# Practical question about 3 phase IR testing

Discuss Practical question about 3 phase IR testing in the Electrical Testing & PAT Testing Forum area at ElectriciansForums.net

#### timhoward

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Regarding 3 phase IR tests for initial verification, I'm wondering how people actually do it efficiently.

GN3 says to IR test between all phase permutations, then:
L1+L2+L3 connected together to N
L1+L2+L3 connected together to E
N to E

The OSG further comments that if the group test to earth is low then do each conductor individually to earth to find where the issue is.
So, two questions:
1) If anyone does it this way, how do you go about quickly joining the lives together, or have people made up special test leads with three probes/leads stacked for the purpose?
2) Isn't it just as valid, quicker, and simpler to IR test each phase to N and each phase to E instead of messing about joining them up? Anyone do this?

2) Isn't it just as valid, quicker, and simpler to IR test each phase to N and each phase to E instead of messing about joining them up? Anyone do this?
This is what I do, plus testing between all combinations of the 3 phase wires, sensitive equipment permitting.

This is what I do, plus testing between all combinations of the 3 phase wires.
Thanks.
It made no sense to me to be messing around disconnecting things to test them and potentially (worst case) introducing faults reconnecting them

If the wires are out, I earth everything except L1 then flash L1-E, then earth everything except L2 then flash L2-E, and so on for L3 and N - 4 tests complete each phase to phase, each phase to N, each phase to E, and N to E.

If all the wires are connected then I just bang through all 13 ways even though this repeats some tests

If the wires are out, I earth everything except L1 then flash L1-E, then earth everything except L2 then flash L2-E,
I don't usually bother re-earthing already tested wires, so:
• L1 - L2/L3/N/E
• L2 - L3/N/E
• L3 - N/E
• N - E
If, for example, you have a L1-L2 fault it appears on the 1st test, so 2nd test you already know that pair are fine and don't need L1 to be earthed to check for it, etc.

This thread hasn't been replied to for 14 days, so replying to this one may not get a response. Post a new thread instead.

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