Problem Grounding a Generator

Tony Sivori · 2009-11-15T22:52:46+00:00

I recently acquired a small portable back up generator for nuisanceoutages. Only paid $200 new. It is 2500 watts continuous, 3250 surge ratedand no 220 volt outlet, so I won't be hooking it up to a transfer switch.Even though I'm going the extension cord method, I decided to properlyground it, and use an inline GFI and surge protector. I'm willing to riskusing a back up computer with it, and I am hopeful that a surge protectormight clean up the "dirty" generator power.Now the problem. I drove an 8 foot ground rod into typical soil, used acorrect copper clamp (nothing improvised), and connected the rod to thegenerator ground lug with a single strand 12 gauge copper wire.Trouble is, the generator outlets still tests as ungrounded.I immediately suspected miswired outlets on the generator. So I triedchecking the resistance from the power receptacle outlet ground to boththe generator frame and the generator ground lug. Both tests resulted inzero ohms of resistance. I'm thinking that would eliminate miswiring onthe generator as the cause.I then removed both ends of the ground wire connection, checked andreconnected them.Same result, tests as open ground with a three prong plug in tester. Ialso tested the tester, and it shows grounded outlets in my house asproperly grounded.I checked the resistance from the generator end of the ground wire to theground rod itself. It was also zero ohms.So it seems to be a case of it has to work, but it doesn't work. Anysuggestions are welcome.-- Tony SivoriDue to spam, I'm filtering all Google Groups posters.

Nov 15, 2009 22 Replies

Rate this thread:

Meat Plow 16 years ago

No it was sold as a Coleman Powermate - now defunct.

Depends on the soil too. Unless you live on a sand dune one 8 footer is usually enough.

Vote

Baron 16 years ago

A troll that jumped on anybody that mentioned surge protectors.

Best Regards: Baron.

Vote

Mike Tomlinson 16 years ago

In article , Meat Plow writes

There was a recent discussion in demon.tech.pc by someone with a very similar problem. (If you're aware of w_tom, you'll not be surprised he featured in that thread.) We managed to establish that some APC UPSes are specified by APC as generator-compatible and also have a button on the back which can be used to reduce the UPS's sensitivity to poor mains voltage.

I told the OP in that thread that his problems may be due to the lack of a ground reference, but not being au fait with the subject had to bow out there. Bear in mind this was a 240V (UK) installation, so I wasn't comfortable with discussing tying one side of the output to ground.

Mike Tomlinson

Vote

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required