Fault finding questions

[Leepato]

1. I carried out a x1 rcd test on a 30ma rcd and the time came in at 44ms with doesn't comply with the circuit disconnecting by 0.4ms. What is the problem? Old/faulty rcd? X5 was 13ms.


2. Done my continuity test on a ring and all continuity was proved. However my neutrals end to end was 0.61, live end to end was 1.45 and earth was 0.97. Why different on my conductors?

 

[Dubbo]

1. I carried out a x1 rcd test on a 30ma rcd and the time came in at 44ms with doesn't comply with the circuit disconnecting by 0.4ms. What is the problem? Old/faulty rcd? X5 was 13ms.


2. Done my continuity test on a ring and all continuity was proved. However my neutrals end to end was 0.61, live end to end was 1.45 and earth was 0.97. Why different on my conductors?

1 1x within 300ms
5x within 40ms
2 loose connection on line conductor

 

[Jabbajaws]

Youre mistaken with your x1 reading. Im sure its either 200 or 300ms on x1 (depending on whether RCD or RCBO) and x5 that its .40ms...

 

[iamelectric]

you sure you have 2391

 

[Jabbajaws]

What are your IR readings? L-E, L-N, N-E?

 

[Leepato]

IR readings weren't the best. They were L-E 0.28, L-N 255 climbing and E-N 200 climbing

 

[Jabbajaws]

Thats a low reading on 0.28 foe the L-E.

Did you omit everything in circuit that could give false readings?

I mean things like Neons on accessories. With the neon being such a high resistance, it can throw the reading of the IR test.

Looks like a potential earth fault, which is the most common problem, l find. You wouldnt have a neon connected in circuit on the L-E reading as it would be connected in things like fused connection units (between L&N).

What is the circuit under test?

 

[Jabbajaws]

Just read that its a ring final sorry for asking.

Look for a line conductor that isnt connected properly and is almost touching the metallic casing. That might explain why youre getting a higher resistance on end to end on the L-L and why youre getting only 0.28Mohms on the IR test.

Just a hunch but l think that you may find that its a possibility..

 

[Leepato]

This is the trouble, without stripping the circuit back and inspecting it thoroughly its hard to see where the fault is. It's possibly the only way and the customer will have to pay an hourly rate.

 

[thekingiam]

0.28 on L-E is obviously a failure as should be much more than 2 Meg, split the cicuit into two radials then retest and the side that has bad reading split down further until fault found.
I personaly wouldn't bother testing rcd on load with those readings.

 

[onions1066]

Leepato what are you actually asking?

 

[thekingiam]

just noticed you live in cardiff, i live in newport if you need a hand.

 

[c.boy]

I think leepato should call an electrician in!!!! Basic tests asking some ridiculous ????? Why are the end results different ????? Hello!!!!! A second year apprentice would know why!!!!!!!!!

 

[BertUK]

1 x 200ms........5 x 40ms.

 

[Geoffsd]

Only 200ms where circuit is 0.2s

Rest is 300ms for some reason.

 

[Ducksy]

I say the op has not only asked for help with one fault finding test but three no less! You only need EFLI and PFC and you have a full house.

To the king I am: is that paid work? If not i could pimp you out for free EICR all day long

 

[telectrix]

44mS is 0.044 secs, so where's the problem with the RCD?

 

[Jabbajaws]

Did you perform the IR test after you secured your second fix (screwed all accessories such as socket fronts in place)?

The reason l asked is that l once did my IR test first with all wires connected but left the socket fronts hanging, so that the plasterer could do his bit.

When l secured the accessories, the RCD kept activating, over and over. When l performed the IR test once more, my N-E readings had plummeted to lower than 1Mohm.

The reason: When l pushed once of the socket fronts on, l had nicked the neutral wire and it was resting against the metal casing, of the backbox.

Im thinking that its a possibility that youve done the same with a line conductor somewhere.

I would follow thekinglam's advice on this one.

To locate the fault, break the ring into two radials. The bad side will have a higher resistance on the line conductor and you can identify the exact location of the fault by splitting it up further eliminating each leg until you find it.

Do you understand what we mean Leepato?

This was meant for the bottom of page 1. Didnt see page 2 (sorry)...

 

[Ducksy]

44mS is 0.044 secs, so where's the problem with the RCD?

I was going to mention that but after reading the above, 3 decimal places and a little m before S is the least of he's problems.