fundamentals of regular electrical maintenance

Fundamentals of Regular Electrical Maintenance

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CONTENTS

Fundamentals of regular electrical maintenance on 5 types of equipment 3

Has your condition-based monitoring program caught up with NFPA 70E? 6

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Fundamentals of regular electrical maintenance on 5 types of equipment Mastering maintenance enhances safety and reliability

By Sheila Kennedy, CMRP, contributing editor

Five critical asset types are common to all industrial oper-ations: cable, circuit breakers, motor controls, relays, and transformers. Each type requires strategic maintenance to enable operational reliability and safety, while myriad standards and

regulations govern how the tasks are conducted.

The preventive maintenance (PM) and predictive maintenance (PdM) tasks may be performed internally or outsourced to experts. In either case, periodic training by an accredited training agency helps

to keep the technicians up on the latest electrical safety and mainte-nance regulations, standards, tools, and techniques.

ELEMENTAL PRINCIPLES

When dealing with thousands of volts on a daily basis, getting it right is a matter of life and death. “Too many technicians are killed or hurt due to lack of training with electrical hazards and mitigation processes,” believes Greg Richmond, a senior training specialist at AVO Training Institute (www.avotraining.com).

Table 1 illustrates the specialty knowledge required to success-fully maintain core electrical equipment. The skills required are always specific to the equipment

Maintenance essentials

Cabling Circuit Breakers Motor Controls Relays Transformers

Common PM and PdM tasks

Non-destructive tests in-clude insulation resistance, time domain reflectometry, shield continuity, power factor/dissipation factor (tan delta), and partial discharge testing. For cable outside the non-destructive category, withstand testing can be conducted.

PM includes exercising the breaker regularly, operating it electrically if applicable, and visually inspecting it for excessive heating (discoloration, blistering of insulation, paint that is peeling on enclosures), signs of moisture, signif-icant amounts of dust or dirt, missing hardware or parts, and any cotter pins, keepers, or other hardware lying on the switchgear floor. PdM includes infrared scans, insulation resis-tance, contact resistance.

Test and operate daily for continuous process plants; clean and inspect monthly in a 24/7 environment (or quarterly if used infre-quently); adjust the elec-trical connection to torque specification semi-annual-ly; and perform insulation resistance measurement and ground-bonding tests annually.

None for microproces-sor-based or solid-state protective relays. For me-chanical protective relays, tasks include burnishing all contacts; removing any foreign material that may have collected since the last maintenance cycle (dust, metal filings, etc.); and generally inspecting the relay for any mechan-ical issues (bent or broken parts, loose screws, frozen or stuck components).

Mechanical tasks include winding resistance, transformer turns ratio, and power factor tests. Non-mechanical tasks include oil sampling, partial discharge, ultrasonic, infra-red thermography, oil level, temperature, pressure, and load testing.

PM/PdM skills commonly found in-house

Insulation resistance testing skills are commonly found in-house.

The PM skills can gener-ally be found or trained in-house.

Most if not all the skills are commonly found in house, at least in military, utility, manufacturing, and energy industries.

All the skills are commonly found in-house.

Visual checks with gauges, equipment, indicators, etc., and taking oil samples can easily be done in-house.

Table 1. Maintenance essentials from aVO Senior Training Specialists Ray pitts, Dean Bartlett, chris Murphy, Dennis Moon, and Greg Richmond

(continued on p.4)

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being maintained, and so is the personal protective equipment (PPE). Outside experts may be contracted for assistance or full maintenance services, whether for liability reasons, limited time or manpower, skills gaps, or the need for expert advice.

Manufacturers require certain lubrication, torque specs, test voltages, etc., tailored to the built equipment. Most will produce

factory tests on equipment that will provide a baseline for technicians to follow. Additionally, maintenance technicians must fully understand the nuances and timing of the PM and PdM tasks and any variables based on the type and state of the equipment.

Basic troubleshooting and maintenance skills require some form of dedicated classroom training by an accredited training

agency as a baseline at the start of the program. Electrical workers also require awareness of rules and standards from organizations such as IEEE, ANSI/NETA, NFPA, OSHA, ASNT, IAEI, and NICET. Since standards and techniques are regularly updated based on field experience and changing processes and tech-nologies, learning is an ongoing endeavor.

Maintenance essentials

Cabling Circuit Breakers Motor Controls Relays Transformers

PM/PdM skills commonly requiring additional training

Time domain reflectometry, power factor/dissipation factor (tan delta), and partial discharge testing all require specialty training on the test equipment to allow the technician to perform the tests accurately as well as properly interpret the test results.

The PdM tasks are more technical and commonly necessitate additional training. They require knowledge of how to safely operate various types of test equipment and then be able to interpret the results.

Static motor testing and safety require ongoing training.

Relay testing, calibration, and communication com-monly require additional training.

Electrical testing will require some sort of initial training to do it correctly.

PM/PdM skills commonly contracted out to specialists

Time domain reflectometry, power factor/dissipation factor (tan delta), and partial discharge testing of cable are most often con-tracted to outside compa-nies due to their extensive training requirements and learning curve.

All PM and PdM tasks are commonly outsourced.

Dynamic motor testing, ultrasonic testing, and infrared testing are com-monly outsourced.

Relay testing and calibration are commonly outsourced.

Outsourcing tends to come from a lack of funding, knowledge, equipment, time, or for liability reasons.

What is the appropriate PPE?

For a fully deenergized circuit or system, PPE is minimal and based simply on the specific test per-formed, from voltage rated gloves to discharge sticks.

PPE for arc flash protection, required only at the time the breaker is being re-moved from the switchgear, is dictated by the level of incident energy. Generally, it will include a CAT-2 shirt, rubber gloves with liner, eye protection, hearing protection, and impact-re-sistant footwear for anyone handling or moving circuit breakers or other heavy equipment or tools.

The appropriate arc flash category PPE is required.

There is no PPE by rule, but individual utilities and facilities may have their own requirements.

The very minimum PPE requirements include bottom line-voltage rated gloves ground specific to the gear, barricades to keep unqualified people out, discharge equipment, and rubber blankets.

Table 1 continued. Maintenance essentials from aVO Senior Training Specialists Ray pitts, Dean Bartlett, chris Murphy, Dennis Moon, and Greg Rich-mond (continued from p.3)

(continued)



SAFETY FIRST

Good sources for electrical safety guidance include NESC, NEC, and NFPA 70E. For example, NFPA 70E Article 120 discusses the establishment of an electrically safe work condition. “This would be the primary focus before beginning any work process as well as ensuring this condition is maintained during ALL testing,” says Ray Pitts, senior training specialist at AVO.

Technicians must be knowledge-able about the normal operating condition of equipment, risk assess-ments, hazard analyses, energized work, energized electrical work permits, and testing frequencies; and must adhere to the appropriate lockout/tagout and job planning procedures and arc flash PPE cat-egory selection. They must also be aware of circumstances where PPE

requirements significantly increase, such as when a circuit breaker is being racked-in or racked-out with

the cabinet door open or off, and when working on a circuit breaker control circuit with energized parts.

Technicians must be knowl-edgeable about normal operating conditions of equipment, risk assessments, hazard analyses, ener-gized work, energized electrical work permits, testing frequencies, and adhering to the appropriate lockout/tagout, job planning proce-dures, and arc flash PPE category selection. They must also be aware of circumstances where PPE requirements significantly increase,

such as when a circuit breaker is being racked-in or racked-out with the cabinet door open or off, and

when working on a circuit breaker control circuit with energized parts.

MASTERY IS ACHIEVABLE

With so much at stake, it only makes sense to enlist electrical safety and maintenance training assistance when needed. Organizations such as AVO Training Institute exist to help electrical workers at all levels, for all types of equipment, to stay on top of the latest skills, standards, and certifications required to support a safe, reliable, and productive workplace.

Getting it right is a matter of life and death.



Has your condition-based monitoring program caught up with NFPA 70E?Be aware of current best practices when collecting data on asset health,

especially electrical equipment is energized and under normal load conditions

by Rudy Wodrich, P.E., MBA, CRL, L1 Thermographer

The 2018 Edition of NFPA 70E Standard for Electrical Safety in the Workplace, was released in late 2017 with little fanfare. However, there are several significant changes in this edition that have poten-tially wide-ranging implications for maintenance personnel collecting condition based data on their electri-cal and electromechanical assets.

The NFPA 70 National Electri-cal Code (NEC) and the NFPA 70E are meant to work hand in hand. The NEC defines how to install listed electrical equipment properly including ensuring that items such as cable ampacity, fuse and breaker ratings, conduit fill guidelines and safe equipment clearances are correct. When elec-trical equipment has been designed, installed and maintained properly and is operated under “normal” conditions with all hinged doors closed, covers on, and guards in place, workers are not exposed to any hazard. The NFPA 70E deals

with how to reduce risk through safe work practices on equipment when it is under “abnormal” con-ditions, either intentionally or unintentionally, and the likelihood of occurrence of a shock expo-sure and arcing fault and arc flash are heightened.

The first major change is that the Hierarchy of Risk Control Methods which were previously a suggested non-mandatory requirement has now been made mandatory to apply to any energized electrical work task

to mitigate exposure or reduce risk. The Hierarchy must be applied in sequence to reduce the inherent or initial risk to a residual risk level that is as low as reasonably practica-ble (ALARP).

The Hierarchy of Risk Control Methods consists of six controls, each which must be considered fully and eliminated as an option to reduce risk before moving to the next lower control of the hierarchy. (The effectiveness of the control reduces as we move down the hierarchy.)

1. Elimination – Eliminate the hazardous energy altogether. In the case of condition based main-tenance (CBM) inspections, most data collection must be performed with the electrical equipment energized and under “normal” load conditions which usually means at least 60% of the normal oper-ating load present. Infrared and ultrasound inspections must be performed energized and under



normal load and, in the case of infrared, thermal stability must be achieved. Most motor cur-rent analysis (MCA) tests must be performed with the motor energized while oil sampling can be performed with equipment de-energized. The fact that taking an equipment shutdown would be inconvenient for the client is not necessarily sufficient cause to bypass Elimination and move to the next control in the hierarchy.

2. Substitution – Involves replacing something that produces a hazard with something that does not produce a hazard. To be an

effective control, the substitution of process or product must not produce another (new) hazard. If we agree that a given CBM work task must be performed with the electrical equipment energized, is there a way to substitute a way to see or listen inside the equipment or collect a sample without exposing energized conductors or circuit parts?

The use of Electrical Mainte-nance Safety Devices (EMSD) such as properly sized and located infrared viewing panes or ultra-sound ports or sensors may allow the Qualified Person to inspect the electrical equipment and collect

data without any exposure to ener-gized conductors or circuit parts. External oil sampling ports can be installed on transformers that allow the Qualified Person to gather a sample without opening the ener-gized terminal chamber. Motor test access panels (MTAPs) can be installed to allow safe closed panel testing of motors.

3. Engineering Controls – Involves a physical or design changes to the electrical equipment, rather than relying on worker’s behavior or requiring workers to wear protective clothing. There can be some confusion as to when

Elimination

Substitution

Engineering Controls

Awareness

Administrative Controls

Personal Protective Equipment

NPFA 70E Hierarchy of Risk Control Methods.



a change is Substitution versus Engineering Controls. My interpre-tation is that Engineering Controls are to protect the worker from himself (e.g., designing in more insulating, guarding, or finger-safe components) or implement design changes to reduce hazard levels (e.g. protective devices which reduce the maximum fault clearing time).

Engineering Controls might include using high resistant grounding instead of solidly grounded systems to limit the phase to ground fault current or selecting Arc Resistant Switchgear. In this manner, the work task will expose the Qualified Person to reduced electrical hazards and will reduce the resultant potential for injury. With this thinking, other examples of Engineering Controls would be tamper resistant hardware and door interlocks (limit switches) that prevent access into hazardous energized electrical equipment or automatically de-energize the electrical equipment if someone manages to open an access point. Touch proof barriers inside of electrical equipment might also qualify as Engineering Controls – although they often need to be removed to perform Infrared inspections creating a secondary hazard for the thermographer.

4. Awareness – Ensures that the personnel involved in a work task have a documented Job Safety Plan that was created by a

Qualified Person. The Job Safety Plan must include:

a. A description of the job and individual work tasks.

b. Identification of the electrical hazards associated with each work task.

c. A documented shock risk assessment.

d. A documented arc flash risk assessment.

e. Use of work procedures involved as well as any spe-cial precautions and energy source controls.

5. Administrative Controls – Includes using electrical safe work procedures and employee training. Specific training for Qualified Persons would include Electrical Safety Training, Lockout Tagout Training, Emergency Response Training, First Aid / CPR (based on Jurisdictional requirements), and PPE training. Training must be documented and retraining / certification must be performed at proper intervals. Even Unqualified Persons who will not be working on electrical equipment need to be trained on basic electrical safety practices. With the Awareness and the Administrative Controls in place, only then can you move to the final control in the Hierarchy.

6. PPE – Personal Protec-tive Equipment. PPE includes equipment such as rubber insulating gloves with leather protectors, using insulated hand

tools, arc-rated clothing, arc-rated faceshields, and arc flash suits. , and is the least effective means of controlling hazards because of the high potential for PPE to be dam-aged, worn improperly, or selected incorrectly for the level of hazard that exists. Open-panel CBM data collection is inherently high-risk work without controls and should only be done as a last resort.

Beyond the formal adoption of the Hierarchy of Risk Control Methods, NFPA 70E 2018 Edi-tion has also codified the need for human error to be considered as part of the Risk Assessment Procedure (RAP) for any work task under consideration. The document recognizes that human error will drive up the likelihood of occurrence of an arcing fault and arc flash or shock exposure to the Qualified Person. For CBM inspections, the greatest risk of human error occurs when removing a bolt-on cover to be able to see into the electrical equipment to perform the CBM work task on the suspect conductors or circuit parts. Quite often, the exact internal nature of the electrical equipment is not known until it is opened as there is limited documentation on the electrical equipment construc-tion available to the inspection personnel. They do not know just how close the energized conduc-tors are, and are often working in restricted spaces.



Another change to NFPA 70E was the addition of Table 130.5(C). This table states that, on electri-cal equipment in any condition (normal or abnormal), performing infrared thermography and other non-contact inspections outside the Restricted Approach Boundary does not increase the likelihood of occurrence of an arcing fault and arc flash incident, so additional PPE is not required. However, the table further clarifies that this does not include opening equipment doors or covers that expose bare energized conductors or circuit parts which specifically does increase the like-lihood of occurrence of an arcing fault and arc flash.

Although not specifically men-tioned in Table 130.5(C), opening an EMSD cover like that on an infrared viewing pane does not expose bare conductors or circuit parts and so my interpretation, verified by others I have spoken to who were on the NFPA 70E Technical Committee, is that no PPE would be required. In this manner, the use of an EMSD and changing the work process to keep the equipment in a closed and guarded condition while perform-ing the CBM task seems to follow Substitution stage guidelines of the Hierarchy of Control.

Finally, the language around the Energized Electrical Work Permit (EEWP) requirements in the NFPA 70E should be mentioned. An Energized Electrical Work

Permit is required whenever per-sonnel will perform work within the Restricted Approach Boundary or when personnel interact with equip-ment in such a way that an increased likelihood of injury from exposure to an arc flash hazard exists – even if conductors or circuit parts are not exposed during the work.

However, there is an exemption to the need for an EEWP for ther-mography, ultrasound, or visual inspections provided the Restricted Approach Boundary is not crossed.

At first blush, one might think that this gives a blanket EEWP exemption for open panel ther-mography. However, this only means that an EEWP may not be necessary but the Hierarchy of Risk Control Methods must still be followed when completing a Risk Assessment Procedure. In addition, an EEWP will still be needed if, in the process of removing the panel cover or opening a door, the Restricted Approach Boundary will be crossed. In my experience, crossing the Restricted Approach Boundary when removing a panel cover is a virtual certainty on most electrical equipment and so an EEWP should be executed. When opening a hinged door, this may not be the case but only prior user experience with the equipment will validate that assumption.

CBM data collection can pro-vide valuable insight into electrical equipment health and drive more

intelligent decision making as to when to perform physical interven-tion maintenance tasks. Most of this must be done with the electrical equipment energized and under normal load conditions to allow the technology to catch the anomalies. The NFPA 70E recognizes the risk inherent with CBM data collec-tion and is pushing for safer data collection practices via the most recent changes including the formal adoption of the Hierarchy of Risk Control Methods as well as updates to other language and reference tables in the document. End users and maintenance personnel should revisit their risk assessments of these work tasks and reconsider the imple-mentation of EMSDs as a strategy to mitigate hazards and reduce risk and comply with the intent of NFPA 70E. Failure to do so not only puts people at increased risk of injury or death but could also result in an expensive legal lesson.

Rudy Wodrich is VP of

engineering services at

IRISS Inc. (www.iriss.

com) and specializes in

designing electrical

distribution systems for high efficiency,

safety and reliability. Contact him at r.

[email protected]. The full white paper

“NFPA 70E 2018 Edition – Changes and

Implications for Personnel Performing

Condition Based Maintenance Tasks,”

from which this article was drawn, is

available at https://plnt.sv/1903-NFPA.



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