Fault Find - advice please!

[MikeKing]

so why are you bothering if she sold the house ?

Because they are still in there for another couple of months with no power to kitchen or down stairs living room.
Also good to get to other perspectives - things I've missed or not thought of!

 

[davesparks]

I think the previous RCD was waiting to be replaced like you've done.

Why? The RCD only failed the test when the test was carried out incorrectly, it would be better to replace the person doing the testing than the RCD.

 

[MikeKing]

Why? The RCD only failed the test when the test was carried out incorrectly, it would be better to replace the person doing the testing than the RCD.

Sorry Dave I've tested RCD's in both ways you've described. But testing the RCD remotely was exactly how I was shown to do it both on my city & guilds and AM2.

I appreciate it may seem obvious to you not to test it on a faulty circuit, but I thought the fault had been rectified.

My question was posted to learn, get some more knowledge, not to be insulted. If you haven't got anything constructive to add, please don't bother. I know I'm not the best sparky in the world, but no-one has the monopoly on good ideas just yet, so I thought I'd try and learn something and post on a forum designed to help people, not shout about how great they are.

 

[buzzlightyear]

so you don't what is causing the RCD faulting .start from one end to the other end, then split up the circuit and start working towards
the c/u.

 

[telectrix]

if he's selling off to a developer,just leave a few live ends lying round to remind him to get s competent spark in to do his new installation.

 

[MikeKing]

if he's selling off to a developer,just leave a few live ends lying round to remind him to get s competent spark in to do his new installation.

Helpful. Thanks for the input.

I read this forum most weeks - I've learnt a lot from other people's questions, but time and time again I see people asking for help just get slated. (DIY'ers aside)

Genuinely, what is the point........... another keen user of the forum lost.

 

[telectrix]

Helpful. Thanks for the input.

I read this forum most weeks - I've learnt a lot from other people's questions, but time and time again I see people asking for help just get slated. (DIY'ers aside)

Genuinely, what is the point........... another keen user of the forum lost.

seems like you can't accept a bit of banter. if so, plumbing might be a better career.

 

[MikeKing]

seems like you can't accept a bit of banter. if so, plumbing might be a better career.

Mate it's difficult to grasp the tone in text and when the last few posts were critical and personal rather than helpful I hope you can see why I may have misinterpreted your post, if it was just banter, then my apologies for flying off the handle.

 

[johnduffell]

To be honest these guys have an c&g in electricians banter, I've struggled past that one too!

 

[Wilko]

Hi Mike - once there are circuit faults you will only get a clear result if you do the RCD test with circuits removed as per #22. Then if RCD tripped at 15mA or less it's out of spec, as it should not trip at 15mA. Since it's not resolved, I would look for N-E fault in any circuit of the installation. Good hunting

 

[Octopus]

To be honest these guys have an c&g in electricians banter, I've struggled past that one too!

C&G

Some of them have First class degrees .....

 

[MikeKing]

Hi Mike - once there are circuit faults you will only get a clear result if you do the RCD test with circuits removed as per #22. Then if RCD tripped at 15mA or less it's out of spec, as it should not trip at 15mA. Since it's not resolved, I would look for N-E fault in any circuit of the installation. Good hunting

Really appreciate that, thanks

 

[johnduffell]

C&G

Some of them have First class degrees .....

You're right, with a student tuition fees loan behind you you'd need a sense of humour

 

[Bob Geldoff1234]

Is the downstairs a solid floor or floorboards? You say the downstairs sockets are a ring.Does each socket downstairs have at least 2 twins in each socket or is the ring upstairs via joint boxes and just legs run down to each socket(if it's solid floors)?

If the floor is floorboards then it should be wired from underneath.In which case you need to start taking off sockets and disconnecting each leg of the ring and testing back to the mains.If that leg is totally clear then move onto the next leg and disconnect and test.My guess is the lack of continuity on the lives is probably where the fault is also.
Don't forget that just because the insulation resistance is reading clear on your meter doesn't mean that there is an arc somewhere within the ring and your tester isn't powerful enough to bridge the gap.If the fault is in the upstairs joint boxes then your going to have a hard time finding it without lifting the floor.

Good luck!

 

[Richard Burns]

When testing your IR to earth did you include the earth bar, i.e. were the cpcs connected to the earth bar at the time of test or were they disconnected cables.
If they were disconnected cables then there maybe a fault from a live conductor to a different earthed part, so a repeat IR test from the live conductors to the earth bar may give a faulty result.
Presumably because the RCD is almost holding at times the fault sound like a progressive fault i.e. it has been getting worse and worse until it just starts to trip the RCD. This would then tend to indicate something like slow water/moisture build up or a partial breakdown of an electronic circuit.
Just some thoughts.

 

[Toneyz]

Mate it's difficult to grasp the tone in text and when the last few posts were critical and personal rather than helpful I hope you can see why I may have misinterpreted your post, if it was just banter, then my apologies for flying off the handle.

Keep on the forum Mike their not all that bad they do warm to you.

 

[Michael Sands]

I know I left after my first x
Unwarranted of course with no explanation as to why everyone does the same jobs ther own tried and tested way but finding out how others do it is sometimes helpful and can help others still not sure and apprehensive

 

[MikeKing]

Hi Mike - once there are circuit faults you will only get a clear result if you do the RCD test with circuits removed as per #22. Then if RCD tripped at 15mA or less it's out of spec, as it should not trip at 15mA. Since it's not resolved, I would look for N-E fault in any circuit of the installation. Good hunting

Really appreciate that, thanks

Is the downstairs a solid floor or floorboards? You say the downstairs sockets are a ring.Does each socket downstairs have at least 2 twins in each socket or is the ring upstairs via joint boxes and just legs run down to each socket(if it's solid floors)?

If the floor is floorboards then it should be wired from underneath.In which case you need to start taking off sockets and disconnecting each leg of the ring and testing back to the mains.If that leg is totally clear then move onto the next leg and disconnect and test.My guess is the lack of continuity on the lives is probably where the fault is also.
Don't forget that just because the insulation resistance is reading clear on your meter doesn't mean that there is an arc somewhere within the ring and your tester isn't powerful enough to bridge the gap.If the fault is in the upstairs joint boxes then your going to have a hard time finding it without lifting the floor.

Good luck!

Thanks Bob - my thoughts exactly. It's lift the floor or chase my tail around a bit more. I appreciate the thoughts on the arcing though. I had split the ring and tested back towards the board, but IR tests came back satisfactory. But I think your right, the brake in the line conductor is likely to be the location of both faults.

 

[MikeKing]

When testing your IR to earth did you include the earth bar, i.e. were the cpcs connected to the earth bar at the time of test or were they disconnected cables.
If they were disconnected cables then there maybe a fault from a live conductor to a different earthed part, so a repeat IR test from the live conductors to the earth bar may give a faulty result.
Presumably because the RCD is almost holding at times the fault sound like a progressive fault i.e. it has been getting worse and worse until it just starts to trip the RCD. This would then tend to indicate something like slow water/moisture build up or a partial breakdown of an electronic circuit.
Just some thoughts.

Thanks Richard, just to answer your question, I did test with the earths connected. I took the neutrals out, but the earths were connected.

I thought the fault might be a component in an appliance that isn't running constantly like a fridge compressor or a heating element in the washing machine etc.

Really appreciate the feedback - thanks

 

[LankyWill]

Fault finding is all a process of steps, it takes a while to learn the shortcuts that can help speed things up. Forget all the leg pulling they’re just teasing, plus don’t take what you did in your am2 as gospel. They don’t like you working in live boards hence the rcd rest remotely, as a spark you will inevitably have to work on/in live boards.

Ramp the RCD at the board with loads connected/Not and note the difference, this is your leakage.

Next do a global IR with all circuits on(mcb not power) and slowly turn them off to find out which has the short.

Then it’s a process of halfing the circuit until you narrow it down, remember the leakage might be accumulative across multiple circuits.

Good luck