100m cable run

uksparks · May 26, 2015

Hi,

you know that thread about running 100m of cable on a farm and it works out at approx 70mm.

just thinking out loud here, how would you terminate 70mm into a consumer unit? Clearly you can't, so what would you use? I was going to say a switch fuse but that's not appropriate.

its not a problem I have come across to be honest.

also you would have the same issue at the supply end.

shanky887614 · May 26, 2015

uksparks said:
Hi,

you know that thread about running 100m of cable on a farm and it works out at approx 70mm.

just thinking out loud here, how would you terminate 70mm into a consumer unit? Clearly you can't, so what would you use? I was going to say a switch fuse but that's not appropriate.

its not a problem I have come across to be honest.

also you would have the same issue at the supply end.

how would you struggle, gland it and be done with it, if there is no space in the board mount into a header or similar

uksparks · May 26, 2015

I meant you can't terminate it straight into the board so you would have to take it into a suitable enclosure and join in or connect to a smaller CSA CABLE.

shanky887614 · May 26, 2015

uksparks said:
I meant you can't terminate it straight into the board so you would have to take it into a suitable enclosure and join in or connect to a smaller CSA CABLE.

like i said a trunking header or adaptable box, the cable size is only to account for vd so doesnt need to be that size for the full length, as long as it is joined properly then there wont be an issue

uksparks · May 26, 2015

That's what I was presuming, so long as the smaller cable is capable of carrying the load and is protected by the OCPD, there's no problem.

Leesparkykent · May 26, 2015

uksparks said:
Hi,

you know that thread about running 100m of cable on a farm and it works out at approx 70mm.

just thinking out loud here, how would you terminate 70mm into a consumer unit? Clearly you can't, so what would you use? I was going to say a switch fuse but that's not appropriate.

its not a problem I have come across to be honest.

also you would have the same issue at the supply end.

Ideally you wouldn't be installing it on an mcb at the supply end as this makes for bad practise due to discrimination etc. At the supply end installing a switch fuse and glanding in to this would be an option and at load end in to an isolator and taking appropriate sized tails for the OCPD in to the CCU at the load end.

Darkwood · May 26, 2015

It was a 3 phase supply so the board you choose ensure it has an option of terminal stubs for larger cables or a expansion option to fit a large incomer switch disconnector or mccb ... this is the correct way but many cut corners with adaptable boxes etc and tails to reduce the swa csa.

Leesparkykent · May 27, 2015

darkwood said:
It was a 3 phase supply so the board you choose ensure it has an option of terminal stubs for larger cables or a expansion option to fit a large incomer switch disconnector or mccb ... this is the correct way but many cut corners with adaptable boxes etc and tails to reduce the swa csa.

i thought it was a single phase supply to the barn conversion.

Darkwood · May 27, 2015

I was reflecting on this thread
http://www.electriciansforums.co.uk...l-electrical-forum/102617-100m-cable-run.html

But the same applies if one Phase.. you can fit a 3phase board and single phase it out with a kit if you cannot find a suitable 1ph option - its poor design to be doing de-rating joints outside the board unless you want to go to the expense of the proper kit but then the above option for this case becomes the better of the two.

Standard incoming 100/125 amp disconnectors usually good to 50mm so you fit the more expensive larger switch disconnector or mccb if needing 70mm - this is why they make mccb's etc to take larger cables to allow for such large runs and larger cabling ...

davesparks · May 27, 2015

Reducing lugs (aka pin lugs) are available to make bigger cables fit into smaller holes if the size difference isn't too much and there is room to sensibly terminate the bigger cable in the enclosure.

If extra room is needed to spread the cores at switchgear or bigger boards then a spreader box is used. For smaller boards you have to make your own spreader box using an adaptable box or a bit of trunking.

Marvo · May 27, 2015

Palm lugs, pin lugs, blade terminals....

Darkwood · May 27, 2015

I mentioned them in post 7 abeit calling them terminal stubbs but went off on a tangent as some set-ups means they are hard to fit unless you have expansion box you end up with bends too tight and hard up pressured against the case due to the compact designs of some boards but yes deffo the best option if they fit.