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chaplainvern · Dec 14, 2007, 07:08 AM

I have a manual transfer switch that I want to use between my house circuits and my 5000 watt generator. I have 3 wire #10 receptical existing from the circuit box over to where my generator sets (it is exhausted outside). Can I use this 3 wire line to connect my transfer switch to my generator or do I have to go to 4 wire recepticals etc? Thanks

hvac1000 · Dec 14, 2007, 08:47 AM

Check with your local code authority. Manual transfer switches are not allowed in some jurisdictions unless it completely isolates the main incoming voltage from the pole or underground, and that switch is very expensive. Since this is 220 volts you will need a dedicated ground of some type because the neutral wire carries current when used in a 115 volt situation.

All work should be inspected because if not done correctly your generator can back feed into the utilities line and kill someone working on the line down the street. You do not need a lawsuit from this so get it inspected then if something does go wrong you will at least have a back up witness in court.

labman · Dec 14, 2007, 11:24 AM

Is it 10-3 or 10-3 with ground? You need the neutral and ground isolated at the generator and then a 4 wire connection from it to your house wiring. Hots to the switch, and ground and neutral to the panel the generator is connected to. Check the receptacle, even a 3 prong one may have a 4 conductor cable to it. My old dryer does. If you don't have a solid 4 wire set up, your furnace may not work.

Expensive? For $150 I got a UL approved interlock plate that allows me to use any circuit in my house with the generator. You may get one for a modern GE or Square D box for less. If you already have a 240 volt circuit you can dedicate, that is all you need. Less work to install too. You may want to take the switch back. For details, see https://www.askmehelpdesk.com/electr...se-123290.html

If you have to run new wire, I think the coil of 10-3 with ground I bought was only $30. You can't use the circuit feeding from the generator for anything else.