Split load consumer unit wiring

[Lancashirelad]

Hi all, thanks for looking in.

I have some knowledge of electrics, including wiring my car workshop 25 years ago, but I'm not upto date with all the latest rules, regs and methods.

I have recently had the house original fused CSU replaced with a Wylex 17th edition 10 way split load CSU of my choosing.The board is in an integral garage.

This is how it has been wired, numbered from the right (nearest the garage door) to left:

MAIN SWITCH

_ _ RCB

1. 40A Spare

2. 16A Hall front power socket (telephone) Garage front power socket, Garage door power.
These are all additions and are wired radially.

3. 6A Door bell, Outside lights (front), Garage light

4. 6A Downstairs lighting + landing

5. 6A Upstairs lighting

_ _ RCB

6. 32A Power Sockets: Hall, Lounge, all upstairs

7. 32A Dining room socket north wall
Cloakroom spur outlet
Kitchen sockets
Water heater

8. 32A Cooker

9. 16A Garage power sockets

10. 32A Spare

I consider the idea of a split load unit so that if an RCB trips you don't lose all power or all lighting.

I think # 5 mcb should be moved to position 10, # 7 to pos. 2, whilst (now having a free space at pos. 5) #s 2 - 4 all physically move one place left. (this keeps the 40a spare closest to the incomer). Finally # 10 to pos. 7 (you could then swap # 7 & 8 positions if you wanted to be fussy)

I realise it takes a bit of thinking to follow it through without a diagram.

Would appreciate your comments. Am I right with my thinking?

 

[Iggifer]

Yea lights / sockets should really be split so they don't all go at once if the RCD trips

One way of doing it is lights up / sockets down & lights down sockets up on different RCD's

Seeing as your socket circuits are not traditional i.e. up/down/kitchen front/back/kitchen then it's up to you how you want to split them

I would get the spark that changed the CU to come back and correct this for you

 

[Lancashirelad]

Thanks Iggifer, that's what I thought.

The only thing that crosses my mind is that he may have been limited by the (lack of) available wire length. The new box is much larger than the old.

 

[ban-all-sheds]

The only thing that crosses my mind is that he may have been limited by the (lack of) available wire length.

Would not have been a problem for a proper electrician.

 

[Spark123]

Or the dreaded shared neutrals...

 

[Iggifer]

True, hadn't considered that. No excuse for putting all of the sockets on one RCD though

If I was doing a board change and there was a shared neutral, I'd be telling the customer and trying to resolve it - assuming the customer wanted to pay for it

OP didn't mention anything about borrowed neutrals though

 

[ban-all-sheds]

Well they would have been found and fixed before the CU change, surely?

 

[Iggifer]

exactly, EICR first, board change second

 

[securespark]

By the looks of the circuit listing, that's been addressed already:

Downstairs lighting + landing.

 

[PrenticeBoyofDerry]

The only thing that crosses my mind is that he may have been limited by the (lack of) available wire length. The new box is much larger than the old.

That problem is easily resolved!
Does not look a well designed divison of circuits to me.
Could I ask what is the current rating of the second RCCB as seem to be a lot more on that split than RCCB 1?

 

[PrenticeBoyofDerry]

By the looks of the circuit listing, that's been addressed already:
Downstairs lighting + landing.

That seems to suggest that the neutral is shared!

 

[ban-all-sheds]

By the looks of the circuit listing, that's been addressed already:

Downstairs lighting + landing.

That would be a bizarre way to do it, as you'd have to ship a N from downstairs up to the landing just for that light - easier surely to replace the traditional linked COM in the hall & T/E strapper to the landing with a T/E drop to the landing switch and a 3C+E strapper to the hall?

Just read the OP paying more attention -I guarantee you that there is a borrowed neutral which the 'electrician' ( ) who replaced the CU did SFA about - just avoided fixing it by putting both lighting circuits on the same RCD.

I wonder if he signed a piece of paper to say that he complied with BS 7671, and exercised reasonable skill & care etc...

 

[securespark]

Not easier. The same.

I have seen this done a few times over the years and not by DIY'ers, either.

You take a 3 core to the hall switch. Then a 3 core up to the landing switch. Then a T&E to the landing light from the landing switch.

Advantage is that the landing light is on the GF circuit, so if the FF lights go out, there is still light on that floor.

 

[Scoby_Beasley]

Not easier. The same.

I have seen this done a few times over the years and not by DIY'ers, either.

You take a 3 core to the hall switch. Then a 3 core up to the landing switch. Then a T&E to the landing light from the landing switch.

Advantage is that the landing light is on the GF circuit, so if the FF lights go out, there is still light on that floor.

That's exactly the way I would do it.

 

[securespark]

You can definitely send me your picture now!