Grounding a Generator rehash

I guys, I think this topic was discussed here some time ago. I saw an article in an insurance industry article on things to do if you have a generator. I was OK with what they were saying until I got to #6 that said: "Ground" your generator. I thought some here said that was not a good idea. What's the truth?

http://www.propertycasualty360.com/2016/10/21/have-a-backup-generator-make-sure-you-do-these-13?eNL=5809129c150ba0c00d4cfe50&utm_source=PC360_NewsFlash&utm_medium=EMC-Email_editorial&utm_campaign=10212016&page=4

IF and I do mean IF, your generator is installed with a three line lead. That is L1 L2 and a true ground. to your fuse box or switching gear. Your power boxes are grounded from the power company "if they know what the heck they are doing" and that should do you good. Understand that 240 will work with only two wires AND NO GROUND. If you are doing a remote direct feed to somewhere then a copper rod pounded into the ground is a good idea. Power tools can leak voltage through crummy insulation or bad cords. And YES you can get a shock from where the cords plug into each other in wet weather. An open ground is not a good thing. This is just a base reply. Lots of others are going to chime in on this one with more tech talk. This is how a GFCI breaker trips off. It will sense the incomplete ground and it is very sensitive. Wet weather can really nail you if you have an open ground. A real cow fence shot in the ****.

I think if you are using it to power your home through a transfer switch you should ground it, but if you are using it as a portable with extension cord
and power tools probably not. But I'm sure you will get lot's of different opinions!

There have been many generator ground vs. not on this site. I would say that if you are to ground your generator, the ground connection point on your generator should be connected to your service entrance ground - not to a separate ground rod. If your generator is connected properly, it's ground should be connected to your service ground through it's cord anyway.
Pete

W-B As usual when there's an electrical question everybody and their brother in law (Including me) crawls out of the woodwork and there are tons of opinions (some right some may get you killed) moreso then on most other topics. I enjoy and appreciate them all, the more the merrier, all a great bunch of gents here who like to help as do I, GOD BLESS THEM ALL

HERES THE REAL DEAL

1) When it comes to Life Safety and risking your life, its your free choice to believe

a) The NEC or the OSHA experts, or trained experienced professional electricians and engineers OR
b) A non electrician or non engineer or non electrical technician or Billy Bob and Bubba who wired their own home while
downing a case of beer and its "always worked" and by golly they are experts and are right and smarter then the NEC and
OSHA

2) Unless trained and experienced and an electrical professional or the NEC or OSHA electrical experts, many (NOT all)
DO NOT UNDERSTAND AT ALL ORRRRRRRRR the difference between NEUTRAL GROUND BONDING and NEUTRAL GROUNDING
and the concept of SINGLE POINT GROUNDING and what's a safe and proper GROUNDING ELECTRODE and what constitutes a safe
and proper EQUIPMENT GROUNDING CONDUCTOR

3) Some non electricians or non engineers or Billy Bob may say "The Owners Manual says to "Ground" your Generator HOWEVER
they do NOT a) Read where it may go on to say GROUND PER THE NEC and they do NOT b) Understand it makes a difference if
the Generator is wired and configured as a "Separately Derived Source, nor c) If the Generator has a FLOATING NEUTRAL or
not or d) If the generator feeds a home via a transfer switch or if it serves ONLY plug and cord connected tools plugged
into onboard receptacles like some construction site generators

4) The NEC and OSHA (see URL Link below) instructs there are times when you do "Ground" your portable generators BUT TIMES
YOU DO NOT AND IF YOU DO ITS HAZARDOUS !!!!!!!!!!!!!!!!!! For example when where and why its HAZARDOUS
see the URL link below

5) Some small Generators come from the factory WITH A FLOATING NEUTRAL while some come form the factory WITH A BONDED
NEUTRAL and they are treated and configured differently

6) It makes a difference if the generator feeds a home via a transfer switch or is a construction site generator

7) It makes a difference as to how many POLES the Transfer switch has IE is the Neutral switched or not??????????

AND THERES LOT MORE DIFFERENCES AND WHEN AND WHEN NOT AND HOW AND WHERE A GENERATOR IS GROUNDED

SEE THE OSHA URL LINK BELOW THAT EXPLAINS HOW IMPROPER GROUNDING A CONSTRUCTION SITE GENERATOR IS A HAZARD



CLOSING,,,,,,,,,,DO NOT TAKE MY WORD FOR IT, CONSULT THE NEC AND OSHA, ITS THEM NOT ME THAT SAYS THIS

If you want to flame on someone and you're right and the NEC and OSHA is wrong TAKE IT UP WITH THEM NOT
ME I'm only the messenger who is trying to save someones life, if that makes me a bad person call me bad

There are times when proper grounding is right and safe, and times when if done wrong IT CAN GET YOU KILLED it all depends on many many of the factors above which are all impossible to explain here.

Its your choice and your life at risk, so do it like your brother in law says or do it like NEC and OSHA says FINE BY ME and tell the NEC why your are right not them , I'm just trying to help and save a life NOT argue with yall HOWEVER having been trained and experienced in electrical safety over a forty year career who has attended NEC updates and seminars and who understands it IF I HAD MY CHOICE ID TRUST THE NEC OVER ANYONE HERE (me included lol) so flame on and argue with them if it makes you feel good and show how you're right and they are wrong, that will be a fun read lol but I will keep an open mind and maybe learn something, never too old to learn

http://www.oshaprofessor.com/helptopics.html

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



John T Long retired and rusty Electrical Power Distribution Design Engineer SO NO WARRANTY consult the NEC NOT meeeeeeeeeee don't do as I say do what the experts orrrrrrrrrrrr Billy Bob says, its your life and your choice
Hazardous Generator Grounding

Well alllllllllllllllllllllllllrighty then...

So instead of trying to read and understand a contradictory 385 page document written by the government, can you sum it up?

Does my generator have a bonded neutral or a floating neutral? The manual just says to ground the generator. Grounding one in certain situations is dangerous, and grounding the other in other situations is dangerous.

I think I'm just going to light a campfire in the middle of my living room floor the next time power goes out.

A simple test, if you are using it portable (not hooked to any mains) use a volt meter and check for voltage to an earth ground at the outlet with it running, if no or very low no need to ground anything to see if it has an isolated neutral check from the ground hole in the outlet to both blade holes (one at a time) same thing if no or very low voltage the it is an isolated neutral.

Sure glad your here John T. I have gone over this. So many times I get nervous when someone says ground.

Keeping your body from completing a circuit is the goal. Generators produce voltage relative between two points Hopefully between the Hot wire and
neutral going through your load, and having it all come back to the generator. Some producing 240volts have 120volts on both sides of the neutral, and
240 between the "hot" points. If the neutral (in the generator is connected to the generators frame, the bond causes the generator/engine to be a part
of the voltage. If that generator is on a wooden pick-nick table, there is no way for voltage to get from the generator output through you to a mother
earth ground. If it is sitting on the ground, or grounded with a rod in the ground, or placed on a steel structure you are working on, it can do so.
If the generator neutral is not bonded to the frame of the generator, the only path back to the generator is through the neutral.
If it is used to power a house, the important thing is to keep all trace of generated voltage out of the power companies wires to the pole. A
disconnect will do this. The best disconnect all three service entry wires. The generator (if hooked up to the 240) system of the house must connect
its neutral to the house neutral which is grounded through the house ground. This provides a path for electricity just as though the generator was the
power company. At that point it does not matter if it is internally bonded or not. Jim

John T , I have a question. I have a i would call construction generator 10,000 watts. Its an older unit i bought new several years ago when the power went out during a winter storm. The way i wired it to my house was i turned the main breaker off then wired it to my breaker panel i think it was 12/3 wire . I did ground the wire in the panel but i didnt ground the generator outside. The question is should i have???.

Short answer: we have a 50kw pto generator bolted
to a steel frame bolted to the concrete floor. An
electrician wired it up and there is a wire fastened to
the ground clamp on the base of the generator and I
can touch the generator while it's running and I
haven't gotten a lift yet anyways.

Unfortunately NOOOOOOO I cant sum it up there are way to many variables and differences such as

Is it configured as a Separately Derived Source or not????????????
Is the Neutral floating??????????
Are you using a transfer switch and if so are you switching the Neutral????????????

Take a continuity tester and go from Neutral to Ground on the receptacle, if its a short circuit its bonded if open its not IE a floating Neutral

Good question at least youre paying attention and doing so may save a life...........

John T Retired Electrical Engineer

Great question but hard to explain yet I will try............

1) If you wired it to your panel by backfeeding a branch circuit breaker (the 2 hots )and you do NOT switch the Neutrals, the Utility Neutral must be bonded to the Generators Neutral BUT THE GENERATOR MUST HAVE A FLOATING NEUTRAL IE sever any Neutral to frame or Neutral to the third wire ground at the generator. In that case the frame is bonded to the Utilitys Equipment GroundING Conductor just like any other non current carrying metal equipment enclosure THATS NOTTTTTTTTTTTT A SEPARATE DERIVED SOURCE

2) If the Neutrals get switched, genny versus Utility, then at the genset the Neutral needs bonded to a Grounding Electrode (like a driven rod) and there's a Neutral to Ground BOND THATS A SEPERATE DERIVED SOURCE

John T

Sounds like your Generator 1) Has a Neutral to Ground BOND,,,,,,,,,,2) Its configured as a Separately Derived Source In which case you would SWITCH THE NEUTRALS IF YOU USE IT TO FEED YOUR HOME

John T

As I expected theres cornfusion below lol I SEE THERES NO WAY I CAN EXPLAIN WHAT TAKES BOOKS AND YEARS OF STUDY AND PRACTICE AND EXPERIERNCE TO UNDERSTAND IN A PARAGRAPH LOL I APOLOGIZE

Where and when and how you ground or not ground depends on

Does the genny have a floating Neutral???
Is it a separately derived Source or not???
Are you using a Transfer switch
If so are you switching the Neutral
plus OTHER FACTORS THAT make a difference

IF YOU DONT KNOW THE ANSWERS OR DONT UNDERSTAND CONSULT A TRAINED COMPETENT PROFESSIONAL ELECTRICIAN OR ENGINEER AS IT CAN SAVE YOUR LIFE

God Bless yall

John T

John T Retired Electrical Power Distribution Design Engineer

Thank you

(quoted from post at 12:48:39 10/24/16) IF and I do mean IF, your generator is installed with a three line lead. That is L1 L2 and a true ground. to your fuse box or switching gear. Your power boxes are grounded from the power company "if they know what the heck they are doing" and that should do you good. Understand that 240 will work with only two wires AND NO GROUND. If you are doing a remote direct feed to somewhere then a copper rod pounded into the ground is a good idea. Power tools can leak voltage through crummy insulation or bad cords. And YES you can get a shock from where the cords plug into each other in wet weather. An open ground is not a good thing. This is just a base reply. Lots of others are going to chime in on this one with more tech talk. This is how a GFCI breaker trips off. It will sense the incomplete ground and it is very sensitive. Wet weather can really nail you if you have an open ground. A real cow fence shot in the ****.

Click to expand...

I'm getting the impression that you are not fully understanding the definition and uses for the neutral vs the ground .