• Steel Soldiers now has a few new forums, read more about it at: New Munitions Forums!

  • Microsoft MSN, Live, Hotmail, Outlook email users may not be receiving emails. We are working to resolve this issue. Please add support@steelsoldiers.com to your trusted contacts.

neutral bonding at the generator

coyote62ny

New member
184
-1
0
Location
sherburne new york
mistaken1 if you or any one else reading this i would not use one of the cheap plastic battery disconnect switches i dont think they would handle the possible amps that could be passed through the switch the switch i used was from an old bulldozer we had all metal switch and marked 200 amp rated
 

bones1

Member
854
4
18
Location
Southern Maryland
The key to the whole seperately derived system nomenclature is "are you switching the neutral when you transfer to the generator". If you do switch to an isolated generator neutral like coyote62ny just described, you have a seperately derived system. If you connect your generator neutral to your house neutral solidly (not switched), then you have a non-seperately derived system (90% of systems are connected this way). Remember, if you do switch the neutral during transfer, the generator should be treated like its own seperate electrical service. This means it needs its own grounding electrode conductor - least a ground rod, plus one other grounding electrode (cold water pipe, metal gas line, auxillary ground rod, etc) AND your neutral and ground are tied together in the generator (because this is now the first means of disconnect). Confused yet?
The way I read this, you only need the ground rod at the generator when you are not connected to the house service panel.

Whoops, this original post is years old. Sorry. Can't find how to delete mine.
 
Last edited:

Keith_J

Well-known member
3,657
1,323
113
Location
Schertz TX
And to muddy the waters further, the latest NEC requires the single point ground to be tested with a special meter to insure a ground of 25 ohms or less. In lieu of such testing, a second, 8' ground rod can be installed 6 feet or more way from the first ground rod and connected to the grounding/neutral bond at service entrance point with its own ground wire. Confusing?

Just had my service entrance upgraded and had to do this before inspection sign off, the electrician allowed me to do this..actually he dislikes driving rods in our rocky soil. I drilled it in past the caprock and used my pneumatic t post driver to finish. 5 minutes of easy work. While I lack the special test meter, I measured 0 ohms between the two and <3 ohms between them and service entrance neutral.
 

bones1

Member
854
4
18
Location
Southern Maryland
This is correct as well. I had to do this about 3 years ago with my new panel install. Thanks guys. I will now put my generator grounding questions to bed.
 

steelandcanvas

Well-known member
6,187
85
48
Location
Southwestern Idaho
Just had my service entrance upgraded and had to do this before inspection sign off, the electrician allowed me to do this..actually he dislikes driving rods in our rocky soil. I drilled it in past the caprock and used my pneumatic t post driver to finish. 5 minutes of easy work. While I lack the special test meter, I measured 0 ohms between the two and <3 ohms between them and service entrance neutral.
There were areas I worked in that I absolutely despised attempting to drive ground rods. One trick an inspector showed me was to drive the rod at an angle, you can do this up to 45 degrees. The angle trick combined with an electric jack hammer made this task bearable.
 

shazam

Member
22
51
13
Location
Ohio
To once again revive a necro-thread...sorry....I want to make sure I do this right. Genset will be connected via 4-wire to the main house box. After reading the post twice, still confusnicated. Do I understand that....

The neutral bond bar in the genset should be disconnected, and the 4 wires go from the corresponding terminals in the genset to their respective places in the main box (two hot wires to the bus (thru a breaker/transfer switch of course), and neutral and ground to the grounding bar)?...and....

a separate grounding rod is/is not used at the genset? If 'is'....to ground the frame only, or to the ground terminal?

My newbieness is showing, and I thank you all for your expertise!
 
Last edited:

DieselAddict

Well-known member
Steel Soldiers Supporter
2,532
2,059
113
Location
Efland, NC
With a 4 wire setup your generator is grounded through the main power system ground BUT you can drive a ground rod at the generator if you wish. No code against that. There is a ground terminal in the generator that you can parallel a local ground rod or you can install a ground lug on the frame. Either way is fine. There is debate whether a ground rod at a generator is a good thing or a bad thing. I personally think its a good thing so long as your grounding conductor is beefy (6 awg or larger). You can search the web and find many arguments on either side of that fence.

You are correct that the neutral/ground bar at the generator is to be disconnected when you are using a 4 wire connection and there is a neutral to ground bond elsewhere in the system. I know people don't agree with this but from a code perspective its clear. Only one ground to neutral bond per system.
 

shazam

Member
22
51
13
Location
Ohio
Thanks, Chris! We'll be doing the final wiring Tuesday, including a remote start switch to the basement, and a small solar panel charger. Can't wait to be up and running!

Jim
 

peapvp

Well-known member
Steel Soldiers Supporter
1,115
1,235
113
Location
Basehor, KS
I am reviving this thread as shazam asked this question back in November 2018 and it was answered by Dieseladdict pointing out the debatable nature of this topic.

Very unfortunately, shazam experienced lighting related issues, which hopefully did not damage his Generator.

https://www.steelsoldiers.com/threads/lightning-auto-start.210434/#post-2457840

We were not asked back in 2018 of our opinion in this matter, neither where we aware of this thread.

We WOULD STRONGLY ADVICE AGAINST REMOVING THE BONDING BAR BETWEEN L0 AND GENSET CHASIS
 
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website like our supporting vendors. Their ads help keep Steel Soldiers going. Please consider disabling your ad blockers for the site. Thanks!

I've Disabled AdBlock
No Thanks