Testing Testing

[AdamGT3]

Thanks for all your help to date ... hopefully doing courses this year if NICEIC e-mail me back re dates!!!

WHat is the correct way to test and record results for the folowing circuits:

1.

Main CU - RCD - 12 outdoor lED lights (mains voltage)

Do you test and record R1 + R2 with the link in placed at the CU and the RCD closed? or test CU to RCD and RCD to remainder of circuit?

2.

Main CU (MCB) - Jn Box (10mm T&E to 10mm SWA) - SHed CU (all RCD protected - 3 MCB's) - Circuits

AGain test and record R1 + R2 at each point or whole circuit?


For both of the above how do you do Insulaion resistance wirh RCD's in the chain?

Many thanks

Adam

 

[Spark123]

To do R1+R2 you need to can insert a link from the outgoing side of the open MCB to the earth rail then measure the resistance at the furthest point. Instead of inserting a link it may be possible to unscrew the outgoing phase wire and pop it into the earth rail.
I use a Megger MFT 1552 which pushes 200mA around the circuit for the low resistance test, this tends to trip RCDs so better to have them out of the circuit.

For a sub main test the R1+R2 of the sub main, this goes on your schedule of test results for where it is fed from.
For the shed you should have a separate schedule of test results with the R1+R2 for each of the 3 circuits.

When IR testing do each circuit on its own - with the phase and neutral disconnected from the CU. Some RCDs specifically say not to IR test them.

 

[dingbat]

Thanks for all your help to date ... hopefully doing courses this year if NICEIC e-mail me back re dates!!!

You could wait a long time.

Give this website a look: www.electricaltraining.co.uk or Try phoning on 0121 358 5858

 

[AdamGT3]

Thanks Spark, just to be clear for the outdoor lighting circuit that goes through the RCD if the RCD trips I should test R1 +R2 for the link from CU to the RCD and a separate test from the RCD to end of circuit.

Same for IR?

Thanks Dingbat will give them a call.

 

[Spark123]

I'm a bit confused, where is the RCD in the circuit? Reading the OP it appears to be in the main consumer unit, if so just ignore it when doing the R1+R2 test, testing the wiring as it leaves the CU.
This way the test current doesn't pass through the RCD and it won't be a problem.

 

[AdamGT3]

Sorry for the confusion. The RCD is remote from the CU. The CU is a LLutron homeworks panel that only has MCB's protecting each lighting circuit.

The RCD is in a metalclad box in the garage 3 meteres from the Lutron panel so there is T+E from CU (lutron) to the RCD (in a hager metalclads box) and the final circuit runs from the RCD.