Sink below consumer unit in garage?

[ph001]

Hi all,

Just had a new garage built adjoining the house and have a question regarding the location of the electrical consumer unit in relation to the handwash sink.

Basically there is an exiting electric feed which comes from the lounge ring main, through the external wall and into the garage area at about knee height. I plan to put an FCU immediately as it enters the garage and then take some trunking directly up to a consumer unit above head height.

There is also a water feed into the garage about 3' away which means effectively the sink will be pretty much directly below the consumer unit. Is this OK in a garage?

Also, the cable through the cavity wall is 2.5mm twin earth which is rated at 24A but the max my FCU can be fused at is 13A. There is a plan to place a 2.8kW water immesion heater above the sink so i could really do with about 20A of capability total but not sure how to do this connection wise.

I realise the ideal thing to do would be to run a completely seperate feed to the house consumer unit but this would be a major headache.

Any help or advice appreciated.

 

[riveralt]

Wasn't this issue sorted out when you submitted your building plans?
If it wasn't then you will need to put a new application to your Local Authority Building Control before you start the work or employ an electrician who is part of a competent persons scheme.
The water heater should be on its own circuit and not linked to the ring final circuit.
The manufacturers instructions will probably stipulate this and highlight the fact that you must have the circuit additionally protected by an RCD.

 

[ph001]

I'm an electronics engineer by trade so have an appreciation of electrics but not up to date on recent standards. I was going to do the work myself and get it signed off by a suitable qualified person. The electrics are not even mentioned in the plans for the construction work.

I was under the impression that 2.8kW would be OK on the lounge ring as long as the whole thing is protected from overloading the 2.5mm feed (24A) then it would be acceptable, albeit perhaps not best practise. Same goes for the CU above the sink?

 

[riveralt]

I'm an electronics engineer by trade so have an appreciation of electrics but not up to date on recent standards. I was going to do the work myself and get it signed off by a suitable qualified person. The electrics are not even mentioned in the plans for the construction work.

You cannot get it signed off without the electrician being involved in the design, installation and testing stages.

I was under the impression that 2.8kW would be OK on the lounge ring as long as the whole thing is protected from overloading the 2.5mm feed (24A) then it would be acceptable, albeit perhaps not best practise. Same goes for the CU above the sink?

BS7671 (my paraphase) states that ring final circuits should have the load reasonably shared around the circuit - they should not supply immersion heaters.......or other loads of a similar profile from the ring circuit.

 

[ph001]

Oh. Thanks for claryfying. Sounds like I might have to do it the hard and expensive way then and have a sparky run a new feed to the house CU. That means three lots of bedroom carpets and floors to come up and of course the joists all run the wrong way!

Bit frustrating when there is already a power feed into the garage.

I would never sacrifice safety on anything like this, but as we all know there are the legal minmum ways of doing things and there are preferred ways and best practises. In any case, there doesn't seem to be any kind of FCU available to limit the current to 20A so I'm not even sure what I was proposing was viable.

Thanks for the help.

 

[riveralt]

I would never sacrifice safety on anything like this, but as we all know there are the legal minmum ways of doing things and there are preferred ways and best practises. In any case, there doesn't seem to be any kind of FCU available to limit the current to 20A so I'm not even sure what I was proposing was viable.

It is one of the conundrums of the ring final circuit.
*Your are allowed to have a 3kw kettle plugged into the circuit but not apparently a 3kw water boiler. Quite what the difference is I'm not sure.*
By the way, you are not allowed to have more than one double socket spur from a ring final circuit using 2.5mm T&E.
But if your replace that double socket with a 13Amp FCU you can have as many sockets or none at all - in your garage as you like after that.
If you think about it - what is the difference between a 13Amp FCU connected to a water boiler and a 13Amp fused plug connected to a water boiler into a socket?

 

[RF Lighting]

I'd have no issue supplying the garage off the ring through an FCU assuming that a 13A supply is enough for you.

If not, assuming the lounge is on the ring, then just extend the ring out of that socket.

There's absoloutely no point faffing about putting in a fuse box. There really is no need for one.

 

[TicklyT]

*Your are allowed to have a 3kw kettle plugged into the circuit but not apparently a 3kw water boiler. Quite what the difference is I'm not sure.*

A 3KW kettle boils, and switches itself off after a couple of minutes, but a 3KW immersion heater usually takes a few hours to heat a cylinder full of water. They present two very differenty duty cycles.

 

[ph001]

Yeh, I think that's the issue. Really need a 20A supply if I'm to run the water heater and a few lights, drills etc.

Doesn't seem to be an easy way to limit it to 20A.

The reason it needs to be less than 24A is that I can't easily upgrade the 2.5mm which comes from the lounge ring as the termination is now behind a brick fireplace. We are only talking about a run of about 30cm through the cavity wall but still have the 24A max rating of that piece of cable to contend with.

 

[riveralt]

*Your are allowed to have a 3kw kettle plugged into the circuit but not apparently a 3kw water boiler. Quite what the difference is I'm not sure.*

A 3KW kettle boils, and switches itself off after a couple of minutes, but a 3KW immersion heater usually takes a few hours to heat a cylinder full of water. They present two very differenty duty cycles.

Yes I agree for that type of water boiler but I was thinking more along the line of the OP's one above the sink which is used basically for hand washing and is nothing more than a plumbed in kettle.
The regs don't seem to differentiate between the different types.

 

[ph001]

Correct - I think they are only really drawing power for quite a short period. I have spotted some 2kw ones such as these on Ebay..

http://www.ebay.co.uk/itm/180860030031?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

 

[EFLImpudence]

Doesn't seem to be an easy way to limit it to 20A.

There is a very easy way but it's irrelevant as it's not allowed.

 

[RF Lighting]

I know, every one on here knows and I pretty sure that you know too, that the only way to do this properly is to have a proper new supply put in from your CU to the garage.

Get an electrician to have a look. We are experts at running in cables with the absoloute minimum of disruption. That's what we do.

 

[ph001]

Oh I know - I'd concluded that by the 5th post. The rest is just out of interest really.

 

[Vicario]

When I finally had my 'boiler upgrade' they reckoned my HW cylinder was knackered and replaced it. It came with an integral immersion heater and I noticed that the installer had fitted it with a 13A plug and had run a spur from the upstairs ring into the airing cupboard. This ring supplies gadgets like a couple of computers, radios etc. I have a Building Works compliance certificate to cover the whole job. I have put the plug into one of those plug-in RCDs for added safety as my CU needs upgrading eventually when I have the dosh. I did ask the Gas Safety inspector about this arrangement (he came as part of their regular checks on gas installers and found the boiler job to be a good one). As for the electrics to the immersion, he said that he could only report on the gas side of things but we 'have to live in the real world' and to run a separate connection to the airing cupboard would add hundreds to the bill - my setup was by far the most usual in his experience, even if technically against the regs. He said that most immersion heaters only heat part of the cylinder water - is that right?