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CU Layout / Circuits


PeterW

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Chatting to the sparky about getting the layout of the circuits sorted and we've decided as previously it will be all RCBO.

 

For an extra £30, is it worth splitting all of the circuits as below..? Bear in mind this is an all electric house which may in the future have solar installed (non-MCS) but only on a south westerly facing roof.

 

Its a 3 bed house, all LED or low energy lighting. Induction hob in the kitchen and electric towel rails in 2 bathrooms along with upstairs electric tile warming (all centrally controlled) and ASHP for DHW and ground floor UFH. Immersion is for boost/legionella cycle.

 

RCBO.JPG

 

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Put the oven on it's own circuit as noted. Also make sure there are 2 or 3 spares ways in the CU, e.g. you might want an electric shower, and of course one for the solar PV.

 

Mains drainage if not a circuit for the treatment plant.

 

I have a broadly similar mix in a 20 way all rcbo board.
 

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I split my downstairs sockets up into 3 areas. 1st was all the utility room, washing machine,dryer freezer. 2nd was the kitchen/sunroom, fridge dishwasher and sockets for kettles toaster and then TV unit plugs. 3rd was the rest of the downstairs, 1 TV computer few lamps.

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44 minutes ago, Steptoe said:

Are you using Double Pole RCBOs, ?

Oh, and I'd have the smoke alarms on with one of the lighting circuits, just a personal preference of mine.

 

+1 for having the smoke alarms on one of the lighting circuits.If they are on there own, you may not notice if they trip. If they are off a lighting circuit you will soon notice.

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On the OP, this is my current setup (4 bed / 2 recep house)

 

All RCBO, upgraded 3 years ago as we ran out of space to a double deck 10+10 model with 2 isolators.

 

100A fuse plus I think mains isolator.

 

6A Security Alarm.

6A Lights Upstairs.

6A Lights Ground Floor 1.

6A Lights Ground Floor 2.

6A Lights Ground Floor 3.

6A Smoke Alarms.

16A unlabelled (oops)

32A Upstairs Shower.

32A Oven. (replaced by range oven below.)

32A Downstairs Shower.

 

40A Range Cooker.

32A Sockets Upstairs.

32A Sockets Downstairs.

32A Sockets New (we added an extra double socket in the utility room).

40A Solar PV. (It is a 10 kWp array) 

 

5 spares, and a box of spare RCBOs that came with the fusebox.

 

Heating is a Combi Boiler and UFH, but with a couple of areas of Electric UFH which are take off the ring mains at those points. Cooking is Gas.

 

The solar, and also a 7kW car charger, are on separate small consumer units. Not sure how the Car Charger is wired in without tracing it.

 

The obvious things missing that would be added are an external socket, and electric gates. 

 

The Unit is a QFS-RRM24FLEXI 20-way from Control Gear, and seems quite solid. The upgrade was notably good value.

http://www.controlgeardirect.co.uk/

 

Question for @PeterW - have you got several unused spares? You may need them.

 

Ferdinand

 

Edited by Ferdinand
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A quick note @Ferdinand

Those are only Single Pole RCBOs,

IMO not really fit for purpose tbh,

You can get daisy chain faults as the neutrals don't disconnect.

And, totally not permitted on TT systems, only can be used on TN, 

I'd advise anyone considering using RCBOs to ensure they are DP, 

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Right... plenty of food for thought ..!!

 

@ProDave I had looked at a pair of 12/10 way units side by side which would give me spares. 

 

@Steptoe taking that point you made on smokes, I will include them on a light circuit and use the spare 6a for the alarm spur (as @Declan52 spotted I missed it..)

 

Interested in the spur vs ring comment - doesn't that give issues on overloading ..??

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14 minutes ago, Steptoe said:

A quick note @Ferdinand

Those are only Single Pole RCBOs,

IMO not really fit for purpose tbh,

You can get daisy chain faults as the neutrals don't disconnect.

And, totally not permitted on TT systems, only can be used on TN, 

I'd advise anyone considering using RCBOs to ensure they are DP, 


Thanks.

 

I will open a new thread to discuss that to avoid derailing this one.

 

F

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30 minutes ago, Nickfromwales said:

Make the boiler feed a 16amp x 2.5mm2 radial and fuse down at the termination point. 6a is too close to the wind imo, with due consideration being given to future proofing. 

 

Why.........?? Not that I'm doubting you, it's just the only thing going on it is a time clock and a pump for the ASHP... 

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Any radials for fixed equipment I've ever put in have always been on either a 16a or a 20a breaker / rcbo and in 2.5mm2. 

The derating always got done at the termination point eg fused spur. There you select the fuse rating accordingly for the connected equipment. My choice here would be to install it so you can hook anything up later without worrying about loading. 

Fwiw I've never run a radial less than aforementioned, only ever deviating when it's outside lighting etc where I use 6a or 10a accordingly.

Just can't see any point in running such a low powered radial unless you plan to run 2.5mm2 anyway ( which would leave you the option to upsize the breaker later on if so required ). I'm a bit old school that way tbh, but that's how I got taught as an apprentice spark with SWALEC. 

If your 101% sure it'll never be needed then take what I say with a pinch, but better to put it in now than later. Remember that you'll need a fused spur or a socket anyway ( so as to get localised fused connection at the termination point ) so not much more money tbh. 

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I'd agree with @Nickfromwales

Its the same amount of labour, and not much more expense, 

If you do decide on a socket, remember it must be UNswitched, 

Personally I have my boiler on a plug and socket, if there is a power cut I can plug it into the Genny so at least I still have heat. 

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2 hours ago, Ferdinand said:

The obvious things missing that would be added are an external socket, and electric gates.

 

So I had an outside socket and typed over it by the looks of it - wondered what was missing !!
Gates are from a separate supply as the main meter box is at the gates along with a modified meter box (including a lock...) containing a new IP65 consumer unit with a gate and a driveway light supply.

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Personally,

Bedrooms on 2x 16a radials,

Living room on a 16a radial,

garage, C32, (what about that welder?)

Smoke alarms with U/S lights

ASHP prob needs a C as well

Be careful on your selection between Bs and Cs, makes a big difference.

 

Just a thought,

Edited by Steptoe
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