|
 |
DOE Handbook
Electrical Safety
- Electrical Preventative Maintenance -
|
3.0 ELECTRICAL PREVENTIVE MAINTENANCE
The term "electrical preventive maintenance" (EPM) refers to a program of regular inspection and service of
equipment to detect potential problems and to take proper corrective measures through the approved work process
controls.
3.1 DEVELOPMENT AND IMPLEMENTATION REQUIREMENTS
An EPM program should be developed and implemented based on the requirements of:
1. DOE O 433.1,
Maintenance Management Program for DOE Nuclear Facilities (2001)
2. NFPA 70B, Recommended Practice for
Electrical Equipment Maintenance (2002)
3. NFPA 70E, Standard for Standard for Electrical Safety in the
Workplace (2004)
4. NFPA 72, National Fire Alarm Code (2002)
5. National Electrical Testing Association (1997)
6. ANSI-C2, National Electrical Safety Code (2002)
3.2 DEFINITION
An EPM program is defined as the system that manages the conducting of routine inspections
and tests and the servicing of electrical equipment so that impending troubles can be detected
and reduced or
eliminated. Where designers, installers, or constructors specify, install, and
construct equipment with
optional auxiliary equipment, that optional equipment should be part of
the EPM program. Records of all
inspections, tests, and servicing should be documented and
reviewed.
All electrical equipment that is
appropriate for EPM should be inspected, tested, and serviced in
accordance with an EPM program.
Inspections, tests, and servicing shall be performed by personnel who are qualified for the work
to be
performed. These qualifications can be shown by appropriate documentation of work
experience, on-the-job, and
offsite formal training to verify understanding and retention of
minimum knowledge, skills, and abilities.
3.3 MAINTENANCE
Electrical equipment should be maintained in accordance with the manufacturer's
recommendations and instructions for the local operating environment. A copy of the
manufacturer's
recommendations should be documented and on file.
3.4 INSPECTION
If an EPM program does not exist, an inspection, testing, and servicing program should be
developed and implemented to establish a baseline to initiate an EPM program. The inspection
3-1
frequency should be as recommended by the manufacturer or as otherwise indicated in NFPA
70B. An
initial period of inspection (sometimes several years) provides sufficient knowledge
that, when accumulated, may permit increasing or decreasing that interval based upon
documented observations
and experience.
One guidance on how to determine inspection frequency is described in various sections of
NFPA 70B, Tables H.1, H.2, and I.1 including, but not limited to, the following sections:
1. Inspection
Frequency for Planning and Developing an Electrical Preventive Maintenance
Program
2.
Recommended Frequency for Substations
3. Frequency of Maintenance for Switchgear Assemblies
4.
Regular Inspections and Special Inspections and Repairs for Liquid-Filled Transformers
5. Regular Inspections and Special Inspections and Repairs for Dry-Type Transformers
6. Visual Inspection Intervals for Power Cables
7. Frequency of Inspections for Enclosures of Motor
Control Centers
8. Recommended Frequency for Ground-Fault Circuit Interrupters
9. General and
Inspection and Cleaning for High-Voltage Fuses
10. Frequency for Rotating Equipment
11. Cleaning Interval for Lighting Equipment
12. Visual Inspection Before and After Each Use, Periodic Inspection of Crucial Wear Points,
Excessive Dirt Accumulation, Insufficient or Improper Lubrication, and Visually Inspected
Before Each Use for Portable Electric Tools and Equipment
13. Special Maintenance Tests, Frequency of
Tests, Inspection Frequency and Procedures,
and Insulating-Liquid Analysis for Testing and Test
Methods
14. Reinspection and Retesting Within One or Two Years After Energization for General
Aspects of Maintaining Medium- and Low-Voltage Distribution Systems, Frequency,
Regreasing, and Frequency
for Lubrication of Rotating Equipment
15. Inspections Should Be Made of All New Installations and Whenever
Alterations Are
Made and; Recordkeeping for Electrostatics Static Grounding (see NFPA 77)
16.
Inspection and Testing of Power Supplies, Functional Systems Testing of Interlock and
Logic Systems,
Visual Inspection of Level Devices, Frequency of Testing Safety and
Shutdown Systems, Frequency of
Testing Alarm Systems, and Visual Checking of
Wiring Systems for Process Instrumentation and Control
17. Frequency for Cable Tray System
3-2
18. Routine Maintenance for Uninterruptible Power Supply (UPS) Systems
3.5 ESSENTIAL ELEMENTS
The EPM program should include the essential elements described in NFPA 70B, Chapter 5,
What is an Effective
EPM Program?. This includes planning, identifying the main parts, and
utilizing available support services for a program. For example:
1. Assigning qualified personnel
2. Surveying and analyzing equipment maintenance requirements
3. Performing routine inspections and tests
4. Analyzing inspection and test reports
5. Prescribing corrective measures
6. Performing necessary work
7. Preparing appropriate records.
3.6 PLANNING AND DEVELOPING AN EPM
PROGRAM, AND FUNDAMENTALS OF EPM
The EPM program should be planned and developed to include each of the
functions,
requirements, and economic considerations described in NFPA 70B, Chapter 6, Planning and
Developing an EPM Program, and NFPA 70B, Chapter 7, Fundamentals of EPM. Chapter 6
includes surveying the
existing electrical system installation, identifying crucial equipment,
establishing a systematic program to
follow, and developing methods and procedures to plan,
analyze, perform, verify, and record.
Electrical
drawings should be kept current. A system of recording changes in electrical systems
and then integrating those
changes into the applicable drawings should be developed and
implemented.
NFPA 70B includes designing to
accommodate maintenance, scheduling maintenance,
personnel and equipment safety, circuit protection, and
initial acceptance testing.
3.7 GROUND-FAULT PROTECTION
The EPM program should include the essential
ingredients of Chapter 14 of NFPA 70B, Ground
Fault Protection. This includes GFCIs and ground-fault protection
for equipment (GFPE).
Ground-fault protective devices are intended to protect personnel and equipment. There
are two
distinct types — GFCI and GFPE — and it is extremely important to understand the difference
between
them.
A GFCI is defined in Article 100 of the NEC as a device intended for the protection of personnel
in their job assignments. (See NEC 210.8, 215.9, 427, 527)
3-3
A GFPE is defined in Article 100 of the NEC as a system intended to provide protection of
equipment
from line-to-ground fault currents. GFPE systems (equipped with or without a test
panel) shall be inspected and tested at installation and at specified intervals as recommended
by the manufacturer.
Figure 3-1 shows a zero-sequence type of ground fault protection.
Figure 3-1. Ground-fault protection shall be provided with 277/480-V, three-phase,
four-wire services
with over current protection devices of 1,000 A or more. A ground
fault sensor (window) can be used to encircle
all service conductors, including the
grounded conductor (neutral).
Inspections, tests, and servicing shall be performed by personnel who are qualified for the work
to be
performed. These qualifications can be shown by appropriate documentation of work
experience, on-the-job, and offsite formal training to verify understanding and retention of
minimum knowledge, skills, and abilities.
3-4
|
|
|
|
|
