Hi whats the professional way to bring SWA into a house to join into the main circuit. Do yo simply bend the SWA at 90deg outside and thread through the wall, strip back inside and join to an internal juntion box OR run into an external junction box on the wall. If the former, what product do you use to make a neat job of the hole - is there a grommet of some description that you feed the SWA through to neaten/protect the wire and hole? Thanks
armoured cable SWA
Mar 07, 2008
28 Replies
I would use expanding foam and mortar.
I have my garage electrics fed from the house via SWA. The SWA does not enter the house, it connects to a watertight junctions box on the exterior wall of the house. In the JB, the SWA connects to ordinary twin core and earth.
On Thu, 6 Mar 2008 23:11:05 -0800 (PST) someone who may be Richard wrote this:-
That rather depends on the size of the cable, which direction it comes from, the space available to work inside, the construction of the wall, where entry is to be made, where the cable is to be terminated and so on.
For the smaller sizes of cable, which I assume you are talking about, they can be bent relatively easily and there is generally no great problem taking them through the wall much like any other cable. Right angle bends are not going to work, but then they are not a good idea with other types of cable.
Up to you. Any of the methods you suggest are fine if done properly. Last job I did I used an internal JB but if I did that job again I would run the SWA to the consumer unit as there is not that much of a cost premium. If you are using the armour for the earth connection you need to strip back and fit a gland to secure the earth connection.
As far as the feed through the wall is concerned I would sleeve it with a suitable size of PVC pipe.
Jim A
When I revamped the feed to my workshop/garage I fitted a plastic box externally, brought the SWA into it with a gland and then fed the inner portion of the cable (without the outer jacket and armour) through a hole in the back of the box aligned with the hole through the wall to the "Garage" breaker on the consumer unit.
This is how I did the my last SWA back to a CU.
As SWA will not fit nicely into a plastic CU I terminated the SWA into a metal clad surface mounted 45 amp switch next to the CU and used T&E from the switch to the CU. This allowed a good connection for the SWA and a very good isolator (if needed) for the shed it powered.
The armoured sleeving needs to be earthed at one end of the supply even if it is not used as the earth. It is classed as an exposed conductive part (ie you could put a nail/spade through the armoured to the live cable and leave the armoured bit live)
There is no need to sleeve but it is worth it should you need to change it.
Adam
Thanks - inline...
That rather depends on the size of the cable,
6mm2 T&Ethe construction of
Cavity
So if you cant have a 90 deg bend how do you run it up the exterior wall from the ground and then enter the wall?
Thanks all for the advice - much appreciated
assuming you mean 6mm2 2c SWA, the minimum bending radius is about 100mm.
so the cable has to leave the ground approx 100mm from the wall. If your desired wall penetration is much more than say 200mm above ground level you may prefer to have a sticky out JB, your choice.
Jim A
For 6mm^2 SWA I would suggest using a waterproof box on the outside wall[1], and terminating the SWA with a gland into the bottom of the box. You can then run T&E through the back of the box and through the wall to the supply.
[1] Something like:
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nicely (and often comes with a free sweetie! (seriously))
neither of mine did :-(
Perhaps you can tell the difference between a rubber grommet and a piece of liquorice. ;-)
I thought it was chewey! in fact it was a small boiled sweet with manufacturers branded wrapper. Perhaps it was a special promotion last time I ordered them. I will find out shortly - just ordered some more.
Pretty sure I got half a dozen assorted sweets in the bottom of the box when I ordered ~£200 of stuff from TLC. Bit random, but I'm not complaining :-)
Pete
My last order was pushing £800, so will have to see what I get ;-)
IIRC expanding foam eats PVC insulation.
John
On Sat, 08 Mar 2008 17:21:35 +0000, John Rumm had this to say:
I hadn't heard that but expanded polystyrene leaches styrene which attacks pvc. The expanded foam stuff is a urethane product
I once got some computer parts delivered at work, and the packing chips were sugar puffs (or rather, the unsugared ones). Presumably they were reject or not not suitable for consumption for some reason.
A lot of the "packing peanuts" are now made of cornstarch instead of polystyrene, I know someone who sells them on as fishing bait.
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