Neutral/ground questions

[Ira]

Apologies for the long post, but I've got a "unique" setup...

Had a 5638 installed recently. Purchased from and installed by the local Guardian dealer. I'm confused by how the master electrician (from the dealer) configured the neutral/ground wires/bars/rods on my somewhat different setup.

My service entrance/meter is on the side of my "shop" building which is about 150 feet from my home. As it is now, the meter is on an outside wall, the ATS (RTSE200A3) is directly behind the meter on an inside wall, a load center (I will call it LC1) is immediately to the left of the ATS, and another load center (LC2) is immediately to the left of LC1. LC1 and LC2 have feed thru lugs, so power from LC1 goes to LC2, then goes underground to a load center (LC3) in my house. LC1 contains a main breaker for everything, as well as a few circuit breakers for my shop and water well pump. LC2 contains only a main breaker which allows me to turn off power from my shop to my house easily from my shop. LC3 (in my house) also has a main breaker.

The generator is located about 15 feet from the ATS, outside my shop.

There is a ground rod next to the generator. I didn't pull the generator cover to get all the details, but there is a ground wire connecting the generator frame to the ground rod.

There is a ground wire going from the ground bar in the ATS to the generator. I assume it is indirectly connected to the ground rod at the generator, also. The neutral bar in the ATS is bonded to the ATS enclosure. The neutral bar contains neutrals from the POCO and the generator and a neutral going to LC1.

LC1 contains both a neutral bar and a ground bar. Both are bonded to the enclosure. A neutral wire from the ATS is connected to the neutral bar, as are all of the neutrals from the shop circuits. The ground bar in LC1 contains a ground wire going to a ground rod just outside the shop (not the one next to the generator), and all of the ground wires from the shop circuits. There are wires on the two hot and one neutral feedthru lugs going from LC1 to LC2.

LC2 -- wires coming from the feedthru lugs in LC1 go to the main breaker lugs and neutral bar in LC2. Wires from the feedthru lugs in LC2 go underground to LC3 in the house. The neutral bar and ground bar are both bonded to the enclosure. There are two (?) ground wires going from the ground bar in LC2 to the same ground rod used by LC1. No other breakers in this box. Here's one of the oddities -- the ground wire going underground from LC2 to LC3 in the house is connected to the neutral bar in LC2.

LC3 (in the house) -- separate ground bar and neutral bar. Ground bar is bonded to the enclosure. Neutral bar is not bonded. All circuit grounds attached to the ground bar. All circuit neutrals attached to the unbonded neutral bar. The electrician did not make any changes to LC3. All of his work was done on the generator, ATS, LC1, and LC2.

I was always under the impression that neutrals and grounds should be isolated all the way back to the main service entrance (the ATS in this case). In other words, the neutral bars in LC1, LC2, and LC3 should be unbonded, and the ground/neutral circuit wires should be attached to their corresponding bars. That's how it was wired prior to the generator/ATS installation. Also, that the only ground wire connected to a ground rod should come from the main service entrance (the ATS), although adding a generator to the mix may change that.

When I discussed my concerns with the master electrician, he simply told me that everything would be done to code. Problem is that I live in an unincorporated area, so there are no electrical inspectors to check out the installation.

Is what the master electrician did correct?

Thanks,
Ira

[SkipD]

Is what the master electrician did correct?I read through your post rather quickly, but I fully agree with you that the ONLY place that the ground circuits should be bonded to the neutral circuit is in the enclosure that houses the primary disconnect for the utility power.

In the case of the RTSE200A3, the Automatic Transfer Switch also functions as the primary disconnect if the utility power is wired directly to it from the meter. That means that the only place that ground and neutral should be bonded together is in the ATS.

[Ira]

That's what I thought, too. The ATS is physically directly behind the meter. POCO service goes directly from the meter to the ATS, so yes, it serves as the primary disconnect.

Now I need to figure out a way to convince the dealer that his electrician did things wrong.

Thanks,
Ira

[NYS SitePower Corp.]

Yep, it should be set up as you understand it, and as Skip said. Your RTSE200A3 neutral should be bonded to ground, but anything thereafter the grounds & neutrals are separate.

Will it work? Yes. Is it to NEC code? No.

We run into a lot of this on low-bid jobs either because the electrician was lazy and didn't want to separate ground & neuts, pull a separate ground, or for whatever reason. Realistically, how many average homeowners would be good enough to catch such a situation considering that it doesn't noticeably affect the operation of the generator? Nice catch on your part :) (At least he used a Service Rated transfer switch; we had one last week that didn't even bother to do that - right from the meter into a standard switch in addition to not isolating grounds & neuts. :eek:

This is a classic case of "do it right the first time and you won't look like an ass down the road when you get caught cutting corners".

You may want to give the electrician the benefit of the doubt that he didn't know of this requirement but ignorance is no excuse. Anybody that installs generators on a full time basis, or as part of their service offerings should know and install to the applicable codes. :D

[NYS SitePower Corp.]

Those 5638s are nice little units too - you should pat yourself on the back for going with a liquid cooled.

[Ira]

Those 5638s are nice little units too - you should pat yourself on the back for going with a liquid cooled.

I spent three years deciding what to get. I was originally drawn to the idea of a genset because of the low prices on the air cooled models. However, I decided on liquid cooled 1800 RPM fairly quickly because I knew I could be without power for days/weeks after a hurricane and I was concerned that an air cooled 3600 RPM genset would struggle for that long of a time.

I had actually decided on a different brand (the brand that went bankrupt days before I decided what I wanted) because Guardian seemed to have a hole in their liquid cooled 1800 RPM product line when I first started looking. I decided to give Guardian another look, and it turns out that the 5638 filled that hole perfectly for me. Since it uses the same 2.4L engine as the 27kW genset, I feel comfortable that it has plenty of power. Very quiet, also. You can easily carry on a conversation standing right next to it. With the aluminum enclosure, it seems to be a lot of generator for the money.

I think the electrician didn't know what was correct. The ATS and two subpanels are side by side (within inches of each other) so it wouldn't be any extra effort to keep the grounds/neutrals separate. The four wires to the house subpanel were already there so that wasn't a problem. The SE-rated ATS was my request.

Regards,
Ira

[Ira]

Sorry about reviving an old thread, but I didn't want to type all that in again.

This problem has never been resolved. The dealer was supposed to get a second opinion, but he went silent on me, and I've been lazy about staying on top of this.

Can anyone provide me with the NEC code that says the current setup is in violation, or the code that says how to do it correctly? I think that would cut down on the discussion quite a bit.

Also, what are the potential dangers of leaving it set up the way it is?

Thanks,
Ira

[Ira]

An update...a few weeks after my last post, the dealer agreed that it was done incorrectly and would send someone out to fix it. I wasn't pushing them on it because I was more concerned about the genset problem I'm having (which is still being worked on).

The dealer is now using a different electrical contractor company. They came out today and immediately recognized all of the problems I had seen (the ground conductors and bonded neutrals in the subpanels and the battery charger tap on the line side of the POCO lug), and fixed all of them. They also discovered and fixed a couple of minor problems, and checked out everything else. I was impressed with these guys.