Voltage Drop help?

[aytac]

Anybody can help me selecting molded case circuit braker and conductor size for transformer and main panelboard .

there is a transformer primary 120/208
secondary 220/380V,30KVA.
cable connecteed primary length 135m.
cable connected secondary is 5m.
What would be cable size and molded case circuit braker will be in feeder panelboard.
Thanks.

 

[templdl]

Re: Voltage Drop help?

Your transformer rating doesn't make sense. From what I guess the transformer probably is 3ph with a 208y/120 primary and a 380y/220 secondary making it a wye-wye which would be very unusual for a small 30kva transformer.
If it were a single phase is the primary 208v which can be reconfigured to be applied at 120v? And the secondary, is it 380v with a tap at 220v?

 

[cselectric]

Re: Voltage Drop help?

Actually, the transformer configuration makes perfect sense... in europe. Anyone good with mtric conversions?

 

[bennie]

Re: Voltage Drop help?

The transformer makes sense in the US. I don't think it is needed in Europe.

Multiply 1.094 times 135 metres to find yards. Multiply yards times 3 to find feet.

Your numbers are 443 feet, and 16.41 feet. respectfully.

The primary at full load is 83 amps.

The rest of the math is yours