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.

 

[Deleted member 105166]

Have you done a ramp test on the RCD?

 

[Pete999]

Not an Electrician then? about time you got one in to test the system properly with the correct test equipment, "lamp and a bulb holder oh dear me DIY disaster on the horizon if I'm not mistaken, do yourself and whoever is helping you a big favour, leave it well alone and get a Sparky in to sort it for you, before you do yourself and your Mate some mischief.

 

[Deleted member 105166]

As an aside, is circuit #3 no longer "spare" ?

 

[Stuportsmouth]

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

 

[Pete999]

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

The 18th edition of BS7871 aint out yet?

 

[Stuportsmouth]

Have you done a ramp test on the RCD?

Circuit 3 is spare it was originally installed for a circuit that's didn' and up being installed and am going to get a blank for that tomo and remove

 

[Pete999]

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

Checked? what with?

 

[Deleted member 105166]

...he is 18th edition certified and have been trained to the qualified standard of him.

The 18th edition isn't published until next year.

 

[Deleted member 105166]

Circuit 3 is spare it was originally installed for a circuit that's didn' and up being installed and am going to get a blank for that tomo and remove

The spare MCB is fine, it was just confusing to see it on, whilst the spare on circuit #1 is off... hence the question as to whether it was really "spare" or the labelling not updated.

 

[Stuportsmouth]

The 18th edition of BS7871 aint out yet?

And it maybe 17th he had as when working with him many years ago it was 16th haven' done a huge amount of electrics in last 15 years however have done bits a pieces in that time if it' not going to be a simple fix then I'll call my mate out to have a look but just can' get my head around why it trips when it's a 1 cuircut feed to shower of around 8 feet and with every mcb switched off it still trips rcd and on a 16amp breaker still trips the rcd with a 1 bulb light fitted

 

[Stuportsmouth]

Checked? what with?

When house was rewired he checked every plug socket unscrewing checked all wiring and earthing and measured each individual with his testing equipment and also pat tested all appliances on house he is full nic eic certified

 

[Stuportsmouth]

When house was rewired he checked every plug socket unscrewing checked all wiring and earthing and measured each individual with his testing equipment and also pat tested all appliances on house he is full nic eic certified

Also forgot to mention I also tried the shower on the unprotected rcd side still tripping the rcd out

 

[Pete999]

Also forgot to mention I also tried the shower on the unprotected rcd side still tripping the rcd out

Did you connect the N to the N busbar that corresponds with the non RCD side?

 

[Stuportsmouth]

Did you connect the N to the N busbar that corresponds with the non RCD side?

Originally no but was done today and still caused the same issue like I said it was all originally working fine without anything being changed over and the old shower unit has also been tested and works fine

 

[Octopus]

Where is the circuit for the shower? What rating is the MCB?

Strikes me that without proper test kit and the knowledge to use it and interpret the results you may well be wasting your time ....

 

[Stuportsmouth]

Where is the circuit for the shower? What rating is the MCB?

Strikes me that without proper test kit and the knowledge to use it and interpret the results you may well be wasting your time ....

40amp mcb and mcb is also not tripping used the spare 16amp with lightbulb circuit and still done same a ramp test could be beneficial to test the rcd but then changing the rcd of possibly faulty is also easy main thing being tho of the rcd is faulty it would trip with all the other circuits on board under load and would assume with then isolated that if there was a fault on a circuit with all mcbs turned off that would isolate any fault.
Shower is currently not on any circuit as removed from box and left isolated outside of fuse box

 

[Octopus]

40amp mcb and mcb is also not tripping used the spare 16amp with lightbulb circuit and still done same a ramp test could be beneficial to test the rcd but then changing the rcd of possibly faulty is also easy main thing being tho of the rcd is faulty it would trip with all the other circuits on board under load and would assume with then isolated that if there was a fault on a circuit with all mcbs turned off that would isolate any fault

Punctuation would help!

using what?

regarding isolation of circuits using MCB's, best you ask your dad about how RCD's work ....

 

[123]

What concerns me here is everything is going to be tried until the shower works and nothing trips...and then its going to be left at that as it works

 

[AJshep]

With the greatest respect Stu. I'm with the others I think it's best to get someone qualified to look at this.
It's going to involve disconnecting and testing circuits, and I personally wouldn't want to advise someone over a forum especially when it could cause serious injury or death.

 

[Stuportsmouth]

The idea of this post is to find out if the rcd could be the possible fault or if it could be a fault somewhere else but surely with one wire direct feed when switched off the rcd doesn't trip meaning there shouldn't be a fault on the other circuits as it' been fine for over a week.

 

[ashrow]

40 amp mcb missing from rcd side so now on 16amp mcb on non rcd side and still tripping rcd. not possible if you are doing things correctly.
If there is a shower isolator check that for correct operation, tightness, burnt out etc etc.
If you been doing it from the age of ten i would not be posting on a forum for advice on basic fault finding. but good luck and happy showering

 

[Pete999]

With the greatest respect Stu. I'm with the others I think it's best to get someone qualified to look at this.
It's going to involve disconnecting and testing circuits, and I personally wouldn't want to advise someone over a forum especially when it could cause serious injury or death.

At last

 

[Stuportsmouth]

40 amp mcb missing from rcd side so now on 16amp mcb on non rcd side and still tripping rcd. not possible if you are doing things correctly.
If there is a shower isolator check that for correct operation, tightness, burnt out etc etc.
If you been doing it from the age of ten i would not be posting on a forum for advice on basic fault finding. but good luck and happy showering

The switch has also been replaced and basic fault finding steps have been looked at all earths neutrals and lives checked on box and nothing has been added or changed so just cannot understand how such a fault just appears the house was only rewired 2 years ago.

 

[Octopus]

The 16A MCB won't last long powering the shower ...

 

[Octopus]

The switch has also been replaced

Randomly changing parts does not replace proper fault finding .....

 

[Pete999]

The switch has also been replaced

Just change everything and then call an Electrician, advice has been given not accepted that's me gone from this thread, I suspect with the OP's agreement.

 

[Octopus]

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

 

[123]

Randomly changing parts does not replace proper fault finding .....

And is generally a false economy, just to save paying a spark to find the actual fault in the first place.

 

[Des 56]

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

 

[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 .