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Page 16
Checklist for Insulation Tests
FAULT
REMEDY
Reduced conductivity of the ground due
to wooden boards, insulating materials,
asphalt surfacing or extremely dry soil.
If possible employ "direct earthing",
see 3.1.1, or draw trailing earth
over conductive ground (see figure
on page 17). Bridge the poorly
conductive ground with a second
earthing rod and earthing cable
(see sketch, page 5).
Insufficient contact area between the
trailing earth and the ground.
Use
ELMED
trailing earths. They
consist of 6.5 m long bronze double
coils for optimum earthing. Do not
use "home-made" earths!
The Isotest tester is earthed, but not the
test specimen.
Connect the test specimen to the
ground using the earthing rod. Use
only
ELMED
earthing rod supplied.
Do not use "home-made" earths!
Poor conductive link between the test
specimen and the ground.
In view of the ground conditions
(sand, extremely dry or stony soil) it
can be expedient to soak the point
at which the earthing rod is inserted
into the ground with water. Clean
point at which the earthing clip of
the earthing rod is connected to the
test specimen (metallically bare).
Pipe, tank, etc. is supported on blocks or
suspended on lifting belts.
Connect the pipe or tank from a
metallically bare point to the ground
using the earthing rod.
Lines with cathodic protection can be
interrupted by insulators.
Earth behind the last insulator or:
Direct earthing.