Adding loads?

[sparky1118]

Hello everyone hope all is well. So I’m not familiar with solar truth be told. A friend of mine had solar installed on his house. He is wanting to add mini splits. I have attached a picture to this post of what sticker they put on his main panel. I don’t know if I can add a lot to the panel or if I cannot. I find it hard to believe that he cannot add anything else to his panel ever. Any insight would be appreciated

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[electrofelon]

sticker they put on his main panel.

The incompetent CMPs have gone so far overboard with labeling for PV that most PV installers slap labels on everything just to be "safe" that they will pass inspections, and thus many times the labels are wrong and/or meaningless. I bet most of the time no one even pays attention to these labels, it's like car alarms now: you hear one go off and a car being robbed is the last thing you think of. Based on your description of this being a "main panel" it is doubtful that you can't add loads. However a picture showing the breakers in the panel would help.

 

[sparky1118]

The incompetent CMPs have gone so far overboard with labeling for PV that most PV installers slap labels on everything just to be "safe" that they will pass inspections, and thus many times the labels are wrong and/or meaningless. I bet most of the time no one even pays attention to these labels, it's like car alarms now: you hear one go off and a car being robbed is the last thing you think of. Based on your description of this being a "main panel" it is doubtful that you can't add loads. However a picture showing the breakers in the panel would help.

It’s definitely the main panel. They also added a sub panel with the same label


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[electrofelon]

A combiner panel is not an officially defined thing, but is usually where multiple inverter outputs are combined into one feedee. Typically they do not have other loads and the bus bar is qualified under the "sum of breakers" rule. There is no restriction to adding loads as long as the sum of all breakers doesn't exceed the rating of the busbar. A main panel is typically qualified under a different rule, the "120% rule" where the PV breakers have to be at the opposite end of the bus from everything else.

The busbar rules are ridiculously overly conservative, and if this isn't getting inspected, I would personally have no trouble violating a busbar rule for a 200 amp residential panel at my house.

 

[tortuga]

Hello everyone hope all is well. So I’m not familiar with solar truth be told. A friend of mine had solar installed on his house. He is wanting to add mini splits. I have attached a picture to this post of what sticker they put on his main panel.

Is the main panel you refer to the one with the service disconnect?
Can you tell how is the solar interconnected? a back fed breaker or a tap off the service?

I don’t know if I can add a lot to the panel or if I cannot. I find it hard to believe that he cannot add anything else to his panel ever.

The sticker is meant to scare DIY and handyman installers away, for licensed electricians it translates to do a 220.83(B) load calc and see article 705

 

[PWDickerson]

That sticker on the "Sub-panel" is likely correct if the sub-panel only has inverter breakers in it. It is incorrect and can be ignored with regard to the main panel. Please post photos of the breakers in the main and sub, and we can give you a better answer. A photo of the inverter label would also be helpful.

 

[ggunn]

That sticker on the "Sub-panel" is likely correct if the sub-panel only has inverter breakers in it.

A panel or sub panel that has inverter breakers in it can also contain loads under 705.12(B)(3)(3). Perhaps that system was installed prior to the inclusion of that language in the code.

 

[ggunn]

That sticker on the "Sub-panel" is likely correct if the sub-panel only has inverter breakers in it.

There is a case where you might see an "add no loads" label on the first panel after the meter. Sometimes a service will be designed with a 200A feedthrough panel that is used only as a service disconnect, i.e., with no breakers in it; I assume it is because the feedthrough panel is cheaper than a 200A disco. This is fairly commonplace in rural services where the meter and disco are some distance from the building(s) served. In that case I have seen a PV backfed breaker added to that panel as a load side interconnection with an "add no loads" label. Of course, whatever is downstream from this must have OCP. It may be a little dodgy but rural AHJ's usually do not have a problem with it.

 

[jaggedben]

Nothing in my field irks me more than illiterate employees slapping the wrong stickers in the wrong places and illiterate inspectors demanding it.

 

[tortuga]

I got to thinking about this thread after I saw another one of these stickers in the wild. What section in the NEC triggers this sticker?

 

[electrofelon]

I got to thinking about this thread after I saw another one of these stickers in the wild. What section in the NEC triggers this sticker?

I'm not sure if there is/was eve anything that specifically said "do not add loads" but it's one of the busbar rules in 705.12(B) that comes close:


(c) The sum of the ampere ratings of all overcurrent devices on panelboards, both load and supply devices, excluding the rating of the overcurrent device protecting the busbar, shall not exceed the ampacity of the busbar. The rating of the overcurrent device protecting the busbar shall not exceed the rating of the busbar. Permanent warning labels shall be applied to distribution equipment displaying the following or equivalent wording:

WARNING:
THIS EQUIPMENT FED BY MULTIPLE SOURCES. TOTAL RATING OF ALL OVERCURRENT DEVICES EXCLUDING MAIN SUPPLY OVERCURRENT DEVICE SHALL NOT EXCEED AMPACITY OF BUSBAR.

 

[Electrical Geek]

That sticker is in the wrong place. It says right on it that it's for a pv combiner panel. You can add loads to that panel.

 

[electrofelon]

That sticker is in the wrong place. It says right on it that it's for a pv combiner panel. You can add loads to that panel.

Yes but I don't believe a "combiner panel" is a specifically defined thing, and you can still (potentially) add loads to combiner panels anyway.

 

[Electrical Geek]

Yes but I don't believe a "combiner panel" is a specifically defined thing, and you can still (potentially) add loads to combiner panels anyway.

There is a definition and you are correct. You can 'technically' add circuits to an ac combiner panel because the definition title is Combiner (DC).

 

[tortuga]

but it's one of the busbar rules in 705.12(B) that comes close:


(c) The sum of the ampere ratings of all overcurrent devices on panelboards, both load and supply devices, excluding the rating of the overcurrent device protecting the busbar, shall not exceed the ampacity of the busbar. The rating of the overcurrent device protecting the busbar shall not exceed the rating of the busbar. Permanent warning labels shall be applied to distribution equipment displaying the following or equivalent wording:

WARNING:
THIS EQUIPMENT FED BY MULTIPLE SOURCES. TOTAL RATING OF ALL OVERCURRENT DEVICES EXCLUDING MAIN SUPPLY OVERCURRENT DEVICE SHALL NOT EXCEED AMPACITY OF BUSBAR.

I never noticed that 'equivalent wording' part in the code. I think any warning stickers required by the NEC should require an exact wording or if they are going to use that equivalent wording thing there should be a code reference and code year.

 

[electrofelon]

I never noticed that 'equivalent wording' part in the code. I think any warning stickers required by the NEC should require an exact wording or if they are going to use that equivalent wording thing there should be a code reference and code year.

Yeah interesting, I never noticed that either.

 

[jaggedben]

Before the rule that electrofelon mentions was made explicit (in the 2014 NEC), some AHJs allowed informal exceptions to the 120% rule for combiner panels. And some asked for this type of 'no loads' label in those cases. Instead of putting this fairly straightforward approach directly into the code, the CMP came up with the 'sum of all breakers' rule electrofelon mentions. One reason was that a combiner panel should be able to have a small load associated with the PV, such as an Enphase Envoy. Another reason is that the broader applicability sometimes allows connections in panels with substantial loads where other rule options don't allow it.

If a panel is really a PV combiner only then I'd say the label in the picture is 'equivalent wording' to the code requirement in that particular situation. But only in that particular situation. It sounds like it does not apply in the OP's situation.

 

[tortuga]

For the electricians running residential service work like @sparky1118, whom don't do solar everyday, a sticker that says 'dont add any loads' is meaningless.
I think if the sticker had a code reference and code year printed right on it, then he would instantly google that and get headed in the right direction.