Grounding Rod For Portable Generators Necessary?

[grsthegreat]

Maybe you ought to read some more of the code book.What year are you reading??? We don't use Zinc coated,but copperclad, some over 8 ft long...and yeap you can put it down with some water for a better readings if you have ground meter, we do..If you wanted real technical IE Portable is under other regulations around here...Just a little more info, but then we are all semi-anonymous folks here, to use someone else's line?

Just look at article 250.34(a) The frame of a portable generator shall not be required to be connected to a grounding electrode...bla bla bla...under following conditions
(1) GEN SUPPLIES ONLY EQUIPMENT MOUNTED ON THE GENERATOR, CORD AND PLUG CONNECTED EQUIPMENT THROUGH RECEPTICLES MOUNTED ON GENERATOR....


enough said. Ive been doing this for 30 years.

The ONLY time you need to use a grounding rod is if the generator is part of a separately derived system AND perminantly mounted.

If the generator is powering a drill, motor, etc wired to the installed outlet......it does not need a ground rod.

 

[grsthegreat]

ALWAYS use a generator transfer switch if powering up to a house panel. The voltage that can go back thru the overhead lines can kill a lineman.

 

[Inspector507]

Just look at article 250.34(a) The frame of a portable generator shall not be required to be connected to a grounding electrode...bla bla bla...under following conditions
(1) GEN SUPPLIES ONLY EQUIPMENT MOUNTED ON THE GENERATOR, CORD AND PLUG CONNECTED EQUIPMENT THROUGH RECEPTICLES MOUNTED ON GENERATOR....

That's what MY code book says too grsthegreat. As usual, you're right.

 

[grsthegreat]

That's what MY code book says too grsthegreat. As usual, you're right.

gee......i wish i could hear my wife say that...just once hehe:laughing:

 

[sailfast]

If you want your UPS or line conditioner to be fully functional, you MUST have a good ground. --> Ground Rod

The more expensive UPS will have indicator lights or status displays for ground faults.

 

[Genermatorman]

The purpose of the ground rod is to prevent there from being any difference in potential between the grounded generator output conductors and the Earth ground. Typically the grounded generator conductor is also bonded to the generator frame. That being the case, if your alternator had some problem in the windings and the genset frame was not connected to the Earth ground by a grounding electrode of some type you might see a higher voltage between an ungrounded generator output conductor and the Earth ground than between an ungrounded generator output conductor and the grounded generator output conductor. The difference in potential would be realized when you touch the generator frame with your bare hand while touching the Earth with your feet. You would become a better path to ground.....zzzzt. If you drive a ground rod and connect it to the genset frame that is already connected to the grounded generator output conductor you have bonded the frame to the Earth so there can exist no difference in potential between them. I am not an engineer but I cannot see this having any effect on breaker or ground-fault circuit interrupting devices. The breakers are tripping based on instantaneous or long term current wherever it goes and the GFCID's are measuring how much current goes out from the ungrounded conductor and how much comes back in on the grounded conductor and tripping when the difference reaches a setpoint of x milliamps. Remember the ungrounded conductor is the hot one, the grounded conductor is the return and the grounding conductor is used to bond conductive materials to the grounded conductor at the electrical service entrance to prevent your stove or dryer or refrigerator shell etc from becoming energized due to an ungrounded conductor coming into contact with it. If contact is made a short-circuit will result in a blown fuse or tripped breaker instead of the metal shell setting there energized and waiting for you to complete the circuit by touching it with one hand while your bare feet are on your concrete floor. Gotta Love it!

 

[danspartan]

In last week's Philly massive power outage, I put my little (3000W) generator to the test.

Generator to power surge strip to extension cords. I ended up wiring it to my furnace by:

1. broke furnace connection at a junction box. (I disabled the furnace breaker 1st)
2. wired a male cord/plug to the furnace wiring.
3. I did nut the furnace, my cord, AND the main house panel ground together (with thought of grounding the generator-should be same as any ground?)
4. I capped the hot and neutral lines coming from the main box (and kept the furnace breaker OFF).
5. plugged furnace into extension cord from fired up generator

Everything ran great through the outage (3 days). Kept furnace and sump on full time, rotated around to freezer, fridge, and even an old school TV to watch the news on occasion.

All sound Kosher? Only point of contact with the house electrical was through that ground connection.

I don't remember seeing anyone's generator around town grounded other than sitting on their driveway or concrete porch.

 

[newbury]

Well since this subject has come up again -

You can probably get by without a ground rod. BUT

I taught Army soldiers to run 10KW to 15KW generators from about 1995 to 2011. They and the vehicles they are connected to are ALWAYS supposed to be grounded.

We had two prime methods of grounding - a 6' or 8' copper rod and the Surface Wire Grounding Kit. The kit consisted of 15 metal stakes connected by 3/16 steel cable.

Since most of our deployed units were in dry desert areas we emphasized moistening the soil often with a saline solution. Usually achieved by filtering water thru the body
/edit - NOT when the generator is running

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA311375

 

[arlen4720]

danspartan DID have a ground rod in this case...he was tied into the building ground system.

 

[bdog]

My current generator has over 3000 hours on it powering my portable office trailer that contains over 100k of computers. I have never used a ground rod. The generator is an inverter and I have a heavy duty battery back up system in the trailer.