Generator Grounding

[John T]

Given all the recent storms, power outages, hazards and life safety concerns, theres been lots of healthy chit chat and questions regarding the necessity, or lack thereof, regarding grounding of home backup generators, so I will take this opportunity to describe WHAT I BELIEVE the NEC has to say about it based on my recollection SO NO WARRANTY consult them not mePS our friend George goes to the head of the class as he has asked a lot of great and very relevant questions.

..

1) Iffffffff the genset is connected to the home distribution system via proper safe and permissible (NO suicide plugs) cords plugs and receptacles in which (very common) case the gensets Neutral and the homes Neutral are connected GROUNDING THE GENSET IS NOT REQUIRED and the Genset should be configured with a Floating Neutral. I believe the NEC allows supplementary grounding if one chooses...

2) Ifffffffffffff a portable genset is used to power cord connected tools via its onboard mounted receptacles GROUNDING THE GENSET IS NOT REQUIRED .

3) Ifffffffffff a construction site genset is used to power tools, again GROUNDING THE GENSET IS NOT REQUIRED and far as I know OSHA even discourages it.

4) Ifffffffffffffff a genset is used to power a SINGLE RV GROUNDING THE GENSET IS NOT REQUIRED..

5) Ifffffffffff a portable genset is used to power a home or cabin COMPLEYELY OFF GRID orrrrrrrrrrrr the home is grid fed HOWEVER theres NO connection of the genset Neutral to the Utility Neutral such as if the Transfer Switch has enough poles so the Neutral is SWITCHED (genset or utility feeds home) Thats considered a Separately Derived System and Generator Grounding IS INDEED REQUIREDSame as the homes electrical supply transformer, being another Separately Derived System requires grounding.

FYI 1 Some gensets (some smaller) come from the factory with a Floating Neutral, others (some larger) with a Bonded Neutral .. .

FYI 2 Purposes of Grounding are for protection against lightning strikes and surges and to maintain the grid at a common low voltage reference.. Mother Earth ..

FYI 3 Grounding in the above sense means connection to a proper approved GROUNDING ..
ELECTRODE of which a MADE ELECTRODE like a rod driven into earth certainly suffices and is the more common..

DISCLAIMERS again DO NOT take my word for this consult the NEC. Of course a person has the free choice to wire or ground a genset however he pleases, , to ignore or adopt any NEC guidelines, as its HIS risk HIS choice, you get NO argument from me..Im ONLY trying to help .


NOTE: If you dont understand the electrical theory or why any of these rules exist study up on the subject. I do understand them but theres absolutely no way I can explain it here in a few sentences. THIS IS ONLY MY PROFESSIONAL ALBEIT LONG RETIRED OPINION, but regardless, yall try to be safe out there and where life and fire safety of your family is in doubt at least consider consulting trained professionals and the NEC. .. Im pretty sure the above is correct BUT AGAIN NO WARRANTY its been a while lol if other professional electricians or power engineers can add to this or cite actual NEC references in support of or opposition to any of this, please do Im always willing to learn..

Best wishes to everyone here, God Bless and keep you safe

John T

 

[buickanddeere]

99% of users figure everything is fine as
Long as the lights come on.

 

[Geo-TH,In]

GROUNDING THE GENSET IS NOT REQUIRED!

Yesterday you were insistent I needed to ground my generator.

Portable RV generators are the next thing to an isolation transformer, no ground, no common, no neutral.

 

[Butch(OH)]

Read an article the other day about the number of people killed and injured by portable generators. Was all about Carbon Monoxide poisonings, not a word about electrocution. While I certainly would not downplay the importance of the ground/neutral relationship amd mother earth locally everytine a generator related injury is reported on the news it from being overcome by exhaust fumes. Last time out power was out (last month) the coop came in my drive to check something on my pole. The supervisor was quite pleased that my stand by set is over 100 foot from the house, said I won't be joining the ranks of those over come by fumes. Makes me wonder how all the stand by set installers are getting away with puttingb the sets right next to the house without regard to exhaust??

 

[UncleTom]

I will add that when my son lost power in Palmer Alaska just like most everybody there and in 40 below temps with wind,people were trying to get there honda generators to run their furnaces and they wouldnt run them. My son called me in the lower 48 and asked me why wont they run. I had did my home work before hand and by u-tube learned that you need to make a plug that bonds the nuetral. He did that and the furnaces all took off.Up there they wire the furnaces with a plug in so you can simply run and extension cord to them. Apparently the circut boards like it only one way.

 

[John T]

George George, with all due respect to my friend and neighbor, perhaps you are confused?? NO I DID NOT INSIST WHAT YOU SAY please go back a page and read my answers to your questions. For your convenience FOR THE RECORD I have copied and pasted what you asked and my answers.....

NOTE: Thanks you for your good questions, you are at the head of the class lol.. Im trying my best here to HELP and you should NOT feel bad if you are confused, Grounding and Bonding are complicated (perhaps you don't understand the difference). I'm NOT here to argue with you, ONLY help, are you arguing with yourself ??


You state above:

Yesterday you were insistent I needed to ground my generator.

FOR THE RECORD HERE IS A COPY OF WHAT YOU ASKED AND WHAT I SAID

1) YOU ASKED: Who is going to require o bond my generator to ground and why?

MY ANSWER:

NOT me neighbor,,,,However FYI, One reason why SOME PEOPLE MAY choose it is if they had say an Energy Management System (sort of like an improved Surge Protector but with many many more features) like some RV's and others use, it's to test for proper wiring, bonding, safety, correct polarity, Neutral and Hot are reversed !!! low or high voltage etc. AND IT WILL ALARM AND CUT OFF POWER if it sees an open Ground SO THOSE PEOPLE MIGHT BOND their portable gensets Neutral to correct that situation..


2) YOU ASKED: So why do I need to ground the metal frame of my generator??

MY ANSWER:

You DO NOT NEED TO if its used to power your house by a cord n plug from the genset to your home by which the genset Neutral and the homes Neutral are connected
Another NOOOOO O you do NOT need to if its a portable genset used to power tools and appliances from onboard mounted receptacles..

Another NOOOOO OOOO you do not need to in the case of construction gensets used on remote job sites HOWEVER if the genset is configured as a separate derived source used to power your home AND THERES NO GENSET NEUTRAL OR GROUND WIRES CONNECTED TO THE HOMES NEUTRAL AND GROUND WIRES The NEC requires connection to a GROUNDING ELECTRODE such as a driven into earth rod.



3) You state: Portable RV generators are the next thing to an isolation transformer, no ground, no common, no neutral.

ACTUALLY GEORGE, here are the facts:

A) NO NEUTRAL ??? SOME (often smaller) gensets come from the factory with a FLOATING Neutral while SOME (often bigger) gensets come with a BONDED Neutral.
B) NO GROUND ??? From the factory the conductive metallic supporting frame is typically connected to the Third Wire Safety Equipment Ground Terminal in the Receptacles.

There ya go neighbor I hope this helps. Remember I'm on your side I'm trying to help you HOWEVER I can not explain Grounding and Bonding in a few paragraphs and you are normal if you find it difficult. I will continue to try and help you but this may be getting above and beyond what can be done here. Feel free to e mail me more questions and FYI check out some of Mike Sokols or Mike Holts instructions regarding Generators if you don't like, believe or understand my answers BUT HEY IM TRYING MY BEST !!!

Best wishes, God Bless you good neighbor, GROUND OR NOT GROUND HOWEVER YOU PLEASE

John T

 

[John T]

X2 CO Poising is hazardous and unfortunately happens all to often grrrrrrrrrr

John T

 

[woodbutcher]

Thanks, John. For several years I used my Lincoln tombstone welder plugged into my Champion 7500 watt generator as a portable welder anywhere I needed to go in my pasture without a ground rod. I never had any problems, but I wondered whether I needed a rod for safety.

Butch

 

[BarnyardEngineering]

(quoted from post at 03:38:03 07/10/23) Read an article the other day about the number of people killed and injured by portable generators. Was all about Carbon Monoxide poisonings, not a word about electrocution. While I certainly would not downplay the importance of the ground/neutral relationship amd mother earth locally everytine a generator related injury is reported on the news it from being overcome by exhaust fumes. Last time out power was out (last month) the coop came in my drive to check something on my pole. The supervisor was quite pleased that my stand by set is over 100 foot from the house, said I won't be joining the ranks of those over come by fumes. Makes me wonder how all the stand by set installers are getting away with puttingb the sets right next to the house without regard to exhaust??

The common thread though, is people running them indoors, inside their garages, just outside the garage with the door open, right outside an open window.

Standby sets are also natural gas or propane powered. They produce much lower levels of CO than a gasoline engine. This is why you don't need ventilation for your gas stovetop/oven. This is why they use propane for forklifts in warehouses.

 

[John T]

Thanks Butch, good question. NOT there or know how everything is configured I cant advise for sure, but most likely you are safe and fine !!!!!

The NEC as I best recall 1) DOES NOT require grounding portable gensets if you power up tools connected into its onboard receptacles 2) OSHA does NOT require even discourages grounding when construction site gensets power up tools.

NOT there so NO warranty but its my opinion (if the genset and welder are what I think??) YOU ARE SAFE NO GROUND REQUIRED..In addition the welder plugged into the genset may well be ??? AN ISOLATION TANSFORMER Sounds like this may be the situation where OSHA is best and there be NOOOOOOOOO grounding !!!!!

John T

 

[buickanddeere]

(quoted from post at 05:45:08 07/10/23) GROUNDING THE GENSET IS NOT REQUIRED!

Yesterday you were insistent I needed to ground my generator.

Portable RV generators are the next thing to an isolation transformer, no ground, no common, no neutral.

RV genset and portable genset for standby power are apples and oranges .
The RV genset does have a neutral and a ground terminal . The neutral is held to the same potential as the motorhome chassis .

 

[John T]

The RV genset does have a neutral and a ground terminal .

EXACTLY X2

Onboard RV Gensets indeed have Neutral and Ground terminals. FYI some additional
info, in the event a Transfer Switch (on many maybe not all) is used to switch FROM
Utility TO Genset, at that time (via extra switch terminal/contacts) the Gensets
Neutral is BONDED to Gensets Ground, and of course the RV frame is also connected
which suffices as an NEC substitute Grounding Electrode. As you know an RV Panel is
treated and considered as a Sub Panel with separate insulated and isolated Neutral
and Ground Busses

Take care my Canadian neighbor and old friend

John T

 

[buickanddeere]

(quoted from post at 08:33:06 07/10/23) X2 CO Poising is hazardous and unfortunately happens all to often grrrrrrrrrr

John T

CO poisoning Usually occurs when generator owners try to make do with some extension cords through the door or window . Instead of using a proper transfer switch .

 

[HFJ]

(quoted from post at 13:37:00 07/10/23)

(quoted from post at 08:33:06 07/10/23) X2 CO Poising is hazardous and unfortunately happens all to often grrrrrrrrrr

John T

CO poisoning Usually occurs when generator owners try to make do with some extension cords through the door or window . Instead of using a proper transfer switch .

this past winter (or was it two ago now?), i read about a household who owed their lives to their cat. none of the humans realized something was wrong after someone thought the garage was a great place for the running generator.

i have no transfer switch, and no open windows or doors either. i turn off my main manually and then backfeed my house thru an exterior outlet

one of these days, i really ought to invest in a propane standby system.

 

[teddy52food]

In my coop you had better have a transfer switch if you are running a generator!

 

[John T]

Some appliance circuit control boards or Energy Management Systems (EMS) will cut off power if theres no Neutral Ground Bond (A Floating Neutral)

Neutral Grounding is NOT the same as Neutral BONDING

John T

 

[Greenfrog]

I have a belt driven generator head that I rigged up to run off my garden tractor.
Do I need to ground this?
With your expert knowledge I seek your answer. Thanks.

 

[DoubleO7]

The current owners manual for a North Star belt drive 2600w unit has an entire page about proper grounding requirements.

 

[buickanddeere]

(quoted from post at 13:15:43 07/15/23) I have a belt driven generator head that I rigged up to run off my garden tractor.
Do I need to ground this?
With your expert knowledge I seek your answer. Thanks.

It is safer when the equipment case and the load current carrying neutral conductor are held to earth potential .