SWA current capacity.

[jam2020]

what is the current carrying capacity for 16mm 3 core swa with>100mm thermal insulation?b2 7671 0nly gives tables for ref method c d and e.

 

[jam2020]

anyone????

 

[sparx24]

Agreed no direct table but looking at tables for other types seems to give a rating of 80% of 'clipped direct' rating so can only use 'rule of thumb' IMHO

 

[jam2020]

i want to run an swa for a sub main of 80a ref method 101. looking like it will have to be in 25mm swa,would you go along with that sparx24???

 

[pushrod]

how are you installing it and how much insulation? More than 500mm?

 

[jam2020]

clipped direct to wood but buried>100mm insulation. method 101

 

[sparx24]

Maybe an easy answer but may not be required, you say 3 core but if only running single phase then use table column 2 not 3.
Also use table 4E4A for xlpe if thats what you are using not 4D4A, lastly can the cable not be clipped above the insulation?
Going up to 25mm jumps the price a lot since it not 'booklet' size for pricing, although it will of course help Volt-drop/Zs readings.

 

[simonspark]

I may be wrong because I havent checked it, but Im sure method 101 is for flat twin and earth

 

[jam2020]

Yes it is for twin and earth problem is there is no table for swa covered in insulation. Think I may just go 25 and have done with it better safe than sorry although stil no rating given for 25

 

[piccollo]

Correct, 101 is Tw/e. also correct column 2 table 4E4A. You could argue & say ref method D, although this is buried in ground, temperature could be lower, but 90 degree C armoured, should be safe in insulation. You dont say length of run. I've got 3 core 16mm2 buried under my insulation & loft flooring run for 6 mtrs, had no warm / heat problems,although it was on top of insulation & has got good air circulation near eaves. piccollo

 

[jam2020]

Ordinarilly I would do just that but it is worrying me abit that there is no definitive answer

 

[jam2020]

Cable run about 8 metres

 

[pushrod]

what is the current carrying capacity for 16mm 3 core swa with>100mm thermal insulation?b2 7671 0nly gives tables for ref method c d and e.

I had not realised initially that you were talking about depth of insulation, hence my previous post

I would rate it as clipped direct but de-rated by 50% because of the thermal insulation so table 4D4A - 89amps derated to approx 45A.

 

[jam2020]

Where do you get 50% fom?

 

[telectrix]

try AEI cable finder wizard.( google AEI Cables) i think 16mm is adequate. if XLPE.