SWA Gland into plastic Consumer Unit
- Thread starter Jupiter01
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We now know (post #6) that the cable is marked as 25 mm - but, as I've said, co-incidentally the outside diameter is likely to be very similar (I think around 24mm). However, as I've said more recently, I would have guessed (maybe incorrectly?) that a gland to take that would require a hole bigger than 25mm?
Kind Regards, John
https://www.enfieldelectrical.co.uk/pages/swa-cable-gland-chart suggests a 25mm gland is suitable for 25mm² 2 or 3 core SWA but 4 or 5 core needs a 32mm gland. I understand there can be some variability between brands though.
Remember SWA glands are not like stuffing glands where the whole cable goes through the gland. The outer sheath and armour terminate outside the enclosure.
Remember SWA glands are not like stuffing glands where the whole cable goes through the gland. The outer sheath and armour terminate outside the enclosure.
Fair enough
Sure, I realise that - which is why I said that I was not sure whether or not my guess was correct!
Kind Regards, John
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Wanted to practice the glanding process as that appeared to be the default approach. That's the only reason I wanted to terminate the gland somewhere.
Have a look at pirhana nuts- much easier to get a good bite on the armour. There's a load of discussion about the wisdom of relying on the armour as cpc- belt and braces approach is if you happen to have 3 or more cores available (for yr 1 phase setup) then use a core as cpc as well as the armour.
Not sure about placcie box in this age of metal cu being required, safest will be metal. Lidl/Aldi sell step drills if knockouts aren't big enough.
IMHO you'll be better off using Henley blocks to split supply before the CU into your swa- N and E can go straight through (N will need additional sleeving), a DIN rail mounted 50A mcb will take 25mm.
Not sure about placcie box in this age of metal cu being required, safest will be metal. Lidl/Aldi sell step drills if knockouts aren't big enough.
IMHO you'll be better off using Henley blocks to split supply before the CU into your swa- N and E can go straight through (N will need additional sleeving), a DIN rail mounted 50A mcb will take 25mm.
And when everybody gets an EV the dno supply cables will be warm as well....
I see a couple of issues here.
1. They are esoteric, I don't think i've ever heard anyone but you mention them and the website has no information on price, minimum order quantities or similar.
2. Some CUs can already be quite cramped and you are proposing bringing the whole cable into the enclosure rather than terminating it on the wall of the enclosure, which is likely to take up even more space in the enclosure.
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I know in the past I have used 2 x 125 mm² instead of one 270 mm² as I simply could not bend the 270 mm² to fit into the generators terminal box. And with smaller cables I have had even 2.5 mm² which one should be able to kick into the space warp the box so lid would not fit. Using cleats so cable can't strain the box is some times required, and even inside the box, I have had the strain the cable put on an RCD stop it working, dressing the cables can be important.
As to EV charging points, still not convinced using a TN-C-S single phase supply is safe with loss of PEN methods being used, so one needs to consider what to do with an SWA as far as the earth goes, some where between a TN and TT supply the earth needs to be broken, the big question is where.
As to using an earth mat and a TN-C-S supply one really does need to know size of supply transformer, the big question is can the PEN or earth cables take the current with loss of PEN? An earth rod OK likely only 8Ω at best, 400/8 = 50 amp, so cable can carry that, but an earth mat, could be 1Ω or less, and unlikely the PEN or earth wires can carry 400 amp.
I noted where I worked we had a large resistor the size of a small van between the DNO earth and site earth to limit the current, unlikely to see this on a domestic install. And we don't fuse the earth or neutral, I have seem diodes in the earth, and I questioned how much power they can take, but if they failed the steel hull of the narrow boat is likely a good earth anyway.
In the main we learn how to do things in collage, university, courses, or tool box talks, the idea of learning by trial and error raises the question can we really have the errors?
As to EV charging points, still not convinced using a TN-C-S single phase supply is safe with loss of PEN methods being used, so one needs to consider what to do with an SWA as far as the earth goes, some where between a TN and TT supply the earth needs to be broken, the big question is where.
As to using an earth mat and a TN-C-S supply one really does need to know size of supply transformer, the big question is can the PEN or earth cables take the current with loss of PEN? An earth rod OK likely only 8Ω at best, 400/8 = 50 amp, so cable can carry that, but an earth mat, could be 1Ω or less, and unlikely the PEN or earth wires can carry 400 amp.
I noted where I worked we had a large resistor the size of a small van between the DNO earth and site earth to limit the current, unlikely to see this on a domestic install. And we don't fuse the earth or neutral, I have seem diodes in the earth, and I questioned how much power they can take, but if they failed the steel hull of the narrow boat is likely a good earth anyway.
In the main we learn how to do things in collage, university, courses, or tool box talks, the idea of learning by trial and error raises the question can we really have the errors?
I think you are suggesting that I have an adaptable box near the CU. I gland into this and then take a sensibly sized cable into the Consumer unit. I appreciate that this will mean that the cable rating would be based on the smaller cable but 25mm is massively oversized and of course, this is a test rig...
If I have understood this correctly, I would appreciate any suggestions for this adaptable box please.
I think several people, including myself, have suggested that. As plugwash has said, what Sunray has suggested is 'esoteric' (i.e. something that I have never heward of people doing, even if there is enough space in the CU).
The rating of the [protective device will obviously have to be below that of the part of the cable with the lowest CCC - which, in the cae you mention, would presumably be that of the bit of cable between SWA and CU. That bit of cable obviously also has to have a high enough CCC fopr the load and, as I've said before, given the 'over-sized' SWA, it makes sense for the OPD to be rated per the load, even if all of the cables would be OK with a higher-rated OK.
I'm not sure why you ask this question again. As I said before, any box large enough to accommodate the SWA gland would do.
Kind Regards, John
I take it you are refering to qualified/competent electricians?
I take it no one on here deals with street furniture then?
Maybe not but I've only ever purchased them from wholesalers.
Yes I agree CU's and other enclosures can be very cramped.
I have to say I was sent on a training course with (what was then) Delta Cables and the fitting of a brass gland did not form a major part of the course EDIT; As they were still fairly new. There are other methods of terminating SWA and apart from the hot lead and pitch pots (which were demostrated only and not practiced) I see no raeson the other methods are currently ignored.
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I think the question is (in this DIY forum) how often anyone (qualified/competent or not) has used the method you describe to terminate SWA in a domestic installation - and I suspect (but, as always, may be wrong!) that the answer is probably "almost never".
Kind Regards, John
And why not when a brass gland into a plastic enclosure is not the most appropriate method?
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