ReWire to a 3 bed house and an outhouse. Comments plz.

[YCWB]

Hi, does this design sound right?

3 bed terraced house.
Living room, dining room, kitchen, 3 beds, bathroom, loft conversion and a small detached outhouse.

Using a split consumer unit:
Downstairs ring circuit for living room, kitchen and dining room.
Upstairs ring for 3 beds and loft conversion.
Downstairs lighting circuit.
Upstairs lighting circuit.
Electric shower.
Radial circuit for outside outhouse.
RCD protecting all socket rings and shower but not lighting.

The kitchen will have a fridge, freezer, electric cooker with a gas hob, electrick hood, microwave, kettle, toaster etc.

The outhouse will have a washing machine, tumble dryer, heater, a light and probably a double socket.

For now downstairs will have a standard ceiling rose in the living room, dining room, hallway, and maybe one or two in the kitchen. The kitchen may have spot lights put in when a new kitchen is fitted.

Upstairs will have 6 standard ceiling rose lights but might have spot lights installed when a new bathroom is fitted.

The electric shower isn’t going to be fitted until the bathroom is replaced but I am going to assume upto a 10kw shower may be fitted.


Downstairs ring on a 32A mcb. 2.5 T+E cable
Upstairs ring on a 32A mcb. 2.5 T+E cable
Downstairs lights on a 3A (or should it be a 6A?) 1.5 T+E cable
Upstairs lights on a 3A (or should it be a 6A?) 1.5 T+E cable

Shower: 10000 / 230 = 43A. 10 sqmm cable. Should it be on a 50A mcb?

Outhouse: Not sure on this. Would a 20A radial circuit using 2.5 SWA cable be upto the job? It’s a run of about 12-15m out to the outhouse from the CU. I was going to run in 6mm SWA cable on a 32A mcb but this might be overkill. Do I have to take into account voltage drop on this and if so, what would it be?

I am going to assume the use of a 3KW heater (not very often though, only when its cold and when washing is being done), A washing machine and tumble dryer at maybe 1KW or 1.5KW each. That’s a total possible load of 5-6KW if my estimates are correct. This would be too much for my 20A radial circuit unless I can apply diversity to the above (assuming ive estimated the power of the appliances correctly)?

For the outhouse, would I be better having a 2 way mini CU with one for the sockets and one for the lights or just running the SWA into sockets and taking a fused spur off for the light? The mini Garage CU I have seen has 1x 16A, 1x 6A and a 30mA RCD. I assume I don’t need an RCD if I already have one on the main house CU and the 16A and 6A wont be big enough for what I need it for.


Is there anything wrong with the design and can I have your views on the questions I have raised

Thanks

 

[Qedelec]

I haven't read all you post cause its a bit long but would suggest you install a separate cicuit for the fridge freezer, not RCD protected.

 

[ban-all-sheds]

Who is going to be doing the work?

 

[racket]

would suggest you install a separate cicuit for the fridge freezer, not RCD protected.

Why would you do this?

 

[teachergeezer]

If the rcd trips while you are out or on holiday you'll lose all your stuff in the freezer. They are so sensitive that even a lamp blowing in a table lamp will take out the rcd. Many people have table lamps on timers so that they can have a light coming on in the house while they're out, this can then go 'pop', and if you're unlucky you could lose a freezer full of food costing many hundreds of pounds.

 

[racket]

But what about the RCD protection on the fridge, this is a big chunk of steel
that people are in constant contact with, surely this appliance should be RCD protected. If it came to loosing a bit of frozen food against getting a 240v belt I know which i would choose.

 

[danlightbulb]

The chance of getting a shock off your fridge is so remote you'd probably win the lottery more often.

The metalwork of the appliance will be earthed anyway.

Also, you might not need to bother with rcd protection for the upstairs plugs?

 

[Qedelec]

But what about the RCD protection on the fridge, this is a big chunk of steel
that people are in constant contact with, surely this appliance should be RCD protected. If it came to loosing a bit of frozen food against getting a 240v belt I know which i would choose.

There is no mention of RCD protection for refrigerators in the regulations. The only requirement is for sockets that COULD be used for portable equipment outside the property, are protected. Fridges are not portable and you don't take them outside. As its possible to unplug the fridge and connect the mower/hedge trimmer etc. it would be advisable to fit a Non-standard plug and socket such as 5Amp round pin plug and socket or square live pins with round earth pin.

 

[Spark123]

I think your 20A feed to the outhouse is a bit on the light side. A washing machine, tumble drier and a heater running simultaneously will almost certainly exceed 20A. A 32A or a 40A feed may be more adequate.

 

[Pensdown]

But what about the RCD protection on the fridge, this is a big chunk of steel
that people are in constant contact with, surely this appliance should be RCD protected. If it came to loosing a bit of frozen food against getting a 240v belt I know which i would choose.

Qedelec is totally right. Racket, you may have forgotten that the primary function of and RCD is not to protect against "direct contact" unless outside where this function is used to offer addtional protecting against direct contract

 

[HDRW]

I think you're underestimating the power requirements of washing machines and tumble driers, which may be up to 3kW each, so I'd go with a 32A feed to the outhouse in 6mm².

As others have said, a separate feed to the fridge/freezer is a Good Thing, as is a separate circuit for the kitchen, since that's where you find most of the high-current stuff (kettle, toaster, microwave, cooker (I think you mean it has an electric oven), dishwasher - you don't mention one, but anyway...).

Oh, and yes, the lighting circuits would normally have a 6A MCB.

Cheers,

Howard

 

[Qedelec]

Thank you Pens (takes a bow)!

P.S. Pens nice looking website

 

[Pensdown]

Thanks Qed, we are now on 000001 on the site hit counter

 

[Qedelec]

Not any more you're not.

 

[Pensdown]

LMAO

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