# Question about copper conductor size.

Discussion in 'Electrical Engineering' started by Peter Jason, May 8, 2006.

1. ### Peter JasonGuest

I have a large electric oven rated at 15KW
resistive load, plus another 3KW for 3-phase
induction motors.

Say 18KW total continuous running.

All this has to be connected to a 3-phase
supply in delta.

How can I determine the conductor size for
each of the 3-phase connections in Amps?

2. ### Peter JasonGuest

message

PS the 3-phase is 415V

3. ### Peter JasonGuest

"TimPerry" <>
wrote in message
Many thanks; The electrician left out the
SqRt3=1.732 in the denominator.

I get Amps = 18000/(1.732 x 415) = 25amps /
conductor

Regards

4. ### Guest

I get 8ga copper. 31.3a
(using the 1.73 factor to account for 3p, and 125% of computed load)

5. ### Peter JasonGuest

message
It runs continuously and unattended during
the off-peak tariff times at night.

It is used for the melting the contents of 4
x 200L (55usg) drums on standard pallets.

It has forced-air circulation directing hot
air to the underside of each drum via air
injectors, by means of a hot-air blower.

It operates at up to 110degC.

6. ### Guest

You are looking at MI cable now. How is your wallet ;-)
6ga MI will be plenty, you still might be able to get away with 8 but
it is shaky