JAC Safety Manual - Chapter 12: Electrical Safety Policy
CHAPTER 12:
ELECTRICAL SAFETY POLICY
A. Policy
JAC's policy is to carry out all electrical work in a safe
manner
consistent
with OSHA requirements. This chapter provides guidance for electrical
safety
practices. Any employee who may be exposed to energized parts is
considered
to face a higher than normal risk of contact, whether they are an
electrical
worker or not.
B. Responsibilities
- Supervisor
-
Anticipates work hazards and ensures that relevant
safeguards
are
utilized.
-
Ensures that all employees are properly trained and
instructed
in the
safe
operation of electrical equipment and aware of all hazards associated
with
the use of these electrical devices.
-
Writes job risk assessments with input from the
employee
and
assistance
from the site safety advisor.
-
Initiates any necessary administrative action
required to
enforce
safety
practices.
- Employee
-
Follows the JAC's electrical safety policies and
procedures and
instructions
of the supervisor.
-
Brings to the attention of the supervisor potential
hazardous
situations
such as discrepancies between instruction, procedures, policies and
manual,
faulty equipment,and misapplication of devices.
-
Takes electrical equipment out of service if it is
known
to be
malfunctioning
and ensures that it is repaired or replaced before use.
-
Communicates the scope of work planned to the Work
Leader and identifies specific safety requirements prior to commencing
work. Reports any safety concerns as required.
- Site Safety Advisor
-
Assists supervisors in defining hazardous
operations,
designating safe
practices and selecting proper application of devices.
-
Participates in reviewing and approving standard
operating
procedures.
-
Evaluates potential electrical hazards during safety
tours to
insure
compliance
with JAC policy and other safety guidelines.
-
Requests support from electrical group on hardware
and
equipment
testing,
tagging out of unserviceable equipment, and taking corrective action
where
necessary.
-
Work Leader
-
Works with the employee performing electrical work
to
highlight any safety requirements which may affect other work
activities and coordinates as required.
-
Checks work status at end of day with employee
performing
work to ensure any reported safety issues are addressed.
-
Does not require electrical safety training to the
same
level as employee performing work.
C. Training Requirements
See
also
Chapter 1
section
C
-
Employees who face a higher than normal risk of
contact
with
electrically
energized parts 50 V or more to ground shall be trained in
compliance
with OSHA Regulation 29 CFR 1910 - Subpart S and 29 CFR 1926 - Subpart
K.
-
Supervisors shall have at least the same level of
OSHA-based
electrical
safety training as the workers for whom they are responsible or whose
work
they plan or supervise.
-
If the worker is unfamiliar with the construction or
operation of
the
equipment
or the hazards associated with the task, additional training may be
required.
In these cases, the supervisor must document the instruction the worker
receives in the use of safe work practices for the voltage levels to be
encountered and the selection, inspection, and use of Personal
Protective
Equipment (PPE).
D. Procedures
Only qualified people may work on electrical systems.
-
De-energizing Live, Exposed Parts
-
Energized parts that operate at less than 30 V or
parts
that have
less
than 1 milliAmp of current potential need not be de-energized if there
will be no increased exposure to electrical burns or to explosion due
to
electric arcs.
-
Electrical parts operating at 30 V or more with a
current
capacity
of 1 milliAmp or more shall be de-energized before they are maintained
or repaired, or parts are exposed within the limited approach boundary.
Lockout tagout procedures must be used except when the equipment has a
cord and plug which is under the direct control of the qualified person
performing the work.
-
Exceptions to this rule are as follows:
-
De-energizing would create increased or additional
hazards
which
include
interruptions of life support systems, shutdown of hazardous location
ventilation
equipment, removal of illumination for an area, or deactivation of
emergency
alarms.
-
De-energizing is infeasible due to equipment
design or
operational
limitations
which include:
-
Testing of electric circuits that can only be
performed
with the
circuit
energized.
-
Work on the circuits that form an integral part
of a
continuous process
that would otherwise need to be completely shut down, creating a
greater
hazard, in order to permit work on one circuit or piece of
equipment.
-
If de-energizing parts will introduce additional
risk or
is
impractical
due to the design of the equipment or operational limitations, a
written
risk assessment shall be required for that work.
-
Release stored electrical energy which might
endanger
personnel.
Discharge
capacitors with a device approved for this use and short-circuit and
ground
high-capacitance elements if the stored electric energy might endanger
personnel.
-
Verify that the field conditions and documents match
and
resolve any
differences
before continuing the work. If there are any unresolved differences
which
could result in an inadvertent re-energization from another source,
take
extra precautions during the potential exposure. Precautions include
verifying
the circuit is de-energized and conducting work using the safeguards
required
for energized systems for the remainder of the work.
-
Safe Practices for Work With Exposed, Energized
Electrical
Parts
-
"Low voltage" systems. Where a system incorporates a
power
supply which
works on mains voltage but supplies a low voltage output, then the
system
may be worked on as a low voltage system provided that all of the high
voltage parts are covered.
-
Work between 30 V and 150 V: Work on exposed
energized
electrical parts
between 30V and 150V and above 1 milliAmp capacity may be carried out
without
further preparation only by one of the authorised staff on the list in
addendum 1. If the work is unusual or especially demanding then a risk
assessment shall be considered.
-
Work above 150V: A written risk assessment shall be
done
for
jobs
requiring
working on exposed energized electrical parts above 150 V and 1
milliAmp,
and consideration shall be given to at least the following areas:
-
The written risk assessment shall document the
hazards
and
the required
Personal Protective Equipment (PPE) for each job. PPE may include
voltage-rated
rubber blankets, gloves, pads, tools, or insulated protective barriers
that provide protection.
-
Do not wear or carry in clothing pockets any
conductive
accessories
(rings,
watches bracelets, metal frame glasses, metal hats etc.) where they may
make contact with exposed, energized parts.
-
Wear natural fiber clothing whenever you may be
exposed
to
voltages of
high energy circuits above 150 V to ground.
-
Inspect the work area for sufficient illumination,
working
space, and
safe
access, and verify that no undocumented risks exist.
-
Cabinet doors shall open at least 90 degrees.
There
shall be
adequate
distance from electrically energized parts to grounded structures or
items.
-
Near exposed energized parts, use only portable
ladders
with
dry,
nonconductive
side rails.
-
Use signs, barricades, or attendants to isolate
the
work area
and warn
others of the exposed energized electrical circuits. Electrical safety
warning signs must be worded: DANGER - ELECTRICAL HAZARDS -
AUTHORIZED
PERSONNEL ONLY
-
If you receive any electrical shock (other than
static), stop
work and
report the incident to your supervisor. Seek medical attention if
warranted.
-
A backup person may be required, to observe the
worker
to
ensure
adequate
clearances and to perform emergency rescue if required. The person must
have been trained in first aid and CPR, or able to call on such
assistance
within the facility.
-
Testing and Troubleshooting on Live, Energized Parts
-
Testing and troubleshooting on live, energized parts
is
allowed.
-
If a problem is discovered during the
troubleshooting and
either a
component
must be removed or rework must be performed, this is no longer
troubleshooting.
At that time, the circuit must be de-energized and locked out.
-
When a fuse in a portable piece of equipment fails,
the
cause
shall
normally
be investigated before the fuse is replaced. If there are no obvious
problems,
it is permissible to change the fuse provided the following checks are
made with the unit unplugged:
-
Check that the chassis is connected to the safety
ground pin
in the plug
-
Check that once the fuse has been replaced and
BEFORE
the
unit is
plugged
in, there is no short between the chassis and the power line.
-
Non-conductive Protective Equipment
-
Store and use according to the manufacturer's
recommendation.
-
Inspect protective equipment before each use to
verify
the item
is in
satisfactory
condition and has been tested as required. Inspect rubber gloves for
holes
and air test before using. Rubber protective equipment shall be
inspected
and tested at the manufacturer's recommended interval, or more often if
necessary.
-
Inspect voltage rated tools for defects and surface
contamination such
as moisture or dirt before each use.
-
Do not rely on insulated tools alone for complete
protection.
-
Electrical Test Equipment
-
Visually inspect electrical test equipment
immediately
before
use and
do
not use if defective. Identify defective test equipment by tagging it
out
of service and repair or dispose of properly.
-
Use electrical test equipment only for intended
applications.
Read the
operating instructions and limitations for the test equipment.
-
Check electrical test equipment for proper operation
immediately before
and after use when verifying that circuits are de-energized. When
performing
zero energy checks, ensure that stored electrical or mechanical energy
cannot re-energize the circuit.
-
Requirements for GFCI Protection of Personnel
-
Use ground fault circuit interrupters (GFCI) on
120-volt
circuits in
damp
or wet work areas and outdoors.
-
Use GFCI for all extension cords except where used
for
extended
service
with equipment with plug and cord and not likely to be damaged.
-
Test portable GFCIs before each use. If any damage
is
evident
that
might
expose people to injury, remove the item from service.
-
Use double insulated tools and equipment when
appropriate.
Double
insulated
tools do not require the use of a GFCI.
-
Requirements for Flexible Cords and Cables
-
Extension cord sets are not to be used as a
substitute
for the
permanent
wiring of a building.
-
Use flexible cords suitable for conditions of and
location of
use.
Flexible
cord sets used with grounding-type equipment must contain an equipment
grounding conductor.
-
Protect flexible cords and cables from damage by
foot
traffic,
vehicles,
sharp edges, pinching, and improper storage.
-
Inspect all extension cords before use and discard
damaged cord
sets or
have any break in the insulation repaired by a qualified person so that
it is equal to or better than the original.
-
Requirements for Drilling into Walls, Floors, or
Outdoor
Slabs
and Excavations
Containing Buried Electrical Cables
As appropriate, review all
drawings
and documentation. Visit
the job
site
to determine if obstructions are in the drilling path before starting
the
job.
-
National Electrical Code
(NEC)
RequirementsInstall all electrical equipment in accordance with NEC
requirements.
- Install all electrical equipment in accordance with
NEC
requirements.
-
All electrical installations and modifications will
be
inspected as
required
by code. The Chief Engineer's interpretation of code requirements shall
be final.
-
Soldering
-
Only solder in well ventilated area
-
Utilize caution due to heating element of soldering
equipment.
-
Wear eye protection whenever soldering
-
Tripped, Locked or Tagged Circuit Breakers
-
Where a panel board circuit breaker of greater than
20
Amps has
tripped,
operation by non- qualified JAC personnel is prohibited except in case
of personal emergency or when the overload that caused the breaker to
trip
is known and corrective action has been taken. Otherwise, a qualified
person
must investigate the fault before operating the circuit breaker.
-
Switching devices which are tagged or locked shall
not be
operated
until
tag is removed by issuer or the alternative steps detailed in Chapter
13 have been followed.
-
Permanently Installed Fuses
Fixed power line fuses shall
not
normally be changed except by
qualified
personnel. It is permissible for the Telescope System Specialist (TSS)
to change the fixed fuses at JCMT under the following circumstances:
-
Contact must be made with Site Safety Advisor (SSA).
-
Steps must be taken to establish what caused the
fuse to
blow
and to
fix
the problem.
-
The TSS may choose to replace the fuse under the
telephone
guidance of
the SSA if they are both satisfied that it is safe to do so.
-
Parts
Removed
from Service
Defective parts removed from
service must be tagged and identified as faulty or immediately disposed
of.
E. Definitions
-
Exposed parts: Energized electrical parts
capable
of
being
inadvertently
touched or of being approached closer than a safe distance (see Table
1)
by a person. It is applied to parts not suitably guarded, isolated, or
insulated.
-
Ground-fault circuit-interrupter: A device
intended
for
protecting
personnel, designed to de-energize the electric circuit within an
established
period of time, when a current to ground exceeds some predetermined
value
that is less than the current required to operate the overcurrent
protective
device of the supply circuit.
-
Limited approach boundary (see Table 1): This
boundary
establishes
the distance around energized parts that only a qualified person may
enter.
If an unqualified person must enter the limited approach space to
perform
a minor task, like inspection, then a qualified person must advise them
of the possible hazards and ensure that the unqualified person is
safeguarded.
-
Restricted approach boundary (see Table 1): This
boundary
establishes
the distance around exposed, energized parts that only a qualified
person
may enter.
-
Prohibited approach boundary (see Table 1): Crossing
a
prohibited
boundary (Table 1) is considered working on exposed, energized
conductors
or circuit parts. This includes crossing the boundary with hands, feet,
other body parts, probes, tools, or test equipment regardless of
protective
clothing.
-
Qualified person: A person trained in and
thoroughly
familiar with
the construction and operation of equipment, regulatory compliance
requirements and the hazards involved.
This
person must also be familiar with the proper use of special
precautionary
techniques for the task to be done, personal protective equipment
(PPE),
insulation and shielding materials, and insulated tools and test
equipment.
-
Training and experience determines whether an
employee is
considered to
be a "qualified person." A person may be considered "qualified" with
respect
to work on or within the limited approach boundary for certain
equipment
and "unqualified" with respect to other equipment.
-
Trainees may be considered qualified persons for the
performance of
certain
duties if they meet all of the following:
-
Are undergoing on-the-job training
-
Have demonstrated ability to perform their duties
safely to
their
level of training
-
Are under the direct supervision of a qualified
person
-
Troubleshooting and testing: Actions necessary
to
measure
voltage
and current and to verify the operability of equipment without
repairing
or replacing components.
Table 1. Approach Distance to Exposed Energized Electrical
Conductors
and Circuit Parts.
Nominal System
Voltage Range
|
Limited Approach Boundary
|
|
Restricted
Approach Boundary
|
Prohibited
Approach Boundary
|
| Phase to Phase |
Exposed Movable Conductor |
Exposed Fixed Circuit Part |
Includes Standard Inadvertent Movement Adder* |
Includes Reduced Inadvertent Movement Adder* |
| Less than 300 V |
10.0 ft. |
3.5 ft. |
AVOID CONTACT |
AVOID CONTACT |
| 300 V to 750 V |
10.0 ft. |
3.5 ft. |
1.0 ft. |
1 in. |
| Over 750 V, to 2000 V |
10.0 ft. |
4.0 ft. |
2.0 ft. |
3 in. |
When assessing
distance, include the length of any
conductive
tools being used to perform work. For SI units: 1 in. = 25.4 mm and 1
ft.
= 0.305 m.
* Adder is defined as: One
that
adds, especially a computational device that performs arithmetic
addition. With
regard to provisions for inadvertent movement, the minimum approach
distances
(working distances) must include an "adder" to compensate for the
inadvertent
movement of the worker relative to an energized part or the movement of
the part relative to the worker.
|