90 or 180 Amps?

Sorry for the hard to see pictures. I’m working on my photography :wink:

Underground service to the meter. 3/0 copper conductors from the meter to the lugs at the main disconnect. Meter rated for 200 Amps (normal around here even for 100 Amp service).

Main Disconnect has two separate bridged 90 amp breakers (one on top and one on bottom)…total of 4 switches.

It is hard to see in the picture since it is a straight on shot. But if you look closely, you can see a silver bar between the bottom 90 Amp bridged breakers. It appears that this silver bar is positioned so that this bottom disconnect cannot trip. The silver bar would be in the way. The top 90 Amp bridged breakers do not have a similar silver bar.

There are two distribution panels side by side in the garage. Appears each is linked directly to one of the 90’s at the main disconnect. There is no large Amp breaker running from one distribution panel to the other. They appear to be separate from each other and one was added years after the first.

Question is: Is this a 90 Amp Service or a 180 Amp Service?



I’m all confused. Maybe if you would tell us what picture is what, it would help. A very convoluted setup, but it looks to me like a 90-amp set-up.

I’m surprised Jeff Pope hasn’t been here yet. Maybe too late for him. He’ll eventually get here, I’m sure, although this might be outside his realm of expertise (Zinsco panels). :smiley:

Hi to all,

subject to the size of the conductors between the 90 amp disconnects and the load centers I would have to agree with Russel, that this is a 90 amp supply.

That being the rating of the lowest rated component.



Circuit breakers are (usually) designed so that if the handle is locked, they will still trip internally. Resetting it would then require freeing the handle and toggling it. I can’t actually see what you’re talking about from the pictures to comment further, so maybe someone else will–I’m pretty sure that there are specific UL listed devices for locking circuit breakers, and specific cases where that would be used, so it is still worth further investigation.


Let me see if I get this straight…Their is 3/0 CU ( based on 310.15(B)(6) can be rated for 225 Amps traditionally…ok…next…

Ie: This accounts for the meter rating…:slight_smile:

Now…sharing a meter we have (2) independent Main Service Disconnects feeding two different panels…seen often down here when we have a garage attached and they run the service to the garage first.

I can’t comment on the “Bar” but I would doubt it has any baring on the trip function of the breaker.

IN my view this is (2) independent 90A service disconnects.....What I can't tell by the images is bonding methods and so on and is the correct wiring method of each sub-panel done the correct way.

Tehehe...YOU will have to do that on the job...:)

P.S. I would most certainly note that homes today are required to have a minimum 100A service and if they have any plans of modernizing the home or making upgrades that is a place to start.

First two pictures are of the main disconnect next to the meter (outside).

Third picture is the original distribution panel built with the home.

Fourth picture is the distribution panel added on sometime after the home was built. The large 60 Amp bridged breaker in the upper right corner is for the A/C.

Both distribution panels are side by side in the garage.

One other thing…there are ‘spare’ unused breakers in both distribution panels…

Thanks Joey,

Any idea why they would even want to lock the handle in this manner?

Thanks Paul,

You’ve got it right. “Now…sharing a meter we have (2) independent Main Service Disconnects feeding two different panels…seen often down here when we have a garage attached and they run the service to the garage first.”

So when you see this set up, do you call it a 90 Amp Service or a 180 Amp Service???

  • “I can’t comment on the “Bar” but I would doubt it has any baring on the trip function of the breaker.” *
    Sounds like you agree with Joey D. that the breaker will still trip internally even if the handle can’t move. Is that what you are saying? Just looking for corroboration.

Grounding, Bonding and Wiring methods all looked good. Subs had separation of ground and neutral…They are connected at Service Disconnect. No double taps. Conductors are properly sized according to the listed breaker Amperage.

Just trying to determine if it is 90 or 180 Service. Keep in mind that there were some ‘spare’ unused breakers in each of the subs. Also a note from an electrician, dated 1984, in the newer sub stating that “the system is already wired, with ground wires, and the potential for increasing the load” and states this can be found in the crawl. This leads me to believe it is 180.

My photo of the note came out all blurry so it is not legible. Still working on my photography. :slight_smile: ](*,)

In a home… I can’t think of any reason. Unless it’s an outside disconnect and there’s a pesky neighbour shutting off the power for fun.

The best example I can think of for when this is actually done is in commercial buildings for circuits such as those powering fire alarms, or any other case where you want to prevent accidental switching off by a person. The breaker still needs to trip internally in the event of a fault.

Let me do some searching… I learned about this somewhere and I bet that I can find it again.

Edit: It is called trip-free. “The circuit breaker can not be held closed against an overload in accordance with IEC 934 / EN 60934.” I did not dig up those IEC standards so it might be restricted to certain applications. I’m sure someone here knows more about this.

Okay I found a bit more… The CEC (Canadian Electrical Code) in 14-300(1) indicates that all circuit breakers must be of the “trip-free” type. I assume in this case that this is also present in the NEC (Paul? Greg?) If so, the breaker in question most surely is trip-free. However, I can still think of a safety concern if the handle is indeed locked and required manual operation during an emergency.


I would say 90 based on what we can see in the pictures.

Good morning to you too Russell :cool:

90 amps.

Interestingly, we did a 5,000 SF home a month ago that originally started out as a 1,000 SF home and had gone through three independent additions. The main panel was 90 amps, which then fed a 125-amp panel which then fed another 125-amp panel which then fed a 200-amp panel. They didn’t like me when I told them that many insurance companies here will decline to provide insurance on the home because it only had 90 amps service capacity.
“What about all these other panels?”
“You still only have 90 amps coming in from the electric company. You’ll find that you can’t use all this stuff at the same time.”
Come to find out, the sellers finally disclosed that there was a lot of “nuisance” breaker tripping and that they were unable to determine why. Well, duh.

I would say it’s a 180A service.

The service capacity is the lesser of: the utility meter/drop capacity; the SE feeder capacity; service equipment rating; and main disconnect fuses/breakers. There is a 200A meter, 225A SE feeders (3/0 Cu), and a main disconnect with breakers that add up to 180A. That is assuming the two panels are rated for at least 90A each.

If you ran across an older split-buss panel, would you rate it at the lowest breaker on the upper part of the buss … no.

JMO & 2-nickels … :wink:

Thanks Robert,

I agree with your assessment…but it appears we are in the minority (RR, Jeff P, Paul A, Gerry B. etc…).

Yes…each of the subs are rated for more than 90 amps. The only things holding me back from claiming a 180 amp service are:

  1. I cannot see the service entrance conductors (underground) leading to the meter…which could limit the size. The 3/0 Cu runs from the meter to the disconnects.

  2. The bottom set of two 90 amp disconnects cannot be manually turned off in an emergency due to the silver bar put in place so the bottom bridged 90 amp breaker cannot be toggled.

Do you still think it is 180?


P.S. In addition to other things, the service bonding appears to be incorrectly done. The neutral-ground bonding/connection should be at the main service disconnect in the smaller panel with the two breakers. Any panels beyond that main disconnect should have separate neutral and ground wires run to them, with isolated neutrals in the panels (i.e. no connection between the neutral and ground).

At least the newer distribution panel is done incorrectly, with a bonding strap connecting the neutral and ground bars that shouldn’t be there. The only place there should be a neutral-ground bond/connection is at the smaller enclosure with the main disconnects.

JMO & 2-nickels … :wink:

Is it correct to add up breakers?

Not unless it limits the service capacity, which in this case it does.

I’m confused. I can’t think of an instance where I would add up two 90-amp breakers to get 180 amps. It seems like 90 amps limits electricity to 90 amps. Perhaps I am going to learn something in this thread.

Establishing the utility drop/lateral capacity is beyond a home inspection, and really doesn’t come into play unless something flags it may be incorrect (e.g. 60A round meter and 100A service panel).

That doesn’t effect service capacity, and if it prevents the breaker from being shut off then it’s simply a defect/concern that should be looked at and possibly removed by an electrician.

Yes … give the others some time to think about it, and lets see where it goes … :wink:

Nice to know I am in good company with my confusion…

My thinking is…

There are **FOUR ** 90 amp breakers…2 sets of 2 bridged 90’s.

Of course we don’t add together the bridged sets of breakers…they are 90 amps each.

The question is, do you add the TWO bridged sets of 90s to get 180…while keeping in mind that both 90’s appear to serve **separate **sub panels? One of which was added after the original (like an upgrade).

The meter and the SE runners from the meter to the disconnects are rated to support up to 200 amps.

No. At least I wouldn’t. Paul’s been here, but he didn’t really say what he thought it would be. He did say that he thought it was two 90-amps, which would mean that service capacity would be 90 amp in my mind. Someone get Joe over here, too.