Page 1 of 2 12 LastLast
Results 1 to 10 of 18

Thread: portable generator bonding

  1. #1
    Join Date
    Feb 2017
    Location
    arkansas usa
    Posts
    4

    portable generator bonding

    Installed 30 amp 4 wire recep and used interlock on a square d meter/combo panel. Have not seen generator yet to see if neutral is bonded to frame but if so my understanding is the neutral and ground need to be split on generator frame because the neutral is not switched and It is not a SDS. Since neutral and grounds are bonded in panel I need to break bond in generator or am I wrong on this?

  2. #2
    Join Date
    Dec 2004
    Location
    Windsor, CO NEC: 2017
    Posts
    16,093
    You're right, also see 702.7(C) for the inlet signage required.

  3. #3
    Join Date
    Jul 2003
    Location
    New Jersey
    Posts
    23,922
    Many new portable generators have the neutral factory bonded to the frame. According to Generac they do not recommend that you un-bond the neutral. Having said that doing so isn't very difficult but can create a problem if the generator is used for stand alone power without connection to a structure where the service has a main bonding jumper.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  4. #4
    Join Date
    Mar 2008
    Location
    Michigan. It's a beautiful penninsula, I've looked around.
    Posts
    9,453
    Quote Originally Posted by infinity View Post
    Many new portable generators have the neutral factory bonded to the frame.
    Some do, some don't, some offer both options for the same model. They should be labeled as to the configuration.
    Cheers and Stay Safe,

    Marky the Sparky

  5. #5
    Join Date
    Apr 2013
    Location
    Swartz Creek, MI. 48473 USA
    Posts
    13

    Portable Generator Connection

    Quote Originally Posted by MDS75 View Post
    Installed 30 amp 4 wire recep and used interlock on a square d meter/combo panel. Have not seen generator yet to see if neutral is bonded to frame but if so my understanding is the neutral and ground need to be split on generator frame because the neutral is not switched and It is not a SDS. Since neutral and grounds are bonded in panel I need to break bond in generator or am I wrong on this?
    Not only does GENERAC recommend NOT removing the neutral-ground bond on portable generators, doing so will likely void the warranty (unauthorized modification). Your best bet for installing a portable generator connection is to do so as a separately derived system using a transfer switch that switches the neutral (i.e. Reliance XS series). This leaves in place the factory installed neutral-ground bond and the unit remains safe for use as a portable generator (i.e. camping, hunting, jobsite, etc.).

    Also by removing a factory installed neutral-ground bond you are by definition removing a "safety device" from a consumer product. IMHO this is a very poor idea! I would strongly advise that you have a discussion of this practice with your legal council prior to proceeding.

    Your MUST also properly label the portable generator power inlet as required by NEC 702.7(C).

  6. #6
    Join Date
    Jul 2003
    Location
    New Jersey
    Posts
    23,922
    I removed the bond from my Generac home generator which is about a 5-10 minute job. If needed I can put it back in the same amount of time.

    IMO these should come with a switching mechanism so they can be used either with or without the neutral bonded. Leaving it bonded and installing it as an SDS with a transfer switch seems to be overkill when for $100 you can buy an inlet box and a breaker interlock and operate the system safely.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  7. #7
    Join Date
    Dec 2004
    Location
    Windsor, CO NEC: 2017
    Posts
    16,093
    IMO, if someone is going to blunder in and connect a generator without understanding what any of this means (Joe Homeowner), then I would like a main bonding jumper covering my fanny, and if they commit a code violation by having a second bonding jumper in the system, then the objectionable current that flows is on their conscience - and entirely unnoticed.

    -The Guy Who Found Another Missing Jumper On A 20-Year-Old Detached Garage Yesterday.
    Last edited by George Stolz; 03-02-17 at 10:40 PM.

  8. #8
    Join Date
    Jul 2003
    Location
    New Jersey
    Posts
    23,922
    Just put up the proper sign and all is good.

    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  9. #9
    Join Date
    Mar 2008
    Location
    Michigan. It's a beautiful penninsula, I've looked around.
    Posts
    9,453
    What is the worst thing that could happen as a result of having the N-G bond at both the generator and the service panel?
    Cheers and Stay Safe,

    Marky the Sparky

  10. #10
    Join Date
    Jul 2003
    Location
    New Jersey
    Posts
    23,922
    Quote Originally Posted by K8MHZ View Post
    What is the worst thing that could happen as a result of having the N-G bond at both the generator and the service panel?
    You would end up with a parallel neutral in the cord set. Not much would happen.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •