Just a quickie. Just reading the instructions for a new 6kW water heater
and it says to calculate cable section as 5A/mm2 for runs under 20m. The
existing cable is 4mm2 but by this reckoning it's too lightweight. I
thought 4mm2 cable was 30A?

Am I wrong, and therefore need to replace the existng cable with 6mm2, or
is 4mm2 fine for a 6kW load?

In article , Danny Monaghan
writes
Just a quickie. Just reading the instructions for a new 6kW water heater
and it says to calculate cable section as 5A/mm2 for runs under 20m. The
existing cable is 4mm2 but by this reckoning it's too lightweight. I
thought 4mm2 cable was 30A?

Am I wrong, and therefore need to replace the existng cable with 6mm2, or
is 4mm2 fine for a 6kW load?

I agree with you, as does the TLC calculator (for all routings except "buried
in a thermal wall").
http://www.tlc-direct.co.uk/Technica...ltageDrop.html
--
fred

"Danny Monaghan" wrote in message
...
Just a quickie. Just reading the instructions for a new 6kW water heater
and it says to calculate cable section as 5A/mm2 for runs under 20m. The
existing cable is 4mm2 but by this reckoning it's too lightweight. I
thought 4mm2 cable was 30A?

Am I wrong, and therefore need to replace the existng cable with 6mm2, or
is 4mm2 fine for a 6kW load?


Cable resistance over 20mtrs on 4 mm csa' is not good, as the instruction
book says, but actually, if the cable run you're making is on or over 15mtrs
in length, then you will need a heavier gauge cable to reduce losses? If it
is over 15mtrs, then you will need to make the cable run in 6 or 10 mm csa'
cable for the load you have on the water heater. You will get away with 4
mm csa' up to 15mtrs for a 6kW load, but only to that length.