Terminate SWA armour outside and take just internal wires into house/CU?

[Risteard]

Exactly my point.

Kind Regards, John

I know it was. I was simply affirming that your view is correct. It is a prohibited cowboy practice to run SWA beyond the gland as an insulated and sheathed cable which is not how it has been designed.

 

[flameport]

This is the CU and location I am trying to get to

The right hand MCB has a hole in the bottom, and live parts may be exposed.

It's also undesirable to add a new circuit to an installation which only has a single RCD - it's non-compliant already and by adding another circuit you are making it worse.

 

[JohnW2]

It is a prohibited cowboy practice to run SWA beyond the gland as an insulated and sheathed cable which is not how it has been designed.

Indeed, but it's fine if within an appropriate enclosure or other protection (as with bernard's oft-posted illustration of SWA terminated into a metal box adjacent to {in contact with} a plastic CU). One just has to think of the cores as 'singles', and ignore the bedding - which, as you say, does not qualify as a sheath.

Kind Regards, John

 

[Iknowcraig]

The right hand MCB has a hole in the bottom, and live parts may be exposed.

It's also undesirable to add a new circuit to an installation which only has a single RCD - it's non-compliant already and by adding another circuit you are making it worse.

View attachment 111689

Thanks flameport, I will replace that MCB, that is the one I plan to use as supply for the SWA as it was originally for a power shower that has now been removed.

So are you saying I would need a new CU to achieve what I want to? Or could I get by with what I have?

Thanks

 

[flameport]

To be compliant with BS7671 you would require a new consumer unit.
The arrangement you have is not unsafe, but does not comply as a single fault will trip the RCD and disconnect power to the whole house.

Adding the garage circuit makes this even more likely, particularly as garages are often damp/wet, the sockets within are likely to be used for things outside, and outside lighting is often installed.
It's still not unsafe - but could result in non-trivial inconvenience in the event of a fault, since you won't be able to switch the power on until the fault is located and repaired.

 

[Iknowcraig]

To be compliant with BS7671 you would require a new consumer unit.
The arrangement you have is not unsafe, but does not comply as a single fault will trip the RCD and disconnect power to the whole house.

Adding the garage circuit makes this even more likely, particularly as garages are often damp/wet, the sockets within are likely to be used for things outside, and outside lighting is often installed.
It's still not unsafe - but could result in non-trivial inconvenience in the event of a fault, since you won't be able to switch the power on until the fault is located and repaired.

Thanks again! As long as there are no safety concerns I will go ahead with the current CU for now and perhaps look at replacing it down the line. I will replace the damaged MCB with a new one when I connect the supply.

 

[JohnW2]

Thanks again! As long as there are no safety concerns I will go ahead with the current CU for now and perhaps look at replacing it down the line. I will replace the damaged MCB with a new one when I connect the supply.

I don't think that anyone has yet mentioned this but, as you may realise, I think you are sailing very close to the wind in terms of 'notifiable' work.

There is uncertainty and debate as to what constitutes "installing a new circuit" (which is notifiable), but I would personally think that feeding a new garage supply from the CU almost certainly does constitute installing a new circuit, even if it uses an MCB (or its intact replacement!!) that was previously used for some other circuit. What you choose to do about that is, of course, up to you.

Kind Regards, John

 

[Simon35]

6mm 3 core swa has a bending radius of approx 100mm. Not easy to come through the wall and then bend it up. You will need to chase out enough of the wall to form the bend in. Same problem outside.

I would want double pole isolation on any outside circuit, particularly in this case where only one rcd feeds the entire house. Just knocking off the mcb won't necessarily allow the rcd to be reset in the event of an outside fault.

 

[bernardgreen]

This worked for me

Untitled

• bernardgreen
• 10 May 2009
• 17

Adding a banjo to the gland and a grommit in the hole at the top of the die cast box would have been improvements.

 

[JohnW2]

This worked for me

Indeed it did, and thanks for posting it. As I wrote:

... (as with bernard's oft-posted illustration of SWA terminated into a metal box adjacent to {in contact with} a plastic CU) ...

However, I rather doubt that that approach would be aesthetically acceptable to the OP - he might possibly accept the surface-mounted metal box and shrouded gland (since it is very high up), but I imagine that he would probably want the SWA to be 'buried' - which would not be easy.

Kind Regards, John

 

[JohnW2]

I would want double pole isolation on any outside circuit, particularly in this case where only one rcd feeds the entire house. Just knocking off the mcb won't necessarily allow the rcd to be reset in the event of an outside fault.

Same here, but in this case I think that DP isolation could reasonably (and perhaps more conveniently/aesthetically) be sited in the garage (maybe as the incomer of a 'garage CU'). Particularly if there are no outdoor JBs, there is really very little prospect of a fault developing between the house and the garage.

Kind Regards, John

 

[bernardgreen]

Sorry John I missed your post. The bedding does act as a mechanical sheath to keep the cores tidy as they go into the consumer unit. Insulation wise it is as you say doubtful to be considered as providing double insulation to the cores.

 

[JohnW2]

Sorry John I missed your post. The bedding does act as a mechanical sheath to keep the cores tidy as they go into the consumer unit. Insulation wise it is as you say doubtful to be considered as providing double insulation to the cores.

Indeed, and the same is true if one takes on board Risteard's frequent assertion that the the required 'second layer' is sheathing, not insulation - the bedding of SWA is not adequate as 'sheathing'.

In passing (since I mentioned Risteard!), whilst I've yet to discover what the Standards for sheathing require, I find it very hard to believe that they do not include some requirements in terms of insulating properties - i.e. I would be very surprised if it would be permissible for, say, T+E or flexible cable to have a significantly conductive (but not earthed) sheath!

Kind Regards, John

 

[ban-all-sheds]

I've used SWA where the bedding is so soft you can cut it away with a thumbnail.....

 

[Simon35]

Same here, but in this case I think that DP isolation could reasonably (and perhaps more conveniently/aesthetically) be sited in the garage (maybe as the incomer of a 'garage CU'). Particularly if there are no outdoor JBs, there is really very little prospect of a fault developing between the house and the garage.

Kind Regards, John

I'm not so sure. A directly buried SWA might develop a fault, especially if the outer sheathing is damaged on installation.

My other question to the OP would be how has the 6mm conductor size been arrived at?