Consumer Unit Feed

[Dunc88]

I've got an awkward job approaching where the consumer unit is to be relocated due to a semi-detached house being knocked into one. It's currently fed via a kmf & 16mm t&e, with a seperate 16mm earth. When the consumer unit is relocated, this wont be long enough, and even if it was this would have to be replaced with swa, to avoid requiring 30ma protection, and as it is >3M in length from the meter.
My questions are;
1. What size swa (will be 15+ circuits but no electric showers/cooker)
2. How many cores? 2core with seperate earth (& earth swa), or 3 core (& earth swa).
I'm thinking 3core 25mm, but surely not!?
Any help, advice appreciated!
Cheers!

 

[Midwest]

Which thread do you wish members to reply too?

 

[Dunc88]

Which thread do you wish members to reply too?

Just trying to work that out now, only my second post haha. The main electrical forum, where's it ended up then? Plumbing?

 

[Midwest]

Consumer Unit Feed - http://www.electriciansforums.co.uk/threads/consumer-unit-feed.119993/

Consumer Unit Feed - http://www.electriciansforums.co.uk/threads/consumer-unit-feed.119994/

 

[Pete999]

I've got an awkward job approaching where the consumer unit is to be relocated due to a semi-detached house being knocked into one. It's currently fed via a kmf & 16mm t&e, with a seperate 16mm earth. When the consumer unit is relocated, this wont be long enough, and even if it was this would have to be replaced with swa, to avoid requiring 30ma protection, and as it is >3M in length from the meter.
My questions are;
1. What size swa (will be 15+ circuits but no electric showers/cooker)
2. How many cores? 2core with seperate earth (& earth swa), or 3 core (& earth swa).
I'm thinking 3core 25mm, but surely not!?
Any help, advice appreciated!
Cheers!

If you could show us your reasoning for you decisions, calculations and the like we may be able to offer some constructive advice, you are going to consolidate all the circuits into 1 CU, have you approached the DNO.

 

[Dunc88]

If you could show us your reasoning for you decisions, calculations and the like we may be able to offer some constructive advice, you are going to consolidate all the circuits into 1 CU, have you approached the DNO.

Yes they're removing one of the supplies, and all circuits are going into one consumer unit...

 

[Leesparkykent]

I've deleted the other thread......Op stick to one thread as it gets confusing

 

[Dunc88]

I've deleted the other thread......Op stick to one thread as it gets confusing

Thanks, I did try to delete it myself but take it I cant? What does OP stand for!?

 

[telectrix]

OP... original post/poster.

 

[David M]

Hi Dunc88 and welcome to the forum,
As Pete said we need a little more information before any constructive advice can be offered, i.e max demand, DNO supply fuse rating, installation method and such...
Your maximum demand may calculate low enough to allow you to use 16mm, though you may need to allow for future additions. Personally if you decide to go with SWA, I would go with a 3 core, even though the steel armour may well be suitable to use as the main earth, for the very little extra cost of the cable - I think its a no brainer.

 

[westward10]

I would also opt for a three core as the armour will not be adequate to support bonding.

 

[PEG]

Hi,so i presume you mean two semi's,being knocked in to one dwelling,or are they both going,and one new property being built?
This makes a difference,as if it is the latter,it may be better,as the DNO are involved anyway,to relocate the remaining supply,to the most suitable area.

 

[Dunc88]

Hi,so i presume you mean two semi's,being knocked in to one dwelling,or are they both going,and one new property being built?
This makes a difference,as if it is the latter,it may be better,as the DNO are involved anyway,to relocate the remaining supply,to the most suitable area.

Hi Peg, thanks for the response! Yes into one (very big) dwelling, with dividing internal walls coming out, the DNO have removed one of the properties supplies, leaving the other in place, which is where I am to take the supply from. I think to cover any potential additional add-ons, I will use a 3core, 25mm swa! Lets hope the chippy can do some boxing in around that swa!

 

[Dunc88]

Hi Dunc88 and welcome to the forum,
As Pete said we need a little more information before any constructive advice can be offered, i.e max demand, DNO supply fuse rating, installation method and such...
Your maximum demand may calculate low enough to allow you to use 16mm, though you may need to allow for future additions. Personally if you decide to go with SWA, I would go with a 3 core, even though the steel armour may well be suitable to use as the main earth, for the very little extra cost of the cable - I think its a no brainer.

Hi David,
Yeah I agree with regards to the cable! I'll calculate the maximum demand but to be honest, it's such a big place I think anything less than a 25mm could potentially be an expensive mistake!

 

[PEG]

OK,so the building work does not require removal of the one,remaining supply,so presumably,intake,metering etc,can stay in original location,with new DB situated in a new spot.

We don't know the nature of your supply/earth arrangements,but suggestions above seem suitable.

On the scale of costs,of the whole job,20m of 3C SWA,will be inconsequential.

 

[Dunc88]

OK,so the building work does not require removal of the one,remaining supply,so presumably,intake,metering etc,can stay in original location,with new DB situated in a new spot.

We don't know the nature of your supply/earth arrangements,but suggestions above seem suitable.

On the scale of costs,of the whole job,20m of 3C SWA,will be inconsequential.

Yes, thats right! Consumer unit couldnt go by the meter unfortunately as it backs onto the lounge & customer (despite my efforts) wont have it there! Thanks for your help peg

 

[westward10]

Yes, thats right! Consumer unit couldnt go by the meter unfortunately as it backs onto the lounge & customer (despite my efforts) wont have it there! Thanks for your help peg

But they don't mind a switch fuse being there because to terminate a three core, 25.0 swa into it it will be bigger than a matchbox.