If you are finding that you can't do your job without asking on a DIY advice forum about how to work out conductor sizes because you haven't learnt how to do it then you have not yet learnt enough to be considered an electrician.
Main supply and earthing conductor
- Thread starter sherman0251
- Start date
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I got the impression that the OP was asking for opinions on reliance on the SWA armour (opinions about which, as we know, vary amongst electricians), rather than about the adequacy of the CSA of the SWA armour.
Kind Regards, John
To be fair to the op, you can have all the qualifactions and a lifetime of experience, and still come up against a problem you're not sure about.
And yes, we are all still learning all the time.
Besides cable calculations, the task in question isn't as typical as one may initially think.
Running SWAs to meter boxes is a bit unusual when most of time one just runs some tails in the cavity of the house wall between the meter box and the cu.
While it may look bad the op asking for advice on a DIY forum, we all know this forum is more than just DIY.
Many pros, including myself, have asked for advice and opinions to one another on this site, and got some very helpful replies.
It's that what makes this forum so special.
And yes, we are all still learning all the time.
Besides cable calculations, the task in question isn't as typical as one may initially think.
Running SWAs to meter boxes is a bit unusual when most of time one just runs some tails in the cavity of the house wall between the meter box and the cu.
While it may look bad the op asking for advice on a DIY forum, we all know this forum is more than just DIY.
Many pros, including myself, have asked for advice and opinions to one another on this site, and got some very helpful replies.
It's that what makes this forum so special.
Thanks sparkwright. You hit the nail on the head as I have never come up against this situation before.
Am I right in saying that I can run a 5c 35mm SWA out of the DNO Meter cabinet cleated to the wall and up into my cabinet glanded into my switch fuse.
Am I right in saying that I can run a 5c 35mm SWA out of the DNO Meter cabinet cleated to the wall and up into my cabinet glanded into my switch fuse.
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I'm not sure.
Will 35mm cable even fit into the DNO meter terminals?
Can you do it so no single insulated wire shows anywhere?
Would it be easier to run tails between the cabinets, will they be too 'unprotected'?
What exactly is the 'switchfuse' you intend to use?
Have you ever handled a 5c 35mm SWA before?
Will 35mm cable even fit into the DNO meter terminals?
Can you do it so no single insulated wire shows anywhere?
Would it be easier to run tails between the cabinets, will they be too 'unprotected'?
What exactly is the 'switchfuse' you intend to use?
Have you ever handled a 5c 35mm SWA before?
If the cabinets are next to each other (or very nearly so), I still think it would probably be easier to join them with suitably sized conduit and run singles across (insulated & sheathed for the three lives & neutral, of course). The SWA will involve a lot more messing around in the intake cabinet to connect up to the meter satisfactorily.
I've asked questions on here about things I'm not sure about. Sometimes because I don't know the answer, and sometimes either for a bit of reassurance or to see if there is an easier / better way of doing things.
That aside, I think the biggest issue here is going to be the physical size of the cable.
You'll need a switch fuse with terminals big enough to take the cores which may mean using an over-rated switch fuse with appropriately sized fuses. I don't think it'll be possible to terminate a cable that large inside a standard polyphase meter box, so you'll need something like a sarel cabinet. Also as mentioned, I don't think 35mm² conductors will fit in a standard ≤100A electricity meter.
The other option is to underground resin joint the cable to a smaller size for the final termination. I have done this previously where 95mm² SWA was required for a long 100A supply to overcome the VD.
That aside, I think the biggest issue here is going to be the physical size of the cable.
You'll need a switch fuse with terminals big enough to take the cores which may mean using an over-rated switch fuse with appropriately sized fuses. I don't think it'll be possible to terminate a cable that large inside a standard polyphase meter box, so you'll need something like a sarel cabinet. Also as mentioned, I don't think 35mm² conductors will fit in a standard ≤100A electricity meter.
The other option is to underground resin joint the cable to a smaller size for the final termination. I have done this previously where 95mm² SWA was required for a long 100A supply to overcome the VD.
Could it not be a resin joint above ground ? Or "Henley" blocks able to take the two sizes of cable ?
Forgive me if I'm being stupid but surely instead of messing around with resin joints & henleys, the connection from meter to switch fuse only needs to be 25mm, which will fit in meter & switchfuse, and then 35mm from switchfuse to DB?
Even the 800KMF etc. (and they don't come any smaller than that!) claims to have a 35mm² terminal capacity - although I can't say I've ever tried anything bigger than 25mm² (which fits easily).
Kind Regards, John
Kmf800 is no good for a TP supply, nor can you gland an armoured into it.
I was referring more to having enough room to phsically get the conductors bent and dressed to the terminal positions.
I was referring more to having enough room to phsically get the conductors bent and dressed to the terminal positions.
I realise that, but was pointing out that even the (AFAIAA) smallest switch-fuse in existence claimed to have 35mm² cable capacity.
Kind Regards, John
The terminals will accept 35mm² conductors but you're going to need a larger enclosure to physically gland and then dress the large conductors into position.
Indeed - one would certainly need an 'adequately large' enclosure.
Kind Regards, John
An MEM Exel2 3P+N switch fuse would fit in this meter cabinet, giving you enough room to gland SWA, assuming you brought it in nice and straight from the bottom
Cab 520w x 750h x 210d
Switch 367w x 503h x 167d
But just for the cab and the switch is going to be in the £600 range, that's before you add in 30m of 35mm 4core armoured + labour
I'd be at least getting a quote to get that supply brought up to the house
Cab 520w x 750h x 210d
Switch 367w x 503h x 167d
But just for the cab and the switch is going to be in the £600 range, that's before you add in 30m of 35mm 4core armoured + labour
I'd be at least getting a quote to get that supply brought up to the house
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