Generator connection mystery

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Old 10-24-20, 06:50 AM
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Generator connection mystery

I bought a DeWalt DXGNR 8000 generator. When I hooked it up to my circuit breaker panel in the house, I found something baffling. Some of the circuits work, and others don’t. It seems to be random—various parts of the panel, powering different areas of the house. Even if I turn off the breakers for all the big items (fridge, well pump, etc.), and only try to power a light on one of these circuits, it does not work. My voltage reads 121.5. When I turn off the generator and reconnect to the grid, everything is fine. What could be going on here?
 
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10-24-20, 09:33 AM
pattenp
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Your generator connection is not legal and dangerous and puts you in a position to be liable for injury to power workers servicing power outages if you forget to disconnect the service.
 
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Old 10-24-20, 06:57 AM
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My first guess is that only one leg of the 240v feed is connected. Typically, this is every other breaker in the panel. I'd measure across a 240v breaker (dryer, oven, etc). you should see 120v from either hot terminal to ground, and 240v between the two hot terminals.

Next question of course is how the generator is connected. Cable to an inlet to a transfer switch? Interlock?
 
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Old 10-24-20, 08:50 AM
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The breaker panel is designed for 240 VAC input. You made a 120 VAC connection from your generator so only the 120 vac breakers on one side (electrically) are powered. Before connecting the generator's output (120/240 VAC) to the panel, you must insure the grid is disconnected first and second, the loads that are ON (via switches or breakers) don't exceed the 8000 watt rating of the generator or you will destroy the generator and maybe some loads. What are you doing before connecting the generator?
 
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Old 10-24-20, 09:08 AM
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This is an older set up with no transfer switch or interlock or anything like that. It just plugs into an outlet that is connected to one circuit in our panel. When needed we disconnect from the grid and turn on the generator circuit and start the generator.

​​​​​​ The test that Zorfdt suggested shows that one terminal to ground produces a 120 , but the other terminal to ground produces zero and one terminal to the other produces zero.

I suspect the problem has to do with the fact that I bought a new generator and had to put a new connector on my wire to plug into the generator because it was different from the old Generator. There are four wires: White, black, green, and red. Should I try switching two of them?
thank you!
 
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Old 10-24-20, 09:33 AM
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Your generator connection is not legal and dangerous and puts you in a position to be liable for injury to power workers servicing power outages if you forget to disconnect the service.
 
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Old 10-24-20, 10:31 AM
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There are four wires: White, black, green, and red. Should I try switching two of them?
Please don't just switch wires. You need to figure out the correct wiring for the plug you're using and wire both ends correctly.

Agreed with Patten too, a transfer switch is definitely something you need to get installed. I hope you're also not using a suicide cord (two male plugs). There are too many cases of generators catching fire or injuring line workers because of no transfer/interlock switches installed.
 
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Old 10-24-20, 12:24 PM
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My understanding is that it would be illegal to install a system this way now, but it is not illegal to have one. It's only my wife and me and we always throw the main breaker before connecting the generator. But thanks for the reminder...
 
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Old 10-24-20, 12:32 PM
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Back feeding with a generator without the proper safety switches and power inlet has never been code compliant in my memory. There needs to be a transfer switch or interlock.
 
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Old 10-25-20, 08:48 AM
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How di you ignore a clear statement that what you are doing is illegal? Geez! The arrogance!
 
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Old 10-25-20, 09:11 AM
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Yeah, Id say its probably backfeeding and is a pretty dangerous situation. Personally, I would add some kind of a transfer switch just for safety reasons and probably hire a professional to install it for you.
Electrical is not something that you want to try to install yourself unless you know what youre doing and just hope for the best. I mean, I worked for Generac for 10 years and could fix anything on a generator myself with my eyes closed and electrical work makes even me a bit anxious. LOL
 
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Old 10-25-20, 01:38 PM
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I understand what you're trying to do. But you are playing with fire and death. Sure it's only you and your wife. You know (and I assume she does also) to disconnect the main. But does she really know? And what happens if a stranger (maybe one of your kids) might need to help you because you're incapacitated? Transfer switches and interlocks makes it fool proof no matter who has to connect or disconnect the generator.
 
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