ATS

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Chris60

New member
Location
Illinois
I will install ATS in small residential dwelling it will switch power to whole 100A 240V 1ph panel. Do I need fused disconnect between Meter and ATS, or can I install only ATS between Meter and Panel ?
 

stickboy1375

Senior Member
Location
Litchfield, CT
You will also need a disconnect between the generator and the ATS

I forgot which brand ATS I installed, but it was service rated, and contained a disconnect for the generator as well, so why doesn't every service rated ATS contain this? Im pretty damn sure every install i've every come across does NOT include a disconnect for the genny except for the breaker at the genny itself.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
I've seen service rated ATS(s) both with and without a means to disconnect the generator.
I would assume not having one would be taking into account 701.11(B)(5) & 702.11 in addition to 225.32 all of which come into play as to the need for such a disconnect and it's location.
 

ceb58

Senior Member
Location
Raeford, NC
I forgot which brand ATS I installed, but it was service rated, and contained a disconnect for the generator as well, so why doesn't every service rated ATS contain this? Im pretty damn sure every install i've every come across does NOT include a disconnect for the genny except for the breaker at the genny itself.

Generac, for one, has stopped installing the generator side disconnect. More money in their pocket because they didn't drop the price.

augie47
I've seen service rated ATS(s) both with and without a means to disconnect the generator.
I would assume not having one would be taking into account 701.11(B)(5) & 702.11 in addition to 225.32 all of which come into play as to the need for such a disconnect and it's location.​
The generator breaker also doesn't comply with 445.18
 

goldstar

Senior Member
Location
New Jersey
Occupation
Electrical Contractor
The generator breaker also doesn't comply with 445.18
I don't agree. You can shut the emergency service down by operating the breaker and locking that side cover (if it's set up that way). A main breaker in a MB panel is an acceptable means of disconnect for that panel why wouldn't the breaker on the generator be considered the same ? You can also shut the gas line down and stop the generator.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
225.31 & 225.32 require a "readily accessible disconnect" located nearest the point of entrance.
225.36 requires that disconnect to be service rated.
The 701 & 702 references provide a bit of leeway, but still require the "readily accessible" and "service rated" stipulations.
Few generators have a "readily accessible" disconnect and fewer have one that is service rated.
 

goldstar

Senior Member
Location
New Jersey
Occupation
Electrical Contractor
Too often when I post comments here, I'm not thinking "out of the box". So, for that I apologize. I just made the assumption that we were talking about residential grade standby generators. For the sake of argument let's assume that we are talking about residential generators. Article 100 defines :

Accessible, Readily (Readily Accessible). Capable of being
reached quickly for operation, renewal, or inspections
without requiring those to whom ready access is requisite
to climb over or remove obstacles or to resort to portable
ladders, and so forth.

225.31 Disconnecting Means. Means shall be provided
for disconnecting all ungrounded conductors that supply or
pass through the building or structure.

Doesn't the breaker on the side of the generator qualify as the generator disconnect means ? (Granted, if the homeowner decides to lock the door to the breaker compartment then it's not readily accessable but we can say that about the transfer switch as well).

225.32 Location. The disconnecting means shall be installed
either inside or outside of the building or structure
served or where the conductors pass through the building or
structure. The disconnecting means shall be at a readily
accessible location nearest the point of entrance of the conductors.
For the purposes of this section, the requirements
in 230.6 shall be utilized.

If the generator output power is wired directly into the transfer switch, why can't the breaker on the generator suffice as the disconnect means ? BTW, If you shut off the gas aren't you accomplishing the same thing ?

If you install a separate disconnect for the generator does that disconnect means have to be "service rated" for the size service you're connecting to or sized for the output of the generator (i.e can I install a 60 amp AC pullout on a 60 amp generator output)?

Seems senseless to me
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Too often when I post comments here, I'm not thinking "out of the box". So, for that I apologize. I just made the assumption that we were talking about residential grade standby generators. For the sake of argument let's assume that we are talking about residential generators. Article 100 defines :

Accessible, Readily (Readily Accessible). Capable of being
reached quickly for operation, renewal, or inspections
without requiring those to whom ready access is requisite
to climb over or remove obstacles or to resort to portable
ladders, and so forth.

225.31 Disconnecting Means. Means shall be provided
for disconnecting all ungrounded conductors that supply or
pass through the building or structure.

Doesn't the breaker on the side of the generator qualify as the generator disconnect means ? (Granted, if the homeowner decides to lock the door to the breaker compartment then it's not readily accessable but we can say that about the transfer switch as well).

It may vary from install to install, but almost every resi generator I've inspected recently has the breaker behind a cover which takes a somewhat special tool to open, IMHO, not readily accessible.
If the breaker was readily accessible, few are marked "suitable for service"


225.32 Location. The disconnecting means shall be installed
either inside or outside of the building or structure
served or where the conductors pass through the building or
structure. The disconnecting means shall be at a readily
accessible location nearest the point of entrance of the conductors.
For the purposes of this section, the requirements
in 230.6 shall be utilized.

If the generator output power is wired directly into the transfer switch, why can't the breaker on the generator suffice as the disconnect means ? BTW, If you shut off the gas aren't you accomplishing the same thing ?
Judgement call, but in/on the generator in the yard is not, to me, the same as "nearest the point of entrance of the conductors"

If you install a separate disconnect for the generator does that disconnect means have to be "service rated" for the size service you're connecting to or sized for the output of the generator (i.e can I install a 60 amp AC pullout on a 60 amp generator output)?
IMO, generator output , just as a feed to a detached garage would be feeder size.

Seems senseless to me

I agree, but mine is not to reason why. :D
 

goldstar

Senior Member
Location
New Jersey
Occupation
Electrical Contractor
Thanks Augie. I still don't see it your way and I'd love to take further issue with you on this but I'm leaving for Australia tomorrow so, I'll have to take a 2 week sabatical from the Forum. If this is still roilling when I get back I'll hop back in.;)
 
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