Electrical Connundrum?

catchdarren

Looking for advice from sparkies!

We recently moved into a Victorian house in London which we're slowly recovering from a hundred years of bodge-jobs... and I've just discovered another!!:eek: :eek:

It appears that the radial circuit, (for plugs etc) and the lighting circuit for upstairs are connected somewhere as they both went dead when the MCB (20A) was pulled out. On the basis that it's obviously been like that for the past twenty years...

1. Are we in immediate peril of electrocution or fire?

2. Has anybody heard of this before?

3. How do I go about finding out where they are connected?

4. Is this gonna cost me a fortune to resolve?

Any ideas or comments would be gratefully received

Darren

mercurystar999

Perhaps!

You need to check that there are no fused spurs upstairs which supply the lights. If the lights are fed from the fused spur the fuse should be 5 amps.

catchdarren

Thanks for a quick reply and a possible answer but unfortunately no there isn't a spur. I can't understand why the electrics have been messed up this way. It's a small house with simple access between the consumer unit and the 4 lights upstairs which are accessible from the loft. Could it be that there are two circuits but they have been terminated at a single MCB?

Perplexed!!!!

Darren

mercurystar999

Thats a possible but then of course you have a problem that the lighting circuit is usually protected by a 5 or 6 amp mcb. How many mcb's of fuses do you have in your consumer unit? Is there another lighting circuit in the house?

It sounds as though you have a old wylex consumer unit which used to have fuses but have been replaced with mcb's? The wiring is probably in excess of 25 years old. It probably could do with a rewire. I doubt that you have an rcd to protect the sockets either?

If an electrician was to come and inspect it i would of thought that there would be a fair page of to do's, bonding etc.

catchdarren

I've got:

downstairs lighting: 5 amp
downstairs radial: 20 amp
Upstairs radial and lighting: 20 amp (gulp)
Cooker: spearate 30 amp

and wierdly another 6amp MCB which doesn't appear to be attached to anything, (as much as nothing goes off when I switch it off)

If you saw this house, nothing would surprise you! I'm going to get a spark to come and take a sharp intake of breath!

cheers

Darren

kat21

sounds like you need to get a qualified electrician in just to do an inspection.
lighting circuits should be seperate, did this not show up when you bought your home? lighting should be five amps ,socket ring circuits should be 30 amps. I tend to wire the landing lights on a separate fuse. upstairs lights one fuse, downstairs lights another fuse, upstairs sockets one fuse (30), downstairs sockets (30) I tend to zone off the kitchen with another circuit, again (30). Sounds like you may have old wiring or a botched job! *sighs*
by wiring as above if there is a problem with one circuit it doesnt kill the others for example upstairs sockets dont go off if theres a problem with the down stairs sockets same with lighting.
cooker sounds about the only thing right, (30)
dont forget to get a certificate for all electrical works completed
kat21

catchdarren

Thanks for all the input! I'm gonna get a spark. Anyone know a good one in Ealing. I haven't had much luck in the past with electricians around here!

Thanks again!

D

happyhero

I would definitly back everyones advice above on getting a qualified spark as what you have found would make me think if that has been done what else might be wrong but not obvious at to you at the moment. Better to be safe than sorry.

Also something else which is important but has not been mentioned above is that, if your lighting has been wired correctly in 1.5mm, it can only take 18amps and yet is protected by a 20amp MCB. The cable could burn out before the breaker ever decided to trip, very nasty or could be. Both will take more current on a slow build up but you see the potential threat there. And if they wired the lighting in 1mm which is done sometimes, it can only take 14amp so your potential for something going wrong is even worse.

Definitly good advice to get a spark to give the whole place the once over.

I am a retired spark and do some work still but I think Ealing would be too far for me as I am in Surrey. Try and find someone that someone else can recommend, that usually helps get someone decent.

bockster

is it possible that that last 6amp breaker (the one with no apparent use) has gone faulty and as a quick remedy :eek: someone has swapped the live feed to the lighting radial from the duff breaker to the 20a one, this would explain it, very quick for sparky to check this.

catchdarren

Bockster, that's what I thought as well! Thanks to all of you for the insights!

Darren

beefster

At the peril off being accused of teaching you to suck eggs....

What cables go into the 20amp upstairs breaker. If there is a 1 or 1.5mm as well as the 2.5mm radial cable then turn the breaker off and remove this cable, this should leave the larger cable for the radial cct. Insulate the end using tape or a block. Turn back on and see if the lights up stairs and or sockets still work. If no lights I would turn the whole board off and check the 6amp breaker thoroughly first... its odd its not in use? It may have burnt out or something... if it looks ok... put the 1 mm cable into the 6 amp breaker with it turned off obviously. Turn on and if the lighting works leave it there.

The cable has been moved for a reason though......

In this scenario i would guess it "may" be that there is a wiring fault on the upstairs lighting cct OR it "may" be a faulty breaker and it kept tripping. Someone has thought the breaker is at fault and moved the cable. A big NO NO. As mentioned the cable is only rated at max 18amps and will start to break down above this. If there is a leakage to earth it could be masked by the 20amp breaker unless you have got an RCD covering the board. This would trip the lot off at any leakage above its rating... usually 30mA, sometimes 100Ma.
To test the breaker if it keeps nusiance tripping once back in use....Turn the power off and swap the breakers or the cables from the 2x lighting ccts. If the same breaker keeps tripping then its the breaker at fault. If the other breaker now trips its the wiring cct upstairs.