Termination of SWA within consumer unit

[HawkEye244]

What is the best way to terminate a 2.5mm2 cable within a consumer unit ? Research suggests I can either drill a hole 18mm-22mm into the consumer unit (this would have to be at the side of the consumer unit) . OR,

Alternatively, there are pre-cut out holes in the consumer unit which I can make use of. As per the photo.

I will be using a gland kit to create the connection in both scenarios.

If I had to choose it would be to use the cut out as it would allow me to drill a series of small holes. The cable feeds perfectly through the smallest of the cut outs. However, I'm not so sure how well the gland itself is going to fit in this scenario.

Could really use some help here.

 

[oldbutnotdead]

Is that a plastic CU?
If yes, you'll be better off buying an adaptable box and a bit of conduit- gland the SWA into the adaptable box, run the tails through the conduit into the CU.
Glanding onto that thin plastic casing will almost certainly deform it, making getting the lid off snd on very tiresome. You may also struggle with space inside the cu to dress the swa tails.

 

[Risteard]

Why would you drill a different size hole to the gland? The gland will be almost certainly 20mm in a domestic installation. But you cannot gland into a flimsy plastic DB.

 

[bernardgreen]

steel armour glanded to box
Internal sheath extends to just above the main switch in the CU

 

[ericmark]

There are with some boxes an internal steel strengthening part with also earths any SWA gland, but unless that is included in the main any SWA gland will warp the box, I fitted a steel socket back box and it doubled as a local socket and a steel box to gland into.

 

[HawkEye244]

Thank you so much for the advice.
Yes it's a plastic consumer unit installed not long before metal became a regulatory requirement.

Having a brief look at the usual merchants I can find a 4 X 4 X 2 adaptable box but nothing smaller. @bernardgreen did you go to a electrical wholesaler for that smaller version of the box ? No major concern really as there is plenty of space for the 4 X 4 X 2.

Thanks everyone for your help with this.

 

[bernardgreen]

@bernardgreen did you go to a electrical wholesaler for that smaller version of the box ?

Probably one of several bought from Evatron

Enclosures and Cases - Evatron Enclosures

Discover our wide range of plastic and metal enclosures available to buy online. Find IP65 rated sensor cases, IP66, IP67 and IP68 junction boxes and more.

evatron.com

 

[ericmark]

Use a socket back box and a blanking plate.

 

[plugwash]

A MK metalclad plus backbox with blanking plate works nicely for this (other brands of metalclad box often have overlapping lips which you don't want if you are going to but it up to another enclosure.

 

[oldbutnotdead]

A MK metalclad plus backbox with blanking plate works nicely for this (other brands of metalclad box often have overlapping lips which you don't want if you are going to but it up to another enclosure.

Aye good call, dunno why but whenever swa gets involved i always visualise 10 or 16mm....

 

[Notch7]

A copper pipe cutter - the sort with the little scoring wheel and a knob to turn to adjust for size is fantastic to use for terminating SWA. Use it first to score the steel armour, then move it along a bit to cut around the black outer cover.

the secret is to disturb the steel spiral as little as possible -DAMHIK

 

[SUNRAY]

If you really must do what I consider to be a botch and add an external ugly box there are other things to use.

 

[ericmark]

If you really must do what I consider to be a botch and add an external ugly box there are other things to use.
View attachment 306054View attachment 306055

Don't forget the gasket, lid and 4 mm screws, I did. Under £2 for box, Gaskets around £1.50 for pack of 10, lids around £1.60 pack of 10, screws around £2.50 for 25, so total around £8 but you have loads of screws, gaskets, and lids left over. Oh and a 4 mm hole lug for the earth.

Back box £2 and lid £2 so under half the price. And less waste.

 

[SUNRAY]

Don't forget the gasket, lid and 4 mm screws, I did. Under £2 for box, Gaskets around £1.50 for pack of 10, lids around £1.60 pack of 10, screws around £2.50 for 25, so total around £8 but you have loads of screws, gaskets, and lids left over. Oh and a 4 mm hole lug for the earth.

Back box £2 and lid £2 so under half the price. And less waste.

I'd only offered a suggestion for another option.

However in my local wholesaler price to me for a through box complete with. flat lid and 2 screws; £1.35 + vat. Gasket or raised lid (If you feel it's required) 20p + VAT or under £2.00 last time I purchased mid summer 2022.

Yeah I agree the extra screw and the ring crimp will be the killer.

The nicer alternative is to work out the best way to avoid using the superfluous additional box if practical. I personally have never found the need/requirement to add an additional box solely for the purpose of running a cable to an enclosure.

 

[RandomGrinch]

The nicer alternative is to work out the best way to avoid using the superfluous additional box if practical.

Out of curiosity, would a gland like this be suitable?

Storm 20mm Small Cable Gland - IP68 - 2 Glands | Storm (STORM20S)