Cummings ATS conduit entry

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Ohms law

Senior Member
Location
Sioux Falls,SD
Engineer for a hospital edition gave us specs for an ATS to have 4" gap from mounting feet to bottom of enclosure. The issue is the unit came with no feet with no gap and sits on concrete pad.

I'm looking for input wether or not we can cut a large rectangular cut out in bottom instead of individual holes for each conduit.

We have 6< 3-1/2" Rigid couplings stubbed up through pad. Does anytime think my idea would be acceptable?



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Ohms law

Senior Member
Location
Sioux Falls,SD
chris kennedy said:
Make and model of ATS? Follow the install instructions as per 110.3(B).
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The installation instructions shows dimensions and where cables and conduits shall enter. It does not specify how to terminate other than by cable or conduit. Obviously I would use bonding bushing and would have to regardless since the conduits go from pvc to Rigid.

I suppose I will have to get a hold of Cummins and see what they say. I was just hoping someone may have encountered this situation.

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chris kennedy

chris kennedy

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Location
Miami Fla.
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60 yr old tool twisting electrician
How big is this switch? Over 600A there may be an over 6'7"" to handle issue.
Could be a sharp engineer that actually looked at the cut-sheet???
 
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Ohms law

Senior Member
Location
Sioux Falls,SD
The electrical engineer is part of one of the code making panels for the NEC.

It is a 800 amp rated ATS. There are two 930KVA generators in parallel feeding multiple ATS units, and 3 of them are all the same situation as I have been describing. And then I have 3 ATS units that are raised with factory feet 4" off the floor.

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rambojoe

rambojoe

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Location
phoenix az
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Wireman
silly questions maybe but they delivered correct gen? they didnt omit some external chassis/fuel tank that the gen was expected to sit on? seems like under the control doors there usually is a open section for your pipes. still, even if you need to re hoist up, count on still liquid tite flexing in the inclosure for vibration. you still have ko's to hit, right? or are the lugs not contained in a seperate cabinet?
 
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Ohms law

Senior Member
Location
Sioux Falls,SD
It is completely enclosed and the enclosure says it has a UL type 1 cabinet listing. The unit is indoors in the electrical room. The weight of the ATS is 1350lbs if I remember correctly. It is not easy to work with.

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rambojoe

rambojoe

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Location
phoenix az
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Wireman
argh...my bad. the transfer switch! not the genset...sorry. check all the shipping manifests, maybe it was a seperate carton w/the feet- or in the ats...hard to believe it doesnt have pipe terminal provisions or a removable base. and that is one big switch! i love setting that kinda gear...
 
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Cow

Senior Member
Location
Eastern Oregon
Occupation
Electrician
Ohms law said:
Engineer for a hospital edition gave us specs for an ATS to have 4" gap from mounting feet to bottom of enclosure. The issue is the unit came with no feet with no gap and sits on concrete pad.

I'm looking for input wether or not we can cut a large rectangular cut out in bottom instead of individual holes for each conduit.

We have 6< 3-1/2" Rigid couplings stubbed up through pad. Does anytime think my idea would be acceptable?



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Click to expand...

We only cut bottoms out when it sits right on the concrete. How will you keep debris and rodents out with it suspended 4" in the air and the bottom cut out? Why can't you install short nipples in the couplings to reach the bottom of the ATS?
 
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Ohms law

Senior Member
Location
Sioux Falls,SD
Cow said:
We only cut bottoms out when it sits right on the concrete. How will you keep debris and rodents out with it suspended 4" in the air and the bottom cut out? Why can't you install short nipples in the couplings to reach the bottom of the ATS?
Click to expand...
The 3 smaller pad mount ATS units are raised with factory 4" tall feet welded/ integrated with cabinet; which are plan to use rigid nipples will work fine.

The 3 larger ATS units do not have feet and sits directly on concrete pad. Nipples would not work because there is no space.

When you have cut out the bottom did you have to supply a letter from the manufacturer for the inspector?

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Ohms law

Senior Member
Location
Sioux Falls,SD
rambojoe said:
argh...my bad. the transfer switch! not the genset...sorry. check all the shipping manifests, maybe it was a seperate carton w/the feet- or in the ats...hard to believe it doesnt have pipe terminal provisions or a removable base. and that is one big switch! i love setting that kinda gear...
Click to expand...
I am afraid that there is nothing else to this cabinet, unfortunately. It's a solid bottom. The sheet with the dimensions shows locations and dimension where you can enter for pipe and cable terminations all around the unit except the rear.

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Cow

Senior Member
Location
Eastern Oregon
Occupation
Electrician
Ohms law said:
The 3 smaller pad mount ATS units are raised with factory 4" tall feet welded/ integrated with cabinet; which are plan to use rigid nipples will work fine.

The 3 larger ATS units do not have feet and sits directly on concrete pad. Nipples would not work because there is no space.

When you have cut out the bottom did you have to supply a letter from the manufacturer for the inspector?

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Click to expand...

Did the engineer spec the ATS? If so, it sounds like an RFI is in order. In the past, when necessary, we've cut the bottoms out of panels, etc without contacting the manufacturer and never ran into any problems at inspection, but I know not all inspectors are the same. It wouldn't hurt to contact Cummins directly and get their input and possibly a letter from them stating it's okay.

Worst case, you build some 4" spacers out of steel and set the ATS on it to get your air gap, then rigid nipple into the bottom.
 
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Ohms law

Senior Member
Location
Sioux Falls,SD
Cow said:
Did the engineer spec the ATS? If so, it sounds like an RFI is in order. In the past, when necessary, we've cut the bottoms out of panels, etc without contacting the manufacturer and never ran into any problems at inspection, but I know not all inspectors are the same. It wouldn't hurt to contact Cummins directly and get their input and possibly a letter from them stating it's okay.

Worst case, you build some 4" spacers out of steel and set the ATS on it to get your air gap, then rigid nipple into the bottom.
Click to expand...
Im going to get a hold of Cummins and discuss this with my project manager. My original thought was to cut out the bottom. I am with in South Dakota State jurisdiction they are not as strict as the city Sioux Falls, SD inspectors. The city inspectors are very difficult at times to deal with especially after they come back from a seminar.

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Chamuit

Chamuit

Grumpy Old Man
Location
Texas
Occupation
Electrician
We have an ASCO at one of our sites. Sounds similar to what you are talking about. It sits flat on a concrete slab, cored for the conduit coming in.
 
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Ohms law

Senior Member
Location
Sioux Falls,SD
Ingenieur said:
http://www.emersonnetworkpower.com/...asco 7000 series_outline-mounting-713201g.pdf
floor mounted switch
looks like there is a defined area for the cutout
I've often seen it with a rectangular cutout for the conduits
how else would you do it?
Click to expand...
Looks very similar to our spec. sheet.

I spoke with another foreman and he said he had the same situation awhile back and the Cummins technician said it was perfectly fine. First situation with this setup; you have to learn some how, right?

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ADub

ADub

Senior Member
Location
Midwest
Occupation
Estimator/Project Manager
I've cut all sorts of panels out of all types of gensets from cummins and cat. If you're talking about just removing a section of the floor so your pipes can enter I see no issue, how would they expect you to wire the thing if you couldn't?


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