re: Running a generator through a dryer outlet

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Which is acceptable, correct? That's what you'd have with the dryer plug suicide cord and main breaker open. The neutral is still bonded inside the breaker panel, so you still wouldn't have to worry about energizing the utility transformer, correct?

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That is correct. Though you would need to make sure your generator has a floating neutral to be code compliant.

Back feeding through your dryer plug is not code compliant. Due to one the suicide cord is not code compliant. Also, you don't have an approved (code compliant) disconnecting means.

All of this to say while connecting through a dryer outlet is not code compliant, it will work.

Got it.

Yea, I still fail to see how the dryer plug thing would be pulling juice on the utility transformer neutral.

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Now I think I'm really confused. My portable generator is neutral bonded to ground according to the specs. Doesn't this mean I don't need to otherwise connect a groundwire to the generator. That is in my very unsophisticated (and hopefully not dangerous) fund of knowledge, I take this to mean that this thing is wired such that the ground in cord is what grounds this thing??

Am I overthinking this for just a guy trying to run a few circuits and not kill himself or someone else?

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There is a bonding wire (or strap) between the neutral and the ground on most portable generators. Per National Electrical Code, this wire (or strap) should be disconnected if you are typing the generator into your house. Your bonding jumper (where the neutral is connected to ground) is located at the service entrance panel of your house. Creating multiple neutral to ground points on a system creates issues during fault conditions.

If you are just using extension cords to feed appliances directly from the generator, the bonding jumper can be left in place.

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Now I think I'm really confused. My portable generator is neutral bonded to ground according to the specs. Doesn't this mean I don't need to otherwise connect a groundwire to the generator.

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Please don’t make that assumption based strictly on my post. I’ll let someone more knowledgeable than me chime in but I don’t think the solution is to leave the generator ungrounded. As I understand it, that’s effectively the same thing as terminating your neutral to ground in an electrical outlet except in this case the “outlet” is carrying the entire load for your house.

ETA: Read msu’s post above.

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And what would the effects be of having the neutral grounded at both the breaker panel and the generator? Circulating ground current risk?

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It allows neutral current to be parallel with and flowing on any metal conductive paths between the two bonding jumpers. It can a shock issue.

The reason why most get away with it is due to the cord running from the portable generator to the house is just a cord, it's not in conduit.

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Exactly what got me noodling in the first place.

I just don't see how it would end up going to the transformer neutral unless the generator neutral wasn't connected or not bonded properly.

He does make a good point though, it wouldn't take much to end up with a good bit of volts on the primary side and light someone's arse up if they just started grabbing transmission cables barehanded.

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I did a little bit more research (i.e. asked someone smarter than me).

You guys are correct to be perplexed. I was wrong, mostly. Perfect time for this topic as I just bought a generator and looking to do this. (thanks TD)

Portable generators are typically spilt load. They are designed this way because the poster who first said the unbalanced would go back to the gen is correct. The gen will not allow you to use more than half the load rating on one of the 120v sides. The other 120v side will handle the other half. Thus eliminating an energizing of neutral that is connected to the frame of the gen. If this was not a thing, then the frame could be energized and cause a safety issue.

Furthermore, the 120/240 single phase at a residential home is a delta configuration without a connection to utility neutral. Any issues on that system will be dissipated through earth ground. Neutral current would only exist on the utility side, after the transformer which is a grounded wye system. The fact that the neutral at the home panel to the meter base is not broken by a transfer switch or a main breaker serves no danger to utility line workers in a backfeed scenario, only the "hot" legs.


ETA: MSU2020 is on it.

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thank you,

this had all at WTF moment and we were all questioning what we knew

if nothing else it spurred discussion that is more technical in nature which i have enjoyed

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Yeah, sorry about that. I learned something today and for that, am grateful.

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Furthermore, the 120/240 single phase at a residential home is a delta configuration

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Well now I'm super confused why Augusta dude was so adamant about backfeeding the neutral. If the transformer secondary is delta, it's impossible.

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Well now I'm super confused why Augusta dude was so adamant about backfeeding the neutral. If the transformer secondary is delta, it's impossible.

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The transformer isn't delta connected. It is a single phase center tapped transformer. The Line to Line voltage is 240V while the line to neutral voltage is 120V. There is a neutral between the utility and the home. There isn't an EGC (Equipment Ground Conductor).

Most people confuse the Neutral (Grounded Conductor) and the EGC (Equipment Ground Conductor). They do completely different things.

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Thanks for spreading the knowledge. I had never thought about removing the neutral bond on the generator before.

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If you do remove the neutral bond, make sure you re-connect it before using the generator for use as a portable generator with plug/extension cord loads. The GFCI's on new generators won't operate properly if you don't.