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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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Guiding Principles and Rules: contd
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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Guiding Principles and Rules: contd
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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Guiding Principles and Rules: contd
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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Written Program Elements
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
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
Procedural element contd:
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
Procedural element contd:
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
Procedural elements contd:
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
Procedural elements contd:
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
Procedural elements contd:
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
Procedural elements contd:
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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Program Administration
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 Administration
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.