Generator Installation Question

[wbrian63]

My mother is getting quotes to have a whole-house generator installed.

One of the installers has proposed the installation as seen in this drawing (nothing is to scale).

As you can see, the main disconnect for the house is on the other side of the building. The garage isn't the whole width of the face, just a standard 2-car affair. Adjacent to that is the entryway, and a front bedroom.

I think their plan is to install the 200Amp ATS over by the main disconnect and run a conduit up the outside of the house, into the attic and across the building, then back down the outside of the house to the generator.

(The panel is across the house from the mains because the house was built with a reversed floorplan, and the electric service was already in place when the structure was built.)

Knowing that the folks doing the quoting aren't electricians, I'm wondering whether it's code-legal to install the ATS on the same side of the building as the generator, disconnect the main feed from the top of the breaker panel (the main 200A breaker that feeds the panel is across the house by the meter on the outside), add a length of wire necessary to get to the ATS, which would be mounted on the outside by the generator. From the ATS, then they could wire back to the main bus on the panel.

So - the question is - is splicing the mains inside the breaker panel code legal?

Doing it this way makes the installation far less complex, IMHO.

For that matter, they could install the ATS on the inside of the garage, above the breaker panel (10 foot ceilings), and pull the main lines out of the breaker panel and have more than enough length to feed directly into the ATS, but I don't know about having the panel not accessible without using a ladder.

Thanks for your opinions.

 

[sands35]

How far away is the neighbor's house? Need to think about where the exhaust gas will go. Fixed generators also do an automatic run every so often, might not be popular with the neighbors if it's next to a bedroom.

Typically, the breaker panels and such have specific height requirements. Basically they need to be at eye level. So putting one up where you need a ladder won't work.

 

[wbrian63]

The drawing shows that the generator is adjacent to the neighbors garage. Additionally, the suggested placement is 40+ feet from any window or door of either house.

I figured that up a ladder was going to be a bad idea.

What about the "splice" inside the breaker panel?

 

[rustyshakelford]

It's cheaper to run gas line than it is to run elec. I'd move it closer to the breaker box and trench from the gas meter

Brett

 

[wbrian63]

It's cheaper to run gas line than it is to run elec. I'd move it closer to the breaker box and trench from the gas meter

Brett

You're not understanding the question.

Does the transfer switch have to be mounted by the main disconnect, or can it be mounted by the breaker panel?

If it's mounted by the breaker panel, a "pigtail" will need to be added to the main lines that feed the buss bar in the panel in order to extend those wires into the transfer switch.

Is it legal to extend a mains feed from inside the breaker panel?

 

[sands35]

It depends on what type of ATS you have. Manufacture with part number and or picture? It needs to be hooked up so you don't back-feed the utility main. Either the main service entry line is interrupted by the ATS, or the ATS interrupts each individual circuit.

Location: It really comes down to costs of pipe vs. costs of cable. Main or panel - doesn't matter (type of ATS you have aside)

Are you under the authority of a codes inspector (do you need to pull permits)?

Garage: sorry, missed it, but the picture isn't clear as to what is house and what is garage, it has no scale and no dimensions. No worries. Though if I where your neighbor I probably wouldn't like it (which is not the same as actually doing something about that). From that perspective, I'd put it on the back of the house.

 

[wbrian63]

It depends on what type of ATS you have. Manufacture with part number and or picture? It needs to be hooked up so you don't back-feed the utility main. Either the main service entry line is interrupted by the ATS, or the ATS interrupts each individual circuit..

200Amp Mains ATS - no individual circuits - switches the entire load.

Are you under the authority of a codes inspector (do you need to pull permits)?

Yes - League City, TX.

Garage: sorry, missed it, but the picture isn't clear as to what is house and what is garage, it has no scale and no dimensions. No worries. Though if I where your neighbor I probably wouldn't like it (which is not the same as actually doing something about that). From that perspective, I'd put it on the back of the house.

No worries - drawing is shoddy. That's what I get for rushing the job.

As for the neighbor, assuming the HOA doesn't have a problem with the location, this is probably the best location for the installation, noise wise. Both mom's house and the neigbor's have only a small window that's above the shower in the master bath on the sides of the houses that face where the generator would be. During the exercising phases, I doubt you'd be able to hear the unit at all from inside the house.

Both houses are new construction <1 year old and full brick veneer construction with double-pane windows, so outside noises rarely penetrate.

When the power is really out - out, gripy neighbors can usually be silenced with a cold beer from your working refrigerator...

The main reason I'm asking these questions is that I don't trust the salesmen to make a proper decision considering installation. All they know is that the ATS interrupts the line from the meter to the main disconnect. They think that means that the ATS has to be installed next to the main disconnect box which is on the outside of the house next to the electric meter. If code will allow pigtailing the mains into the ATS, that would avoid having to run any conduit on the outside of a brand-new house, other than what is required to connect the ATS to the generator, plus it would be a LOT less work.

Quotes for these jobs are all coming in >$10k for a 17kw Generac Guardian unit. This is the same unit I can buy for about $4200. If we place the generator near the gas meter, if any digging is required, it would be less than 5 feet. If we can avoid having to put the ATS on the other side of the house and string cable through the attic, that avoids a lot of work and co$t.

I'm considering buying the generator directly and contracting out the electrical and gas work to the proper folks, with the proper permits pulled. Any digging I'll do myself - I'm not paying plumbers or electricians rates for ditch digging. So long as the trench is deep enough to meet code requirements, who cares who dug it.

Thanks for your input thus far.

 

[Chitown_hillbilly]

.

When the power is really out - out, gripy neighbors can usually be silenced with a cold beer from your working refrigerator...

Or an Extension cord... I never complained when my old neighbors genny fired up, just meant my Sump pump was about to get power and I was going to be wading around in the basement.

 

[sands35]

Beer works. (but ya never know about some neighbors)

Since you are under authority, you should be able to ask the inspector for the relevant NEC sections pertaining to the generator disconnect. You will probably be directed to section 250, 445 and 702.

But it's a good idea to ask since that will get him on the record about what he will look for. If you are going to DIY it, you will want to create or pull down a wire diagram from the interwebs.

Good reading:
http://gfretwell.com/electrical/generator_webcast.pdf

and:
http://www.mikeholt.com/mojonewsarchive/GB-HTML/HTML/NECArticle250Sections250.20-250.34~20020124.htm

A simple disconnect is an AC system pull out. You can also find 2 phase and 3 phase outdoor safety switches for under $100. (I don't know if your system will be a 2 wire w/ ground or 3 wire w/ ground - probably 3 wire w/ ground.) They also give you a nice, weather tight, way to pierce the wall with the power lines.

The need for a disconnect is ambiguous in the NEC code and it's really up to the local inspector.

Do you know if your proposed system has a bonded neutral or a floating neutral? That changes how it gets wired up. Code allows for only one place where neutral and ground are bonded together - which is typically in the main breaker panel.

(edit, just saw you are going to part out the job to contractors...)

 

[nehog]

You will want to look into what the minimum separation between the generator and the occupied building(s). It appears there is only about 10 or 15 ft between the buildings, which may be much too close, and that creates a CO risk.

 

[Rookie2]

what KW generator? If its a small one use a subpanel & smaller transfer switch (at the main panel) and cover just emergency circuits.

BTW: the neighbor will hate your mother (noise) unless she shares her generator !