Radial MICC spur

[gsparks101]

Hi i need to test a Radial MICC spur and was wondering do i follow my normal test procedures for it as in any radial installation?? how would the continuity test be verified. installation resistance test and Ze

thanks

 

[Spark123]

Is this for the 2391?

First two are dead tests hence the board needs to be isolated.

R1+R2 (and polarity dead)
Link the pyro live to the earth bar in CU.
Measure the R1+R2 at the remote end.
Also ensure the conductors are ID'd.
Return to normal

IR
Disconnect neutral in board.
Assuming no current using equipment attached, measure IR between L-E, N-E, L-N.
Return to normal

Ze
Ensure board is isolated
Disconnect the Earthing conductor.
Measure the efli between the earthing conductor and each of the lives as they enter the isolator. Highest one is your Ze.
RE-CONNECT the earthing conductor!

 

[gsparks101]

yep for the 2391. Thanks for explaining that. For the MICC are there any more tests to do?

So for the MICC you treat the CU as the earth.. you jst clip line MICC to CU.... Nothing for neutral

 

[Spark123]

It depends how it's been wired, as MICC uses the outer sheath as the CPC then there should be a good connection with the gland to the earth rail in the CU. Some pots have a flying lead which is also a good way to earth the MICC.
You don't need to involve the neutral in R1+R2 measurements as you are measuring the resistance of the phase and earth conductors (and adding to Ze) to confirm the circuit will disconnect within time should a phase to earth fault occur and not leave exposed conductive parts live for too long in the event of a fault.