120/240v single phase subpanel fed from 208y/120v three phase main breaker panel

[chris k baker]

I'm looking for suggestions on the best way to run a 60 amp 120/240 single phase subpanel from a 208y/120 three phase panel. Is a buck boost transformer needed, etc. Thanks for any help!

 

[infinity]

Are you looking for 240 volts that's why you need a transformer?

Welcome to the Forum.

 

[chris k baker]

The subpanel is a pool automation panel that is single phase.

 

[infinity]

The subpanel is a pool automation panel that is single phase.

So it won't work with a 208 volt supply it's requires 240 volts?

 

[chris k baker]

Some of the pumps are not rated for 208

 

[LarryFine]

Welcome to the forum.

For an automation system, I suggest a step-up, not a buck-boost.

I believe the line-to-neutral voltages will matter more.

 

[infinity]

Welcome to the forum.

For an automation system, I suggest a step-up, not a buck-boost.

I agree.

 

[retirede]

Some of the pumps are not rated for 208

Most pool pumps today are powered by a VFD. If so, I would think that the drive could handle the voltage difference.

 

[ActionDave]

Some of the pumps are not rated for 208

I would double check. There aren't many single phase motors that aren't usable at 208V.

 

[winnie]

Welcome to the forum.

For an automation system, I suggest a step-up, not a buck-boost.

I believe the line-to-neutral voltages will matter more.

This.

Buck-boost transformers are ideal if you need straight 240V. But if you need 120/240V they are bad. When you use a normal buck-boost on a 208V system, one L-N voltage is 120V; the other leg ends up about 146V L-N.

If you fed a panel and could _guarantee_ that your 120V loads were on the 120V leg... (what is the likelihood that something gets changed 5 years down the road and a 120V device gets hit with 146V??)

If you want a 120/240V panel, use a step up transformer as @LarryFine suggests.

The other option worth considering is to feed the panel with 208V, and then use individual buck-boost transformers for the specific L-L loads which require 240V.

-Jonatahn