Ampage of a wire

[scottb]

HI,

Could anyone tell me what is the maximum ampage that can be drawn down a twin and earth 2.5 and 1.5mm cable

Thanks

 

[andy]

HI,

Could anyone tell me what is the maximum ampage that can be drawn down a twin and earth 2.5 and 1.5mm cable

Thanks

depends on many factors. clipped direct for 2.5mm is 27A. 1.5 is 20A

other stuff like thermal insulation etc affects the rating

 

[scottb]

The place I work has a heater which has a motor that pulls 28A on start up and a running current of 6A

The heater will run on its own breaker

The electrican that came said a 2.5 or 4.0mm would do the job

Seems small for a motor that requires that much amp to start up...?

The cable runs through trucking in an open and cold factory for the length of 15m

thanks

 

[vince knight]

I would wire it in 4mm to be on the safe side.

Vince

 

[Adam_151]

its not so much a case of current carrying capacity (6A is neither here nor there), but a case of keeping your Z's in spec, its going to have to be a C rated breaker, I'd go for a C10 and work from there, which gives you 1.92 ohms as your max Z's , which in all honesty shouldn't be that difficult to meet, whats the Z's at the distribution board this is going to be fed from?

 

[scottb]

Not sure of the Z's at the board until tomorrow.

Will the C10 be enough to cope will the intial 28A draw ??

 

[Big_Spark]

C10 will easily handle the momentary 28A startup current drawn by the motor, and depending on the run length from the source and the ambient temperature of the environment, as well as other factors, 2.5mm T&E will be sufficient.

 

[Spark123]

According to the charts in the regs a C10 will take 30A for 40s.