insulation resistance test

[still learning.]

hi, just want to confirm I have got this right. If I am doing a insulation resistance test on a ring circuit and it has fixed equipment then a soft test at 250v is required and the socket switches in the on position.

cheers

 

[malcolmsanford]

First thing to be honest why can't you unplug the appliances on the Ring Final circuit?

The 250v test would be something you would consider on a PIR , example if you could not disconnect a piece of current carrying equipment and you were worried that a 500V test would destroy it, so you do a 250v soft test, which would give you a low reading or you can test 500v between lives and earth, i.e L-E N-E.

As stated this is normally carried out on a PIR. For an Initial Verification you should always do a full IR test on the installtion.

Again if you can get to the ring final circuit and the switches why are you leaving the current carrying equipment plugged in

 

[still learning.]

i' m practising testing in my house, some of the kitchen sockets are on the downstairs ring and i have a built in dishwasher, fridge and extractor fan for the cooker which have a switches on the wall so shall I disconnect the wires from the back of the switch first?

 

[telectrix]

if they are double pole switches, just switch them off. this will IR up to the switches. if you want to test down to the sockets, yu'll have to unplug the appliances. usually these sockets are accessible without pulling the appliances out.

 

[still learning.]

thanks, also I havn't got seperate circuits for my bathroom and I have an electric shower would the soft test apply for that ring?

 

[ukpablo]

electric shower on the ring?
do u mean radial?

 

[telectrix]

you can test up to the switch at 500v with the switch OFF, or disconnect L and N in the shower itself. (rem. to isolate beforehand)

 

[telectrix]

missed that one. radial 6mm or 10mm for shower! (unless it's a power shower)

 

[still learning.]

just tried the shower it is definately on the upstairs ring circuit, i turned the shower on, turned the power off to the upstairs ring and the shower motor stopped. Also when testing a ring L-N do you test both line and both neutral wires together or just one of each?

 

[telectrix]

it's a power shower then, just a pump off the ring. test L/N, L/E, N/E . if you are doing a PIR, it's acceptable to short L/N and test between that and E.

 

[still learning.]

what i meant about the wires is for each ring circuit at the cu there are two line and two neutral wires do you clip both line on one test lead and both neutral on the other or just use one of each

 

[still learning.]

thanks what i meant about the wires is there are two line and two neutral and two earth wires for the ring circuit, do you test both line wires on one test lead and both neutral on the other test lead or just one of each

 

[telectrix]

no, you test , live/cpc, neutral/cpc. if you want to test live/neutral you have to remove the load or you will be reading the load resistance, not the cables

 

[DurhamSparky]

providing you have checked Continuity on the Ring you can place one or both wires into the clip

i normally just place probe into top of MCB (turned off) and other on the neutral bar/Earth Bar

 

[still learning.]

thanks but do i use both (line,neutral,earth) wires on each test lead or just one

thanks your post hadn't come through when i wrote this