Sticker on Main Panel

[andrew.tkelly]

Hi,

I'm looking at a main panel with (2) 2-pole breakers in it. One is 90A and the other is 50A. The busbar rating is 125A. There is a small sticker below that reads "Each Handle In This Device Is A Service Disconnect". I've never seen this sticker before.

This appears to be what I call a "line-side panel", as the two breakers feed downstream subpanels. The PV breaker will be 20A, and I plan to quad it with the existing 50A 2-pole breaker. Do you think the inspector will try to enforce the 120% Rule for backfeeding in a situation like this? I'm a little nervous they might try to say something like: 120% x 125A = 150A.... minus 90A, minus 50A = 10A available for solar.

Does anyone have experience with this?

Thanks!

Kind Regards,
Andy

 

[ggunn]

Hi,

I'm looking at a main panel with (2) 2-pole breakers in it. One is 90A and the other is 50A. The busbar rating is 125A. There is a small sticker below that reads "Each Handle In This Device Is A Service Disconnect". I've never seen this sticker before.

This appears to be what I call a "line-side panel", as the two breakers feed downstream subpanels. The PV breaker will be 20A, and I plan to quad it with the existing 50A 2-pole breaker. Do you think the inspector will try to enforce the 120% Rule for backfeeding in a situation like this? I'm a little nervous they might try to say something like: 120% x 125A = 150A.... minus 90A, minus 50A = 10A available for solar.

Does anyone have experience with this?

Thanks!

Kind Regards,
Andy

The sticker means that it is a MLO MDP with no upstream OCPD, so all the breakers are service disconnects. Since there is no main breaker and apparently no OCPD between the panel and the service, the 120% rule does not apply.

I don't know what you mean by "quad it", but the PV should have its own 2 pole breaker. Your AHJ may require that you also have a lockable bladed disco irrespective of your means of interconnection; all AHJ's in Texas do.

 

[andrew.tkelly]

Ah, I guess I'm not sure what this is properly called, but I've always heard it as "quad-breaker". It's when you have (2) 2-pole breakers in the same amount of space a standard, single 2-pole breaker would normally take up. Kinda like this.... "2 1 1 2", where the 1's represent the first breaker, and the 2's the outer breaker.

What is this normally called?

Andy

 

[MAC702]

Ah, I guess I'm not sure what this is properly called, but I've always heard it as "quad-breaker". ... What is this normally called?

I call it a double-tandem, or 2-pole tandem, but understood what you meant when you said "quad." Indeed, I just checked Home Depot's website, and their Eaton and Murray examples are called a "Quadplex" even though I've never heard that term before.

 

[BillK-AZ]

Check your 90A and 50A breakers, they should be listed for service disconnect. You are not likely to find tandem 50A service listed breakers.

Since each breaker is a Service, your PV 20A can be installed in either subpanel following the usual 120% rules. Just make sure the sub panel bus ratings are high enough, upgrade if necessary. Your calculation is not correct, you consider only the breaker feeding the subpanel with the PV breaker, not the other.

 

[jaggedben]

Do I think the inspector will try to enforce the 120% rule? Maybe, it's happened to me before. But the last time I had to explain to an AHJ the difference between line side and load side rules was more than 3 years ago.