This panel feeds most of the general loads at the Co-gen for the company we work for... I've not seen 240Y/120V anything before... then it says 1Ø and there are 3Ø breakers inside (I haven't had a chance to remove the cover, I'm almost afraid to!) nor do I know the meaning of "bypass", but I'm hoping it isn't a backfeed from the UPS system.

The last pic is in the room with the UPS batteries and inverter... No one I've talked to can offer a clue as to why the fan was installed this way!

Few guesses would be:

1. The 3 poles are terminated only on two legs. The cheap thing to when you have a couple of spares sittng around and plenty of spare spaces to waste.

2. The wrong dead front was put on from a single phase panel

3. Split bus-panel

Longshot on them all but I go with number 1. I like the "service diconnect" for the fan? at the bottom of the post.

___No one I've talked to can offer a clue as to why the fan was installed this way!____

I work "inside". I know why.
They are too damn lazy to go to the supply room and get what they need!!! It may run into their break!!!.
All day to do it right! No time limits, etc,etc,etc... Yet, this is what they do.
Disgusting.

I see it every day. No way do I meen to infer that all inside guys/gals are this way. BUT.. the majority are!

Thats sad.

FDB breaker in that Box ?? it sure don't look right at all and very instering to see the label printed wrong if that is the case.

Merci,Marc

I suspect that the fan is wired that way so that the fan can be plugged in to the UPS during an extended outage.

Is there a transfer switch at the UPS output, or maybe built in to the UPS to allow the load to be powered while the UPS is taken offline for servicing?

Is there a transfer switch to allow the UPS to be powered by a generator, separated from the building power? That could also explain the fan wiring, since during heavy charging is when you would really want to have that fan operational.