Grounding a portable inverter generator? What?

Yeah nobody does it, but everyone should for a few reasons.

It does protect the Harbor Freight company (and others) from a certain number of lawsuits and injuries related to electrostatic discharge ignited refueling fires each year and that's something.

What about the ground connection to the house, doesn't that count?

Sure, assuming your house grounds are any good...

For the record I did not drive a new rod next to my generator site, but I did wire up a drag chain to automatically create a crude ground through simple contact. It literally just drags on the ground. Better than nothing and easier than a lot.

 

Pretty much any piece of electrical equipment, they want it grounded nowadays. It's not going to hurt anything, and who knows? it might just help you out.

 

You may have a friendly neighborhood electrical contractor with a grounding electrode tester who can answer questions like "how much better than nothing", "how good is the house's ground", and so on.

Those are kind of fascinating instruments.

 

If you set up this generator anywhere near the house's electrical service entrance, it shouldn't be hard to just add another clamp to the existing ground rod and run the needed copper wire to it.

My house now has 5 ground rods scattered around the perimeter, all wired together. The original utility service rod, a too-small one next to the first antenna mast, the first PV system rod that struck an impenetrable object before reaching required depth, a make-up rod at another location that did reach full depth, and a final one for the PV expansion on the other side of the house. Rather than remove the too-small and too-shallow units, I just left them in place and wired them in.

 

+1

Somewhere near your power meter there should already be an earth ground, and this is (presumably) what your electrical panel is grounded to using “acorn” nuts or clamps illustrated above.
Sometimes my company will use a grounding rod and similar clamps in places where the network interface (phone box) enters the premises if the power isn’t co-located.

I used a jumper cable in lieu of a grounding wire once in a pinch.

If the genset is located far away from the house, perhaps for noise reduction, you can buy (and drive or even bury horizontally in a pinch) a grounding rod close to the generator if this is cheaper than running a #4 wire.
In NECC I had to explain to an LT once that a diving weight and bare wire thrown off a pier was “good nuff” for a temporary ground for certain applications.



Ground is ground the world around.

As mentioned above, it is important enough to want to do, even though many do not.

 

Yes, really.
Well.....maybe.
Check your local codes, as the requirements might vary some.

If you are going to connect the generator at or very near to the entrance service box (breaker panel) AND that panel has a good ground and a neutral to ground bond (if required) is present, then the extra ground on the gen should not be required.......electrically.
But it is never a bad idea.

Note: Not sure I would trust a gen from Harbor Freight since so much of their electrical stuff is cheap Chinese junk.
But I have no real information about their generators........except I do remember reports that they are LOUD.

If I were to get one, it would be propane or natural gas powered so there would be no worry about the fuel going bad.

 

Hmmph

I'm old enough to remember when it was cheap Japanese junk.....

 

... and then an intermediate step, cheap Taiwanese junk.

As their economy continues stepping up, China should sometime be able to continue the tradition of passing along this 'cheapness' crown to a newer emerging market. But due to their enormous size, they'll probably hold it a bit longer than others did.

 

I would definitely ground it like @fuzzy1 and @ETC(SS) recommended. If it's close to the service entrance there should already be a ground connection there as also mentioned.

The generator probably has the neutral and the ground wires connected. At least it should. It's called "bonding." But if the ground wire on the generator isn't connected to earth ground it and the neutral could be at any voltage above earth ground (also known as "you"). I once got nailed pretty hard by an unbonded house when I touched a refrigerator while lying on a tile floor. I checked and the neutral was 70 volts above earth ground while the "hot" leg was only 50 volts.

 

The distribution transformer on the pole outside your home reduces the 13,800 volts at the top of the pole down to a center tapped 230 volts for your home. The center tap of the transformer (neutral) is supposed to be grounded at the pole but it could be damaged by construction or catching that ground wire with a mower etc. That break puts the job of grounding the transformer secondary to the ground rod at your service entrance.

Jerry mentioned experiencing weird voltages to ground and I experienced those in a previous home. The center tap of the transformer on our pole developed a bad connection. Without a good center tap (neutral) connection, the voltage on each side of the transformer is dependent on how balanced the load between the two sides is. The side with the greater load has low voltage and the side with the lesser load has high voltage.

With our typical loads in the evening, we began popping a lot of light bulbs. After changing one of those light bulbs, I got out my multimeter and measured 155 volts at that outlet. I called the electric company and explained. They said that it was probably the meter I was measuring with. When I explained that at times, my tv picture would condense down to just the middle of the screen with black bars top and bottom. I measured the voltage to that tv outlet while it was happening and it was about 75 volts while other outlets in my home were measuring 155 volts.

They sent a lineman out and he repaired a bad neutral connection at the transformer. He also cleaned and checked both the ground wire connections at the pole and at my ground rod.

Connections can get oxidized which could be dangerous and generator manufacturers specify the "belt and suspenders" approach to avoid the liability if something were to go wrong. Probably why the first 5 pages of a 10 page users manual are safety disclaimers on anything that you buy today.

 

Yup! That's exactly what happens with a loose or disconnected neutral. One of our mantras in the electric shop was "When weird stuff happens, check the neutral." I've seen that happen to two friends' houses. The first one burned up his furnace blower motor and microwave. The other one escaped with no damage.

The other hidden gotchya is a bad bond between ground and neutral. That lets the neutral float. Everything works OK, but you can get really clobbered just by being barefoot on a tile floor and grabbing the handle on the refrigerator door. Very unpleasant experience when the neutral happens to be floating about 70 volts above ground.

 

2 weeks ago a lady I work with who lives in Tampa Teco the power company was working on her power pole out front and she was home and said everything in her house exploded.

Somehow the pole crew sent 13kv volts down her power line hooked it up wrong. Somehow those idiots bypassed the transformer.
Blew the power box off the wall and destroyed everything that was plugged in.
Sparks came out of the outlets and it blew up the water pipes too. They bond to water pipe. Started multiple fires. she was out on catastrophic leave.
She said there at $40,000 worth of damage so far.

I was thinking I would make Teco buy the house if that was me.
I wouldn’t trust the wiring after that. Can you imagine all the Rolex has to be replaced in your house? It’s a 50’s house there built like bricks. No drywall it’s chicken wire lathe and mud. Wall is like a rock.

Unreal.

 

Funny how autocorrect goes for Rolex, when probably most of us are on more of a Romex budget.

 

WOW!!! I would expect all kinds of hidden damage to the wiring in the walls. It's probably easiest to remove all the plaster & chicken wire on the walls. All new wires, new plumbing, new appliances. She'll be living in a hotel for a while. They better give her a nice suite and be glad no one got killed.

 

Exactly Jerry.

And yes I meant Romex.
In a 50s house around here romex is cloth/burlap covered. Good quality copper though not the Shiite now.

 

I have one of the Harbor Freight Predator 3500 gensets. Actually two of them. They are quiet and work well. I have two so that they can be used singly while servicing one or in parallel when we want to use the oven.

In my case, the gen set uses the house ground by way of a commercial transfer switch. I cleared that with the building inspector when we installed the transfer switch.

 

But that insulation was probably 60 ℃ rated, with the modern stuff at 90 ℃.

Not that that would have probably made much difference in the face of 13 kV coming in....

 

Well maybe they'll spring for Piaget or Longines this time?

Meanwhile back to the Casio...

My little generator got a workout yesterday. An aggressive pear tree had seen fit to disconnect my line from the transformer on the pole.

I think it's only the second significant outage since we bought this house, and it was a learning experience. I've decided that our genny is just too small. With the governor set a tad low, the voltage is too low to kick my well pump. With the governor set a tad high, the pump starts but the voltage is high enough to upset the UPS systems and kick them off the line and onto battery- right when I want them on-line and charging! Sadly there isn't a goldilocks setting for the governor.

I could rewire the well pump to be 240 instead of 120 and that would potentially solve the issue, but the generator is already 18 years old with >1000 hours on it. That's already a great career for a 250cc Briggs. It was a hand-me-down from a smaller house.

So I think I'm starting the hunt for a 7kw rig.

 

True dat! Dielectric rating and temperature rating are quite different. Max voltage for Romex is 600V. At that point, the insulation starts to conduct.
("Romex," by the way, is actually a brand name that's become used like "Kleenex.")