Portable Generators and Grounding Rods

[DC1]

I've got a portable generator to use for power outages. I don't ever remember running a grounding rod in the past, but was reading the manual and it said to.

Is there a standard? I have pretty much red clay type dirt. It's a 7k generator.

 

[Russ from MN]

O boy! This subject got beat to death a couple of years ago, it will be interesting to see the consensus this year!

 

[DC1]

I didn't look in archives.

 

[Russ from MN]

I think the common opinion is that if you are connecting the generator to an electrical system that is grounded, like a home
or other building, then it should be grounded. If you are using an extension cord and portable tools they you don't. But I'm
sure you will get other opinions!

 

[Geo-TH,In]

Only when you think this horse is dead and buried in the GROUND, it comes back to life. Need to put a COMMON copper clad rod in it's heart.

 

[John T]

AS a retired electrical power distribution design engineer I have studied this topic and YES there is a standard.


HOWEVER the answer depends on factors such as:


1) Does the genset have a Bonded or a Floating Neutral ????????

2) Is the genset configured as a "Separately Derived Source" ????

3) Is the genset connected to a Transfer Switch or other transfer method ??

4) If so how many poles does it have ??

5) Does the Transfer switch or method switch the Neutral as well as the hots ???


THERE SHOULD BE ONLYYYYYYYYYYYYYY ONE NEUTRAL GROUND BOND


FYI if a portable genset feeds plug and cord connected tools direct via onboard mounted receptacles THERE IS NO REQUIREMENT FOR CONNECTING TO A PROPER GROUNDING ELECTRODE

CAUTION Subject to the questions and answers above (IE it depends on certain situations and wiring configurations) CONNECTING A PORTABLE GENSET TO AN EARTH GROUND ROD CAN BE HAZARDOUS AND GET A PERSON KILLED DEAD !!!!!!!!!!!!

The CORRECT answer is IT DEPENDS but one has to know the situation and answers to the questions above to give a safe accurate answer.

NOTE I have a PDF file that explains much of this but I cant locate the URL link I copied it from. I'm at Half Century of Progress in Rantoul and busy but will try to locate it later.

AGAIN THE ANSWER IS YES AND NO in some situations a ground rod is good in others its bad and hazardous so get it right or take the risks

WARNING when life safety is at stake consult trained professionals and the NEC and DO NOT bet your life on lay opinions as it could get you killed dead grrrrrrrrrrrrrr As always electrical questions draw more responses and opinions.

I will try to find the info that explains how a ground rod can be hazardous and get you killed orrrrrrrrrrrrr on other situations save your life BUT ITS FIELD DEMO TIME AT HALF CENTURY NOW yayyyyyyyyyyyyyyyyy

John T BSEE, JD Long retired electrical power distribution design engineer and a tad rusty so no warranty but believe the above is still correct ANSWER THE QUESTIONS ABOVE THEN CONSULT THE NEC NOTTTTTTTTTTTTTTT ME

 

[John T PS]

EUREKA

I found it, read this OSHA article to see how a ground rod could get you killed dead and other related articles


http://www.oshaprofessor.com/Portable%20Generators%20and%20OSHA%20Construction%20Standards%203-05.pdf

https://www.osha.gov/OshDoc/data_Hurricane_Facts/grounding_port_generator.pdf

https://www.osha.gov/OshDoc/data_Hurricane_Facts/portable_generator_safety.pdf

John T KEEP SAFE YALL consult NEC and OSHA and trained competent professionals where life is at risk
Generator Ground Rod Hazards

 

[Billy Shafer]

I am sure glad you covered it. After forty years I am kinda tired talking about it. Tired of fighting inspectors. Have fun.

 

[Goose]

I hired a licensed electrician to do the hookup for the house on my generator. He only charged me about a hundred dollars, and the onus is on him for it to be done right.

 

[John T]

Thanks Billy, like you I have explained this all before.

John T

 

[John T]

CONGRATULATIONS you done good. There are just more variables then a non electrician might not understand.

Bonded or Floating Neutral,,,,,,,,,Switched or non switched Neutral,,,,,,,,,,,,Separate Derived Source or not,,,,,,,,,,,,Plug and cord connected to onboard receptacles or not,,,,,,,,,,,Whats a grounding electrode and whats not,,,,,,,,,,,,When can iron frame be used as such,,,,,,,,,,,,,,,When is an earth driven made electrode ground rod proper OR NOT,,,,,,,,,,,,,

John T

 

[DC1]

Thanks everyone. I had spent the breakfast hour or so looking at all the archived responses and think I have a pretty good handle on what to do.

Brought back some memories, had a friend years ago that was electrical engineer by profession and I remember him telling me there were actually "grounding" engineers as a subgroup of the profession.

Anyway, I am only using it with good cords to run frig, couple of lights, box fan and internet during power outages. Probably going to have one this weekend when the hurricane comes through.

 

[kcm.MN]

John T -- If someone wasn't sure whether their ground with a generator was sufficient, would one of these small testers be enough to safely show that?
https://www.amazon.com/Electrical-Receptacle-Outlet-Ground-Tester/dp/B0012DHVQ0

The OSHA link above keeps going to a 404 Page Error screen. Did a search online and found a pretty well-written article on generators and grounding:
http://www.forconstructionpros.com/...25/proper-grounding-and-bonding-of-generators

 

[John T]

GOOD AND THOUGHTFUL QUESTIONS... Looks like if the genny has a bonded (non floating) Neutral those cheap testers will work okay.

That looks like a pretty good article but it DOES NOT explain and describe how use of a ground rod in a construction site genset can be an electrocution hazard as well as the articles I referenced. They work fine here I'm unsure why you get an error ??????????????

John T

 

[John T]

"there were actually "grounding" engineers as a subgroup of the profession."

I'm not sure of that but can tell you proper grounding is one of the most complicated parts of the NEC and its difficult for lay persons let alone even engineers to understand it lol...........

John T

 

[kevinthefixer]

John, you take all the fun out of it restricting it to just one neutral ground bond. Diagnosing ground-loop problems is SO exciting. Especially after somebody has installed an auto transfer switch that didn't interrupt the extra bond! The newer HF battery chargers just love that setup, never know what'll come out the DC end.

 

[Russ from MN]

I know that a GFCI won't work with my generators.

 

[DC1]

Naw, pretty sure what he said. He dealt with power stations, relay stations. Maybe it was an off the cuff remark.

But a little digging into the intricacy's of the grounding aspects of EE, and the volume of literature on the subject of grounding (like on this forum) , leads me to believe there are engineers in the juice profession that focus on grounding, aspects, attributes, safety and viability.

 

[JMOR]

(quoted from post at 21:08:09 08/24/17) "there were actually "grounding" engineers as a subgroup of the profession."

I'm not sure of that but can tell you proper grounding is one of the most complicated parts of the NEC and its difficult for lay persons let alone even engineers to understand it lol...........

John T

EC writers made it 'complicated' by such terms as grounded & grounding. A child could have made the differentiation clearer! I have worked with the BS for enough decades to comprehend, but still say what a crock! :evil:

 

[Geo-TH,In]

Wasn't the post about portable generators, not whole house stationary generators?

 

[Dusty MI]

(quoted from post at 01:38:07 08/25/17)

(quoted from post at 21:08:09 08/24/17) "there were actually "grounding" engineers as a subgroup of the profession."

I'm not sure of that but can tell you proper grounding is one of the most complicated parts of the NEC and its difficult for lay persons let alone even engineers to understand it lol...........

John T

EC writers made it 'complicated' by such terms as grounded & grounding. A child could have made the differentiation clearer! I have worked with the BS for enough decades to comprehend, but still say what a crock! :evil:

To me neutral wire/conductor and ground wire/conductor, was simple.
Now they changed them to grounded conductor and grounding conductor. My mind is shrinking and I have a hard time remembering which is what.

Dusty

 

[kcm.MN]

Same here. There was a time when I could muddle through OK, but nearly always only stuck with things like switches and outlets - nothing concerning generators or grounding. But seems the older I get, the less I seem to understand what the heck they're saying!

I know there will be improvements from time to time, but why they can't keep calling a cat, a cat is beyond me.

 

[John T]

Kevin, heck it may be exciting for sparkies but it bores others to tears lol

1) If you DO NOT switch the Neutrals when using a portable genset you MUST configure the genset with a FLOATING Neutral and the iron frame bonds to the Equipment Grounding Conductor

2) If you DO switch Neutrals, the genset needs a bonded Neutral and is configured as a Separate Derived Source

3) Earth grounding the Neutral in portable gensets can create a hazard as the OSHA article clearly describes

Nice chattin with you

John T

 

[John T]

I for sure understand the confusion regarding the terminology over Grounding and Bonding but as one who used and practiced the NEC daily with it by my side as my bible lol and had to attend update seminars I appreciate and understand it HOWEVER I can see how its sooooooooooooo confusing for most other gents. Maybe this will help.

DEFINITIONS

The Live Hot wire in say a 120/240 volt single phase three wire system is called the UNGROUNDED CONDUCTOR because DUH it (unlike the Neutral) IS NOT GROUNDED

The Neutral is GrounDED (to mother earth) so its called the GrounDED Conductor

The Safety Equipment Ground Buss in the main panel is where all the bare and green Equipment GroundING conductors attach

At the transformer the Neutral is attached to a GroundING Electrode Conductor (No 4 bare copper) which leads down the pole to a GroundING ELECTRODE (driven into earth coper rod)

At the main distribution panel,,,,,,,,,,or at the service drop,,,,,,,,,,or in the meter base,,,,,,,,,The Neutral is again connected to GroundING Electrode Conductor which leads to again another GroundING Electrode........ I call that Earth Grounding

Bonding the Neutral to the Equipmemt Ground Buss in the main panel is NOTTTTTTTTTT the same as Earth Grounding of the Neutral (to a GroundING Electrode at transformer and again service entrance) to protect against electrical strikes and surges

SOOOOOOOOOOOO these are specific technical terms used by most (maybe not all) design engineers and technicians and electricians who understand the terms and talk to each other. HOWEVER just because most people and non sparkies don't understand them (I wouldn't expect them to) DOES NOT MAKE THEM A BAD PERSON............

I'm not a doctor so don't understand medical terms and I'm not a plumber so I don't understand their terminology nor carpenter talk but I do understand MOST (not all) electrical power distribution terms and after lifes work and study and experience I cant help to try and use the ENGINEERING CORRECT terms ITS IN MY DNA LOL

So just because a person who doesn't use these terms or doesn't understand them is nothing to worry over, you don't expect one to understand medical or legal terms or plumbing or carpentry terms who aren't educated and experienced in those fields so this shouldnt be a concern

NOTE not even all who work in the electrical industry (electricians technicians and engineers) use all these precise terms the NEC uses and again that can vary in certain areas or industries and that's just how the world works lol I try to use them as that's how I was taught and practiced and I OFTEN get them wrong and mAKE MKISTAKES BUT HEY GIVE ME CREDIT I TRY MY BEST

Headed to Half Century Field demos yall keep safe now, hope this HELPS

John T

 

[Goose]

This is portable. I had the electrician do the wiring into the double throw switch on the meter pole. It plugs into the generator.

 

[Billy Shafer]

I always hated going to the NEC up date lecture. Plus the high voltage lectures and testing. Different terms used across the country made it hard to keep up sometimes. Plus they were boring as H!ll.

 

[buickanddeere]

Depends if the generator or panel has floating or bonded neutral.