mm2 ampacity restrictions

[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:

 

[Marvo]

Depends on several variables such as cable insulation material, length of cable etc etc. Can you be more specific?

 

[Gardner]

Depends on several variables such as cable insulation material, length of cable etc etc. Can you be more specific?

Within a wall, conduit and within fiber glass insulation.

 

[jackhammerJIM]

What is a race way ?

 

[Gardner]

What is a race way ?

My mistake. A catch all term for conduit or tubing that holds the wires. The corrugated plastic tubing used frequently in IEC countries would be an example.


To clear up confusion, from the 2011 NEC:

 

[Darkwood]

He's American ..different lingo, at a guess a trunking or something like?

 

[Andy78]

I'm guessing trunking or maybe a chase

 

[shanky887614]

What is a race way ?

containment.

seen it decribed as tray,trunking etc on the interwebs

 

[jackhammerJIM]

im guessing ??????

conduit

 

[Gardner]

Correct! :biggrin: See post #5. Sorry about the pic though, I thought it was smaller when I uploaded it.

 

[Darkwood]

Correct! :biggrin: See post #5. Sorry about the pic though, I thought it was smaller when I uploaded it.

Our British Standards have differing factors to be applied when calculating the current carrying capacity of a cable.. as a raceway is a term that covers many installation methods as in post 5, there is no definitive answer. You need to be more specific.

Cable length
Cable type
Cable size
Specific installation methods (What is the containment in your case)
Nature of the load
Cable grouping
Ambient temp'........etc etc! - give us all this info and we can give you an answer, but its only applicable in the UK not in America, you will have to adhere to you own Electrical regulations

 

[rapparee]

Our British Standards have differing factors to be applied when calculating the current carrying capacity of a cable.. as a raceway is a term that covers many installation methods as in post 5, there is no definitive answer. You need to be more specific.

Cable length
Cable type
Cable size
Specific installation methods (What is the containment in your case)
Nature of the load
Cable grouping
Ambient temp'........etc etc! - give us all this info and we can give you an answer, but its only applicable in the UK not in America, you will have to adhere to you own Electrical regulations

In fairness to him he is talking about our sizes of cable (not awg), i think he is just trying to get a grasp of our cable relevant to his own yank cable.

 

[Darkwood]

Possibly Rapparee but my post will give insight as to what we need to know to answer his question, not knowing the American way its hard to approach this with any other answer unless the OP gives more detail or expresses why he's after this info..

 

[Gardner]

Our British Standards have differing factors to be applied when calculating the current carrying capacity of a cable.. as a raceway is a term that covers many installation methods as in post 5, there is no definitive answer. You need to be more specific.

Cable length
Cable type
Cable size
Specific installation methods (What is the containment in your case)
Nature of the load
Cable grouping
Ambient temp'........etc etc! - give us all this info and we can give you an answer, but its only applicable in the UK not in America, you will have to adhere to you own Electrical regulations

Ambient temp is around 86 degrees Fahrenheit max. The containment is mostly conduit with some SWA, PVC jacketed copper conductors encased in a wall for general equipment loads. The wall is insulted with fiber glass and covered with fiberglass panels. This is for a mobile trailer that is being wired to BS7671 standards since it will be used for export.


In so far, I converted the America wire gauges to mm2 and I calced around the following max amperage:

1.5mm2= 10amps

2.5mm2= 16amps to 20amps

4mm2= 20amps, 32 amps exposed

Of course this is just based on engineering calculations and some conservative estimates so it may be off from the actual code.

 

[davesparks]

Do you have a copy of BS7671?