personal protective grounding - training presentation

7/27/2019 Personal Protective Grounding - Training Presentation

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Personal ProtectiveGrounding Standard

Establishing and Ensuring a SafeWork Environment


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Introduction

The following information is provided as an overview of

the new Personal Protective Grounding standard.

The presentation provides key elements of the standard.

Further details of the standard are listed in the document

and will require review to ensure all aspects of the

standard are clear and understood.


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Purpose

The Personal Protective Grounding standard is designed to:

Prove that the electrical circuit or equipment is in fact

removed from a dynamic source of electrical energy.

Provide protection in the case of accidental re-energizationthat may be caused by operator error, contact with

neighboring circuits, lightning, backfeed, insulator failure,

etc.

Provide protection from electrostatic and electromagneticinduction that may be caused by adjacent energized circuits,

wind or energized equipment.


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Regional Responsibilities

Using the standard each AES Operation must:

Develop a site specific Program that complies with the

Personal Protective Grounding standard

Ensure all applicable governmental regulations regarding

the Personal Protective Grounding procedures are

complied with.


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Application

The Personal Protective Grounding standard applies to:

All work on de-energized circuits of overhead and

underground transmission and distribution systems, and

in substations.Exemptions

Electrical protection and grounding for conductor stringing

operations is covered in a separate standard.

Electrical protection for people working around boom-

equipped vehicles in the vicinity of live circuits is covered

in a separate standard.


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There are a number of Definitions provided in the

standard to provide explanations for the various

terms used. The following are some examples:

Protective Grounding (Earthing) Effectivelyconnecting an electrical circuit or electrical

equipment to ground/earth potential.

BondingConnecting all grounds (bonds) to a

single point to eliminate differences of potential at awork site.

Definitions of Terms


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Definition of Terms contd

Bonding Principle Bonds are installed so that a workeris kept in an equipotential zone. A worker must not beable to bridge between a grounded circuit and anyunbonded structure, vehicle, boom, wire or any other

object that is not tied into the bonded network.

Grounding Principle Protective grounds are installed toreduce any current flow through a worker to an acceptablelevel by providing a low resistant parallel shunt around the

worker. If the circuit is, or becomes energized, thegrounds must be large enough to withstand any faultcurrent in the circuit.


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Definition of Terms contd

Bracket Grounding (box grounding) Grounding ateach potential source, not more than 2 miles (3km) oneach side of the work site. Bracket Grounding shall onlybe applied when no possible source of re-energizationmay occur.

Equipotential GroundingGrounding and bondingtogether all objects, including the structure to a singlepoint to eliminate differences of potential at a work site.

Grounding Plan An approved written document for

planning the complete isolation of a circuit and thelocations for the installation of protective grounds.


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Guiding Principles and Rules:

Working on an isolated electrical circuit, or equipmentwithout personal protective grounds, has the potential tokill or cause serious physical harm.

Proper grounding ensures the correct isolated circuit is

identified, the circuit is protected from accidentally beingreenergized and high inductive voltage and/or current isreduced to safe levels.

If a circuit is isolated in order to carry out the work safely,then the circuit must be grounded.


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Guiding Principles and Rules: contd

To be assured that a person will not be exposed to any

hazardous current or voltage after the protective grounds

are installed, the installation of the protective grounds

must comply with the Grounding Principle and the

Bonding Principle.

When there is a need for an exception to equipotential

grounding, such as the installation of bracket grounds, a

written protective grounding plan must be prepared and

approved


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The Grounding Principle

Protective grounds are installed to reduce any current flow

through a worker to an acceptable level by providing a low

resistant parallel shunt around the worker. If the circuit isor becomes energized, the grounds must be big enough to

withstand any fault current in the circuit.


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To adhere to the Grounding Principle

The available fault current at each substation and for eachcircuit must be determined so that the correct size groundsets can be specified.

The ground set specified must be able to withstand thefault current for a time necessary to clear the fault. Theminimum size cable must be # 2 copper.

The ground sets must be tested at least annually to

ensure that they will continue to provide a low resistantpath around a worker.


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To Adhere to the Bonding Principle

Equipotential (single point) grounds or bonds must be

installed at the point of work so that a person will not be

subject to any potential difference between any objectsthat can be contacted. The structure must be bonded to

the grounds.

Equipotential bonding on underground systems must be

put in place by working from a ground gradient control matbonded to the equipment or cable.


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Requirements

Each owned and/or operated facility must develop and

implement a ProtectiveGrounding Program that at a

minimum contains the following elements:

Written Program Elements

Procedural Elements

Program Administration


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The Protective GroundingProgram must have the followingwritten program elements:

Be legible, readable, and accessible to all operationspersonnel.

The written program must identify the position in theoperation that is ultimately responsible for theimplementation and maintenance of the operationsProtective Grounding Procedure.


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Written program elements contd:

The written program must clearly and specifically outlinethe scope, purpose, responsibility, authorization, rules,and techniques to be applied to the use of Protective

Grounding and the measures to enforce compliance withthe program.


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Procedural Elements

The Protective GroundingProgram must have the followingprocedural elements:

Arranging for De-energization of the Circuit - Theprocedure must have the requirement that a circuit isguaranteed to be isolated and remain isolated and thattags and/or locks are on isolation points as per the AESOperations lock out/ tag out procedure.


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Procedural Elements

Procedural element contd:

Determining Suitable Grounding Location(s) - Grounds

must be placed at the point of work in an Equipotential

Zone configuration.Bracket grounding does not adequately protect workers

from accidental re-energization. Bracket grounding shall

only be applied when there is no possible source of re-

energization. Bracket grounding requires the preparationof a grounding plan approved by a supervisor.


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Procedural Elements


Determining the Proper Grounding Assembly or Set -

The grounding set must be large enough to carry the full

fault current available at the work location, to ground andstay intact until the circuit protection opens.

Each AES Operation must determine the fault current

availability for the circuits to be worked on. Circuits that

require ground sets larger than the minimum establishedsize (# 2 copper) must be determined and the ground set

requirements specified for each of these circuits.


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Procedural Elements


Choosing the Most Effective Ground Electrode -The

grounding set must be large enough to carry the full fault

current available at the work location, to ground and stayintact until the circuit protection opens.

Each AES Operation must determine the fault current

availability for the circuits to be worked on. Circuits that

require ground sets larger than the minimum establishedsize (# 2 copper) must be determined and the ground set

requirements specified for each of these circuits.


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Procedural Elements

Procedural elements contd :

Connecting to the Ground Electrode - The connectionto the ground electrode must be made before any otherconnections and must be removed last.

Establishing a Bonded Work Zone at the Work Site -Grounds must be installed to establish the bond betweenthe ground electrode and the structure. To keepeverything in the work zone bonded, any wires or winchcables brought into the work zone need to be bonded to

the same ground electrode.


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Procedural Elements

Procedural elements contd:

Establishing a Bonded Area on the Ground - Workers

on the ground that are handling conductors are outside of

the bonded zone and need to use rubber gloves or inmore hazardous situations, work from ground gradient

mats.


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Procedural Elements


Testing the Circuit to be Grounded to Verify Isolation -

The AES Operation must use an approved potential tester

to verify that the circuit is isolated. Buzzing or teasing isnot a reliable method to distinguish between induction or

static charges and dynamically alive circuits.

Ensuring Low Resistant Connections - The conductor

and the inside of the ground set conductor clamps mustbe clean. The ground set must be visually checked,

maintained and tested at least annually.


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Procedural Elements


Installing the Ground Clamps on the Phase

Conductors - All personnel must be either completely in

or completely out of the planned bonded work zone beforeinstalling the protective grounds.

Live line or Hot Stick tools must be used and proper eye

protection must be worn when installing ground clamps.

The proper sequence for installing the conductor clampsshould be specified in the Protective Grounding Program.


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Procedural Elements


Removing Grounds - Grounds should be removed in the

reverse order to which they were installed.

In high induction areas, removing the grounds caninterrupt current and drop voltage. Therefore, live line

tools must be used and eye protective must be worn when

removing grounds.


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Procedural Elements


Preparation of a Protective Grounding Plan - Each

AES Operation should prepare a protective grounding

plan where bracket grounding is used to protect theworker. See Appendix A of the Standard for an example

of a protective grounding plan.

The plan needs to show the extra steps taken to ensure

that the risk of accidental re-energization from dynamicsources is as low as reasonably achievable.


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The Protective GroundingProgram must have the

following program administrative elements:

Enforcement - of the AES Standard and Program

Clearly Defined Roles Responsibilities - for those

positions involved in protective grounding.

Inspections - Inspection of the application of grounds by

Operations Supervisory staff.

Audits - Annual audits to determine the effectiveness of

the Protective Grounding program.


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Program administrative elements contd:

Training - All employees that install, remove and inspect

grounds must be trained and knowledgeable on

grounding and bonding principles, procedures forinstallation and removal of grounds and testing and

maintenance procedures.

Maintenance - At least annually, ground sets must be

inspected, maintained and tested with a ground set tester.


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Conclusion

Applying the Personal Protective Grounding standard willallow a Region, facility, work group or contractors to worksafely and be protected from hazardous energy sources ifimplemented correctly

The Region must ensure proper implementation of aPersonal Protective Grounding program

Employees must ensure individual Personal ProtectiveGrounding responsibilities are complied with to protect

themselves and others when working in a hazardousenergy work environment


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Key To Successful Personal

Protective Grounding

Everybody working together to

establish a trusted and safe work

environment.

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