I have read countless posts regarding not hooking up a generator with a bonded neutral to a 240v 30 amp house connection with a mechanical interlock in the house panel, and still have come away a bit confused.. This is the setup, I have, and for the last three or four years, during power outages, I have been hooking up my bonded generator.to the house connection without any problems. I note that I open all my breakers in the house panel, before I hook up the generator, and then only close the four I care about (fridge, freezer, well pump, and one lighting circuit).. None of these circuits have CGFI outlets, nor CGFI breakers in the panel. Perhaps that is why I am not encountering problems? I am not an electrician, and am slow to understand anything electrical, so only understand these things in very basic terms. From posts I have read, it would seem that the way I have things set up would be considered "bad". Since everything works, I know it is not "bad" from an operational standpoint. So my question is what specific real world risk am I taking? For example, am I putting my generator, house wiring, or appliances being powered at risk of being damaged? Is there a safety risk where I, or others, would have an increased chance of receiving an electrical shock at my generator? Is there some other specific safety risk I am taking? For example, If I was running my generator in a storm, and a lightning struck, is there an increased chance of it flowing back through my generator and blowing it across the yard (We have had a lightning strike hit a tree next to the house which destroyed my phone system, computer, well pump controller, and blew chunks of the tree clear over my house, so I know the power of lightning)? I am asking these basic questions as if there is a significant safety risk, or risk to my generator, I will unhook the wire in my generator, so it has a floating ground. I prefer not to do this as I also use the generator as a stand alone for home projects around our property, besides just plugging it into the house. Which is the greater risk? Using it on my house the way it is, or using it with a floating ground as a stand alone? I know I could put a special transfer switch in at my house also, but really would like to avoid the bucks for this.
Bonded Generators 101
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Try to look-up "objectionable current". There's even a video on YT about it explaining why it is considered not best practice, if not dangerous under certain situations.
FWIW, if your Neutral is already bonded to Ground at the main electrical panel, there shouldn't exist such bond anywhere else in your house. So it would be in your best interest to remove the N-G ground in the generator.
However, if you have a transfer switch that opens the N-G bond when in generator mode, you need to keep the N-G bond at the generator intact.
FWIW, if your Neutral is already bonded to Ground at the main electrical panel, there shouldn't exist such bond anywhere else in your house. So it would be in your best interest to remove the N-G ground in the generator.
However, if you have a transfer switch that opens the N-G bond when in generator mode, you need to keep the N-G bond at the generator intact.
Thanks. I read about objectionable current and understand a little better. If I understand it right, it appears there are four drawbacks of it. First, it can affect the operation of CGFI outlets. This does not affect me, as I am not powering circuits that have them. The second is greater risk of fire, if enough objectionable current is flowing through a connection that is loose, causing overheating, and if that connection is near combustible material. Probably not likely in this scenario, but a valid point. The third is risk of shock on metal parts that could have objectionable current flowing through them. Since the generator plugs into the house. with a heavily insulated cord, I do not see a viable metal path exists in this situation. Fourth, objectionable current can mess with power quality. While the risk does not appear to be extreme, I have concluded that I will unhook the wire and turn it into a floating ground generator. When I use it as a stand alone, I will hook it back up. It is a Champion and their help center has a video showing one how to do it. Looks like a 5 minute job, so not a big deal to restore it the couple of times a year I use it as a stand alone..
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For the most part and within the context of your setup, you will unlikely run into issues. However, one can argue that big problems are born out of small, often insignificant omissions.
The metal frame of the generator constitutes an enclosure that might be a path for objectionable current to flow.
I have a question. If this is a 240 volt generator and you unhook the neutral, what is going to keep the voltage on L1 and L2 both at 120 volts? Isn't is possible for one side to go high, like 200 volts or so and the other side to go low like as in 40 volts or so? Then half the light bulbs in your house burn out and the other half glow really dim?
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If the circuit is absolutely balanced, both legs will remain at 120V. But that is more hypothetical than what you will usually see in real life, unless you're doing the experiment in a lab. So yes, if there's an imbalance, the leg that has more load on it would have a lower voltage across while the leg that has the least amount of load will experience an overvoltage.
So, best we don't forget that all-important Neutral wire.
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You are NOT unhooking the neutral. You are disconnecting the neutral wire from the ground wire (this is the neutral-ground bond). The N-G bond is reestablished when the gen is connected to the house. You should only have one N-G bond in the electrical system. The N-G bond is often found in the main breaker panel, or if you have a disconnect at the meter service entrance it can be found there.
All neutral currents should return back to the source on the neutral wires and not on the ground wires (NEC 250.6 Objectionable Currents). It's a safety issue.
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Does My Generator Need a Ground Rod? Probably Not. Here's why. - YouTube Came across this video recently and found it very informative. You may find it assuring after watching it that your setup is OK and removing the wire when using the unit for projects outside the house is right thing to do.
I believe I have the same set up as yours with my portable generator to house main panel's 30 Amp 240V breaker via a mechanical lockout device which separates the gen/house electrical system from the public grid. Had this setup for 20+ problem free years ( average once or twice power outages per year/ genie operating from 2 -8 hrs per instance .
I believe I have the same set up as yours with my portable generator to house main panel's 30 Amp 240V breaker via a mechanical lockout device which separates the gen/house electrical system from the public grid. Had this setup for 20+ problem free years ( average once or twice power outages per year/ genie operating from 2 -8 hrs per instance .
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Nice video, but, just for clarity, this thread is not about ground rods. It is about having a bond between the ground wire and the neutral wire. People often confuse ground rods and ground wires.
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That's the opposite of what needs to happen, actually.
In a nutshell, you'd want the N-G bond inside the generator to exist when utilizing it to power tools, appliances and other loads directly or using extension cords.
If you're connecting the generator to your main panel interlock (which supposedly already has the N-G bond), it's advisable to remove the N-G bond inside the generator.
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