I need to get from 480 to 208 and need 200amps what size transformer do I need?

480 X 200 = 96,000 Watts(VA)

I would wait for an answer from TK, Stanforty, or Missouri, or other qualified.

200 Amps x 208 volts x 1.73 = 71.968 KVA

You need a standard size 75 KVA transformer.

Check with your supplier for pricing and what the customer needs are, may need isolation, K rated, Low Temp, etc.

Do need to consider, is the total connected load 200 amps?

Can load a transformer 80% of nameplate rating.


Since your dealing with 480 volts, I assume you're an electrician and know all the rules regarding transformers, feeder rating, etc.

Thanks tkrussell

Your welcome, Soupy,but you did not answer my questions about calculated load and your qualifications.

By the way, my calculation includes a shortcut I did not show.

The actual formula is: KVA=I x E x 1.73/1000

Using your values:

KVA = 200 Amps times 208 Volts x 1.73 (assuming 3 phase) and divide by 1000 will result in 71.968 KVA

You can see this and other useful power formulas here:

Useful Formulas (http://www.elec-toolbox.com/Formulas/Useful/formulas.htm)