G
Gardner
Under BS7671, what is the amperage of 1.5mm2, 2.5mm2 and 4mm2 copper conductor restricted to when inside a race way or cable of no more than 3 current carry conductors? Thank you! :smiley2:
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Discuss mm2 ampacity restrictions in the UK Electrical Forum area at ElectriciansForums.net
A couple ot three comments in no particular order.
Wire nuts went under the name "Scruit" not screwit - that's a whole different thing. Particularly if you spell whole incorrectly. Scruit was/is a trade name IIRC.
RS Components and others still supply them.
As far as I can tell, they are not illegal in UK. I see nothing in BS7671 that proscribes their use
No, I haven't seen them used in at least 40 years. In any case, the need for them has largely gone away. Fittings have screw terminals on which to land conductors that just need to be connected together.
And the mention of amperage (a horrid non-word IMHO) in the opening post was a pretty good clue that the poster was American. Yank? Maybe not. That would depend on which side of the Mason-Dixon line he's from.
My sweet Southern Belle would be quite offended, horrified even, to be called a Yank.
origional poster
forget posting here
go to an american site
And the mention of amperage (a horrid non-word IMHO) in the opening post was a pretty good clue that the poster was American. Yank? Maybe not. That would depend on which side of the Mason-Dixon line he's from.
My sweet Southern Belle would be quite offended, horrified even, to be called a Yank.
Apologies to the potential redneck johnny reb, if he is from the south ... long live the confederacy and the south shall rise again etc etc
A couple ot three comments in no particular order.
Wire nuts went under the name "Scruit" not screwit - that's a whole different thing. Particularly if you spell whole incorrectly. Scruit was/is a trade name IIRC.
RS Components and others still supply them.
As far as I can tell, they are not illegal in UK. I see nothing in BS7671 that proscribes their use
No, I haven't seen them used in at least 40 years. In any case, the need for them has largely gone away. Fittings have screw terminals on which to land conductors that just need to be connected together.
And the mention of amperage (a horrid non-word IMHO) in the opening post was a pretty good clue that the poster was American. Yank? Maybe not. That would depend on which side of the Mason-Dixon line he's from.
My sweet Southern Belle would be quite offended, horrified even, to be called a Yank.
Table 4D2A – Multicore 70c thermoplastic insulated & thermoplastic sheathed cables (e.g. PVC T&E), non-armoured.* All values assume an ambient temperature of 30c and a conductor operating temperature of 70c.*
Im assuming reference method a
1.5mm = 14A
2.5mm = 18.5A
4mm = 25A
My sweet Southern Belle would be quite offended, horrified even, to be called a Yank.
Our calculations work a bit differently to that,
We select an OCPD rating based on the load to be supplied, then apply correction factors for temperature, insulation, grouping etc to that, then the result of that calculation is used to select cable size.
The cable selected will be whatever has a rating equal to or higher than that calculated value.
After that voltage drop, CPC size and earth fault loop impedance calculations are carried out to ensure compliance with those rules.
The exception to the rule is a fixed load which by its nature is not subject to overload, on this case the cable size calculation is based on the actual load and not the OCPD rating.
I have to wade through the NEC with no help, you can do the same for BS7671.
What would you like to know?
Reply to mm2 ampacity restrictions in the UK Electrical Forum area at ElectriciansForums.net