One for the sparkies

My uncles just sent me this pic asking about wiring, i havent a clue.
The fuses ive seen look like

The below is a photo of a board in a shed at his new house.
These seem to only have top input and one single output. Anyone explain?

I know but I’m not telling. If I did you’d have a go yourself and I’d have to explain to the coroner.

Dont make me go round there with a multi meter. Im aware the one on the left is likely to fall apart during a light breeze.
http://wiki.diyfaq.org.uk/index.php?title=Taking_electricity_outside#From_a_spare_way_in_the_CU_2

Im guessing one is positive one negative? and the newer one was fitted as there were two of the original metal ones?

Swear filter prevents me from answering.

BigJohn – I too have a query but I think this one is slightly less fatal:

From a sparky report in french on a consumer unit:

several circuits have a common neutral conductor and their conductors are not correctly protected against excess current. It is recommended that a qualified electrician regroups the phase conductors under the same protection or removes the common neutral conductor.

pic of the offending installation:

I dont see the problem myself of common neutrals through the breaker? Or is it suggesting that the neutral conductors should all be on a common rail and not through the breaker?

I’m not qualified to comment on that. If it’s to French standards, I’d do what the report says. Which seems to be the opposite of what you’re inferring.

Which seems to be the opposite of what you’re inferring.

indeed. That’s what was confusing me, the wording didnt seem to tie up to the image unless it’s saying that the breaker on the left shouldnt have both neutral conductors in there – but that makes no sense either.

I will have to get M. Le Spark in at some point I guess.

A UK CU will have 1 or more RCDs and MCBs in it. The RCD detects monitors the balance between phase and neutral. If you’ve got 2 RCDs you should have 2 neutrals.

if it’s talking about “Excess Current” does it mean that the neutral conductors arent protected by the MCB? Rather than an issue with RCDs.

I’d just snip the seals and have a look inside….

You can buy replacement lead seals off Ebay, that’s what I did when I moved my consumer unit.

MCBs don’t normally have neutrals. The neutrals would all be commoned in groups, as posted above. RCBOs would have a neutral. Is this some crazy French system to go with the mix and match colours? The excess current thing sounds like they have been wired up in some fashion that might allow the MCB to be bypassed, ie one circuit could potentially power another. Do you have a wider picture to show the whole lot?

As for the OP I’d say that’ s a job for the professionals unless it is a spur from the house CU and you can somehow isolate properly (and check that it is dead). My supplier charged me around £80 to fit an isolator. Well worth it IMO (and I’m tight and a keen DIYer)

Re Stoner, normally in France (& Germany) every circuit has it’s own dual pole MCBs, with a separate L&N. In your photo the LH MCB has two circuits joined together, which could be what they are referring to?

MCBs don’t normally have neutrals.

They do in France, it’s all dual pole on most of the continent, which allows for proper isolation unlike the daft UK system where a N/E short on an ‘isolated’ circuit still trips the whole house.

The second picture looks like a service cut out to me, on the right will be a fuse and left a terminal. This would then feed a Meter and the Meter would feed a consumer unit, just as per the top photo. You certainly shouldn’t use that supply directly as it’s usually be fused with a 100a fuse

The interesting bit is why the incoming cable is singles rather than a cable with some form of sheath and/or armour. Can you find out where that cable comes from.

flaps – thanks, that’s the only conclusion I could come to – that the CU ran out of space for another MCB and they had put two circuits on one MCB and somehow that wasnt to code in France. Im not sure what makes it a problem though, other than theoretical rather than practical.

Im not sure what makes it a problem though, other than theoretical rather than practical.

Neither do I as you have two circuits into one fuse which reduces the total current which can be drawn, so *should* be safer.

At a guess it might just fall foul of either a rule or just convention. Download their regs “NFC-15-100”, if you can find it, and read that.

Or buy a book:

The right cutout says 60a on it. On the main board in the house theres a breaker for “outbuildings” but nothing in the garage bar those two cutouts. He wants to add a board to wire up sockets and lights.

If you’re lucky those cables are dead. If not…

And there’s no such thing as negative and positive in mains. There are phases though.

Why bother replying at all BigJohn? Seems rather counter productive to say (and then keep saying): “I know, but I’m not saying…”.

Bit like this post really.

Why bother replying at all BigJohn? Seems rather counter productive to say (and then keep saying): “I know, but I’m not saying…”.

Bit like this post really.

I’d like to agree with this post, but I can’t. Although…

a) there are 2 separate questions.

b) wysiwyg might endanger himself if he tries DIY whereas Stoner probably won’t.

Im more likely to endanger myself when im not given instructions and just have a go.. which I inevitably will.

Re: No 2 have they uprated the MCB to make up ‘2 circuits worth’ of current? – that would be dangerous. Even if not still not clever as it’s likely to be tripping out all the time.

Re: No 1 it’s the same set up as in the first pic. the fuses on the top pic are a single phase and neutral to the meter (from the supply) and the second set of (red and black) cables are the feed to the fusebox/RCD (via the copper pipe acting as ducting). Are there 2 cables from the breaker in the house to the shed? If not those cables are coming from somewhere else. Either way you’re gonna need a sparky to sort it.

I cant trace the cables back, they just appear, the garage is 40m from the house with no visible cabling anywhere.

As it’s got a seal in the fuse of implies that it’s a non metered connection so is illegal to tamper with.

Is the ‘breaker’ in the house part of the consumer unit or is it separate? My suspicion is that this connection is a T off before the meter for the house.

On the other hand if the cable to the garage comes off the house consumer unit all you need is to have a small garage distribution board installed assuming the cable is healthy and you’ve got a suitable earth. The distribution board will have 1 MCB for lights and 1 for sockets. You can do all this legally yourself, but unless you have the right test gear I’d recommend getting a sparky in.

Agreed. if it’s an unmetered supply might I suggest getting some lamps and hydroponics in? 😀

Those ‘users’ just bypass the meter anyhow, normally with 2.5mm cable…….

Part of the consumer unit. Marked up as outbuildings.
I thought the cutout should have two outputs no?

No, Both your photos are identical in reality, just the top one is a combined unit. The cut out only has a fuse on the live. Neutral is normally just a terminal. Earth connection varies, and if these cables come off your consumer unit like you think they do is the earth connection you might struggle with as in that photo there is no earth.

This is the same on the consumer unit, live is fused or on a MCB neural is just a bolted connection

The next step is to trace the cables and prove that these ones are the ones you’ve found in the house.

The first check is are the cables visually the same size and type at both ends

If they’re not the ones I assume it’s just part of an old board when the outbuildings were workshops. And poss separately metered. One would therefore assume it’s cut off, but just a case of multi metering between the two cutouts or using a “pen”. I would assume he doesn’t want to call an electrician out just to test it.

This guy will sort you out 🙂

http://www.bbc.co.uk/programmes/articles/4tCvhRBNhsHLQGQBqxHX1wR/blessed-electricals

One would therefore assume it’s cut off

!!!!If it’s a seprate supply it’ll be live!!!!!*

*more than likely. Unless they’ve replaced the main. Or it was a single supply run from the substation (unlikely) and has been disconnected.

Obv I need to test it. Switch off “out buildings” and test again.

Edit. Many many moons ago I remember a lorry taking down the mains at the house. If it was an old mains feed they poss didn’t rewire when they put the new line and post in.

This guy will sort you out

http://www.bbc.co.uk/programmes/articles/4tCvhRBNhsHLQGQBqxHX1wR/blessed-electricals

‘kin ‘ell 😯

One would therefore assume it’s cut off

Old electrics. Never assume anything.

It really looks like a sepperate supply from the DNO, where abouts does your uncle live ? I think his first step is to call his DNO and they should be able to advice on that connection

I’d start to trace that ‘outbuilding’ supply now and rule this one out

Sunny newark on Trent. Served by eon.

I’ve asked him to check the unit in the house and he says there’s no obvious cable from there to the garages. There’s a cable outside that just appears to be the earth

We’ve just moved into a house that had a cable near the house terminated with a 3 pin plug and the other end came out in the garage 25 metres away. The idea was to throw an extension lead out of a window, plug it in and put a bucket over it to keep the rain off.

The cable was a good thick steel wired armoured one. But when it came out of the ground in the garage the cores were different colours. Somebody must have measured a bit short and made a join which is now somewhere underground. The cable they used to extend it is 110v. tool cable. Going straight in to a junction box with nice rubber insulated wires coming out. And when I did a Megger test (which should show a infinite resistance), let’s just say the readings were very finite 8) In other words, just plugging it in would act like under soil heating.

1st job was to rip it all out and start again with 6mm SWA, an MCB coming off the unprotected side of the CU in the house and a proper RCD protected CU in the garage.

Why unprotected? So if I get a short in the garage it doesn’t kick off the power in the house.

I’d recommend your uncle calls western power distribution on0845 724 0240 to find out if that cut out is Thiers

Why unprotected? So if I get a short in the garage it doesn’t kick off the power in the house.

I just added an extra mini-consumer unit (single MCB) and protected the connection to the workshop with a 50A MCB and a 100mA RCD. The workshop itself has it’s own consumer unit with 30mA RCDs.