Can’t imagine why there would be 3/0 Cu between the meter and the disconnects if it was installed with a 90 amp service. This seems to be a much larger difference than is typical (90 disconnect to 225 conductor).
Could it be the 3/0 was added when the second sub panel was installed in order to accomodate 180? This would appear to be a much more typical difference (180 disconnect to 225 conductor).
Hi to all,
I have been giving this more thought, and after Rob O has beaten me up privately 
I am leaning to the 180 amp service capacity, that being the total available supply to the home.
originally I missread the post and belived that one of the breakers was suppling a remote panel in the garage, I now think that this is just the same as we see on a high amperage supply say a 400 amp, split between 2 200amp panels
Regards
Gerry
The neutral-ground bonding/connection is made at the main service disconnect in this case. You just can’t see it in the picture
The ground bar of the sub panel is on the far right side(mostly covered). So are you saying that what you have labled as the bonding strap is connecting the neutral bar and the ground bar through the metal connection of the subpanel box and not directly?
I thought metal strap/bar you have labeled as the bonding strap was connecting the two sides of the Single Bus Panel. I recall looking at the base connections of both the neutral and ground bars and one of them had a floating connection (insulated) to the box.
Based on this I don’t believe they are connected.
I’ve never seen 400 amps to a residence yet. I have seen 200 amps feeding two 200-amp maximum capacity panels.
Why did Rob beat you up privately? How does that help us learn here? We want our fights on the message board! :twisted:
Look at it this way. The panel next to the meter is essentially the “service panel” with 2 twin 90A breakers. To get the service capacity you don’t take the rating of only one breaker/twin (unless it’s the main single breaker/fuse). In another thread, there were five breakers in the service panel … http://www.nachi.org/forum/showthread.php?t=1595 … and the service wasn’t limited by any one individual breaker (e.g. 100A).
If there were say four (4) dual-pole/twin 90A breakers in that panel, I would then say it’s a 200A service capacity (limited by the meter rating … not an individual dual-pole/twin breaker).
Another way to look at this, is 180A at 240/120V can safely flow through the service (assuming defects are corrected, and everything else is okay).
JMO & 2-nickels …
I would. I’m waiting for some definitive education here, though.
Looks like a different setup with different information. There we’re told that it’s 200 amps. Here we don’t know the service capacity. I find that to be a big difference. I would also note on that 200-amp that if they try to use everything at one time, they might have some breaker-tripping problems.
All other things being equal, I would say a 90-amp that is going to have some breaker tripping problems if lots of things get used at the same time.
I’m not seeing that. Yet.
Russel,
If the 200 Amp feed was broken into two 100 amp breakers/twins at the service panel…with each one feeding two separate 125 amp maximum capacity panels…what amperage rating would you give the service?
Dumb ?
From any of these panels where could you get 125 amps if needed ?
It isn’t about these specific panels.
It was asked as a hypothetical question to the situation similar to the one RR described.
Great thread!!
90A 240/120V can flow through the lower twin-breakers/wires (two black hot wires) to the older sub-panel, while at the same time an additional 90A 240/120V can be flowing through upper twin-breakers/wires (black & red hot wires) to the newer sub-panel. Thats a total of 180A 240/120V flowing through the 3/0 Cu SE feeder (which has a capacity of 225A) between the service panel and the meter (which has a capacity of 200A) at the same time without overloading the service (again taking all else fixed/okay).
I think what some may be missing is the enclosure next to the meter is the service panel. If it had a 180A main breaker, and then two 90A dual-pole/twin breakers feeding each of the sub-panels it would be a no-brainer … 180A service capacity. Just because there isn’t one 180A main breaker doesn’t change the capacity … 
For two (2) 200A panels the service capacity depends on the way they are fed.
If it’s 400A rated SE feeders in a wiring trough or splice box with 200A taps/feeders to the panels, then it is indeed a 400A service/capacity.
If it’s 200A rated SE feeders to a 200A service panel, with a 200A main breaker and two 200A breakers/feeders to the panels then it’s 200A service capacity. I would also write that up as a concern due to the potential for nuisance tripping of the main 200A breaker.
If it’s 200A rated SE feeders that are then taped off in a wiring trough or splice box to two 200A panels then it is a 200A service/capacity … it’s also wrong and a defect because the SE feeders could be overloaded.
JMO & 2-nickels …
P.S. Although it looks about right, I am also assuming that the sub-panel feeders shown in the original post are at least #2 Cu to handle the 90A load to each one.
Okay, when all else fails, I go take a nap. And when something bothes me, I usually wind up dreaming about it. So I suppose you know what I dreamed about.
Here’s what I came up with.
The 3/0 is rated for 225 amps. So that, to me, is the MAXIMUM service capacity. However, two 90-amp breakers is going to limit that to 180 amps. Here’s what’s confusing me, though.
Okay, so what is the rating of the main disconnect? 90 amps? It would be a 90-amp current service capacity, capable of being upgraded to 225 amps with new main disconnect.
But then we’re told:
Is that two switches or four switches? To me, it is two switches since they are bridged. Unless you destroy the bridge, one cannot operate one switch without it’s bridge also operating. So I’ve got two switches, both at 90 amps. So one could pull 90 amps through both switches, leading one to believe that there is a current maximum of 180 amps. And since the 3/0 is rated higher than the total of the two switches, the 180 amps of the two switches would seem to be the current limiting factor. So 180 amps current service capacity, capable of being upgraded to 225 amps.
But then we’re told:
With that caveat, I’m back to 90 amps current service capacity, capable of being upgraded to 225 amps.
So I’m back to 90 amps.
That seems to be the tricky part for some. There is actually no main disconnect/breaker in the service panel. Again, if there was a 180A main breaker in the service panel, with (2) 90A dual-pole/twin breakers feeding the sub-panels it would be a no-brainer that it is indeed a 180A service capacity.
How about 180A service capacity, that can be upgraded to 200A (the limit of the meter) …
Stupid electric meter. Forgot about that durn thing. Okay, upgraded to 200 amps maximum.
But I’m still not finding two 90-amp dual-pole/twin breakers. See my previous post. There appears to be a modification that makes the four 90-amp breakers with two bridges act as one 90-amp breaker.
I don’t think he is talking about a tie between the upper twin breakers and the lower twin breakers. I believe he is talking about a breaker lock for the lower twin breakers (see attached pic). So the upper twin and lower twin breakers are independent, and can each draw 90A … which adds up to 180A if my math is correct …
P.S. Even with a breaker lock, a breaker that is operating correctly will still trip internally when overloaded. A breaker lock installed in the “on” position is just to keep someone from accidentally shutting down a breaker you don’t want shut off.
I might go with you then, but I would reserve my decision based on actually seeing the setup versus pictures and descriptions here. I’m still hesitant, though. Do all breakers have internal breakers? That I didn’t know, and, not to doubt your word, but I’d like to see some schematics of circuit breakers showing that. It would be a cool fail-safe. Is that something that occurred after the FPE Stab-Lok fiasco, because they certainly don’t trip?
I’m seeing two 90-amp breakers fed in parallel from the main SEC’s.
If you moved the two 90-amp service disconnects, one to each of the separate panels (with a split feed from the meter) that would effectively be the same. Either way you end up with two 90 amp panels for a total of 180 amps (which is my vote).
Two 90’s in series would , of course, only be 90 amp.
On the “siver bar” thingy. Is it possible that rather than preventing the bottom breaker from tripping, it’s actually a linkage to the top? So that you can disengage all power with a single **downward **throw of the lower? Just a thought, as I’ve never seen the set-up before. I just can’t see why you would prevent someone turning off a service disconnect (other than a removeable padlock, etc).
Yes…they were properly sized.
You are correct Russel. It is two 90 amp switches…each one comprised of two bridged switches.