Have a Project we are sourcing a transformer for.

We have a 208/120v 200amp 3phase panel to work from. We are trying to run 15 dehumidifier appliances that are 277v and draw 9amps each. Dehums will start at most 3 at same time, but will often all be running at same time. All 15 appliances on their own circuits, so 5 per phase equally balanced.

Electrician suggested a 480/277 panel (that we have already on site available to use) for distribution to the dehumidifier appliance circuits, and a transformer between the 208/120 feed panel and the 480panel that will only be used for these dehumidifiers.

Can you recommend a specific transformer for this application, and availability? And 3pole breaker size on the 208 panel to feed it.

Thanks