Ground Rod at Standby Generator

[StreamlineGT]

I have a Kohler Generator that I installed, my first one, and it has a poly enclosure. The Generacs I have done previously are pretty straight forward, with a lug on the enclosure to connect the grounding electrode conductor. The Kohler has no such provision, and was wondering if there is anyone out there that has installed one, and what they have done to install one. Did you even install one? Is it required with a poly enclosure?

TIA

Brendon

 

[infinity]

Is this set up as a separately derived system? Do the manufacturers instructions call for a ground rod?

 

[StreamlineGT]

How do you install a generator that is not a separately derived system? Maybe that is a stupid question. The instructions simply say to install one if codes require it.

 

[augie47]

How do you install a generator that is not a separately derived system? Maybe that is a stupid question. The instructions simply say to install one if codes require it.

(since Rob hasn't posted, I'll take the liberty)....

Separately Derived System. A premises wiring system whose power is derived from a source of electric energy or equipment other than a service. Such systems have no direct electrical connection, including a solidly connected grounded circuit conductor, to supply conductors originating in another system.....................................................
........................................................
Tells us if the transfer switch does not switch the neutral, then the generator would not be considered an SDS.
If it is not a SDS, the Code does not require a ground rod unless the mfg. does.

 

[taylorp]

How do you install a generator that is not a separately derived system? Maybe that is a stupid question. The instructions simply say to install one if codes require it.

I would say that your installation should begin with 250.35 Permanently Installed Generators. They are either Separately Derived Systems or Nonseparately Derived Systems. The definition of which is which has to do with how you wire in the Grounded Conductor (commonly called Neutral) from the Generator to the Service Equipment.

Secondly, in my opinion, according to 250.50, all Permanently Installed Generators are going to require a Grounding Electrode at the Generator. How and where you wire in the Grounding Electrode Conductor to this Grounding Electrode depends on whether the Generator is Separately Derived or Nonseparately Derived.

The discussion on how to do this is too long for a single post in this forum, so I will let others join in the discussion.

 

[StreamlineGT]

The neutrals are solidly connected in the transfer switch.

 

[taylorp]

The neutrals are solidly connected in the transfer switch.

Then you have a Nonseparately Derived system. You still need a Grounding Electrode and Grounding Electrode Conductor at the Generator.

 

[augie47]

The neutrals are solidly connected in the transfer switch.

Then the generator is not an SDS and there should be not connection between the generator grounded (neutral) and grounding means.
An equipment grounding conductor should be installed to the generator.

 

[StreamlineGT]

There is an equipment grounding conductor a the generator. What would be an acceptable means of terminating a grounding electrode conductor to the generator, if no factory provisions are present? Tap a lug somewhere on the metal framework inside the unit?

 

[taylorp]

Then the generator is not an SDS and there should be not connection between the generator grounded (neutral) and grounding means.
An equipment grounding conductor should be installed to the generator.

As Augie has pointed out, you will need an Equipment Grounding Conductor or Supply Side Bonding Jumper from the Generator to the Service Equipment. You will connect the Grounding Electrode and Grounding Electrode Conductor to this EGC. I am assuming you did run an EGC?
:happyyes:

 

[augie47]

with the understanding that you do have to have one (a grounding electorde), you can do as you state of provide an aceptable lug where your equipment ghround connects and add the supplemental electrode conductor.

 

[taylorp]

There is an equipment grounding conductor a the generator. What would be an acceptable means of terminating a grounding electrode conductor to the generator, if no factory provisions are present? Tap a lug somewhere on the metal framework inside the unit?

Surely this generator has a EGC connection point somewhere on the Generator frame? I can't recall seeing a Generator without one. If not, then yes, you need to to have some type of connection point on the Generator frame. I.E. the stator frame of the Generator.

From this point you need to also connect the GEC and route it to your Grounding electrode.

 

[StreamlineGT]

All the generator has visible is the terminal strip where the EGC terminates. What I don't understand is, why after spending twice as much as a Generac, do I have to modify this unit. If this was a seperately derived system, how would this be different? The EGC and neutral would be bonded, with a GE and GEC at the unit also, no? Maybe I am just confused.

 

[taylorp]

All the generator has visible is the terminal strip where the EGC terminates. What I don't understand is, why after spending twice as much as a Generac, do I have to modify this unit. If this was a seperately derived system, how would this be different? The EGC and neutral would be bonded, with a GE and GEC at the unit also, no? Maybe I am just confused.

You need to read and understand 250.30 and 250.35. The code rules have changed for Generator installations. Generators are grounded and bonded differently depending on whether they are Separately Derived Systems or Nonseparately Derived Systems. It is much too long of a subject to cover in one post. Sorry.

Unfortunately the Generator Manufacturers apparently don?t read the NEC when they build Permanently Installed Generators, or else they would get their act together and build Generators which could be easily adapted to either System.

I can?t tell you how many Generators I have had to disassemble in order to disconnect the Grounded Conductor from the Generator Frame. :rant:

 

[don_resqcapt19]

Then you have a Nonseparately Derived system. You still need a Grounding Electrode and Grounding Electrode Conductor at the Generator.

What code section would require a grounding electrode at the generator?

 

[taylorp]

What code section would require a grounding electrode at the generator?

250.50 Of course I am referring to Permanently Installed Generators, as was my understanding from the original post.

 

[StreamlineGT]

The Kohler has a jumper that you remove to do that, and is easily accessible inside the compartment cover. I removed that jumper. Therefore I need to connect a GEC from the GND terminal to the GE. There is only one terminal for GND, and my EGC uses it. The factory installed jumper uses the same terminal as well, and if left in place, two wires would need to be installed under the same terminal, a violation in my eyes. I guess I will drive the GE and somehow run a GEC from a lug that I install, to it. There is also a bonding jumper in the transfer switch, which is not the first point of OCP or disconnect, so I would need to remove that as well, correct?

 

[taylorp]

The Kohler has a jumper that you remove to do that, and is easily accessible inside the compartment cover. I removed that jumper. Therefore I need to connect a GEC from the GND terminal to the GE. There is only one terminal for GND, and my EGC uses it. The factory installed jumper uses the same terminal as well, and if left in place, two wires would need to be installed under the same terminal, a violation in my eyes. I guess I will drive the GE and somehow run a GEC from a lug that I install, to it. There is also a bonding jumper in the transfer switch, which is not the first point of OCP or disconnect, so I would need to remove that as well, correct?

Okay here is a photo. This is something I drew for my files. I hope my attachment is readable.

 

[augie47]

What code section would require a grounding electrode at the generator?

250.50 Of course I am referring to Permanently Installed Generators, as was my understanding from the original post.

I have to join don with the question as I see nothing in 250.50 that leads me to think a grounding electrode is required. Can you elaborate ?

 

[StreamlineGT]

Do you have a diagram for when the transfer switch is service entrance rated, and the neutrals and grounds are tied together in the transfer switch?