Megger WM6, User Manual

Preventive Maintenance

The proverb ‘A stitch in time saves nine’ inspired the
title of an 

Megger Limited 

booklet on insulation

testing, as it neatly sums up the benefits of
preventative maintenance. The savings come in
financial terms from costly repairs, lost production, lost
profits and in human terms, from lives saved in the
event of dangerous electrical faults. 
Regular insulation testing of electrical equipment can
help to detect deteriorating insulation. The effects
which cause insulation to deteriorate include
mechanical damage, vibration, excessive heat or cold,
dirt, oil, moisture and localized voltage stresses - all of
which can arise on most industrial or utility equipment.
Insulation tests are sometimes used in isolation as
absolute measures of the quality of the insulation. This
is most appropriate when equipment is being installed
and checked for compliance with a specified ‘Pass’
level. For operational equipment the key factors are
trends in the insulation readings.
It is therefore important that records of insulation
readings are kept, relating to each piece of equipment
or ‘Asset’ in your testing regime. 

Megger Limited

supplies test record cards to assist with such record
keeping. There are also a  number of influences on the
insulation readings - temperature, humidity and
surface leakage for example and a range of test
techniques have been developed to help with the
interpretation of your insulation tests. 

10

Test Record Example