Hooking up a whole house generator.

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rhamblin

rhamblin

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Kaukauna, Wisconsin
My wife's grandfather got a great deal on a used whole house generator, and figures I can hook up the electrical. I'm fully capable of doing it of course, but the only problem is, I've never hooked up a generator before. I have the manufacturers instructions, and can figure out where all the wires go. The unit is a 12kw 240V single phase natural gas generator.

Regarding where to install the ATS, I originally thought I would reroute the wires feeding the main breaker, to the ATS and then add wire from the load side to the Breaker Panel. But then, the ATS wouldn't be protected by any OPD, so what is typically done here? Mount a single breaker (200 A) in a separate enclosure and then feed the ATS and then the panel? I don't know if the meter base has any main breakers in it, I guess if it does, then I wouldn't need the other breaker. If I do need a separate OCPD ahead of the ATS, maybe a fusible disconnect will be cheaper than a breaker in a separate enclosure?

Regarding the grounding, and let me know if my thinking is off here. I am thinking the ATS does not transfer the neutral, therefore the generator is not a separately derived system, and therefore I can just size the grounding conductor off of the ungrounded conductors and I won't need to drive a ground rod. Just bond the grounding conductor from the generator to the panel in the basement.

Question regarding 445.18, I'm thinking the plumber is going to be putting in a ball valve for the gas line coming out to the generator. If I can convince him to install a lockable ball valve, I won't have to worry about a separate lockable disconnect, right? Or can you use the main 200 amp breaker in the panel as the separate lockable disconnect, assuming it is lockable?
 
ActionDave said:
What's on the outside of the house? Just a meter?
Click to expand...

Yeah, it's a Wisconsin amendment that allows for the disconnect to be inside the house no more than 8 feet. Beyond that you'd need a disconnect or something. I think the vast majority of houses in Wisconsin have the panel right inside from the meter base.
 
rhamblin said:
My wife's grandfather got a great deal on a used whole house generator, and figures I can hook up the electrical. I'm fully capable of doing it of course, but the only problem is, I've never hooked up a generator before. I have the manufacturers instructions, and can figure out where all the wires go. The unit is a 12kw 240V single phase natural gas generator.

Regarding where to install the ATS, I originally thought I would reroute the wires feeding the main breaker, to the ATS and then add wire from the load side to the Breaker Panel. But then, the ATS wouldn't be protected by any OPD, so what is typically done here? Mount a single breaker (200 A) in a separate enclosure and then feed the ATS and then the panel? I don't know if the meter base has any main breakers in it, I guess if it does, then I wouldn't need the other breaker. If I do need a separate OCPD ahead of the ATS, maybe a fusible disconnect will be cheaper than a breaker in a separate enclosure?

Regarding the grounding, and let me know if my thinking is off here. I am thinking the ATS does not transfer the neutral, therefore the generator is not a separately derived system, and therefore I can just size the grounding conductor off of the ungrounded conductors and I won't need to drive a ground rod. Just bond the grounding conductor from the generator to the panel in the basement.

Question regarding 445.18, I'm thinking the plumber is going to be putting in a ball valve for the gas line coming out to the generator. If I can convince him to install a lockable ball valve, I won't have to worry about a separate lockable disconnect, right? Or can you use the main 200 amp breaker in the panel as the separate lockable disconnect, assuming it is lockable?
Click to expand...
The ones I have done were "suitable for service". They were 200amp ATS's. Do you have a 200amp tranfer switch? As you said we would take the feed from the meter out of the panel and go to the 200amp breaker in the ATS, then the double lugs load side feed the panel and one set to the generator. The ATS is now your first means of disconnect so you have to redo the grounding.
 
Hooking up a whole house generator.

House has 240 volt, 100 amp main, as it turns out. The new breaker will be the first disconnecting means. Redoing the grounding means removing the green screw (main bonding jumper) from the main breaker panel, installing the green screw that came with the new breaker in the new breaker enclosure. Correct me if I'm wrong, but the Grounding electrode conductors (I'm thinking one #6 for the ground rods and another #6 for the water pipe) have to move to the new breaker enclosure as well.


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rhamblin said:
House has 240 volt, 100 amp main, as it turns out. The new breaker will be the first disconnecting means. Redoing the grounding means removing the green screw (main bonding jumper) from the main breaker panel, installing the green screw that came with the new breaker in the new breaker enclosure. Correct me if I'm wrong, but the Grounding electrode conductors (I'm thinking one #6 for the ground rods and another #6 for the water pipe) have to move to the new breaker enclosure as well.


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Correct and you also have to separate the neutrals and grounds in the 100 amp sub-panel. (that's always fun.....)
 
Hooking up a whole house generator.

qcroanoke said:
Correct and you also have to separate the neutrals and grounds in the 100 amp sub-panel. (that's always fun.....)
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Yeah, they're probably all crammed on the same bar, forgot about that...may have to buy another ground bar for the panel.

Thanks for mentioning that, forgot about it.


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rhamblin said:
Yeah, they're probably all crammed on the same bar, forgot about that...may have to buy another ground bar for the panel.

Thanks for mentioning that, forgot about it.


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You will have to buy a ground bar that bolts directly to the can. Neutral bar is isolated from can by plastic standoffs.
make sure you take out the bonding screw too.
 
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