frederic
New member
Currently, I have four APC SmartUPS 1400 units, each on it's own 15A single pole breaker, those breakers in a subpanel.
The subpanel is fed 240V @ 30A, and in the main panel there's a double pole 30A breaker.
At some point I decided to install a 20A 3-way switch between one of the UPS units and the 15A breaker that feeds it, allowing me to select between that breaker (mains) and a generator. The 3-way switch is a break-then-make type.
The generator provides 240V through an L14-20 connector, so I've connected the black (120V hot) to the 3-way switch, the white (neutral) to the subpanel's neutral bar, and the green (ground) to the ground screw in the subpanel as well.
This leaves the red (hot) available to drive the sump pumps, and I could do that with a 3-way switch as well. However, the neutral of the sump pump feed goes to the main panel and not the subpanel. The subpanel cannot support another circuit physiically or in ampacity, at least without uprading the panel, the wire, running conduit, and so on. A job quite honestly, I would like not to do due to time, expense and complexity (the path is insane).
So the question is, how does the sump pump get "neutral" from the generator, safely and legally.
Any ideas?
Here is the diagram.
http://frederic.woodbridgedata.com/_diagrams/ups-generator.jpg
The subpanel is fed 240V @ 30A, and in the main panel there's a double pole 30A breaker.
At some point I decided to install a 20A 3-way switch between one of the UPS units and the 15A breaker that feeds it, allowing me to select between that breaker (mains) and a generator. The 3-way switch is a break-then-make type.
The generator provides 240V through an L14-20 connector, so I've connected the black (120V hot) to the 3-way switch, the white (neutral) to the subpanel's neutral bar, and the green (ground) to the ground screw in the subpanel as well.
This leaves the red (hot) available to drive the sump pumps, and I could do that with a 3-way switch as well. However, the neutral of the sump pump feed goes to the main panel and not the subpanel. The subpanel cannot support another circuit physiically or in ampacity, at least without uprading the panel, the wire, running conduit, and so on. A job quite honestly, I would like not to do due to time, expense and complexity (the path is insane).
So the question is, how does the sump pump get "neutral" from the generator, safely and legally.
Any ideas?
Here is the diagram.
http://frederic.woodbridgedata.com/_diagrams/ups-generator.jpg
