generac automatic transfer switch

[mcgovtav]

Have an inspector asking for the gutter fill calculation for a generac 200 amp service entrance rated ats. Can anyone tell me how to calculate this.Generac doesn't know. Replaced exterior 200 amp main breaker nippled in to meter with the 200 serv rated ats. Thanks

 

[tom baker]

What! Generac didn't know? You pulled back the curtain on the mighty Oz er, Generac...
It would be similar to a cabinet, see 312.8
In a panelboard, there are wiring areas on the sides, its pretty clear what they are. Lets say they are 4" x 5" or 20 sq inches. When you do the calcs in 312.8, it takes a lot of wires to exceed the limit.
I am thinking that the ATS enclosure is considered an enclosure, thats what it looks like but there may be some UL rule on this. It might be worth looking in the UL White Book to see whats there.

 

[mcgovtav]

What! Generac didn't know?
It would be similar to a cabinet, see 312.8
In a panelboard, there are wiring areas on the sides, its pretty clear what they are. Lets say they are 4" x 5" or 20 sq inches. When you do the calcs in 312.8, it takes a lot of wires to exceed the limit.
I am thinking that the ATS enclosure is considered an enclosure, thats what it looks like but there may be some UL rule on this. It might be worth looking in the UL White Book to see whats there.

 

[mcgovtav]

Thank you, that makes some sense ,appreciate it

 

[LarryFine]

Welcome to the forum.

It won't be specified for ATSs, but you'll never approach any fill limit, like 40%.

Ask him for a code reference; he's supposed to cite which article you're violating.

 

[mcgovtav]

Welcome to the forum.

It won't be specified for ATSs, but you'll never approach any fill limit, like 40%.

Ask him for a code reference; he's supposed to cite which article you're violating.

Thanks he didn't specifically say it was a violation but asked for the calculation

 

[LarryFine]

Thanks he didn't specifically say it was a violation but asked for the calculation

Okay. Calculate the area the wires pass through, calculate the area of those wires, and subtract.

Tell him that's your calculation. I'd be surprised if your wires take up 10% of any given area.

 

[mcgovtav]

Okay. Calculate the area the wires pass through, calculate the area of those wires, and subtract.

Tell him that's your calculation. I'd be surprised if your wires take up 10% of any given area.

Are we using 366.22 and 376.22 referring to 20% I know you mentioned 40 % earlier Thanks

 

[JGinIndy]

As Larry and Tom mentioned within the ATS would be a Cabinet so 312.8 comes into play 40%. The Gutter as you mentioned threw me.

 

[mcgovtav]

As Larry and Tom mentioned within the ATS would be a Cabinet so 312.8 comes into play 40%. The Gutter as you mentioned threw me.

Thank you ,only mentioned gutter because that is what the inspector is referencing (gutter fill )

 

[JGinIndy]

Thank you ,only mentioned gutter because that is what the inspector is referencing (gutter fill )

Yeah I got myself going in all sorts of directions as in auxiliary gutters and deflection of conductors on the other place as you know.

 

[mcgovtav]

Did the same, Thank you