C120-H007-05EN 89
6.8 Distribution Line Insulation Testing
6.8 Distribution Line Insulation Testing
This section specifies the test voltage for distribution line insulation testing and
explains the points to watch when performing phase and grounding cable insulation
tests and interphase insulation tests.

6.8.1 Test voltage

Use an applied test voltage within DC250 V for distribution line insulation testing.

6.8.2 Phase and grounding cable insulation test

Perform an insulation test with each phase of the distribution line and the grounding
cable for the following conditions:
zOn the distribution line from the distribution panel to each device, keep the
device's power cable connected (directly connected to the distribution panel or
plugged into an outlet).
z Leave devices off.
To avoid damage to server systems, interphase insulation testing should not be
conducted in these conditions.

6.8.3 Interphase insulation testing

Interphase insulation testing is required only for new distribution lines and can be
bypassed in subsequent scheduled inspections.
When performing interphase insulation testing, take notice of the following
precautions:

(1) Interphase insulation test within the distribution panel

Turn off all the breakers for the server system to perform an interphase insulation test
within the panel.
To avoid server system failures, do not apply a test voltage between different phases
of the device power cable.