Lighting transformer wiring

[karn]

I'm only about 90% sure on wiring this, I'd like to be 100%.

There's 2 sets of wires, set one is labeled COM and 120, set two is labeled COM and COM.

Would it be safe to say the COM paired with the 120 is the 277 input, and set two would have 1 COM for 277 neutral and 1 COM for 120 neutral?

 

[ActionDave]

It looks to me like you got one to many Comms. Where is the 277V hot?

 

[karn]

Yeah that's what I'm trying to figure out

 

[infinity]

Is the conductor grouping in photo #2 from the factory? If so I would just follow that. You could ring it out with an ohmmeter.

 

[ActionDave]

Looks to me like the comm paired with the 120V goes out to the light. You could test it by hooking the other two up to 120V and see what the out put on the orange and white is.

 

[karn]

I wired up the com from set 1 to 277 and 1 COM from set 2 to the 277 neutral, it is outputting 120 from the 120 leg to the other com in set 2, I'm assuming they just made a manufacturing error and used a com wire instead of the 277 wire

 

[karn]

I solely based my assumption off the fact that I have seen lighting transformers from 277 to 120 that only had 1 neutral and the 277 neutral had to be tied to the 120 neutral in that specific diagram and on this one it appeared to be grouped in a similar way in this diagram

 

[synchro]

I solely based my assumption off the fact that I have seen lighting transformers from 277 to 120 that only had 1 neutral and the 277 neutral had to be tied to the 120 neutral in that specific diagram and on this one it appeared to be grouped in a similar way in this diagram

It sounds like you wired it up correctly based on your measurements in post #6. You should be able to confirm which of the "COM"s is for the two neutrals because the resistance between the two should be very low because they are tied together as you mentioned. You'd likely measure the same resistance between these two COMs as when you short your two meter probes together (which may or may not show exactly zero ohms).