Grounding my Generac 550W LP generator?

[Soundchasm]

Finally bought the generator. Took a few more months before I assembled it. Got the propane tank and was considering adding the oil and firing it up when I got confused on the manual's caution on grounding.the unit.

Sounds like it reads that they've connected the frame to ground terminals in the AC receptacles and the unit can be used as a portable without grounding the frame.

However, it talks about grounding the unit in a building stand-by application with #10 AWG stranded Cu wire to an earth-driven grounding rod.

So if I want to start this thing, run it for 30 minutes to drop and replace the engine oil, I don't have to ground it?

BTW, I won't understand any explanations I get, but I will follow instructions! Maybe this thread goes in DIY, but I got it to run the blowers on the wood stoves among other things.

 

[ewdudley]

Have a look at Mike Holt's video: (Start at about 9:20 if you're in a hurry, but the whole video is worthwhile.)

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One thing he says for sure is you need to maintain an "equipment ground conductor". He is generally opposed to driving ground stakes at generators.

 

[Soundchasm]

I've gotten up to about 8 minutes. This guy is a whirlwind of info. I always have the same problem with smart guys. I'm smart enough that I almost get it, and I'm dumb enough that I'll never get it.

 

[Flatbedford]

I was afraid to watch the video.
In my training as an entertainment electrician, the chassis of the generator is an acceptable ground, however, that will not provide lightning protection. I think that if the machine is connected to a building's electrical system with a grounding conductor you are good. but I am just a guy on the internet. Check with a real electrician or find it in the NEC.

 

[Flatbedford]

Ok, I watched. At about 16 minutes he explains why NOT to ground an auxiliary generator. Just be sure that your generator has a grounding conductor to the building if it is tied to the building's electrical system.

My comment about grounding in entertainment applications, I believe, applies to when the generator is powering equipment that will not be grounded to any other power system or building, or is as you said "portable".

Ok. I didn't pay enough attention to your first post and gave some lousy information. See, you can't trust the internet.

 

[Flatbedford]

Here's where I try to make up for my lousy answer.
https://www.osha.gov/OshDoc/data_Hurricane_Facts/grounding_port_generator.pdf

"the frame of a portable generator need not be
grounded (connected to earth) and that the
frame may serve as the ground (in place of
the earth):"

 

[Soundchasm]

Well, after all this (who knew this could get so complicated??), I think I'm safe to throw some oil in there, fire it up, and then drop the oil and replace. I'm one of those guys with a little information and a big imagination. When you don't understand something, it's easy to get spooked.

Flatbedford, I'm glad for your experience in the entertainment industry and jealous. I bet you've seen some real shows and set up some complex stages. In audio, I chased my fair share of ground loops trying to get the gear to shut-up. I've also thought my lip would get welded to the mic a few times. In the bars, you never know what you're going to run into.

 

[Soundchasm]

I put the oil in, followed the instructions for priming and starting, ran it for 15 minutes and dropped the oil. Not surprisingly these days, it had enough "crushed pearl" in there to concern me. I'm tempted to drop what I just put in there, but with the price of oil these days, it's aggravating. I'll let it run another 15 minutes and put it up for the time being. I'll change the oil one more time before winter hits.

 

[TheRambler]

Operational wise it doesnt need to be grounded ,unless it has the wheel kit on, if it does then you need to connect a gec. This is a short ground from the gen to any suitable point. This is purely for safety, ie gen has a problem and you touch it you dont get shocked and die. Otherwise the gen frame sitting on the ground provides "adequate" grounding. I would strongly recommend connecting a gec all the time. This is not the electrical ground, this is a equipment grounding conductor/frame ground. I am a field eng that works on and installs back up power systems and gens daily.

 

[TheRambler]

I usually connect mine to a water pipe or piece of rebar on my foundation. I have a 6ft cable with an alligator clip on one end and just a ring terminal on theother where it connects to gen.

 

[BrotherBart]

Portables have a bonded ground to the frame. I grounded mine and the ground light went out on my power distribution unit. So I took the ground back off.

 

[TheRambler]

Not ALL portables are bonded. And i was mainly talking if you have a wheel kit on as that makes for either no or a very poor frame ground/earth connection. If your ground light went out then you either hooked it up to a poor ground , something wasnt tight, or you made a ground loop which caused circulating current.

 

[maple1]

My 3000w inverter has wheels.

(Plus I usually put it in a wagon behind the ATV or ride-on when I need it, for easier moving around).

The manual says to ground it from the ground terminal to the earth with a spike or some kind of grounding rod.

So that's what I do. (Use a spike).

But I assume I could also rig that with a clip that I could clip to my house grounding rod? Would just be a bit less clumsy & the rod is very close to where I set the genny up when the power goes out.

 

[TheRambler]

Yes you can use your house ground rod, that is perfectly safe and acceptable.

 

[Highbeam]

You'll never get a good answer on this issue. Everywhere you look will be people guessing, assuming, lying, or equally confused. You have a portable genset, there is no need to ground it with it's own rod.

I've run my genset, a portable, to power all sorts of expensive equipment at my home (ground rods for house panel which do connect) and also in my RV which sits on rubber tires and is not "grounded". It always works and nobody gets shocked.

Don't think too hard about this, no need for a ground. It won't hurt though.

 

[TheRambler]

A vehicle uses a totaly different grounding scheme and method than a building connected to the physical earth. Grounding a generator isnt about electrical functionality. Its about safety in the event of an equipment fault, thats it plain and simple. You have have used your generator a thousand times without issue, but that one time it has a fault to ground(the frame) and it isnt grounded you could recieve a potentially lethal shock. .1 of an Amp can kill you, so a generator is more than capable of deliving that miniscule amount of current. Accidents happen, and a proper ground is there to safeguard you, those you care about, your equipment and property, as well as just any random person off the street. It takes literally 2 seconds to hook up a ground, why wouldnt you do it?

 

[BrotherBart]

What OSHA has to say about it.

https://www.osha.gov/OshDoc/data_Hurricane_Facts/grounding_port_generator.pdf

 

[TheRambler]

Directly from the NEC:
III. Grounding
702.10 Portable Generator Grounding.
(A) Separately Derived System.
Where a portable optional
standby source is used as a separately derived system,
it shall be grounded to a grounding electrode in accordance
with 250.30.
(B) Nonseparately Derived System.
Where a portable optional
standby source is used as a nonseparately derived
system, the equipment grounding conductor shall be
bonded to the system grounding electrode.

 

[Soundchasm]

Directly from the NEC:
III. Grounding
702.10 Portable Generator Grounding.
(A) Separately Derived System.
Where a portable optional
standby source is used as a separately derived system,
it shall be grounded to a grounding electrode in accordance
with 250.30.
(B) Nonseparately Derived System.
Where a portable optional
standby source is used as a nonseparately derived
system, the equipment grounding conductor shall be
bonded to the system grounding electrode.

I appreciate all the discussion. It helps me to see all the points of view. I don't understand electronics, but I do understand conductivity. It does puzzle me that this generator has wheels and rubber feet. Even I understand those appear to be insulators, and even if the frame is "earth", I sure don't see a literal path to momma Earth.

If this was one of those frames that makes contact with the ground, I could see not grounding it. What little common sense I have can't make out the harm in grounding it in a purely portable operation.

The NEC seems to be the ruling authority in all situations so far. Those guys are a lot smarter than me.