SWA Distribution

[ADS]

Hi,

I can't think of anything wrong with this, but I thought I'd run it by you chaps, just in case.

Running a 10mm SWA around the outside of a three-bedroom semi to feed a second CU in a two story extension that's being built.

We were going to run it in with the 'footings', around the outside of the building, but we'd save quite a bit on the length of run if we took it through the extension, as oposed to around it. (i.e. under the new concrete floor).

Can anyone see any problem with this?

 

[safedepth]

I can't think of an issue but stand to learn.

I am in a similar position on a job and intend to install in 4" conduit. Only reason being possible intention to pull through further supplies at a later date.

 

[Andy™]

Hi,I can't think of anything wrong with this, but I thought I'd run it by you chaps, just in case.

Running a 10mm SWA around the outside of a three-bedroom semi to feed a second CU in a two story extension that's being built.

We were going to run it in with the 'footings', around the outside of the building, but we'd save quite a bit on the length of run if we took it through the extension, as oposed to around it. (i.e. under the new concrete floor).

Can anyone see any problem with this?

as long as its deep enough & has marker tape etc etc, cant see a problem with it

 

[kme]

No issues at all, as long as:

1. you`re deep enough to avoid the risk of damage due to floor fixings, etc.......

2. is there going to be any thermal correction required, if your cable travels through any expanded polystyrene?

If the option is there, I`d duct it....purely to allow for future upgrade / replacement, though it isn`t a requirement to regs.

HTH

KME

KME

 

[ADS]

Thanks.

I didn't think there was an issue - I'll keep that in mind, KME, when we establish exactly where we're running it.

I'll keep it in the footings if there isn't a great saving.

One other thing - I was going to terminate the SWA in a 'box' on the external wall of the extension and then go out the back of the 'box' and through the wall.

The reason is that the home owner is going to fit a 'log cabin' at a future date, so the thinking is, we could just run straight off the junction box to power it.

Is there a better way, or is this what you'd do?

 

[Andy™]

will there be enough capacity in the 10mm to feed both second CU in house & log cabin?

if the new CU is on the other side of the wall, may be easier to take SWA straight to CU, then if required, another SWA from CU to cabin?

 

[steptoe]

[quote name='Andy

 

[steptoe]

TT ? ROTFWL

does the pope like boys?

 

[kme]

I dunno.

Could you ask him next time he visits?

 

[ADS]

It's gonna be 10mm or 16mm - I've got to do the final calcs when he confirms for definite what he's having..........I'm hoping 10mm coz 16 is a bugger to work with.

You've also got to bear in mind, here, it's going to be feeding a kitchen (oven only, gas rings)with ring final and lighting, a bedroom power and lighting and a log cabin power and lighting.

There are still a lot of 'whole' houses being fed by 16mm tails on 60 A fuses, so I'm sure it's going to be fine on 10mm - BUT I will do the calcs, so calm down - I was only concerned about the cable route.

Next I'll have someone telling me it's notifiable

 

[kme]

BTW mate - you DO know you need to notify the work? :coat

 

[ianmacd]

You may have issues with LABC as you may potentially be breeching the DPM layer.

 

[ADS]

You may have issues with LABC as you may potentially be breeching the DPM layer.

So if we do it this way it's got to go right underneath before any of the 'floor' layers are put down - maybe dig a channel and lay it in that.

Or do you mean the fact that we'd be coming up through it?.....you might be right, that could be an issue.

 

[ianmacd]

I mean that you are comming though it, Not an issue outside but inside its an added complication.

 

[Larnacaman]

No reason why you can't run your SWA in the screed, it's normally around 4''+ in depth!! You could also run any downstairs circuits for the kitchen etc, in Plastic conduit in the screed too. Though why your running a cable for a separated CU is beyond me, just as easy to extend the existing lighting and power circuits. You can still run the SWA cable to a suitable location ready for that future log cabin...

 

[ianmacd]

Screed may not be a good option if they are having underfloor heating.

 

[Larnacaman]

No-ones mentioned anything about underfloor heating!! Screed conduit systems are the norm on concrete framed buildings, and totally acceptable within other types of building construction. Not so good, where underfloor heating is a feature though...lol!!

 

[ADS]

No reason why you can't run your SWA in the screed, it's normally around 4''+ in depth!! You could also run any downstairs circuits for the kitchen etc, in Plastic conduit in the screed too. Though why your running a cable for a separated CU is beyond me, just as easy to extend the existing lighting and power circuits. You can still run the SWA cable to a suitable location ready for that future log cabin...

Layout isn't actually anything to do with me - they told me what they want and I'm doing the calcs and pricing on that.

The bloke who owns the house is 'project managing', so to speak, so it's up to him - he must have his reasons.

I think one of his reasons is the existing, (small), kitchen is on the main house ring and he wants it seperate - running new cables through the house from existing CU isn't an option.....so outside we go.

 

[ianmacd]

No-ones mentioned anything about underfloor heating!! Screed conduit systems are the norm on concrete framed buildings, and totally acceptable within other types of building construction. Not so good, where underfloor heating is a feature though...lol!!

Anyone planning and not incoporating UFH on a domestic ground floor extension is, IMO, a loon. Why tie yourself down with ugly inefficiant and static rads?

 

[Larnacaman]

Layout isn't actually anything to do with me - they told me what they want and I'm doing the calcs and pricing on that.The bloke who owns the house is 'project managing', so to speak, so it's up to him - he must have his reasons.

I think one of his reasons is the existing, (small), kitchen is on the main house ring and he wants it seperate - running new cables through the house from existing CU isn't an option.....so outside we go.

From the way you described it, it sounded as if the Kitchen was going to be in the new extension...