Bonding Neutral to Ground: Why or why not? Predator 5000W Inverter Generator 

Finally someone did a video on this, thanks. Quick and to the point, perfect. For more detail, what I have is: 1. What does ground do - Ground serves some distinct purposes. In normal operation with everything connected working properly, ground is not supposed to have any current flow. It is connected to things like the metal case on your toaster oven, the metal case on a plug in power tool, a stationary desktop computer case, surge protector fault path, GFCI, etc. Ground both provides a low resistance path to source and a distinctly different function is to provide a common ground voltage reference. So it actually splits off into two different paths, each with different purposes in mind. 2. What a surge protector does - A surge protector dumps excess voltage to ground. If the excess voltage is from the source creating too high of a voltage, say a traditional generator experiences abrupt changes in load and can't adjust its throttle setting fast enough (like in a car if you have your foot on the gas peddle going up a hill and the gear shifter gets bumped into neutral for those who remember manual stick shifts), if the voltage gets high enough, the excess power will get dumped to the ground wire, return to source, and limit the voltage on the hot wire. If enough power ends up flowing through, it should pop the breaker. Now say you are connected to the grid and there is a lightening strike creating a voltage spike. The surge protector senses the voltage spike and dumps power to ground, which flows through the grounding rod voltage reference and equalizes the voltage with Earth ground. Granted with a small generator right there that you are controlling, you are probably not too concerned with this latter case of a lightening strike as you are not doing a round the clock grid power connection. 3. When you need to be able to have a low resistance path back to source - Say the hot wire in your toaster oven goes bad (maybe the toaster oven sucks and the insulation on the wire gets too hot and melts off) and makes contact with the metal case. If the ground wire is not ground - neutral bonded, then everything on the ground wire becomes energized. Electricity is always searching for a path back to source. The other problem is people are always finding ways to kill themselves and you won't draw enough current through your body to pop a breaker as the body acts as a resister as in some current will flow through you, which can easily get to lethal levels (say you are hot and sweaty and your hands are wet) while being far from the current needed to pop a breaker. You only die once with it often being that thing you didn't understand nor realize was going on was actually happening and this case you just needed to inadvertently end up completing the circuit through your body with enough current flow to die. So energized surfaces you can touch is a bad thing and is causing the ground wire to do the opposite of what is safe when there is no ground - neutral bond. However, if there is a ground - neutral bond allowing a low resistance path to source, a high current will flow through this and pop the breaker, clearing the fault. A surge protector needs to see a high voltage differential between hot and ground to work. If ground is not hooked up to anything, a circuit cannot be completed and thus this first point is moot. If ground is only hooked up to Earth ground, not ground - neutral bonded, then your neutral has a floating voltage and is not referenced to ground. Again at best something 'weird' happens, but a surge protector cannot work as intended because neutral is not referenced to ground voltage and there is no return path to source to dump excess power to. Granted, if you are using a well regulated inverter generator, it can be argued a surge protector is not going to do anything anyway because it will never see a high enough voltage to trigger. An interesting thing if you put your AC sine wave on a scope from one of these inverter generators with floating neutral, it will look very noisy when referencing to the ground pin, the line will be very thick from all of the electrical noise. While between hot and neutral you won't see it, it is very pronounced between either hot or neutral and ground as you end up seeing ~60V on each leg. I have hooked up analog security cameras with no bond to a generator and the cameras had trouble initializing and the ones that did initialize were showing high frequency harmonic noise in the camera feed. (A different way of seeing the noise seen in a scope.) It seems electronics in general are designed to have neutral tied ground via a ground - neutral bond or else this high frequency noise gets in there. I suspect what is happening is the inverter in the generator is using a PWM (pulse wave modulated) signal to create the AC sine wave and the ground wire is connected to surfaces that allow some level of capacitative loading, damping the electrical noise of this PWM switching. At least with the ground - neutral bond, I cannot see this high frequency harmonic noise at all and my camera initialization problems go away. If you hook up a scope, it is also gone there. If anything, I would argue it looks slightly better than on grid power as grid power isn't exactly clean either in terms of electrical noise and these old analog cameras seem particularly sensitive to electrical noise. Curious and would like a better explanation into the exact mechanism if someone has it. A GFCI outlet cannot work properly without a ground - neutral bond. I suppose there is the question of if ground and neutral are not bonded, how can the test button create a differential current between hot and neutral? Granted if the current is flowing through your body, the power may be finding a different path back to source than that ground wire, but I would think under normal circumstances, that would be the only mechanism the tester button would have to create an alternate path back to source. 4. Another use of a ground wire may be to have say everything in your home tied to the same ground voltage reference. Say you have analog audio cables going between devices or copper Ethernet cables going between devices, you don't want excess power going over those conductive wires because things are at different reference voltages. At best you hear an extra hum with your audio equipment, at worse you have fried electronics. 5. The reason you don't bond on a generator when using say a transfer switch to power your home is maybe you already have the ground - neutral bond in your home. (Something you need to check for.) Having two bonds is against NEC codes. What it does is create a ground loop and thus current flow over the ground wire and remember in #1, having a regular current flow over ground is a big no-no, especially with exposed surfaces you can come in contact with. If your generator has GFCI, you will have nuisance tripping as you end up sharing load between ground and neutral with a double bond and thus hot and neutral will have different current flows as there is one hot wire with load and two other wires, ground and neutral sharing the 'return' load. It is just a bad idea and you don't want to do it. However, if you are hooking up to a trailer or RV or just using extension cords, there is no bond in the system by default and so you need this bond in place in / at the generator to comply with NEC codes because of all of the reasons stated above. (If your trailer or RV did have a ground - neutral bond, then you would create a ground loop when say plugging into the outlet you setup to plug it into your home as your home has one.) Seems kind of odd that these 120V generators that normally are never hooked into a home almost never have a ground - neutral bond while the bigger 240V generators commonly used for whole home backup power often do have a ground - neutral bond. Just seems backwards from what people actually need to comply with codes and operate a safe electrical system.

One important thing to consider is whether or not you are switching the neutral along with the line wires on your back feed. Electrical systems are bonded to ground meaning the neutral and ground connect together at the first disconnect. This connection can by code only be done in one location. So if you're running a bonded neutral generator the system neutral must also switch transferring that bond connection to the single generator location and now your backup is a separately derived system. While the system will still work with a bond in two locations, it's not safe because current can travel along the grounded components and be hazardous. This is when the code is very clear on this point.

Thanks for adding the “ why and why not it’s necessary” part at the end. That alone is super valuable to know when and when not to use it

Thanks for sharing I just picked up this generator and thought it was my victron system never thought about ems which I have this will help a bunch

Thanks for pointing out NOT to do this mod if (like me) you also plan on using it for the home in case of blackouts etc. I simply use the bonding plugs that you can get on Amazon etc. Buy two, keep a spare in the RV. Good video!

Wondering if this will solve my issue with a GFCI on my pressuer washer that keeps tripping when I use it with the generator and when i use the pressure washer on the house outlet the gfci does not trip at all.

I have no EMS system on my motorhome, would it still be a good idea to do a grounding rod? Just wondering if that somehow makes it safer or actually makes it less safe.

So if I want to do dual purpose with a generator (house backup and rv) I can't do this mod? So at that point I don't use my surge protector on the rv to make things work?

Do you recommend doing this even if not using a surge protector?

If this is a good and safe idea then why wouldn't the manufacturer do this ?

The owner’s manual says F7TC plugs. I got the NGK Spark Plug Iridium-IX BPR7EIX NGK. Is this ok? Your link was. NGK 5534 Standard Spark Plug - BPR7ES, I can send my purchase back if you would not use it.