Disconnect Main Panels

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Here's a picture of a 125A panel that is in question: View attachment 22641

The AHJ is telling us that this 125A disconnect main cannot have more than a combined total of 125A of over current protection devices installed into it.

Are they correct?

If not, can anybody help me with information to convince them otherwise?

Thank you in advance.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
The attachment is not showing. Maybe try the picture again.

My best guess without the picture is that you have multiple service disconnects. In that case take a look at 230.90 Exception 3, and remember the solar isn't a load.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
The AHJ is telling us that this 125A disconnect main cannot have more than a combined total of 125A of over current protection devices installed into it.

Are they correct?

If not, can anybody help me with information to convince them otherwise?
Not correct. Proof is lack of requirement to do so.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Here's a picture of a 125A panel that is in question: View attachment 22641

The AHJ is telling us that this 125A disconnect main cannot have more than a combined total of 125A of over current protection devices installed into it.

Are they correct?

If not, can anybody help me with information to convince them otherwise?

Thank you in advance.

If it really is the AHJ saying this then they are of course correct. if it is just an inspector, he is probably wrong about it.
 
The attachment is not showing. Maybe try the picture again.

My best guess without the picture is that you have multiple service disconnects. In that case take a look at 230.90 Exception 3, and remember the solar isn't a load.

There are two breaker spots in the 125A panel. (we have been calling this a 'disconnect main panel')

One breaker spot is a 90A feeding the house sub. The other breaker spot has a 40/20 quad. (40 for AC)

We planned on putting a 40/40 quad, relocating the 20, and 30A of solar to a new sub.

But the AHJ is saying that you cannot have more than 125A of breakers. (combined total)

So per their rule, the existing is already over the panel capacity??

I would love to be able to explain to them and correct their thinking if they are wrong about this.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
There are two breaker spots in the 125A panel. (we have been calling this a 'disconnect main panel')

One breaker spot is a 90A feeding the house sub. The other breaker spot has a 40/20 quad. (40 for AC)

We planned on putting a 40/40 quad, relocating the 20, and 30A of solar to a new sub.

But the AHJ is saying that you cannot have more than 125A of breakers. (combined total)

So per their rule, the existing is already over the panel capacity??

I would love to be able to explain to them and correct their thinking if they are wrong about this.

So I see a couple things I see going on here...

First issue is that before you guys arrived on the scene the panel is already potentially out of compliance. There's 160A of load breakers on the 125A panel. That's not necessarily a violation. Find your codebook and read that 230.90 Exception 3 that I mentioned above. That is pretty key. You've got to do a load calculation on this house and show the plan checker that the calculated load is under 125A. (Note: the solar is not a load.) If it isn't under 125A, well, that's the customer's problem...

Second potential issue ... I'm not sure from what you've said if the plan checker is just concerned about the first issue or if he's also got a wacky interpretation of 705. In the meter main, you're doing a supply side connection under 705.12(A). Well, in this case you have a load side connection in series with a supply side connection, but none of the 705.12(D) rules apply to the meter/main busbar because it is not on the load side of the service disconnecting means. If the quad wasn't blocking you, you could put a 125A solar breaker in that second spot as a supply side connection. Perhaps he's looking at 705.12(D)(2)(3)(c), but I just think that is wrong because the beginning of (D) refers to load side connections and so, to repeat, that section doesn't apply to a busbar on the supply side of the service disconnecting means. I have done a lot of interconnections on these types of panels under this logic.

If you can get on the right side of this guy you'll save yourself a good deal of trouble in Oakley where I'd guess a sizable percentage of houses have a meter/main with two breakers, one for a sub and another for the A/C.
 
So I see a couple things I see going on here...

First issue is that before you guys arrived on the scene the panel is already potentially out of compliance. There's 160A of load breakers on the 125A panel. That's not necessarily a violation. Find your codebook and read that 230.90 Exception 3 that I mentioned above. That is pretty key. You've got to do a load calculation on this house and show the plan checker that the calculated load is under 125A. (Note: the solar is not a load.) If it isn't under 125A, well, that's the customer's problem...

Second potential issue ... I'm not sure from what you've said if the plan checker is just concerned about the first issue or if he's also got a wacky interpretation of 705. In the meter main, you're doing a supply side connection under 705.12(A). Well, in this case you have a load side connection in series with a supply side connection, but none of the 705.12(D) rules apply to the meter/main busbar because it is not on the load side of the service disconnecting means. If the quad wasn't blocking you, you could put a 125A solar breaker in that second spot as a supply side connection. Perhaps he's looking at 705.12(D)(2)(3)(c), but I just think that is wrong because the beginning of (D) refers to load side connections and so, to repeat, that section doesn't apply to a busbar on the supply side of the service disconnecting means. I have done a lot of interconnections on these types of panels under this logic.

If you can get on the right side of this guy you'll save yourself a good deal of trouble in Oakley where I'd guess a sizable percentage of houses have a meter/main with two breakers, one for a sub and another for the A/C.

Yes many homes in Oakley have this same type of set up.

Thank you all for your time.

I've tried to explain and show them the supply side connection but they keep going back to the max allowed in that panel cannot add up to over the panel rating.

So I guess the only way is to get a load calculation.

Thank you again!
 
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