Rcd advice needed faulty or fault

[Stuportsmouth]

So had to fit a new shower as old one kept tripping the rcd after few seconds assumed the shower was to fault as made a buzzing noise and tripped, on fitting the new shower it had same faukt so checked pressure of water no issue then checked wiring at box also no issue so moved onto next possibiliy of short on cable.
Yes maybe should of used multimeter and tested each one out but easier as short run in walls so run new cable exactly the same.
So decided to wire a small flex with bulb holder on that trips rcd changed the 40amp mcb to a 16 amp tried light also trips could this be a faulty rcd its rated 80amp 30ma, we also tested the the curcuit with every mcb turned off with only shower circuit on and also tripped.

Any help would be greatly appreciated as would like to think in a 6 bedroom house with each room occupied that of rcd was faulty then it would trip as currently has approx 8 circuits on and only randomly started to happen nothing new has been added.

 

[Stuportsmouth]

You know what don't care I can't here to ask a question just because I'm not qualified doesn't make me incompetent of knowing what I'm doing working with someone who's qualified from a young age and being overseen and checked on standards of work and also working on 3 phase and also being more than competent of doing so is more than some newly qualified electricians have in experience.
As most newly qualified electricians just goto college learn sit a test and have a certificate being trained alongside a family member rewiring houses at weekends and then working doing air conditioning from the age of 14 until I was 19 and being trained to a standard by a qualified person is more than anything on a piece of paper and all on this forum are so stuck up there as**s that I'll seek advice on a different forum

 

[ashrow]

post a picture of installed shower, isolator, cable run, 40amp mcb in place and we can see to help ???

 

[Pete999]

Pete ................. you can lead a horse to water ..............

Yes Murdoch I agree but this one ticks me right off, sorry said I was out, my error, say no moooore

 

[Stuportsmouth]

If the Rcd was faulty I would expect the same tripping problem for other loads that are used on circuits on the Rcd side of the board

I would expect to find a neutral-earth fault on the shower cable,but without having at least a insulation resistance tester you may be a long time finding the problem

Thanks for the helpful respose I cannot see a neutral earth fault as it's literally a single cable of 6 feet brand new

 

[HandySparks]

... dads fully qualified also worked doing electrics for both single phase and 3 phase air conditioning installs he is 18th edition certified and have been trained to the qualified standard of him.
...

As he's fully qualified, what thoughts does your dad have on this situation?

 

[AJshep]

Stu I re-read your first post originally I assumed it was your house, but since we seemed to have hit a nerve, im now not so sure that this isn't job your doing for someone.

 

[Stuportsmouth]

As he's fully qualified, what thoughts does your dad have on this situation?

No longer speak to me dad had a falling out a couple of years ago after a family member had a stroke and all he wanted o know is how much money he was getting left if they passed away I've messaged a few sparkys I know but thought I would try the forum as process of elimination before messaging one as worse comes to worst they will get called out

 

[Deleted member 9648]

It's likely that there is a N-E fault somewhere (anywhere) on the installation (not necessarily on the shower circuit) which results in a parallel path for the return current from any part of the installation. Depending on the resistance through the fault it's likely that only when heavy loads are on, such as the shower, will sufficient current divert to earth through the fault to trip an RCD.
Of course with the OP's wealth of experience and competance he will already have considered this.

 

[ipf]

You know what don't care I can't here to ask a question just because I'm not qualified doesn't make me incompetent of knowing what I'm doing working with someone who's qualified from a young age and being overseen and checked on standards of work and also working on 3 phase and also being more than competent of doing so is more than some newly qualified electricians have in experience.
As most newly qualified electricians just goto college learn sit a test and have a certificate being trained alongside a family member rewiring houses at weekends and then working doing air conditioning from the age of 14 until I was 19 and being trained to a standard by a qualified person is more than anything on a piece of paper and all on this forum are so stuck up there as**s that I'll seek advice on a different forum

You may know the basics of installation, be it domestic or industrial, but if you've not got basic understanding of what you're doing, its nothing but labouring.
Hands on, understanding and experience are the three basics. Lacking in any is lacking, full stop. (not an intentional reference to the lack of punctuation, by the way)

 

[Stuportsmouth]

It's likely that there is a N-E fault somewhere (anywhere) on the installation (not necessarily on the shower circuit) which results in a parallel path for the return current from any part of the installation. Depending on the resistance through the fault it's likely that only when heavy loads are on, such as the shower, will sufficient current divert to earth through the fault to trip an RCD.
Of course with the OP's wealth of experience and competance he will already have considered this.

Yeh I understand this however with the switch disconnected and a choc block with just a flex with light fitting there should be no extra load on circuit ie should work fine on the 16amp mcb and not trip.
I would understand if the shower was on and tripped but with a light bulb on didn't as would prove that there was too much drain on circuit to trip rcd of current load was overloading circuit.

However if rcd was faulty then it would surely trip with load of house appliances and rooms etc this is reason was asking here of anything else that could be worth testing before paying for it to be investigated to be told well yeh its something we have over looked .

 

[Deleted member 9648]

Yeh I understand this however with the switch disconnected and a choc block with just a flex with light fitting there should be no extra load on circuit ie should work fine on the 16amp mcb and not trip.
I would understand if the shower was on and tripped but with a light bulb on didn't as would prove that there was too much drain on circuit to trip rcd of current load was overloading circuit.

However if rcd was faulty then it would surely trip with load of house appliances and rooms etc this is reason was asking here of anything else that could be worth testing before paying for it to be investigated to be told well yeh its something we have over looked .

Ramp test RCD's and IR test the whole installation. It'll either be a faulty RCD or a N-E fault anywhere on the installation, assuming neutrals are correctly connected in the DB

 

[Stuportsmouth]

Ramp test RCD's and IR test the whole installation.

Will get that done talking with a mate who runs his own business atm on fb he hopefully may be able to take a look tomo

 

[Stuportsmouth]

I must say just for safety I always wear a pair of marigolds just in case

 

[lurch]

. . . .

Yeh I understand this however with the switch disconnected and a choc block with just a flex with light fitting there should be no extra load on circuit ie should work fine on the 16amp mcb and not trip.
I would understand if the shower was on and tripped but with a light bulb on didn't as would prove that there was too much drain on circuit to trip rcd of current load was overloading circuit.

However if rcd was faulty then it would surely trip with load of house appliances and rooms etc this is reason was asking here of anything else that could be worth testing before paying for it to be investigated to be told well yeh its something we have over looked .

oh dear!!!

 

[Toneyz]

Been doing electrics since the age of 10 mate dads fully qualified also worked doing electrics for both single phase and 3 phase air conditioning installs he is 18th edition certified and have been trained to the qualified standard of him.
I also run all the electrics in the house when was converted in the property it located in and as you can see was fully inspected and checked by a fully qualified electrician and signed off as you can see in the picture of the fusebox I am more than capable of checking things out.
Also I have checked all earths neutrals and lives on the mcb

Please can you tell me what is in it so do I have to install earth rods.