ATS Feeders Cont'd...Any thoughts, please?

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360Youth

360Youth

Senior Member
Location
Newport, NC
I statrted this thread some time back and wanted to revisit because to day we went to make our recomended changes but was called offy HO and oroiginal generator EC. We were originally called to do service work on a generator and in the process I was called about my opinion on the following install. An existing residence with a 400 amp service had a 60 kw generator with 400 amp ATS installed. The new ATS was fed from two existing 200 main disconnect panels which in turn feeds two 200 amp house panels. My problem was a single 400 amp "load center" ATS being fed from two separate 200 sources. The installer called it a parallel installation with conductors properly fused at 200 amps each. My thought is that there is the potential of the entire house load chosing only a single set of conductors back to utility. If the entire load stays under 200 amps then in theory the install works (theory, not code, IMO). HO and EC agreed that there was no concern and the existing install should be left alone. Am I correct? Or is this ok and I am missing something.

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To start with I believe the install is in violation of 240.8.
Do the inside panels have main breakers ?
 
There a several violations but looking at the pictures it looks like if you shut one main off the other panel would be backfed thru the transfer switch and remain energized. I hope that this install has not been inspected yet.
 
I wasn't aware one could connect two breakers in parallel like that.

What's happening with the line- and load-side neutrals and EGC's, too?

Added: I think the proper install would be either a single 400-a main, or a service-rated T/S, either one fed by a single set of conductors from the meter, and then split into two 200a mains.
 
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SEO said:
There a several violations but looking at the pictures it looks like if you shut one main off the other panel would be backfed thru the transfer switch and remain energized. I hope that this install has not been inspected yet.
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This is install was done more than a year ago. I have no what was inspected when.

LarryFine said:
Added: I think the proper install would be either a single 400-a main, or a service-rated T/S, either one fed by a single set of conductors from the meter, and then split into two 200a mains.
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This was our attempt at a fix. Like I said, got ruled out by the bill payer at the last second. I tried to state our psition as diplomaticly as possible with both EC and client there. Had it been just me and the EC I would have pushed the issue alittle more, but I was not going to get too accusatory in front of his customer. Not very professional, IMO.
 
However, if you're asked for your professional opinion, you should give it, and don't hesitate to suggest it be (re)inspected for clarification's sake.
 
LarryFine said:
However, if you're asked for your professional opinion, you should give it, and don't hesitate to suggest it be (re)inspected for clarification's sake.
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I did state my opinion, that from a code point of view I thought it needed to be changed. Not sure that I would suggest a reinspection unless I thought there was an obvious hazzard. I will only step on somebody else's toes so hard. ;) I have made my share of NEC mistakes in the past (and future :))but have always done my best to insure safety.
 
360Youth said:
I did state my opinion, that from a code point of view I thought it needed to be changed. Not sure that I would suggest a reinspection unless I thought there was an obvious hazzard. I will only step on somebody else's toes so hard. ;) I have made my share of NEC mistakes in the past (and future :))but have always done my best to insure safety.
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AFAIC, this has nothing to do with "code", and has everything to do with it actually WORKING. This situation may "work", but it doesn't "WORK". Get what I am saying? This is stuff you learn in 9th grade theory. This does not work and needs to be changed. Awful, simply awful.











was I too harsh?
 
From the pics it looks like the feeds to the ATS are coming from the lugs on the BOTTOM of the panel buss, which would mean that the main breakers in those panels will have no effect under certain conditions. (Utility/Gen? Both?)

I don't think the parallel feeder rules apply here in any event.

Forget tact and diplomacy, if I am seeing this right it is a huge hazard for backfeed.

Get the AHJ involved IMMEDIATELY as it is definately not right.

Have you been able to trace out the paths of all those lines and if so can you give a flow description?

EDIT: 360youth, maybe you should send a PM to iwire and direct him to this thread as he is very sharp on this kind of thing.
 
mxslick said:
From the pics it looks like the feeds to the ATS are coming from the lugs on the BOTTOM of the panel buss, which would mean that the main breakers in those panels will have no effect under certain conditions. (Utility/Gen? Both?)

I don't think the parallel feeder rules apply here in any event.

Forget tact and diplomacy, if I am seeing this right it is a huge hazard for backfeed.

Get the AHJ involved IMMEDIATELY as it is definately not right.

Have you been able to trace out the paths of all those lines and if so can you give a flow description?

EDIT: 360youth, maybe you should send a PM to iwire and direct him to this thread as he is very sharp on this kind of thing.
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Meter feeds the top of each 200 amp panel. Feed thru lugs from each panel feeds the utility side of ATS. Load side of ATS feeds to each of the 200 amp panels where it split bolts (or whatever means is under the wrapping of tape) to the house panel feeders. I have not found evidence of back feeding, which was one of our initial concerns, but I did not probe that deep into the entire install. It was clear the elctrician and HO were fine with "as is" so we wrote ourselves off from it and sent a bill for our travel time.
 
360Youth said:
I seem to have a habit of starting short-lived threads. I don't know if my questions are to obvious or to vague. I was hoping for some input on this one. I am not looking to trash anyone's install I just want to be correct on my code stances.
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I glanced at your pics yesterday but didn't have time to get how it would (or wouldn't) work. As someone already said, it "works," but it doesn't work. I'd not want this result on a job I was involved with. Let me look at it some more.
 
I assume the HO has no concern beacuse it works. As noted in Post #2, the installation is in violation of 240.8. Depending on the arrangement of the condcutors on the load side of the ATS, it may also be in violation of 240.21.
I'm not real sure what you are asking. If it's not your install, I;m unsure there is much you can do except advise the homeowner it doesn't meet Code. Since you have done work at the site, I would suggest any such notification be in writing to CYA.
 
mxslick said:
I don't think the parallel feeder rules apply here in any event.
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I was curious about this. When Thom and I talked on the phone I was curious as to whether this is a parallel feed. They do originate and end at the same point but take different path.

Any thoughts?
 
I don't understand the purpose of the 400A transfer switch is here....

Let me get this straight in my mind....

400A Service entrance & meter.

two 200A disconnect panels fed from meter base.

Each panel feeds into ATS Line side.

ATS output feeds two 200A load centers.

Is this correct?

I can't see getting more than 200A out of the ATS ever.

With only one 400A feeder, the power is either on or off, so why the ATS?
 
Right off of my head from the pictures and how you describe it each panel and the conductors should be protected from overload, but it is definetly a 240.8 and 352.30 violation, and why not throw a 110.12 at it too :grin:
 
augie47 said:
Since you have done work at the site, I would suggest any such notification be in writing to CYA.
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If we get paid for our travel time and a few other items with few arguments I will be happy. I stated more than once, professionally and diplomaticly, I hope, that I thought it needed changing for code purposes and potential current flow issues, but was out voted 2-1. :rolleyes:
 
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