Does a portable generator need to be grounded?

Status
Not open for further replies.
Joined
Aug 18, 2009
Messages
4,487
Location
Ohio
After reading about the HF 2 cycle generators here, I picked up one last fall during a parking lot sale for $79. Got it out of the shed today and broke it out of the box and swapped out the spark plug as has been suggested. In reading the directions, it mentions grounding the unit, which would obviously impact the portability and convenience of the unit. As I have never owned a portable generator before, are any of you using this unit grounding it?
 
How does it impact the portability? Id imagine you could ground it reasonably well with a metal tent stake or a 3' pipe.
 
Its best to ground it to the ground rod that your electric service is grounded to.

I would say almost no one does however. I would not really worry about it too much. But a roll of stranded wire (say #10 or #12) is pretty cheap also. You could install the wire to near where you are going to use the generator and then its only one screw to connect it when you roll out the generator. Probably more important if you are going to connect it through a transfer switch (don't backfeed).

I have a 5000W LP gas Winco I bought used. The previous owner grounded it, to the negative of the 12V battery (in addition to the negative battery cable). Obviously the prior owner was not a member of Mensa.
 
My purpose for the generator is to move it around my yard to use electric yard tools (such as hedge trimmer,etc) to save the hassle of running extension cords. I thought that I could ground the unit by running an 8 gauge wire off the unit, and use some sort of spike to attach to the ground, as you had mentioned. However,in doing a Google search, I found that proper grounding is a 8'rod and that using a spike is actually against code. If I have to go to all that hassle, may as well just use the extension cords and forget the generator.
 
It's not overly critical, but without it there's the possibility to have something plugged into it float to some unknown voltage. Floating grounds can "bite" if you touch the appliance. As an example, RVs with broken ground wires have been known to have their chassis shock people who were standing on the ground when they touched it, because a little bit of leakage current caused the chassis to float to a high voltage.

That said, I've never grounded my generator.

Edit: Even if you had a short metal rod that wasn't up to code, it would still be better than nothing at all, since it would still have a ground connection, even though it may not be a perfect one.
 
Last edited:
Originally Posted By: tom slick
The main reason for grounding is lightning protection.
How many portable generators get struck by lightning?

The main purpose of grounding is to prevent an insulation fault or wiring issue from causing the chassis to become electrically hot and posing a shock hazard. Grounding will cause the breaker to trip in that case.
 
Originally Posted By: RF Overlord
Originally Posted By: tom slick
The main reason for grounding is lightning protection.
How many portable generators get struck by lightning?

The main purpose of grounding is to prevent an insulation fault or wiring issue from causing the chassis to become electrically hot and posing a shock hazard. Grounding will cause the breaker to trip in that case.


+1, all generators should be grounded.
 
Last edited:
Get a GFCI adaptor like this one. "They" let you use a GFCI outlet in an old house without a grounding wire, this is the same premise.
 
If it's being connected to building wiring, then it needs to be grounded. If it's being used with an extension cord to operate power tools (for example), there's no point to grounding it, and a fault will trip the breaker/GFCI regardless of whether it's connected to a ground rod or not.
 
If you have a metal fence in your yard , ground it to that just to say you did. Impress the wife.. By code portable generators do not have to be grounded. Tell me again how a cut wire is going to touch the frame and electrify it without the ground fault plug (now required) from tripping.
Its almost impossible.
 
Originally Posted By: Donald
Probably more important if you are going to connect it through a transfer switch (don't backfeed).



But the ground that is bonded in the main panel should be usable, if convenient, right?

In our panel, we have heavy solid copper going out of the house to a long rod in the ground.
 
Originally Posted By: chad8
Tell me again how a cut wire is going to touch the frame and electrify it without the ground fault plug (now required) from tripping.
Its almost impossible.
I was speaking generically. Certainly if a working GFCI is in place then the point is moot.
 
Originally Posted By: chad8
If you have a metal fence in your yard , ground it to that just to say you did. Impress the wife.. By code portable generators do not have to be grounded. Tell me again how a cut wire is going to touch the frame and electrify it without the ground fault plug (now required) from tripping.
Its almost impossible.


Are you saying a ground fault plug (I think you meant outlet) is now required on a generator? So all new ones will have this?
 
Originally Posted By: RF Overlord
Originally Posted By: tom slick
The main reason for grounding is lightning protection.
How many portable generators get struck by lightning?

The main purpose of grounding is to prevent an insulation fault or wiring issue from causing the chassis to become electrically hot and posing a shock hazard. Grounding will cause the breaker to trip in that case.


You may want to do a little more homework before discounting my claim. Specifically NEC Article 250.
 
A few years ago there was a news clip about a soldier getting fatally electrocuted while taking a shower with a electric water heater powered by a generator, without proper grounds.

However I can tell you from personal experience that many electric water heater elements have too much leakage to use a GFI on them. Along with grounding the water heater and generator, if a GFI can not be use because the equipment being powered normally has too much leakage, then an isolation transformer between the gen-set and the equipment and proper grounding of the generator and equipment is the safe way to still operate.

Leaky electric equipment is very serious business. Humans can easily be killed with much less than one amp of current passing through them.
 
Originally Posted By: JimPghPA
The main reason for grounding is to avoid killing someone by electrocution.


which has nothing to do with an insulated power tool in your yard as far as I'm concerned.

it makes 0 sense to ground a 40# 1000watt portable generator you are using with hedge trimmers.

The whole point of using it is to be portable without a 200ft extension cord

I think we need to get back to the question asked and not a general question about generators being hooked to houses etc.

thats a totally different question.
 
Last edited:
I think this might answer the OP's question:

(from NEC 250.34)

"250.34 Generators-Portable and Vehicle-Mounted
(A) Portable Generators. The frame of a portable generator is not required to be grounded to the earth if:
(1) The generator only supplies equipment or cord-and-plug-connected equipment through receptacles mounted on the generator, or both, and
(2) The metal parts of generator and the grounding terminals of the receptacles are bonded to the generator frame."
 
Status
Not open for further replies.
Back
Top