhiu mch ch do mt dng chnh cung cp th dng in ti a dng ch c 5A.

Cc loi ng c s dng trong cng trnh nh my bm , my iu ho khng kh cng nh cc thit b bo v ca chng phi t ni thun tin cho s dng v phi c ngi c chuyn mn phc v mi c s dng. Nu vic cung cp in cho ng c ng thi l dy dn cho chiu sng phi m bo khi chy ng c , khng lm nhiu lon n chiu sng.

4. Lp t bng in chiu sng:

Bng in chiu sng t trong nh phn phi , tnh ton in nng , ng thi bo v qu ti dng ngn mch trong mng in 3 pha xoay chiu in p 380 V c trung ho ni t trc tip.

Bng in thng c t hp theo cc cch lp t nh sau:

(i) Loi bo v cc tng nh ( cu thang ) c kh c in bo v.

(ii) Loi bo v cng cc tng nh ( cu thang ) c kh c phn phi in nng , bo v v cng t in.

(iii) Loi phi hp dng cc tng nh ( cu thang ) c kh c phn phi in nng, bo v v cng t in.

(iv) Loi dng trong phng , c kh c phn phi in nng ( cho loi bng t hc tng), bo v v cng t in.

Cc thit b in trong nh v cng trnh cng cng phi c ni t v ni trn khng kh theo Quy phm ni t cc thit b in QPVN 13-78 v Quy phm trang b in QT 11 TCN 18-1984.

Cc bng chiu sng phi c gn cht vo tng nh . Trong iu kin c th , lm thnh cc bng ring t trong khung , t , st vo tng hoc cc kt cu ngn cch , khng nh hng n li qua li v m bo an ton chung cho s dng cng trnh.

5. Vn an ton trong xy lp in An ton lao ng trong xy lp h thng in ht sc quan trng. Theo thng k ca Cc Phng Chy Cha Chy B Cng An th 70% cc v chy trong ba nm va qua do nguyn nhn t h thng in. in d gy tai nn cht ngi. An ton cho h thng in l yu cu hng u ca h thng in hin i.

Ngi k s t vn bn cnh ch u t c trch nhim n c cc nh thu phi thc hin y ni quy an ton lao ng , trong c ni quy an ton lp t v s dng h thng in. Chu trch nhim trc Nh Nc v cht lng cng trnh v an ton sn xut l nhim v ca Ch u t m ngi k s t vn l ngi gip Ch u t n c chnh nhng nhim v ny.* Tai nn do in c th c trn cng trng

Vic s dng in mang li li ch to ln cho sn xut nhng phi tin hnh nhng bin php phng nga tai nn do in gy ra cho ngi sn xut.

Mt t l cao ( trn 70%) vi cc v chy l do cc trang b in khng hp chun. Trong nhng tai nn v in th khng t hn 30% v gy cht ngi.

Vic loi tr tai nn v in cn c tnh ton ngay t khi thit k cc bin php thi cng. Mi kh nng gy tai nn do in sinh ra cn c phng nga trc. Cn lp bin php phng nga v kin quyt thc hin nhng bin php phng nga tai nn v in lm cho sn xut c an ton v iu ny cng chnh l gp phn cho sn xut t cc mc tiu ca n.

Tai nn do in c th gy ra trn cng trng quy t li ba dng chnh:

Da ngi b tip xc trc tip vi dy dn hoc thit b ang mang in.

Da tip xc trc tip vi kim loi ca thit b in c cch in nhng phn cch in b h hng.

Thn th ngi lao ng tip xc vi in d r trong t do dy in b t chm xung t m s tiu tn dng in cha p ng cc yu cu v an ton. Hin tng ny gi l in p bc.

Cn mt dng tai nn xy ra do ngi lao ng khng tun th nghim tc cc quy trnh ng ct in. ng hoc ct in m khng kim tra k nhng mi lin quan n mch in s c thao tc: ng in khi c b phn ang thao tc trong mng m khng c bo trc. Ngt in t ngt lm ngi thi cng khng chun b trc phng php phng tai nn cng nh cc thao tc sn xut thch hp.

* Tc hi ca dng in i qua c th ngi

Dng in c in p trn 36 vn i qua c th ngi gy ra s hu hoi cc t bo ca ngi hoc lm h thn kinh c nhng phn x tiu cc.

S nh hng n sc kho con ngi do dng in gy ra tu thuc in p, in tr ca ngi, cng dng in ca dy ti in, tn s v loi ng in. S tc hi ca dng in i qua c th li ph thuc ng i ca dng in v thi gian tc ng ca dng in. Nhng iu kin ngoi vi nh m ca mi trng, vt liu ca kt cu m c th tip xc nh sn nh, gh ngi ...

in p s dng kh ph bin ca cc my mc v trang b mang in trn cng trng xy dng thng l 127, 220 v 380 vn, hin nay c th dng n 1000 vn. in truyn c qua c th thng qua lp sng ngoi da. Nu da kh th in tr ca lp sng ny t 60.000 n 400.000 Ohm/cm2.

Nu da b t hoc c m hi, in tr ca lp sng ngoi da ch cn trn di 100 Ohm/cm2. Da nhiu m hi th in tr lp sng ngoi da cn 1000 Ohm/cm2.

in p cao th lp sng ngoi da b hu hoi nhanh. in p thp th lp sng hu hoi chm hn. Trong tnh ton , thng ly in tr ca lp sng ngoi da l 1000 Ohm/cm2. Khi da b m hoc nhiu m hi th in tr ca da gim r rt.

Dng in qua c th ngi ta gy ra nhng phn ng lm thay i trng thi thn kinh, bin i thnh phn mu hay gy chy bng. Ngi ta bt u cm thy c dng in qua c th khi cng dng in khong 0,6 ~ 1,5 mA vi dng xoay chiu, tn s cng nghip l 50 hertz v 5~7 mA i vi dng in mt chiu. Tc hi ca dng in qua c th ngi tu thuc dng in mi tip xc ( dng 1 ), dng in dn qua c th ( dng 2 ) v dng in b gi li c th ( dng 3).

Dng in mi tip xc vi c th( dng 1 ) ngi ta thng nm trong khong 0,6 ~ 5 mA. Dng in mi tip xc vi c th c coi l khi ngi ta cn c kh nng t tch mnh ra khi mng in. Dng in dn qua c th ( dng 2) trong phm vi 15 mA vi dng in xoay chiu v 50 ~ 80 mA vi dng mt chiu. Dng in lu gi li trong c th ( dng 3) khong 15~20 mA vi dng xoay chiu v 80 mA vi dng mt chiu. Dng in dn qua c th ngi ta ( dng 2) c th coi l t nguy him v khng gy tc hi ngay. Nhng nu khng tch c dng in nhanh khi c th th s tr ca dng in b tng lm cho c th b t lit.

Dng in lu gi li trong c th ( dng 3) rt nguy him v dng ny gy ra co git h thng thn kinh, c bp b co dt mnh v sau b t lit, trc mt l c th khng th t iu khin c. Hin tng tip theo l ngng tim, ngng th.

Nhi nghin cu v tai nn in cho thy ch cn dng xoay chiu 25 ~ 30 mA rt nguy him. Trn 50 mA c th gy ra tai nn nng n mc cht ngi. Dng in trn 0,1 A , tc l 100 mA thng gy cht ngi.

V tn s th tn s in ph thng l 50 hoc 60 Hertz rt nguy him. Tn s cao ln nguy him li gim i. Khi tn s dng in trn 1000 Hertz thng khng gy ra nh hng n h thn kinh m ch gy bng cc b. Trong y t, nhiu loi thit b in li li dng tn s in cao iu tr mt s bnh.

V tr ca c th tip xc vi dng in ht sc quan trng v n to ra lung in dn qua c th. Ta hnh dung ra dng in qua c th phi dn t ngun c in n t hoc vt kim loi dn tip. Thng thng, dng in i t tay phi, qua c th dn xung chn ni vi t l lung nguy him nht i vi c th ngi. Lung ny dn dng in qua tim v phi nn d gy t vong. Lung in i qua ngi t chn n sang chn kia dn tip t nguy him hn v dng in ngn nht khng i qua cc b phn iu khin s sng quan trng trc mt ca c th nh tim, c, phi.

Thi gian tc ng ca dng in qua c th cng di, cng nguy him. Dng in qua c th ngn hn 0,2 giy cha gy nguy him. T 0,5 giy bt u gy nguy him cho ngi.

* Tai nn in vi h thng dy dn: trn khng v cp ngm

Trong mng in xoay chiu c in p di 1000V, mi dy dn in lm cch li vi t. Tr s in tr cch in ca cc dy dn c ly theo kt qu tnh ton l 1000 Ohm/V . Vn dy l in p ca mng. C th ly in tr ca dy dn l Rcd = 1000 Ohm.

in tr ca dy dn i vi t khi cho th nng ca t l 0 bao gm in tr cch in ca dy dn, ca cc in tr mc vo dy trn ng t dy dn n t c tng in tr l Rcd . Dng in i qua dy dn c in tr Rcd gi l dng in r . Tr s ca dng in r c gii hn l 10A.

Khi ngi b chm vi mt cc ( mt dy ) i vi phn dn in in tr ca ngi coi nh mc song song vi in tr cch in ca pha . Nu chm phi hai dy trong mng ba pha hoc mt pha vi dy trung ho, to nn mch kn m ngi coi nh ni tip vi mch in rt nguy him n tnh mng. Sau y l mt vi khi nim nh lng trong tnh ton:

Khi ngi chm phi mt pha c in, mch in ang c cc in tr khc th dng in i qua ngi c in tr Rn s l:

Khi tip xc vi mt pha khng c in tr khc hay hai pha hai v tr khc nhau , c th coi ngi l vt dn in c in tr Rn c mc theo kiu ni tip , lc ny s c dng in qua ngi s l:

Nu in tr ca ngi ch l 1000 Ohm hoc nh hn th ngi chc chn s b t vong.

Tai nn v in xy ra vi ngi do dy dn trn trn khng thng hay gp l b phn c th ngi chm phi dy dn in. Ngi cm hay mang vc thanh kim loi hoc cy di , m, va chm phi dy dn trn khng cng l l do in git. c nhiu tai nn khi xy dng di hoc gn ng in trn khng, cng nhn chuyn nhng thanh thp di va chm phi dy dn nn b in git. Khng t trng hp cng nhn thao tc trn u ct cao m dy dn ang mang in b in git do va chm vi dy in.

Mt dng tai nn c th xy ra do ng in trn khng ct ngang trn ng l bn di khng m bo khong cch gia mt ng n ng dy theo ng quy nh vng vi phng tin xe c di chuyn bn di, nht l khi xe cht ti qu cao.

ng dy dn trn khng vt qua ng giao thng bn di phi m bo cao ti thiu l 6 mt. Phi c tn hiu treo trn dy in nhc nh cao ca dy dn theo ng quy nh v ng dy in vt ngang ng l.

i vi dy cp i ngm tai nn thng xy ra do my o t hot ng va chm vi dy cp dn. Khi lp bin php thi cng o t cn cm ch gii cho my o khng gy tai nn dng ny. Trong nhiu trng hp, phi ngt in trong dy cp khi thi cng o t gn ng cp m bo an ton tuyt i cho cng nhn o t cng nh cho ng cp.

My mc nng di chuyn ln ng cp ngm bn di m ng cp chn khng su cn thit hoc cp khng i trong ng bo v ng quy cch cng l nguyn nhn gy t cp, in b r qua t gy tai nn.

ng cp ct ngang ng giao thng phi chn su sao cho p lc ca xe c di chuyn bn trn khng lm cp b dn di gy nguy him. Cp i di ng giao thng phi lun trong ng thp hoc ng b tng m ng knh ng phi ln hn ng knh ca dy cp ti thiu ba ln.

* Tai nn in khi vn hnh thit b in

Khi vn hnh thit b in cn c trang b cc nghi kh cch in , m bo an ton tuyt i. Cng nhn phi ng lm cc thao tc trong mi trng kh ro, chn ng c thm cch in. Chn phi mang giy m bo cch in. Tay ngi cng nhn phi i gng cch in. Phi mang knh v c m cch in. Khi tip xc vi cc b phn kim loi ang c in phi dng cc dng c chuyn c cch in tho ng. Nhng dng c ny phi c thng xuyn kim tra cch in p ng cc yu cu v an ton s dng in.

Hin nay phn vn hnh thit b in t ng ho cao, iu khin bng my tnh. Cn khai thc ht kh nng ny. Khi iu khin h thit b in l theo phng php th cng, phi m bo cc iu kin trang b cho cng nhn nh yu cu trn.

Tai nn hay xy ra khi vn hnh thit b in v bin php ngn nga phi nh sau:

Mi trng vn hnh m t. Vi nhng iu kin mi trng m t, phi c bin php thch ng mi c vn hnh.

Trang b c nhn khng p ng cc yu cu cch in cho mi b phn c th c kh nng va chm vi cc b phn mang in. Khng iu kin trang b an ton, khng vn hnh thit b in.

Va p dng c kim loi ang cm tay vo cc b phn c in. Phi ht sc ch khi thao tc v mi dng c phi c tay cm cch in vi in p tng ng.

Khi ln cao , mt ng khng vng chi, khng cch in. Phi c sn ng vng chi v mt chn ng phi c lp thm hoc lp m cch in.

Mi cng vic vn hnh thit b in cn ng trn cao phi c mt t cng tc t nht hai ngi, mt ngi thao tc v mt ngi cnh gii, nhc nh iu kin an ton.

Mi thit b in phi c ni t dng in song song qua ngi nu xy ra l nh, khng gy t vong hay tai nn.

* Tai nn in do thao tc k thut

Ngi cng nhn vn hnh cc thit b in v thi cng s dng in phi c hun luyn v an ton s dng in.

Mi thao tc ca cng nhn phi thun thc, hn ch ti a cc thao tc do khng thun thc m va chm vi cc thit tr in.

Ngi cng nhn phi c trang b cch in cho c nhn y v ch thi cng khi mang y cc trang b bo v cch in.

Tro cao trn ct in, trn sn thao tc cc thit tr in phi mang dy an ton ng quy nh, phi s dng y trang b an ton cho c nhn nh m, knh, gng, giy, qun o. Khng bao gi c lm mt mnh trn cao m phi lm theo t cng tc t nht l hai ngi, mt ngi thi cng v mt ngi cnh gii tai nn.

Trc khi thc hin thao tc k thut in cn kim tra mi iu kin an ton. Khi c nghi ng, th d cha r cui ngun in c ai ang thi cng hay khng, cn kim tra trc khi tin hnh ng in. Ch ni mch in khi mi iu kin v an ton m bo tuyt i.

* Tai nn in do ni lm vic b m hoc thm nc

Mi trng lm vic lin quan n an ton s dng in c chia thnh ba nhm:

Cc phng t nguy him v in l phng c mi trng khng kh tng i kh. m tng i ca khng kh khng qu 75% khi nhit t 5 ~ 25oC. Sn ca loi phng ny c in tr ln v khng kh khng c cc loi bi dn in bay l lng.

Phng nguy him nhiu l phng c m ln trn 75%, nhit trung bnh trn 25oC. m tng i c lc nht thi tng n bo ho nh cc phng hp hi, phng ang bo dng b tng bng hi nc nng. Mt s phng kh, c hoc khng c l si v trong phng c phun m nht thi. Nhng phng c nhiu bi dn in nh phng nghin than, xng chut ct thp cng l phng nguy him nhiu v mt an ton in. Nhng phng nguy him cn l phng c nhit trn 30oC lm ngi lao ng trong lun chy m hi. Khi ngi c m hi, khi va chm vi in th mi nguy him tng gp bi.

Phng c bit nguy him l cc phng rt m. m tng i ca loi phng ny xp x 100%, mt tng, mt trn thng xuyn c lp nc ngng t. Phng thng xuyn m m sn li dn in nh bng tn dp chng trn hoc c nhng sn ng thao tc bng tn.

Nhng phng gia cng cht n cng nh cc phng c hi d bt chy n, cc phng c nhiu bi khi to vi khng kh thnh cc hn hp n th d nh trong cc gian nh kho cha cht n trn cng trng thu in.

Ti nhng phng ny, ng dy dn in phi c thit k c cch in cao. Trong mi ng dn cha dy in ch c c mt dy, khng c b tr nhiu dy dn in. Mi kh c in u c cha trong cc hp m iu kin cch in m bo khng gy ra hin tng phng in.

Cng nhn thao tc v lao ng trong nhng mi trng nguy him cn c trang b qun o an ton cch in.

nh sng trong nhng phng ny cn y nhn r mi chi tit ca dng c, vt , my mc ang vn hnh v cha ng trong phng.

* An ton khi hn

My hn h quang in s dng cng sut in ln, dng in qua dy hn c cng cao ( xp x 100 A ) . Qu trnh hn, u que hn hoc m hn pht ra nh sng h quang ng thi pht ra cc tia hng ngoi v tia cc tm. nh sng h quang v cc loi tia hng ngoi, tia cc tm lm hi mt v da ca c th ngi. Kim loi b chy do nhit cao di tc ng ca dng in hoc hi chy lm bn vng ra x hn ( gi l tia la hn) c th gy bng v chy.

Dy dn in hn thng tri ngay trn mt sn i li v my hn v v tr vt c hn khng c nh. Phi thng xuyn kim tra cch in ca dy dn dng in hn. Nu c du hiu b try, xc phi dn bng cch in kp thi, khng in r r ra bn ngoi.

Nhiu v chy nh v chy kho lp t ti cng trng sng , nh Trung tm thng mi ITC thnh ph H Ch Minh nm 2002 do tia la hn gy ra.

Cng nhn hn v ngi ph hn phi eo knh v mt n bo v mt v mt khi b nh sng v cc dng tia lm hi. Cng nhn hn phi mang gng tay di bo v tay khi b sc nng ca tia la hn, ca kim loi nng chy v bc x. Cng nhn cn mang giy cao c chng tia la bn vo chn. Phi lm nhng vch ngn khng ngi qua li nhn trc tip vo tia h quang. Ngi v nhn trc tip vo ngn la h quang khi ang hn c th b tn thng mt do tia bc x v cc tia cc tm, tia hng ngoi.

Hn hi thng dng kh axtylen v xy. Bnh cha tng loi kh cn tch bit v hn hp hai kh ny, nu r r c th gy n mnh. Cc bnh kh hn phi xa ngun nhit v nh nng mt tri. Kho cha cc bnh kh phi c thng gi tht tt. Nhng bnh ang dng phi t trn gi hay xe y, khng c ng n c t do. Thit b ct ngn la tt li ca thit b hn hi phi c lp trn van iu chnh ca bnh v van mt chiu phi c lp u ng dn, pha c ngn la.

ng dn kh phi tt, d phn bit v c bo v chng nng v chng b va chm, bi bn hoc b du, m bm. Mi mi ni ( mngxng ) phi cht, kht, khng c r r. Khi bnh axtylen b pht nng, phi kho van ngay tc th, pht lnh bo ng s tn ngi khi khu vc s nguy him v tm nc lm lnh bnh nhanh chng ng thi pht lnh bo ng chy, gi cu ho.

Khi cng nhn ang s dng cc cng c cm tay c in, phi tt in cc cng c ny trc khi t cng c xung t. Tuyt i khng c dim hay bt la trong ti khi hn.

Khi hon thnh cc thao tc hn, phi kho cc van cn thn. Khng c dng kh xy phi bi trn qun o.

Khi hn trong mi trng kn, kim loi c hn trc y sn, do nhit cao, kh c s bc hi lm nguy hi cho cng nhn. Khi s dng mt s loi que hn c bit cng c th c kh c bc ra gy hi cho cng nhn khi ht th. Nu mi trng hn khng th thng gi c th ngi lao ng phi c trang b mt n v c cung cp dng kh. Nu kim loi hn c che ph b mt bng cc hp cht c cha kim loi ch, km, thu ngn, cadmi th mi trng hn nht thit phi trang b ht khi v nhng hn hp c cc kim loi ny rt c, rt nguy him. Tt nht, trc khi hn nhng kim loi c ph bng sn hay cht do, hy ty sch sn v cht do ri mi tin hnh hn.

* An ton in khi hn trong nc

C hai cch hn di nc l:

Cch hn t

Cch hn kh

Cch hn di nc theo kiu hn t l hn trc tip trong mi trng nc. Que hn l loi c bit dng hn di nc ging nh hn trn cn. Hn kiu ny hiu qu cao v kh kinh t. Nng lng dng hn b tr trn xung ngay trn mt nc m bn di tin hnh cng tc hn. Ngun in hn l dng in khng i. Dng in t t 300 ~ 400 A. ng c ca loi my hn ny chuyn dng pht ra ngun in cho vic hn di nc.

Th hn trong nc phi mc qun o th ln, c th hon ton cch bit vi nc. Mi trang b in nh dy dn, m hn, phi cch nc tuyt i.

Vic b tr mch hn nh sau:

M hn

Que hn

Cu dao

Hn theo quy trnh t r v cng c hiu qu cao nn c s dng ph bin. Tc hn nhanh v cng tc chun b tn t thi gian. Tuy nhin kim loi nhng trong mi trng nc nn b ngui nhanh, s phn b phn t kim loi khng nh mu kim loi ban u m b gin. Tuy nhin cc iu kin v an ton lao ng kh ngt ngho. Nh m t qu trnh cng tc hn th vic trang b an ton cn rt cn thn. Nhng tai nn c th xy ra l bng da, r in l kh d.

Cch hn kh c chun b ht sc k cng. Phi lm mt bung kn bc quanh kt cu cn hn. Trong bung bm y kh, thng l kh helium cha xy c p sut 0,5 bary.Bung ny gi l bung p lc cao. Cng tc hn tin hnh trong bung kn ny nn cht lng m bo tt. Vic hn xy ra di p sut cao cn bng vi p sut ca mi trng nc bn ngoi bung kn cha kt cu hn.

ang hn di nc theo quy trnh t

nh ang hn di nc theo quy trnh kh

Cc iu kin v an ton rt ngt ngho. Ngi phi hn trong bung kn v chu cnh p lc cao, nng cng nh nh sng chi chang ca tia la hn. Cc cht kh hydro v xy sinh ra khi hn d gy n m sinh ra tai nn. Kh nit to ra trong qu trnh hn s lu trong mu lm cho ngi lao ng b nh hng sc kho. Ngi th hn phi c hun luyn v ngh nghip, k nng cng nh rn luyn sc kho c th chu dng c iu kin lao ng. Trang b bo h c ch trng ng mc trnh n mc ti a nhng nh hng tiu cc n sc kho ngi cng nhn.

Trang b to ra bung kn i hi ng b v phc tp nn gi thnh cui cng ca ng hn kh cao. Ch khi no i hi cht lng rt c bit mi dng phng php hn kh.

* Hun luyn v thit k, lp t cng nh lao ng trong mi trng c in m bo an ton trong xy lp in.

Khi thit k h thng in trn cng trng , phi t thit b bo v nh aptomat hoc cu dao in tng cho ng dy in chnh trong nh, cho tng ng dy in ph, cho tng thit b c cng sut ln. Phi t cu ch trc tng cm in, m bo khi c chm chp ct ngay c ngun in.

Tit din dy dn phi chn sao cho c kh nng ti dng in n cc thit b, dng c in m n cung cp. Khng dng dy c tit din nh cho cc dng c in c cng sut qu ln trnh gy ho hon.

Khng dng ph ti qu mc cho php ca cng sut thit k v s gy qu ti dn n chy thit b, dy dn, gy chy n.

Khng dng dy in, thit b in trong nh c cht lng km.

Nhng thit b in, in trong nh qu c cn phi c kim tra thng xuyn c k hoch i tu hoc thay th.

Khng dng bp in un nu m khng c ngi trng coi.

Thit b in, in dng trong nh khi khng s dng phi ngt ra khi ngun in.

Trc khi ra khi nh hoc trc khi i ng phi kim tra li cc thit b, in, n, qut.

Khng tr nh, ngi mc bnh tm thn s dng cc thit b in, dng in trong nh.

Khng lp t hoc cc thit b . dng in c to nhit nh chn lu, bng n, bn i, bp in trn cc vt dng d chy nh g, giy, giy cc tng, tm xp ngn nga ho hon. Khi ni dy phi ni so le v qun bng keo cch in cn thn.

Khng t cc cht d chy ( gaz, xng, du , giy) gn cc thit b, dng c in nh n, bn i, bp in, cm in.

Khi xy ra chy do chp in, phi nhanh chng ngt cu dao in tng, bo cho mi ngi xung quanh bit, bo cho cnh st PCCC v dng phng tin cha chy ti ch dp la. Cm dng nc cha la khi cha ct in.

* Bin bo v nhng gii php an ton c bn cho h thng in tm trn cng trng

chng in git, v tr nhng vt dn in phi t ni thch hp. Nhng cm phi t cao trn 1,2 mt. H thng u mi in phi trong khng gian c bo v nh t cha, phng ring. Phi chng in git do con ngi tip xc gin tip qua kim loi khi dng in b r. Phi lm cc tm che chn ni cha thit b in m nu con ngi v c th va chm ngoi mun. Cc vt dn in phi c cch in vi mc cch in an ton cho ngi. Vi nhng ph ti thng xuyn tip sc vi ngi c gi l thit b nhm II, nh qut my, ng ngt in, nhng thit tr m ngi hay tip sc phi lm bng vt liu khng dn in nh bnt hay loi nha tng ng.

Bo v chng cc tc ng nhit thng dng cc thit tr che chn. Ch yu chng cc tc ng nhit nhm chng chy. Khng c lp t ng dy in, bng in trn ng thot him. Vt liu xy dng s dng ti li thot him phi l vt liu kh chy. Lu rng dng in r c th khng ln gy in git, lm nh hng n an ton ca con ngi nhng nu ko di c th gy ra chy.

Trong h thng cc thit b in phi lp cc thit tr t ng ngt mch khi c s c.

Ti nhng u mi ca cng trnh in nh

* Cc thit b phn phi v trm bin p trong nh , trm bin p ngoi tri

* Cc b chnh lu

* Cc my in , thit b khi ng , iu chnh v bo v

* Thit b in ca my trc

* Cc h thng thanh ci

* Cc thit tr in phn

* u mi cc thit b chiu sng

* u ngun ng dy in 1 chiu v xoay chiu

* u ng cp in lc

* u ng dy dn in trn khng.

phi c bng ghi r tn ca u mi ny, cc tnh nng k thut ch yu ca ton b u mi, s h thng cc thit b t trong u mi, ch dn vn hnh v an ton khi thao tc. Bng ln ch vit khng qu nh hoc qu dy c. Kh ch cao t nht 2 cm, nt dy trn 2 mm.

ng dy trn qua l giao thng, ti im thp nht ca ng dy phi treo mt tm bin c kch thc 0,8 x 0,5 mt bng vt liu cch in, nn sn mu da cam nht. Trn bin phi ghi dng trn cng hai ch nguy him , dng di ghi cao hin nay ca dy ti im ct ny ( n v mt) so vi mt ng, tit din dy v in p ti.

* H thng tip t

Ti ni bt u ca dy tip a phi c bin bo nh du. C s ng tip a chn ngm gn trn tng c th nhn bit phn nm di t.

K hiu ni bt u ca dy tip a.

Mt s k t trong h thng tip t:

T l k t u ghi cho c ni vi h thng tip a.

I l k t u ghi cho c tch ri

T l k t th hai cho c ni trc tip vi t

N l k t th hai cho c ni vi trung tnh ti gc h thng lp t.

TN-C l k t th hin dy trung tnh (N) v dy t (PE) ni vi nhau (PEN).

TN-S l k t th hin dy trung tnh (N) v dy t (PE) khng ni chung

TN-C-S l k t th hin TN-C hng ngc v TN-S hng thun trong cng h thng ( ngc li vi TN-S hng ngc v TN-C hng thun l khng c php.

Vic la chn h thng tip t tu thuc tiu chun ca cc nc. Nc ta cha c cc tiu chun cho h thng ny nn B Xy dng ang khuyn khch p dng cc tiu chun ca th gii IEC 60364.

C hai hnh thc ni t bo v cho thit b in:

+ Ni t bo v trc tip:

Ni b phn kim loi trn v thit b in bng dy kim loi lc bnh thng, khng c in vi cc ni t bng st, thp chn di t c in tr nh i vi dng in r qua t v in tr cch in cc pha khng b h hng. Hnh thc ny thng p dng mng 3 pha c trung ho cch in.

Dng in r trong cc mng vi trung ho cch in c in p di 1000V, khng ln qu 10A, cc ni t vi in tr tnh ton nh (