We are installing several back-up power systems and at the generator installing a single ground rod, which connects to the frame. There is internal bonding between the motor and the frame and neutral to ground connections do not exist. I am sure this is correct but am having a problem with the utility company, where they are demading that we install a ground loop around the generator and connect to their transformer ground ring and establish 5 ohms or less to ground. I have not been asked to do this before and can't see where we should have to go beyond the NEC. PLease shed some light on this.
Permanent Generator Grounding
- Thread starter tbone
- Start date
- Status
- Location
- Massachusetts
Re: Permanent Generator Grounding
Confused.
Re: Permanent Generator Grounding
Sorry for the confusion. You are correct the neutral is not connected to the ground and I am sure we are installing this per the NEC, because the electrical inspectors have indicated such. I don't feel as though we should have to go the extent that the utility has requested.
Sorry for the confusion. You are correct the neutral is not connected to the ground and I am sure we are installing this per the NEC, because the electrical inspectors have indicated such. I don't feel as though we should have to go the extent that the utility has requested.
- Location
- Massachusetts
Re: Permanent Generator Grounding
The only thing I can suggest is to find out the power companies rules in writing, do not take someones word for what is required.
I am not saying someone is lying to you, they may just be mistaken.
Most power companies will post the rules right on their web site. It may be a down loadable pdf file or right on the web site.
The only thing I can suggest is to find out the power companies rules in writing, do not take someones word for what is required.
I am not saying someone is lying to you, they may just be mistaken.
Most power companies will post the rules right on their web site. It may be a down loadable pdf file or right on the web site.
Re: Permanent Generator Grounding
tbone
This is still confusion in you post. You need to determine if the neutral is being switched by the transfer switch. If the neutral is switched, then you must have the neutral bonded to the frame of the generator along with the ground rod. If the neutral is not switched, the neutral bonding jumper is removed and you must connect the system equipment grounding conductor to the generator frame and the system neutral to the generator neutral. A ground rod may be installed and bonded to the frame. Please verify your connections. From your post it does not sound like your installation is correct.
[ June 11, 2004, 05:05 PM: Message edited by: bob ]
tbone
This is still confusion in you post. You need to determine if the neutral is being switched by the transfer switch. If the neutral is switched, then you must have the neutral bonded to the frame of the generator along with the ground rod. If the neutral is not switched, the neutral bonding jumper is removed and you must connect the system equipment grounding conductor to the generator frame and the system neutral to the generator neutral. A ground rod may be installed and bonded to the frame. Please verify your connections. From your post it does not sound like your installation is correct.
[ June 11, 2004, 05:05 PM: Message edited by: bob ]
Re: Permanent Generator Grounding
Thank you all for your assistance. To answer your question Bob, the neutral is not being switched at the transfer switch and the grounding is done as you have stated. A ground rod will be installed and connected to the frame, in order to meet NEC requirements.
iwire: I don't see where the utility has a saying on this when they don't own or service the equipment and our install meets NEC.
Thank you all for your assistance. To answer your question Bob, the neutral is not being switched at the transfer switch and the grounding is done as you have stated. A ground rod will be installed and connected to the frame, in order to meet NEC requirements.
iwire: I don't see where the utility has a saying on this when they don't own or service the equipment and our install meets NEC.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: Permanent Generator Grounding
tbone:
"the neutral is not being switched at the transfer switch and the grounding is done as you have stated. A ground rod will be installed and connected to the frame, in order to meet NEC requirements"
If the neutral is not being transferred, then the generator is not a separately derived system, and a grounding electrode system (ground rod or rods) is not required at the generator.
See article 100 definition of separately derived systems and section 250.20(D)
tbone:
"the neutral is not being switched at the transfer switch and the grounding is done as you have stated. A ground rod will be installed and connected to the frame, in order to meet NEC requirements"
If the neutral is not being transferred, then the generator is not a separately derived system, and a grounding electrode system (ground rod or rods) is not required at the generator.
See article 100 definition of separately derived systems and section 250.20(D)
- Status