Frequency of Maintenance Tests
These specifications have been developed
by the
InterNational Electrical Testing Association
for use by
electrical power distribution system engineers.
© Copyright 2001
InterNational Electrical Testing Association
PO Box 687, 106 Stone Street
Morrison, CO 80465
Voice: 303.697.8441 Facsimile: 303.697.8431
Email: neta@netaworld.org • Web: www.netaworld.org
Page 1
NETA recognizes that the ideal maintenance program is reliability-based, unique to each
plant and to each piece of equipment. In the absence of this information and in response to
requests for a maintenance timetable, NETA’s Standards Review Council presents the
following time-based maintenance schedule and matrix.
One should contact a NETA Full-Member company for a reliability-based evaluation.
The following matrix is to be used in conjunction with NETA’s Frequency of Maintenance
Tests table. Application of the matrix is recognized as a guide only.
Specific condition, criticality, and reliability must be determined to correctly apply the
matrix. Application of the matrix, along with the culmination of historical testing data and
trending, should provide a quality electrical preventive maintenance program.
MAINTENANCE FREQUENCY MATRIX
EQUIPMENT
RELIABILITY
REQUIREMENT
EQUIPMENT CONDITION
POOR
AVERAGE
GOOD
LOW
1.0
2.0
2.5
MEDIUM
0.50
1.0
1.5
HIGH
0.25
0.50
0.75
Page 2
MAINTENANCE FREQUENCY MATRIX (cont.)
Inspections and Tests
(Frequency in Months)
Multiplier for Inspections and Tests
(Multiply Value by Matrix)
Visual
12
Visual &
Mechanical
12
Visual & Mechanical
& Electrical
24
2
1
12
12
36
24
1
-
12
-
24
12
2
2
2
-
12
12
12
-
36
36
24
12
7.5
7.5.1.1
7.5.1.2
7.5.1.3
Liquid-Filled Transformers
Sampling
Cables
Low-Voltage Cables
Medium- and High-Voltage Cables
Metal-Enclosed Busways
Infrared Only
Switches
Low-Voltage Air Switches
Medium-Voltage Metal-Enclosed Switches
Medium- and High-Voltage Open Switches
2
1
12
12
12
36
24
24
7.5.2
7.5.3
Medium-Voltage Oil Switches
Medium-Voltage Vacuum Switches
1
1
12
12
24
24
7.5.4
Medium-Voltage SF6 Switches
1
12
24
7.5.5
7.6
7.6.1.1
Cutouts
Circuit Breakers
Low-Voltage Insulated-Case/Molded-Case CB
12
24
24
1
12
36
7.6.1.2
7.6.1.3
7.6.2.1
Low-Voltage Power CB
Medium-Voltage Air CB
Medium-Voltage Oil CB
Sampling
High-Voltage Oil CB
Sampling
Medium-Voltage Vacuum CB
Extra-High-Voltage SF6
Circuit Switchers
Network Protectors
1
1
1
1
1
1
1
12
12
12
12
12
12
12
12
12
36
36
36
12
12
12
24
12
12
24
Section
7.1
7.2
7.2.1.1
7.2.1.2
Description
Switchgear & Switchboard Assemblies
Transformers
Small Dry-Type Transformers
Large Dry-Type Transformers
7.2.2
7.3
7.3.2
7.3.3
7.4
7.6.2.2
7.6.3.1
7.6.4.1
7.7
7.8
Page 3
MAINTENANCE FREQUENCY MATRIX (cont.)
Inspections and Tests
(Frequency in Months)
Multiplier for Inspections and Tests
(Multiply Value by Matrix)
Section
7.9
7.13
7.14
Description
Protective Relays
Electromechanical
Electronic
Instrument Transformers
Metering Devices
Regulating Apparatus
Step-Voltage Regulators
Sample Liquid
Induction Regulators
Current Regulators
Load-Tap-changers
Sample Liquid
Grounding Systems
Ground-Fault Protection Systems
7.15
7.15.1
7.15.2
7.15.3
7.15.4
7.16
7.16.1.1
7.16.1.2
7.16.2.1
7.16.2.2
7.17
7.18
7.18.1
7.18.2
7.18.3
7.19
7.19.1
7.19.2
Rotating Machinery
AC Motors
DC Motors
AC Generators
DC Generators
Motor Control
Low-Voltage Motor Starters
Medium-Voltage Motor Starters
Low-Voltage Motor Control Centers
Medium-Voltage Motor Control Centers
Adjustable Speed Drive Systems
Direct-Current Systems
Batteries
Battery Chargers
Rectifiers
Surge Arresters
Low-Voltage Devices
Medium- and High-Voltage Devices
7.10
7.11
7.12
7.12.1.1
7.12.1.2
7.12.2
7.12.3
Page 4
Visual
Visual &
Mechanical
Visual & Mechanical
& Electrical
1
1
12
12
12
12
12
12
12
12
36
36
1
12
1
1
2
2
12
12
12
12
12
12
24
12
24
24
24
12
24
12
1
1
1
1
12
12
12
12
24
24
24
24
2
2
2
2
1
12
12
12
12
12
24
24
24
24
24
1
1
1
12
12
12
12
12
24
2
2
12
12
24
24
MAINTENANCE FREQUENCY MATRIX (cont.)
Inspections and Tests
(Frequency in Months)
Multiplier for Inspections and Tests
(Multiply Value by Matrix)
Section
7.20
7.20.1
7.20.2
7.20.3.1
7.20.3.2
7.21
7.22
7.22.1
7.22.2
7.22.3
7.23
7.24
7.24.1
7.24.2
7.27
Description
Capacitors and Reactors
Capacitors
Capacitor Control Devices
Reactors - Dry-Type
Reactors - Liquid-Filled
Sampling
Outdoor Bus Structures
Emergency Systems
Engine Generator
Functional Testing
Uninterruptible Power Systems
Functional Testing
Automatic Transformer Switches
Functional Testing
Telemetry/Pilot Wire SCADA
Automatic Circuit Reclosers and Line Sectionalizers
Automatic Circuit Reclosers, Oil/Vacuum
Sample
Automatic Line Sectionalizers, Oil
Sample
EMF Testing
Page 5
Visual
Visual &
Mechanical
Visual & Mechanical
& Electrical
1
1
2
1
1
12
12
12
12
12
12
12
24
24
12
36
1
1
1
1
2
12
12
12
12
2
12
2
12
2
12
1
1
12
12
12
12
24
12
24
12
12