another COSTCO GEN SET Q

[bullheimer]

okay so i don't know. i have read that i can use a 100A ATS (honeywell made by generac, comes from costco with a generac/honeywell gen and a 100A ats but NO Control panel) as long as i do service calcs and 100A will cover it.

ie, i can use this 100A ATS on a 200A panel. right? according to the wiring diagram, the ATS is in front of and in series with the main panel. the ATS has a 100A breaker that will NOT accept 4/0 AL. so that is my problem. the ATS says Service Rated all over it, which is required, but i don't see how in hell this is going to work. customer doesnt want to run whole house but dont see anything limiting that (he just wants to run a feezer, non elec, furnace, and lights)

here are the ats specs: http://www.honeywellstore.com/store...lt-sync-transfer-switch-non-service-rated.htm


wiring diagram (from what i remember from this morning, soooo very long ago) looks just like this one, here: on page 8: http://www.guardiangenerators.com/PublicPDFs/0E9905.pdf

i just think that if an ATS is in between the meter and the main panel then it also has to be a:rated at 200A and b: wired with 4/0. or am i seeing a parallel set of conductors coming out of the bottom of the meter. if so, does the meter have to have lugs for two wires? i thin so.

i have searched this, after about ten threads i'm done. thx. sb

 

[hillbilly1]

Use reducer/splicers to downsize your wire to match the lugs. HD sells them all day long. Cleaner look though would get Ilsco or Polaris or Burndy insulated taps from your local supply house.

 

[Volta]

Not sure I understand, are you proposing to run a 200 amp circuit through a 100 amp switch?

It seems like you need a 100 amp main at the meter then to downgrade the entrance.

 

[bullheimer]

I spoze that would work too. pretty full @ 38 breakers.
model # search didn't find anything. i am in washington state tho, so anyone from there who knows the wac please to chime in.

 

[hurk27]

If you have a 200 amp service you will need a 200 amp ATS simply because it will be switching the rating of the service, now if you find that they don't need a 200 amp service then down size the conductors to 100 amp and go from there, but keep in mind that since you have relocated your service disconnect to this transfer switch your grounding and bonding have now all changed, the grounding electrodes now have to go to this ATS, and the main panel is now a sub panel requiring the grounding and neutrals to be separated, I have installed a few 20kw Generacs on a 200 amp service but I used a 200 amp ATS, even though the calculated demand load was only 65 amps, much easier to install.

 

[ceb58]

Every thing Wayne said. You will have to install a service rated disconnect before the ATS unless it is service rated. Your equipment rating must be for the largest size in the system.

 

[bullheimer]

that's pretty much what i was thinking. good heads up on the Main to a Sub tho. I don't think the owner is going to like the concept of downsizing so i know he can buy a 200A ats for not so much, same brand, think that link i gave has them too. well $700 anyway.

 

[realolman]

Doesn't it have to go through a set of fuses or breaker to become a sub?

 

[hillbilly1]

If you have a 200 amp service you will need a 200 amp ATS simply because it will be switching the rating of the service, now if you find that they don't need a 200 amp service then down size the conductors to 100 amp and go from there, but keep in mind that since you have relocated your service disconnect to this transfer switch your grounding and bonding have now all changed, the grounding electrodes now have to go to this ATS, and the main panel is now a sub panel requiring the grounding and neutrals to be separated, I have installed a few 20kw Generacs on a 200 amp service but I used a 200 amp ATS, even though the calculated demand load was only 65 amps, much easier to install.

The OP said it was a service rated transfer switch, so it does not matter if the service is 200 amps or more because it contains the proper overcurrent protection, as long as the AIC rating of it's breaker is correct, then the only problem would be reducing the wire size to fit the 100 amp breaker. Of course this is assuming that this will be the service disconnect now instead of the exsisting panel, but you now what assumptions lead to!:roll:

 

[realolman]

I'm lost... seems to me if you are going to put a transfer switch on a 200 a service , it needs to be a 200 amp switch, and if you're going to use a smaller switch you need to put it on a separate panel with a smaller main breaker.
:huh:

 

[hillbilly1]

I'm lost... seems to me if you are going to put a transfer switch on a 200 a service , it needs to be a 200 amp switch, and if you're going to use a smaller switch you need to put it on a separate panel with a smaller main breaker.
:huh:

Many services are oversized for what is the actual loads, Mcdonald's restaurants at one time were putting in 1200 amp three phase services, (this was about 25 years ago, I don't know what they spec now) they wanted future expansion capability. Home Depot averages a 1200 amp 480 volt three phase service, but their average load is around 500 amps. That being said, sure you can downsize the service, but it will limit you on future expansion. The homeowner may decide later they want to add a large spa, steam room or any other high wattage item, then have to pay to upgrade the service back to a 200, along with load shedding to keep from having to upgrade the generator too.

 

[Len]

ats

ats

if you have a 200amp service then you must have a 200amp rated ats....

 

[hillbilly1]

if you have a 200amp service then you must have a 200amp rated ats....

If the service disconnect is 100 amp, the service is no longer 200 amp. Please post a code reference that prevents you from reducing the service size if the smaller service is adequate.

 

[realolman]

Are you considering the ATS to be the service disconnect? Does it have an OCPD? I understand that the service may be too large for the load.... probably many are... but I cant see where that would allow you to put the hundred amp switch in the service fused at 200 A... If you could depend on circuits not drawing any more than they were supposed to, there would be no need for breakers or fuses at all.

I can't provide any NEC reference, but it sure doesn't seem right to me... could you put in a 100 a meter base, or 100 a conductors as well?

 

[hillbilly1]

Are you considering the ATS to be the service disconnect? Does it have an OCPD? I understand that the service may be too large for the load.... probably many are... but I cant see where that would allow you to put the hundred amp switch in the service fused at 200 A... If you could depend on circuits not drawing any more than they were supposed to, there would be no need for breakers or fuses at all.

I can't provide any NEC reference, but it sure doesn't seem right to me... could you put in a 100 a meter base, or 100 a conductors as well?

The OP said it was a service rated T-Switch.

 

[ceb58]

if you have a 200amp service then you must have a 200amp rated ats....

If the service disconnect is 100 amp, the service is no longer 200 amp. Please post a code reference that prevents you from reducing the service size if the smaller service is adequate.

Lets reword every thing. If you have a 200amp service, and you want to keep the 200amp service, the ATS must be rated at 200amps.
Never had a call to down size a service :roll:

 

[hurk27]

Are you considering the ATS to be the service disconnect? Does it have an OCPD? I understand that the service may be too large for the load.... probably many are... but I cant see where that would allow you to put the hundred amp switch in the service fused at 200 A... If you could depend on circuits not drawing any more than they were supposed to, there would be no need for breakers or fuses at all.

I can't provide any NEC reference, but it sure doesn't seem right to me... could you put in a 100 a meter base, or 100 a conductors as well?

While I agree it seems strange but there are many utility's that require a 200 amp meter base installed and we will install a 100 amp service off it, sometimes we just do it because its what we have on the truck, and makes future upgrades a snap, but with what the OPer has said, I think the issue is going to be the demand load of this house, an ATS can not be used if the generator can not handle the load, and in the OP he clearly says the home owner only wanted certain loads fed which sounds like the generator is not big enough, a 20kw can provide 83 amps, but if this house demand load is over 62.25 amps then it is a no go with a ATS, then a sub panel will have to be used to feed only the loads the generator can handle, and the a non-service rated ATS will need to be fed from the main panel. I see no other way to do this easily.

 

[bullheimer]

Hence the 100A breaker. However there is a fly in the ointment. if the meter is feeding the ATS, then the ATS is your main now, as we said, and i have been told that that means the generator is NO LONGER and Emergency power supply but an Alternate Power supply, and that therefor the Generator has to be able to handle the ENTIRE load of the house, so the 50A breaker on my customer's genset would indicate it is not capable of doing this, therefor we will have to feed the ATS from a breaker on the Main panel, to a sub panel with all the circuits in it that he wants protected being the only thing that the ATS connects and disconnects.

i hope i said this right.

Crap, i posted after the last post on the first page. ANYWAY, WHAT HE SAID (Hurk27 among others) thanks and peace out.

I was thinking about $800 for doing this (an hour out of town, but now i am more inclined to equate this with my charge for a panel change: $1600) i did a subpanel with a manual interlock (sweet cover came with it for real cheap) at $800 and i felt like i almost did it for free. it had a gen/recept under it too. This is a propane unit and needs to have conduit run to it outside the house. i think 1600 is about spot on. if that's not a contradiction.

 

[realolman]

Hence the 100A breaker.

I will admit to not being familiar with this, but why is this not just a switch? I am at a loss to see where there is a 100A breaker involved with this thing...

However there is a fly in the ointment. if the meter is feeding the ATS, then the ATS is your main now, as we said, and i have been told that that means the generator is NO LONGER and Emergency power supply but an Alternate Power supply, and that therefor the Generator has to be able to handle the ENTIRE load of the house, so the 50A breaker on my customer's genset would indicate it is not capable of doing this, therefor we will have to feed the ATS from a breaker on the Main panel, to a sub panel with all the circuits in it that he wants protected being the only thing that the ATS connects and disconnects.

i hope i said this right.

Crap, i posted after the last post on the first page. ANYWAY, WHAT HE SAID (Hurk27 among others) thanks and peace out.

I was thinking about $800 for doing this (an hour out of town, but now i am more inclined to equate this with my charge for a panel change: $1600) i did a subpanel with a manual interlock (sweet cover came with it for real cheap) at $800 and i felt like i almost did it for free. it had a gen/recept under it too. This is a propane unit and needs to have conduit run to it outside the house. i think 1600 is about spot on. if that's not a contradiction.

It seems to me that you need to consider the switch as a double throw switch with the common feeding the sub panel and the generator feeding one end of the DT switch and the breaker in the main panel feeding the other end of the DT switch... the ATS need to dis - connect the main panel before it connects the generator when the commercial power dies..

I think stuff like this thread is why it gets my hackles up when I read threads where contractors think they oughta just be able to charge homeowners any amount of money to cover their expenses, and think the homeowner oughta just pony up.

 

[hurk27]

I will admit to not being familiar with this, but why is this not just a switch? I am at a loss to see where there is a 100A breaker involved with this thing...

When a ATS is placed in the service conductors like between the meter and main it has to be service rated which will require it to have a breaker ahead of the transfer switch and or Incorporated within it to protect and disconnect the ATS this becomes your service disconnect, but if you place the ATS after the service disconnect and even after a feeder breaker from the main panel then it doesn't need this disconnect with OCPD, and will be protected by the feeder breaker.