Practical question about 3 phase IR testing

[timhoward]

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?

 

[brianmoooore]

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.

 

[timhoward]

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

 

[Julie.]

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

 

[pc1966]

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.