Single Phase Panel fed by a Three Phase Transformer

[jchristopherslice]

We were asked to create construction drawings for a commercial retail space where the owner wants to reuse the existing panels. The 480V panel feeds a three-phase transformer. However, the secondary side of the transformer appears to feed a 120/240V panel. It appears to function, but is this allowed by the code?

 

[petersonra]

We were asked to create construction drawings for a commercial retail space where the owner wants to reuse the existing panels. The 480V panel feeds a three-phase transformer. However, the secondary side of the transformer appears to feed a 120/240V panel. It appears to function, but is this allowed by the code?

This is common because single phase 240/120 panel boards are cheaper than 208/120 3 phase panel boards.

 

[cyriousn]

We were asked to create construction drawings for a commercial retail space where the owner wants to reuse the existing panels. The 480V panel feeds a three-phase transformer. However, the secondary side of the transformer appears to feed a 120/240V panel. It appears to function, but is this allowed by the code?

Is the transformer part of the design as new equipment or is it existing? If the transformer isn't existing, just use a 480V to 240V/120V transformer instead.

If existing, wouldn't 110.3(b) come in to play for using equipment for it's intended listed purpose? Are there any 240V loads that will be effected by being served by 208V? Are the OCPD amperages sized correctly based on only having 2 poles seeing the loads? Why

 

[petersonra]

Is this by any chance a 480 to 240 transformer with one side center tapped? Also common if most of the loads are 240 but you also need some 120 vac stuff.