Consumer Unit Wiring

[Greenie9657]

Hi All.

Although im a decent DIYer (electrics and plumbing) im definately not trying this one but im just wondering what would you guys fit to each RCD/MCB. I have a friend who is qual'd and ive bought this consumer unit for him to fit which has the following:

100A DP Main Switch
• 2 x RCDs (1 x 63A, 1 x 80A)
• 10 x MCBs which are rated at:
3 x 6A
2 x 16A
4 x 32A
1 x 40A)

At the minute i have an old style fuse board and it only has 6 fuses. These are Upstairs ring, downstairs ring, upstairs lights, downstairs lights, immession heater (ive just bought the house and it hasnt even got an immession heater) and Cooker. I also need to wire a garage into it.
I know the CU has far more than what i need but im buying now as we are planning to extend and hopefully it'll be future proof.

Thanks for looking.

 

[bernardgreen]

Sorry to be blunt but one normally buys a consumer unit to meet the requirments on the house after doing a design process for what is needed.

You seem to want to arrange for the house to meet the capabilties of the consumer unit which is not a good design process.

Your friend should have designed the installation before you bought the consumer unit.

 

[Greenie9657]

thanks for your reply.

Dont worry about being blunt. I dont mnd. I kind of bought the consumer unit then asked him if he could fit it for me. So im to blame. But as i have around 10 different circuits in the house and the unit came with a load of free sockets then i think it was a good buy. Anyway, what do you think about my original post? The circuits id like are:

upstairs sockets
downstairs sockets
kitchen
cooker
upstairs light
downstairs light
loft light (maybe)
outside lights
garden Electrics
Shed/Garage

Loft light, Garden electrics and outside lights are in yet but like i said its there for future developments. And the kitchen is on the downstairs sockets which id like to seperate.

 

[Iggifer]

Some typical values of breakers, this is by no means a guarantee they're what you'll need, but without further information thats the best I can offer

upstairs sockets 32a
downstairs sockets 32a
kitchen 32a
cooker 32/40a
upstairs light 6a
downstairs light 6a
loft light (maybe) (just get him to put this on the upstairs lights, no need for separate circuit)
outside lights 6a
garden Electrics 16a
Shed/Garage 16a

 

[Greenie9657]

Thats exactly what answer i was hoping for, many thanks for that Iggifer. The cooker is 6mm wire and at the minute is on a 30A fuse. The hob is gas and seperate to the oven.
As for the loft light. I didnt want it on the upstairs lights incase i had to work on that circuit in the attic and still need the loft light. Would it be ok to use a FCU (3a) from the upstairs ring to run the loft light? bit of a wasted MCB thinking about it.

 

[rjm2k]

RCD split suggestion can be found here

http://en.wikipedia.org/wiki/Consumer_unit

But I'm sure your friend will know anyway.

Didn't the CU come with standard design suggestions?

 

[PrenticeBoyofDerry]

With what you have something like this could do:
100A DP Main Switch

RCCB 80A
cooker 40A
upstairs sockets 32A
Shed/Garage 16A
downstairs light 6A


RCCB 63A
downstairs sockets 32A
kitchen 32A
garden Electrics 16A
upstairs light & loft light (maybe) 6A
outside lights 6A


But you will need to confirm that the circuits are rings and radials sockets are 4.0mm
I try to get any heating circuits on there own and if the facility to fit RCBOs is a available get the boiler on one and at least one socket.

 

[bernardgreen]

loft light (maybe) (just get him to put this on the upstairs lights, no need for separate circuit)

Not a good idea to have loft light on the same circuit as upstairs lights.
[1] when working on the upstairs lights there is not loft light
[2] if you are in the loft and the lights trip both sides of the access hatch are in darkness.

Outside lights and electrics are prone to faults that are not urgent to repair ( unlike indoor faults ) so better outside electrics do NOT share an RCD with indoor circuits. ( or can be fully and quickly isolated to allow shared RCD to be reset )

 

[ban-all-sheds]

Thats exactly what answer i was hoping for.

I'm sure it is, because your story of having a qualified friend to install this CU is complete b*ll*cks, isn't it.

 

[Greenie9657]

Thats exactly what answer i was hoping for.

I'm sure it is, because your story of having a qualified friend to install this CU is complete b*ll*cks, isn't it.

Ha you know me too well sheds!!!!

But seriously I am getting a friend to install the CU this time. I'm not messing with the main fuse, ill let someone who is qualified do that just in case. I'm getting mates rates anyway. There isn't just the CU that needs replacing, I have a second smaller CU sat next to it which I think was there to run storage heaters which are no longer fitted so I'm hoping to get that removed too.
I'm away with my job in 2 weeks so I'm hoping he has done it by the time I'm back in April.

But you did actually make me chuckle saying that. But I'm honest enough to say if I was going to.

 

[sparkwright]

Thats exactly what answer i was hoping for.

I'm sure it is, because your story of having a qualified friend to install this CU is complete b*ll*cks, isn't it.

Ha you know me too well sheds!!!!

But seriously I am getting a friend to install the CU this time. I'm not messing with the main fuse, ill let someone who is qualified do that just in case. I'm getting mates rates anyway. There isn't just the CU that needs replacing, I have a second smaller CU sat next to it which I think was there to run storage heaters which are no longer fitted so I'm hoping to get that removed too.
I'm away with my job in 2 weeks so I'm hoping he has done it by the time I'm back in April.

But you did actually make me chuckle saying that. But I'm honest enough to say if I was going to.

Don't forget you may be able to convert the old storage heater points into sockets, so don't rip too much out yet.

 

[Greenie9657]

I thought that but when I tested the live with a tester it read zero volts but I'm sure the thing sparked the other day so I need to make up a longer wire to volts check it again to a known good neutral just in case the neutral is damaged. Or I might just use one of the screw driver things with the light in. (I do hate them though)

 

[17thman]

I dont like iggifers idea of having a garage on a 16A supply, it leaves nowhere to go with discrimination

 

[RF Lighting]

Why not? You can use a 3A fuse for the lights.

 

[17thman]

if you mean a fused spur or the socket circuit then a fault on the lights will take out the sockets. If you mean a 3a fuse in the cu then where do you go from there for the sockets?