new shower crossed wires??

[dubdad]

hi all
hope there is a sparks in the house!
my question/problem is this:
had an electrician in today to install an updated CU and wire in a new shower at the cu. job done, electrician leaves and i try the shower(to commision it really), and it trips out along with the main RCD !

now he is coming back in the morning to see whats up. sounded a bit puzzled when i let him know what happened.

just to clarify. i have allmost finished a bathroom refit, doing nearly all the work myself. so i installed the shower(mira elite 9.8kw) myself along with the isolating switch and ran the cable back to the old fuse board and decided rightfully that the rest was a job for a qualified lad

surely the rcbo should trip out by itself and not interfere with the the rcd as they are seperate circuits

one last thing -sorry lads- the rcd is mid-way along the board and the rcbo is second last, should it not go:
main fuse, rcd, rcbo, mcb's(descending in load, like cookers, sockets, lights ??

just like to b a little more clued in when i am talking to this guy in the morning
thanks in advance for any replies and sorry about so many basic questions as i am not an electrician, unlike the tradesman who did the work for me today(and is reg'd & insured)

 

[viewer]

Didn't he check it worked as well as carry out the electrical tests before he left?

 

[dubdad]

no he didn't check the shower. i was even kicking myself for not checking it either before he left, (4 kids & easily distracted, thats me

 

[dubdad]

feel partly responsible as i installed the shower myself.
i'm sure my end is ok though.
used 10mmsq cable and a 45amp isolating switch all connectioins nice and tight.
get a red neon on the iso switch, turn on the shower and get a power on light, then when i hit the 'run' switch on the shower it trips (with the shower set to cold only)
so i turned it off and rang the sparks...
just curious as well as easily distracted

 

[riveralt]

It would be helpful if you would outline the details from the electrical installation certificate in relation to the shower circuit.

Ze reading would also be helpful.

Also the reading from the RCD tests conducted in ms.

Cannot understand why the electrician didn't commision the shower - it is one of the requirements for testing.

Is this the same shower?

//www.diynot.com/forums/viewtopic.php?p=1772026#1772026

 

[sparkwright]

In a cu there is often one or two RCDs (RCCBs) that protect some or all MCBs.

When you have RCBOs you don't usually have an RCD protecting those as well.

It may be a case he has connected the shower neutral to the wrong neutral connection in the cu. Or something along those lines.

 

[JohnW2]

had an electrician in today to install an updated CU and wire in a new shower at the cu. job done, electrician leaves and i try the shower(to commision it really), and it trips out along with the main RCD !

surely the rcbo should trip out by itself and not interfere with the the rcd as they are seperate circuits

one last thing -sorry lads- the rcd is mid-way along the board and the rcbo is second last, should it not go:
main fuse, rcd, rcbo, mcb's(descending in load, like cookers, sockets, lights ??

When you say the RCBO is 'second last', do you mean that it goes:
main switch, RCBO, RCD,MCBs ?
If so, that's what I would expect - the RCBO not being protected by the RCD (but providing its own protection).
If that's the case, then I think it's very likely that he's connected the RCBO to the wrong neutral (the RCD, rather than non-RCD, one) - which is something he should be able to correct in just a few moments.

... but he really should have tested the shower circuit!

Kind Regards, John.

 

[sparkwright]

The fault may lie in the rest of the shower installation; an earth terminal pinching against one of the conductors, or the switch wired up wrong.

Check the terminals are tight in the shower isolator terminals, as fiddling about with it may loosen them.

 

[dubdad]

thanks john
no
1,main switch
2,mcb-lights up
3,mcb-lights down
4,mcb-cooker
5,RCD
6,sockets-up
7,sockets-down
8,sockets-kitchen
9,RCBO-SHOWER
10,mcb-shed
sorry i have not got a copy of the tests he done as he had to send them off to the network/supplier as i am also requesting an upgrade in my meter tails and also tails from the supplier fuse to the meter.
i should mention i am in dublin so the legal end may differ a little.
Sorry for not posting on the rest of the world forum as i was sure that the info here would be more similar than say europe or usa etc...

 

[JohnW2]

no 1,main switch; 2,mcb-lights up; 3,mcb-lights down; 4,mcb-cooker; 5,RCD; 6,sockets-up; 7,sockets-down; 8,sockets-kitchen; 9,RCBO-SHOWER; 10,mcb-shed

Hmmm - unless something very odd is ging on inside the CU, that certainly seems to imply that the shower RCBO is probably being fed from the RCD - which doesn't make much sense. If that's the case, it's still possible that he's connected the RCBO to the wrong neutral - but the opposite way around from what I suggested before. Also, as others have suggested, there may be a genuine fault in the shower circuit (or shower) - and if the RCBO is fed from the RCD, it's quite possible that both would then trip.

i should mention i am in dublin so the legal end may differ a little.

Irish electricity and RCDs/RCBOs etc. is much the same as ours - even if the regulations and laws differ

Kind Regards, John.

 

[skenk]

Sounds like you need a COMPETENT electrician!

 

[sparkwright]

thanks john
no
1,main switch
2,mcb-lights up
3,mcb-lights down
4,mcb-cooker
5,RCD
6,sockets-up
7,sockets-down
8,sockets-kitchen
9,RCBO-SHOWER
10,mcb-shed

This implies the lights and cooker are not RCD protected. Assuming these circuits have cables buried less than 50 mm in the wall, he should provided RCD protection when fitting the new consumer unit. (Hang on, did you say Dublin?)

It also seems he has fitted an RCBO for the shower on the side of the consumer unit that is already RCD protected, which is insane.

 

[dubdad]

hopefullly its just a simple one like the neutral (he did start talking about a neutral when i called him)

just did a quick check there:
if i hit test on the rcbo if also trips out the rcd
this suggests to me that they are sharing a neutral?

tripping out the rcd with test leaves the rcbo on

??

thanks a lot for all the comments lads

do u think i have had the lone ranger in, or is this a simple mistake by a hungry electrician, close to dinnertime!!

 

[JohnW2]

do u think i have had the lone ranger in, or is this a simple mistake by a hungry electrician, close to dinnertime!!

I'm afraid that the order you have described for things within the CU (plus not testing the shower) rather suggests the former! Did you pay him a 'reasonable' amount for the job, or something which 'sounded too good to be true' (and we all know what makes things sound like that!)?

Kind Regards, John

 

[skenk]

Sure someone can make a 'mistake' but also 'forget' to do about 8 tests including even the most basic tests that anyone could do (like testing the shower and the RCBO)?

Yee Ha!


Of course without seeing it who knows and it could be your work at fault. . . . How about a picture of the CU??