200 amp or 400 amp service?

[hausdok]

I guess the question I have for the original poster is whether or not there was a gutter that wasn't sealed near the panels where he could have seen the service conductors feeding the panels.

Most of the larger services I see around here have underground laterals because they are in neighborhoods where everyone wanted the power below grade. In upper end neighborhoods with very large homes, I occasionally find multiple panels with a gutter and inside the gutter I find larger cables bringing power to those panels.

If you were to look at that meter and see that it was a class 320 meter and inside the unsealed gutter you find 400 kcmil copper cables or 600kcmil aluminum cables then you know that the service capacity is 400 amps and there is no issue

I think you could have, for instance, a 200-amp panel feeding a main floor and another one feeding a second floor. Each panel could be individually fed by cables rated for 200 amps and have a 200 amp breaker, but you don't know the real size of the service until you look in the gutter. If those service conductors are only 2/0 copper or 4/0 aluminum the service capacity is 200 amps, in which case, a 60% load on both of those panels simultaneously would exceed the capacity of those service cables, no?

ONE TEAM - ONE FIGHT!!!

Mike

[Marc]

I guess the question I have for the original poster is whether or not there was a gutter that wasn't sealed near the panels where he could have seen the service conductors feeding the panels.

Most of the larger services I see around here have underground laterals because they are in neighborhoods where everyone wanted the power below grade. In upper end neighborhoods with very large homes, I occasionally find multiple panels with a gutter and inside the gutter I find larger cables bringing power to those panels.

If you were to look at that meter and see that it was a class 320 meter and inside the unsealed gutter you find 400 kcmil copper cables or 600kcmil aluminum cables then you know that the service capacity is 400 amps and there is no issue

I think you could have, for instance, a 200-amp panel feeding a main floor and another one feeding a second floor. Each panel could be individually fed by cables rated for 200 amps and have a 200 amp breaker, but you don't know the real size of the service until you look in the gutter. If those service conductors are only 2/0 copper or 4/0 aluminum the service capacity is 200 amps, in which case, a 60% load on both of those panels simultaneously would exceed the capacity of those service cables, no?

ONE TEAM - ONE FIGHT!!!

Mike

It would exceed that capacity, yes.

I'm not sure what you mean by 'sealed' gutter. Every gutter that I've ever seen has screws for removing the cover. As an inspector, I don't dare remove those covers because the cables within are often very cramped and some may have damaged insulation. With nothing other than the utility super lag fuse to protect them, I won't take chances with arcing. I deal with those dangers only when I'm there as an electrician.

Marc

[hausdok]

Around here gutters are sealed with a couple of screws with holes in the head and a wire passes between them with a crimped seal on the wire so that you can't twist the screw out without cutting the wire. If it's sealed, it's the utility's, if it's not sealed it's the consumer's.

ONE TEAM - ONE FIGHT!!!

Mike

[Jim Katen]

Inappropriate yes, I've never liked calling it that. But, it's 2-200 amp panels fed with separate 200 amp cables, each with it's own 200 amp disconnnect.

And it's not a 400 amp cable feeding the meter can.

So, I call it the wrong thing because I can't think of how else to describe it satisfactorily.

I don't understand the difficulty. If you've determined that the cable feeding the meter can is not appropriate for a 400-amp service then you need only determine what size it *is* appropriate for and that will be the service size.

- Jim Katen, Oregon

[Jim Katen]

Yeah, we are required by the State to "describe" what's there; I'm not going to say I can't tell.

And, this goes to what Bain just said......folks aren't going to understand or care about fine tuned distinctions.

It's a couple 200 amp rated panels with separate disconnects, each fed with separate 200 amp cables.

What should I call it?

It kind of gets to the same idea of "is it 110 or 120v?"........does it matter to anyone other than us and a bunch of double e's?

It matters a great deal if the service is undersized for the house. I think it's worthwile for us to make a good faith effort at figuring out what the service size is and consider whether or not it's reasonable for the house.

If I were to find that I couldn't do that, then I'd advise my customer to get an electrician to figure it out.

- Jim Katen, Oregon

[mgbinspect]

Inappropriate yes, I've never liked calling it that. But, it's 2-200 amp panels fed with separate 200 amp cables, each with it's own 200 amp disconnnect.

And it's not a 400 amp cable feeding the meter can.

So, I call it the wrong thing because I can't think of how else to describe it satisfactorily.

I don't understand the difficulty. If you've determined that the cable feeding the meter can is not appropriate for a 400-amp service then you need only determine what size it *is* appropriate for and that will be the service size.

- Jim Katen, Oregon

It's pretty typical to run across upgraded 200 AMP panels on original overhead aluminum #2 or #2/0 here. I used to encourage my buyers to contact the local power company and request that they upgrade the service cable. The local power company usually deems it fine, due to being air-cooled.

I still identify it as technically undersized cable, but tell folks to not be surprised if the local power company assures them that it's fine.

[Marc]

It's pretty typical to run across upgraded 200 AMP panels on original overhead aluminum #2 or #2/0 here. I used to encourage my buyers to contact the local power company and request that they upgrade the service cable. The local power company usually deems it fine, due to being air-cooled.

I still identify it as technically undersized cable, but tell folks to not be surprised if the local power company assures them that it's fine.

'Undersized cable' has a completely different definition when it comes to utility lines. As long as that cable will hold an overcurrent or fault current long enough for the transformer fuse to open, that's all they usually care about, or need to. As an HI, I don't bother with trying to judge it's adequacy.

Marc

[mgbinspect]

It's pretty typical to run across upgraded 200 AMP panels on original overhead aluminum #2 or #2/0 here. I used to encourage my buyers to contact the local power company and request that they upgrade the service cable. The local power company usually deems it fine, due to being air-cooled.

I still identify it as technically undersized cable, but tell folks to not be surprised if the local power company assures them that it's fine.

'Undersized cable' has a completely different definition when it comes to utility lines. As long as that cable will hold an overcurrent or fault current long enough for the transformer fuse to open, that's all they usually care about, or need to. As an HI, I don't bother with trying to judge it's adequacy.

Marc

My son worked for the local power company here for four years, and they certainly seem to have it all figured out. And, I too have come to understand that transmission line and service entry cable sizing is a science that is not as bound by rules we're familiar with.

[kurt]

It matters a great deal if the service is undersized for the house. I think it's worthwile for us to make a good faith effort at figuring out what the service size is and consider whether or not it's reasonable for the house.

If I were to find that I couldn't do that, then I'd advise my customer to get an electrician to figure it out.

- Jim Katen, Oregon

I'm not sure how I went from not knowing if I should call something a 200 amp service, or 2-200 amp panels, to acting in bad faith and not trying to figure out the size of the service and if it's appropriate for the house........(?)..... There's a pile of implications in that comment.

What's most interesting to me right now, is no one has answered the original question of the OP, nor mine.

What do you call it? Do folks call 2-200 amp panels a single 200 amp service?

And as far as the customer is concerned, does it really matter if it's 110v or 120v? Like, there's something someone's going to do about it?

I just wanna know what to call it, and I'm thinking I'm just going to keep calling it 2-200 amp panels.

[mgbinspect]

It matters a great deal if the service is undersized for the house. I think it's worthwile for us to make a good faith effort at figuring out what the service size is and consider whether or not it's reasonable for the house.

If I were to find that I couldn't do that, then I'd advise my customer to get an electrician to figure it out.

- Jim Katen, Oregon

I'm not sure how I went from not knowing if I should call something a 200 amp service, or 2-200 amp panels, to acting in bad faith and not trying to figure out the size of the service and if it's appropriate for the house........(?)..... There's a small pile of implications in that comment.

What's most interesting to me right now, is no one has answered the original question of the OP, nor mine.

What do you call it? Do folks call 2-200 amp panels a single 200 amp service?

I continue to blissfully call two 200 AMP panels 400 amps of service -right or wrong. Unfortunately, around here, the only time I ever see two side by side panels, the service is always underground to the meter base, so I have yet to see the cable coming in. But, one has to assume that the local power company has it set up to handle both panels at more than the 80% rule. Doesn't that seem reasonable?

[Jim Katen]

It matters a great deal if the service is undersized for the house. I think it's worthwile for us to make a good faith effort at figuring out what the service size is and consider whether or not it's reasonable for the house.

If I were to find that I couldn't do that, then I'd advise my customer to get an electrician to figure it out.

- Jim Katen, Oregon

I'm not sure how I went from not knowing if I should call something a 200 amp service, or 2-200 amp panels, to acting in bad faith and not trying to figure out the size of the service and if it's appropriate for the house........(?)..... There's a pile of implications in that comment.

You asked whether the service size matters to anyone other than us. I gave one reason and opined that it's worthwhile for us to try & figure it out. I didn't say you were acting in bad faith, nor did I make a "pile of implications."

What's most interesting to me right now, is no one has answered the original question of the OP, nor mine.

I answered it in post #6 and again in post #20. If there are 2, 200-amp panels and the meter is a class 320, it's nearly always going to be a 400-amp service.

What do you call it? Do folks call 2-200 amp panels a single 200 amp service?

In conjunction with a class 320 meter, yes. If there's a class 200 meter, then I'd have to guess that it's only a 200-amp service -- not because the meter itself limits the service, but because the power company is unlikely to install the wrong meter.

And as far as the customer is concerned, does it really matter if it's 110v or 120v? Like, there's something someone's going to do about it?

The difference between 110v and 120v is not particularly important and, no, no one's likely to do anything about it. But the size of the service is critically important and, if it's wrong, someone is most certainly likely to do something about it. The voltage and the service size are not analogous with regard to their importance to the customer.

I just wanna know what to call it, and I'm thinking I'm just going to keep calling it 2-200 amp panels.

If you want to know what to call the service size, you have to look beyond the number & size of the panels.

On the other hand, if you just want to describe the panels that are present, you can say that there are 2, 200-amp panels. But that's not the same as the service size.

- Jim Katen, Oregon

[Marc]

A guy goes to the service station intent on buying 7 gallons of gas. He doesn't have a 7 gallon gas can, but he does have two 5 gallon gas cans. He fills one can and then pumps gas into the other can until the meter says 7 gallons.

Does he have two 5 gallon gas cans? Yes. Does he therefore have 10 gallons of gas? No.

The two gas cans correspond to the two service panels. The quantity of gas corresponds to the rating of the service conductors that bring power from the meter box to the panel or gutter, whichever the case is.

Client wants to know how much gas he's got, if you know it.

[]

Marc

[MMustola]

I have always called it 400 amp. It would be very rare for me to find two 200 amp panels that did not have underground service so I can not see the service lateral. Also, the meter bases are always huge entangler boxes. Honestly I have no idea what the meters are rated at.

[kurt]

- Jim Katen, Oregon

You asked whether the service size matters to anyone other than us.

Where did I say that? You're answering to statements I didn't make.

I gave an example of 110v vs. 120v, and indicated that the distinction doesn't mean much to anyone. The idea being, if we call it 2-200 amp, or a 400 amp, it doesn't mean anything to my customers. I try to form statements in language where folks have some basis for understanding. Heck, I'm not sure I understand meter socket and utility stuff.......

If there are 2, 200-amp panels and the meter is a class 320, it's nearly always going to be a 400-amp service.

Except when it's not. Which goes back to the original question, so far still a little unclear. Unclear, because I'm looking for language that's comprehensible to the customer, not meter class size.

I think the answer would be best formed in language that folks understand.

And, I understand that if a cat gives birth in the oven, the kittens aren't muffins........

[Jim Katen]

I have always called it 400 amp. It would be very rare for me to find two 200 amp panels that did not have underground service so I can not see the service lateral. Also, the meter bases are always huge entangler boxes. Honestly I have no idea what the meters are rated at.

All you have to do is look at the face of the meter. It'll say "Class 200" or "200 CL" or "320 CL" or something similar if it's fairly recent -- say, the last 40 years or so. Older meters might only list the test amps (TA). TA 15 would be a 100-amp meter, TA 30 would be a 200-amp meter, and TA 50 would be a 400-amp meter.

Also, if the installation is more than 30 or 40 years old, larger services might have used current transformers. In that case, the service power wouldn't actually flow through the meter, there would be a set of small current transformers (like little dounuts) around the service conductors and the meter would read the stepped down current from the transformers. These are always easy to spot because you'll either see the current transformers at the weather head or they'll be contained in a large wiring box right next to the meter. Also, the meter test amps will be a ridiculously small number, like 5 amps.

It's useful to get to know the different meters in your area because they're an important clue in determining service size even though the meter itself doesn't limit service size.

- Jim Katen, Oregon

[Jim Katen]

- Jim Katen, Oregon

You asked whether the service size matters to anyone other than us.

Where did I say that? You're answering to statements I didn't make.

You said it when you wrote this:

And, this goes to what Bain just said......folks aren't going to understand or care about fine tuned distinctions.

It's a couple 200 amp rated panels with separate disconnects, each fed with separate 200 amp cables.

What should I call it?

It kind of gets to the same idea of "is it 110 or 120v?"........does it matter to anyone other than us and a bunch of double e's?

I gave an example of 110v vs. 120v, and indicated that the distinction doesn't mean much to anyone. The idea being, if we call it 2-200 amp, or a 400 amp, it doesn't mean anything to my customers. I try to form statements in language where folks have some basis for understanding. Heck, I'm not sure I understand meter socket and utility stuff.......

And my point is that the difference between 110v and 120v is unimportant, but the difference between 2 200-amp panels on a 200-amp service and 2 200-amp panels on a 400-amp service is important. The number of panels is not necessarily equivalant to the service size and simply stating that there are 2 200-amp panels present might lead someone to conclude that they have a 400-amp service when they might, in fact, not have it.

If there are 2, 200-amp panels and the meter is a class 320, it's nearly always going to be a 400-amp service.

Except when it's not. Which goes back to the original question, so far still a little unclear. Unclear, because I'm looking for language that's comprehensible to the customer, not meter class size.

I think the answer would be best formed in language that folks understand.

Understanding the meter class size isn't important for the customer, it's for the inspector. By learning & understanding the meter designation, an inspector will have another clue to piece together the service size. Then he can simply communitcate that to the customer as "You have a 200-amp service" or, "even though you have 2 200-amp panels, you only have a 100-amp service. Better get that looked at." Or something equally comprehensible.

And, I understand that if a cat gives birth in the oven, the kittens aren't muffins........

[kurt]

Now we're getting somewhere.

I'm getting this as a 200 amp meter. Is that right?

Click to Enlarge

44.65 KB

[Jim Katen]

Now we're getting somewhere.

I'm getting this as a 200 amp meter. Is that right?

Yes. You can tell by the 200 CL and the TA 30.

If you were to find 2 200-amp panels fed, in parallel, through this meter, it would be a big red flag. Not necessarily wrong, but a red flag because the service drop or the lateral would almost certainly only be intended for a 200-amp service. Someone might have snuck in the 2nd panel without informing the utility.

- Jim Katen, Oregon

Click to Enlarge

52.88 KB

[mgbinspect]

This all raises another interesting concern: If, for instance, you have a 150 AMP panel without a main breaker, which meets the "six throws" requirement, and it's on a 200 CL meter, then a 150 main breaker is NEEDED to limit potential to the panel rating. Yes?

When you can behold the service entrance cable, such a need is obvious. The meter is another possible tip to the condition. The only down-side; I doubt there are 150 CL meters?

[Marc]

This all raises another interesting concern: If, for instance, you have a 150 AMP panel without a main breaker, which meets the "six throws" requirement, and it's on a 200 CL meter, then a 150 main breaker is NEEDED to limit potential to the panel rating. Yes?

Breakers respond to the current that flows through them and interrupt it if it is excessive. They do not 'limit the potential rating' of the panel. If you meant to say that a 150 amp main breaker is needed to protect the panel, then the answer is 'no'. If it's 6 throws or under, a main breaker is not needed. What's needed is that the rating of the meter box, the rating of the service conductors and the rating of the panel all be equal to or in excess of the calculated ampacity requirement of the dwelling. The smallest of the these three components is the ampere limit of the service. An inspector should try to determine if that ampere limit seems adequate for the dwelling.

Marc

[Jim Katen]

This all raises another interesting concern: If, for instance, you have a 150 AMP panel without a main breaker, which meets the "six throws" requirement, and it's on a 200 CL meter, then a 150 main breaker is NEEDED to limit potential to the panel rating. Yes?

Not in the U.S. The service is calculated to meet the needs of the house. There's no requirement for a single main disconnect. You can have 6 main breakers on 6 main panels or you can have 6 main breakers on one main panel.

- Jim Katen, Oregon

Edit: I see that Marc already answered this.

[mgbinspect]

Then exceeding the needs of the house and the rating of the panel is not a concern, as long as the six breakers are properly sized. Got it.

[Marc]

Then exceeding the needs of the house and the rating of the panel is not a concern, as long as the six breakers are properly sized. Got it.

Properly sized for the individual branch circuit loads that they serve, that is. They are not a consideration in calculating the total electrical demand for the dwelling. That can only be calculated.

Marc

[Jim Katen]

Then exceeding the needs of the house and the rating of the panel is not a concern, as long as the six breakers are properly sized. Got it.

If it's done properly, the panel rating is not being exceeded. The panel rating is matched to the calculated load.

If it's done improperly (or if someone adds loads to the house without re-calculating the load) then it would be a big concern. The panel rating might easily be exceeded.

That's why I think it's important for us to find out the service size and, if we can't, then to refer it on to an electrician -- particularly if we suspect that the service is undersized. Merely citing the number & size of the panels doesn't necessarily tell the service size.

- Jim Katen, Oregon

[mgbinspect]

Of course, I've always understood that an undersized cable is a bad thing, but I always figured that too much power coming in, un-checked by a main breaker properly sized for the breaker panel, could be a big problem too.