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D

DanBrown

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Can anyone shed a bit of light on correct sizing of mains tails...
I am always let to believe that all cables need to be protected by the correct size fuse...
So i know in a domestic that 25mm2 is the minimum permitted cable CSA and can take 114 Amps.
What happens in a commercial building for example and has a 300A service head??, according to OSG the closest to match 300A is 95mm2 CSA and that can only take 284A.. What is the correct size to use?:)
Thanks in advance guys..
 
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S

Spudnik

  • Thread Starter Thread Starter
  • #3
I would think that you have 100A per phase, so in which case 25mm tails and 16mm M.E. would be fine.
 
D

DanBrown

  • Thread Starter Thread Starter
  • #4
No, i actually meant 300A per phase
 
K

kung

  • Thread Starter Thread Starter
  • #5
Hi Dan
300a per phase is 35mm they will always fit these to anything from 100A to 300A and CT whole currant ! only time this changes is in some factories where they dont norm have meters they fit a small sub station near/next to building which is 400A and run 50mm into building for supply !
Regards
Kung.
 
Last edited by a moderator:
G

Guest123

  • Thread Starter Thread Starter
  • #6
Personally I always use 70mm on a 400A supply.
 
K

kung

  • Thread Starter Thread Starter
  • #7
yes but we only use very small amounts compared to the millions of meters the DNO use so every little helps !
Regards
Kung
 

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