Health Care Occupancy ATS's

C

Clint4539

Member
Location
Florida
Occupation
Maintenance Director
Nursing home facility with a Type I electrical system has a life safety branch ATS and a critical branch ATS. Very typical setup, so no issue there. What is a bit atypical is the presence of another large ATS upstream of the two other ATS. It is a large Zenith ATS, pictured here:
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Any ideas why this ATS would be present? NFPA 99 was not out at this time, and the ATS does not have indicator lights or other position indicators per NFPA 110.
 
Looks like it was originally installed per 517.42 (modern day code number) for a small facility and the two downstream ATS's added later. Just a guess.
 
I'm trying to decipher the wiring shown. If the top terminals are "normal" and "emergency", are the small terminals on the bottom "load".

I only see 3 conduits, but there are 2 sets of wires on one set of line side terminals, and it doesn't look like they all go into the same conduit.

Just wondering if they have emergency and normal in separate conduits like they need to be.


And i don't see any neutral wires in the middle conduit?

Anyhow, I'm still wondering how this ATS feeds the other two. Does it "load" terminals feed both sets of emergency terminals on the other ats's?
 
And the bottom lugs have wires going in the top and bottom. never seen that before - is that allowed?

Its making a little more sense, conduit on the left is the load conduit.

Edit: No, that's not right. some wires from the bottom lugs go into each conduit??
 
Now I see the big wires on the top left must go out the top through a conduit just outside of the photo.

But yes, I can't make sense of the bottom.

And given the large size of the top left wires, the bottom ones seem really small. Even if they are all in parallel, and all go to the same place.
 
Small community hospital I used to do work for had a transfer switch that was nearly identical looking as that one. It was a early 1970's addition that it was installed in. They closed the place several years ago but still operated a clinic until a year or two ago. I seen a few days ago the entire facility was being demolished.

Pretty sure those two electronic timer relays about the center of everything were not original components.
 
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