Running cables in parallel.

[securespark]

Have read a few threads about running two smaller cables in parallel instead of one larger one.

Is this strictly within regulations?

Just something someone said to me a long time ago about this - I can't remember what the explanation was, though, but the guy said it did not comply with regs for some reason or other.

 

[passerv]

BS 7671

523-02-01

 

[securespark]

Cheers!

 

[holmslaw]

..

 

[ColJack]

so to paraphrase the above quoted reg...

yes, you can do it as long as the cables are the same size, length, and material and have no branches off one to unballance the load?

 

[Lectrician]

Only ever done it once, and that was on a run from a 630amp generator to the changeover switch. Even then I recall we used 4 runs of 185mm 4 core alu armour. The four cores in each cable where put into a single alu lug. Each cable was effectively a single core. I believe it would have had to have been over a 600mm cable otherwise.

 

[plugwash]

why did you use 4 core with the cores commoned rather than big single core? was it just a matter of what you had handy?

 

[sparkydude]

We did it last year on a job in wales, 4x4 core 185mm SWA cables lugged off to the same termianls of a switch fuse at one end and to the incoming terminals of a large 1600A mccb the other end, all four cores of the cable to their relevant phase terminals. Lot of hard work, abut did the job in the end. We only used the 4 cables as it worked out a hell of a lot cheaper than a big single core armoured strangeley

 

[ricicle]

As long as the cable has non-magnetic armour

 

[ColJack]

what part of the reg states non magnetic armor?

 

[passerv]

Think thats

521-02-01

 

[ricicle]

Think thats

521-02-01

That's the one - you just beat me!

Cables for a.c circuits - electromagnetic effects

 

[ColJack]

so to once again clarify...

reg: 523-02-01 says...

yes, you can do it as long as the cables are the same size, length, and material and have no branches off one to unballance the load?

but

reg: 521-02-01 says....

you can't run AC down a SWA single...?

just out of curiosity then, why do they make single core SWA?
presumably for DC.. but then what kind of load can you run off a 250mm² single SWA?
that's a hell of a battery charger....

 

[ricicle]

No - most (if not all) single core armoureds have non - magnetic armour anyway (usually Al) so they can be used on a.c. circuits.

I was concerned that a 4 core swa (which will probably have magnetic armour) was being used as a single core and thus leading to the possibility of eddy current heating in the armouring

 

[ColJack]

SWA = Steel Wire Armored..

so my sumation is correct..