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Discussion Starter · #1 ·
I just had my solar installed and had a question about how they tapped into the electrical.

Here’s a before picture of my outside box before the install.

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Here’s the after with the load side tap and the insulation piercing connectors.

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I need to take a closer look tomorrow, but can anyone guess what this is? This sort of “bubbling” on the line?

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My inspection from the county is next week and then the electrical company is in two weeks. I have to assume if something is damaged or unsafe it will get caught during inspection…right?
 

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Discussion Starter · #3 ·
What maroons! Why on earth would they do that, when there are breaker spaces right there? I guess taps were cheaper. Well, they are UL listed taps, presumably.

SMH solar people.
Can i check that they are UL listed?

I was told they couldn’t use those breaker spaces on my outside box.

To use the breaker, I was told they would have had to drill through the wall and use the breaker spaces in my sub panel in the garage…they were going to do it, but I preferred having everything kept outside and not in garage.
 

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it is fine, you need to stop worrying so much

you keep posting threads about work you have had done by professionals, and you keep questioning their work, why?

why don't you trust these people?

have they given you a reason not to trust them?
 

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Discussion Starter · #5 ·
it is fine, you need to stop worrying so much

you keep posting threads about work you have had done by professionals, and you keep questioning their work, why?

why don't you trust these people?

have they given you a reason not to trust them?
Agreed. It is most likely fine…but I was told that they could have used those breaker slots on the outside breaker….but that would require them having to derate the main breaker to 200amps (and I didn’t want to derate breaker).

But I just looked and the outside box and appears to already be 200amps.

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I think they thought I had an 225amp breaker since the inside breaker shows 225amps (pic below)…but it doesn’t matter since the connection was happening in the main breaker outside.

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Again, it appears everything is up to code…but I would have preferred them use the breaker slots than the insulation piercing connectors.
 

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Discussion Starter · #7 ·
it doesn't matter what you prefer,

you hired a professional to do a job, and they did their job,

let it go
If the professional shows my plans as 225 amps at the main breaker and do the line tap based on that…but it’s only 200 amps (where the line tap isn’t required) it makes me question some things.

Again, I don’t think it’s “wrong” but as @seharper says the breaker slots would have probably been better.
 

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Presumably the design team at the solar installer checked this, and then the plan checker checked this. And you still have the inspector and POCO (since this is meter main) that have a shot at commenting on this.

I'd personally accept this was done acceptably. Actually I think connecting an energy source to a tap is more work, math wise, than landing on the busbar with a breaker.
 

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you hired a professional to do a job, and they did their job,
No, they did another craft's job. This is no different than when the A/C guys slap the wrong breaker in your panel. You say "that's forbidden in Code" and they hand you a copy of the HVAC installation Code and say "Really? Show me where."

If the professional shows my plans as 225 amps at the main breaker and do the line tap based on that…but it’s only 200 amps (where the line tap isn’t required) it makes me question some things
Well the 120% rule creates a lot of confusion. What it is saying is "do not let "the sum of utiiity + solar" overload the panel bus rating. Exception: if the solar and utility breakers are as far apart as possible (opposite ends) of the panel, then together they can load the bus to 120% of rating since they're feeding opposite ends and there are a bunch if loads between them".
It does not give any authorization whatsoever to overload feeder cable!

Now think about it.

Yeah, we may have a bit of a mess. But there might be a way out, that as a side effect would remove all limits and let you go 200A of solar if you wanted.

You have a subpanel where all your house breakers are. What is the size of the main breaker in that subpanel? If it has none, is it convertible?
 

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No, they did another craft's job. This is no different than when the A/C guys slap the wrong breaker in your panel. You say "that's forbidden in Code" and they hand you a copy of the HVAC installation Code and say "Really? Show me where."



Well the 120% rule creates a lot of confusion. What it is saying is "do not let "the sum of utiiity + solar" overload the panel bus rating. Exception: if the solar and utility breakers are as far apart as possible (opposite ends) of the panel, then together they can load the bus to 120% of rating since they're feeding opposite ends and there are a bunch if loads between them".

It does not give any authorization whatsoever to overload feeder cable!

Now think about it.

Yeah, we may have a bit of a mess. But there might be a way out, that as a side effect would remove all limits and let you go 200A of solar if you wanted.

You have a subpanel where all your house breakers are. What is the size of the main breaker in that subpanel? If it has none, is it convertible?
Good point, not enough information here, there needs to be a schematic here (actually preferably pictures that overkill on showing the exact conditions, since I don't think OP is qualified to try to summarize). The way this is connected triggers more complicated pieces than the 120% or sum of breakers rules. There are rules in 705.12 about how to have multiple power sources on feeders, and how do deal with things like feed through to lugs (it could be either feed through to lug or main, picture wasn't shared). I believe the acceptable range of things to do here is 100% prescribed by 705.12 in its modern form. By my understanding, 120% can't be used here without evaluating what's going on in the feed-through, since the bottom of this panel isn't the true effective end of the busbar, it extends through to the other subpanel.

I thought solar contractors were supposed to defer to electrical contractors / their in house or outsourced design team when things get as complicated as is going on here.
 

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Discussion Starter · #11 · (Edited)
Presumably the design team at the solar installer checked this, and then the plan checker checked this. And you still have the inspector and POCO (since this is meter main) that have a shot at commenting on this.

I'd personally accept this was done acceptably. Actually I think connecting an energy source to a tap is more work, math wise, than landing on the busbar with a breaker.
No, they did another craft's job. This is no different than when the A/C guys slap the wrong breaker in your panel. You say "that's forbidden in Code" and they hand you a copy of the HVAC installation Code and say "Really? Show me where."



Well the 120% rule creates a lot of confusion. What it is saying is "do not let "the sum of utiiity + solar" overload the panel bus rating. Exception: if the solar and utility breakers are as far apart as possible (opposite ends) of the panel, then together they can load the bus to 120% of rating since they're feeding opposite ends and there are a bunch if loads between them".
It does not give any authorization whatsoever to overload feeder cable!

Now think about it.

Yeah, we may have a bit of a mess. But there might be a way out, that as a side effect would remove all limits and let you go 200A of solar if you wanted.

You have a subpanel where all your house breakers are. What is the size of the main breaker in that subpanel? If it has none, is it convertible?
Good point, not enough information here, there needs to be a schematic here (actually preferably pictures that overkill on showing the exact conditions, since I don't think OP is qualified to try to summarize). The way this is connected triggers more complicated pieces than the 120% or sum of breakers rules. There are rules in 705.12 about how to have multiple power sources on feeders, and how do deal with things like feed through to lugs (it could be either feed through to lug or main, picture wasn't shared). I believe the acceptable range of things to do here is 100% prescribed by 705.12 in its modern form. By my understanding, 120% can't be used here without evaluating what's going on in the feed-through, since the bottom of this panel isn't the true effective end of the busbar, it extends through to the other subpanel.

I thought solar contractors were supposed to defer to electrical contractors / their in house or outsourced design team when things get as complicated as is going on here.
So, I think I can clarify everything.

I didn’t get the plans until after the installation and I noticed a slight error. Here are the plans.

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I noticed one error…or I think it’s an error. They have my main panel listed as 225 amps, but it’s really 200 amps. See here.

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I believe this error occurred because they asked to look at the inside breaker (see below) and it shows 225 amps…because they were originally going to drill through the wall and connect inside, but they ended up doing the installation outside on the main 200 amp breaker.

Font Handwriting Paper Parallel Publication



From what I’ve read, I shouldn’t have any issues since they did a load side tap, but I just wanted to ask if anyone could confirm?

I haven’t had my inspection yet and I wonder if this is going to cause any issues 🤔

All in all everything looks good…but sometimes I’m a bit detail oriented and don’t love when things don’t match perfectly and wanted to ask.
 

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Well, let's suppose you're heavily loading your indoor panel due to doing a bunch of things at once. Maybe your gas furnace quit and you're running space heaters all over the house, doing a dryer load, cooking Thanksgiving dinner etc. It's all going to town. You're pulling 270A on one phase and 265A on the other phase.

70A of that is coming from solar, and the other 200A is coming from the utility. These are on-spec so the utility breaker is not tripping, and the solar fuse is not blowing.

The feeder between the solar tap and your indoor panel is carrying 270A.

Does anything prevent this? Is there a "main breaker" in the indoor panel? Could there be?

How big is that main feeder wire and what metal?
 

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Discussion Starter · #13 ·
Well, let's suppose you're heavily loading your indoor panel due to doing a bunch of things at once. Maybe your gas furnace quit and you're running space heaters all over the house, doing a dryer load, cooking Thanksgiving dinner etc. It's all going to town. You're pulling 270A on one phase and 265A on the other phase.

70A of that is coming from solar, and the other 200A is coming from the utility. These are on-spec so the utility breaker is not tripping, and the solar fuse is not blowing.

The feeder between the solar tap and your indoor panel is carrying 270A.

Does anything prevent this? Is there a "main breaker" in the indoor panel? Could there be?

How big is that main feeder wire and what metal?
There’s not a main breaker on the indoor panel. The indoor panel is in the garage, and just on the other side of the wall (behind it) is the outdoor panel where those feeder wires connect the main panel to the sub panel (and the load tap is connected).

The wire says Southwire 2/0 AWG

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FWIW, there are some critical questions being asked in this thread that you have missed.

Is the subpanel convertible? If you are not sure, send EVERYTHING from the sticker. Then if you provide a subset of the necessary info in your text response, perhaps someone can see the model number and look it up or see the wiring diagram.

Is the feeder to the inside panel 2/0 Copper or Aluminum? I think I see Cu in one of the pictures, which I understand to be fine for this specific use case (service entry or service to first subpanel) but I'll defer to someone in the trade for that.

Anyway, from what I see here this does not feel kosher, no way 2/0 can handle 200A from service + 62.5A from combiner panel.

In the plans, they have 225A main breaker on the subpanel, which you say does not exist. (and anyway this is a little suspicious, that means 225A could be pushed across your 2/0 feeder?!?. My guess is they saw 225A service + feed through to subpanel from the data provided and assumed the feeder was sized appropriately (3/0 copper).

The reason seharper is asking about whether the subpanel is convertible is that it gives more freedom to do this properly. If the subpanel is not convertible, then as I understand it you will need one of:
  • hoping Eaton has 200A regular breakers
  • install a new main breaker subpanel ahead of your subpanel
  • replace your subpanel with a main breaker subpanel
  • derate main breaker
Might want to torpedo the inspection and force them to rework this. Unfortunately with things done over text versus them sending someone to your house to take pictures of panel and site survey, they may be able to finagle the situation into, you being responsible for the change order :(. Depends on if you went overkill with sending photos of absolutely everything, or relied on communicating with text (there is some important inconsistency in details contained in your textual description of your setup in this thread, so it's possible that occurred in your text with the contractor).
 

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Discussion Starter · #15 ·
FWIW, there are some critical questions being asked in this thread that you have missed.

Is the subpanel convertible? If you are not sure, send EVERYTHING from the sticker. Then if you provide a subset of the necessary info in your text response, perhaps someone can see the model number and look it up or see the wiring diagram.

Is the feeder to the inside panel 2/0 Copper or Aluminum? I think I see Cu in one of the pictures, which I understand to be fine for this specific use case (service entry or service to first subpanel) but I'll defer to someone in the trade for that.

Anyway, from what I see here this does not feel kosher, no way 2/0 can handle 200A from service + 62.5A from combiner panel.

In the plans, they have 225A main breaker on the subpanel, which you say does not exist. (and anyway this is a little suspicious, that means 225A could be pushed across your 2/0 feeder?!?.

The reason seharper is asking about whether the subpanel is convertible is that it gives more freedom to do this properly. If the subpanel is not convertible, then as I understand it you will need one of:
  • hoping Eaton has 200A regular breakers
  • install a new main breaker subpanel ahead of your subpanel
  • replace your subpanel with a main breaker subpanel
Might want to torpedo the inspection and force them to rework this. Unfortunately with things done over text versus them sending someone to your house to take pictures of panel and site survey, they may be able to finagle the situation into, you being responsible for the change order :(. Depends on if you went overkill with sending photos of absolutely everything, or relied on communicating with text (there is some important inconsistency in details contained in your textual description of your setup in this thread, so it's possible that occurred in your text with the contractor).
This is a big and reputable company…there’s no way they botched this and the inspection is coming up. Is it safe to assume they’ll fail it if it’s wrong? And the POCO has to come out as well.

From what I’ve been told, Load Side Taps are great if you don’t want to exceed the main breaker/bus and derate it…they’re great for larger systems.

And they confirmed on site it’s a copper wire as well.

Are you familiar with solar and load side taps? I was just inquiring if there was going to be an issue with their calculations showing 225 when it’s 200.
 

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This is a big and reputable company…there’s no way they botched this and the inspection is coming up. Is it safe to assume they’ll fail it if it’s wrong? And the POCO has to come out as well.

From what I’ve been told, Load Side Taps are great if you don’t want to exceed the main breaker/bus and derate it…they’re great for larger systems.

And they confirmed on site it’s a copper wire as well.

Are you familiar with solar and load side taps? I was just inquiring if there was going to be an issue with their calculations showing 225 when it’s 200.
Inspection failure -- depends on how carefully they check in your city for solar. In my city they seem to rely primarily on the plan check for my recent (non-solar) subpanel. They only spot checked conductor sizes, but were anal about feeder torque. This was even with me having done all the work and design as the owner-builder, so you'd think they would be more suspicious of my claims that I did everything reasonably.

In your case, here are the failure modes I can imagine:
  • Incorrect information used for plans, so plans are drawn wrong
  • On-site contractors assumed that the plans are correct / the site survey was correct. And missed the fact that the plans did not match the existing conditions. In fact, they FOR A FACT missed that your service disconnect is 200A while the plans said 225A. They could have missed other things.
  • Your city and POCO are lax or only spot check things here and there.
With regard to solar and load side taps. Well I'm not an electrical contractor or a solar contractor, but I'm an engineer that's been micromanaging my own upcoming solar install and making sure the subpanels I'm getting installed are as future proof as possible. Seharper is an EC and knows the code quite well.

The only way to say load side taps are OK is to do a full calculation, and that requires having the full information as required by 705.12. That includes things requested already on this thread that I don't believe you've provided (this isn't an exhaustive list) -- the feeder conductor size, feeder conductor metal, busbar of both meter-main and subpanel, breaker size of both meter-main and subpanel. Out of these, the conductor size, metal, subpanel breaker could all have values that are not OK given the other facts you've provided. You will need to disambiguate that.

And if there is remaining ambiguity that could indicate a faulty design / installation, you can point out those ambiguities to a combination of your inspector and contractor.
 

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Their "engineer" clearly understood your setup, because they drew it into the drawing reasonably correctly. They assumed your main subpanel has a 225A main breaker, when it actually has none at all, which makes overloading of the main feeder a serious problem. They still made a mistake; if you had in fact had a 225A breaker there, the main feeder would need to be upgraded to 3/0 (225A x 0.83 -> 187A, too much for 2/0Cu).

This kind of mistake just happens because of the "gold rush" of solar and the high production rate of too few qualified people doing too many solar jobs.

But @zanydroid is onto my line of thinking. If you can slap a 200A "main breaker" into the main subpanel, all problems are magically cured, and what's more, you get a free hand to put up to 200A of solar breakers in the main panel.

I have no earthly idea why they insisted on a solar fused disconnect instead of a CH breaker. Sales markup maybe? Conformance with their internal "cookie cutter" standards? Part of the solar salesman's job is to make the installations as "cookie cutter" repeatable as possible as it lowers the skill level needed by the staff they can barely find.



The taps are UL Listed, I can see the mark. ILSCO is a good vendor. However that "9.8" on the bolt indicates it is made of metal. What the...???? NEC 110.3(B) requires that the listed equipment must be installed according to its labeling and instructions which might be this. Hmm, don't see a problem but it is silent on the question of whether that bolt is energized. I would measure it with a meter.





This is a big and reputable company…
That means nothing. The solar business is in "gold rush mode" so getting good staff is super hard. These big companies are subcontrating out to anyone who can fog a mirror.

The MAIN main breaker is 200A. Per NEC 310.15(B)(7) the service wire size must be 83% of that or 166A. 2/0 Copper is adequate for 200A service because of that.
 

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I have no earthly idea why they insisted on a solar fused disconnect instead of a CH breaker. Sales markup maybe? Conformance with their internal "cookie cutter" standards? Part of the solar salesman's job is to make the installations as "cookie cutter" repeatable as possible as it lowers the skill level needed by the staff they can barely find.
I vaguely remember reading somewhere that some jurisdictions require a separate solar disconnect even when using interactive power sources and even when you have a breaker that could otherwise be used for it 🤷‍♂️. I've seen a lot of solar disconnects in my neighborhood, and this is including new installations (EG all grid tie solar inverters are interactive, and rapid shutdown of input to string inverters is required)
 

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Interesting, a separate switch for appearances for firemen. OP's system is microinverter, so Rapid Shutdown just happens because each of the microinverters is grid-interactive (UL 1741) and will shut down when the main breaker is pulled. Perhaps they are worried about future installation of grid-forming inverters like PowerWall which will spoof the panels to come back online, so they want a separate well-marked disconnect to positively take them off.
 

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Discussion Starter · #20 · (Edited)
Inspection failure -- depends on how carefully they check in your city for solar. In my city they seem to rely primarily on the plan check for my recent (non-solar) subpanel. They only spot checked conductor sizes, but were anal about feeder torque. This was even with me having done all the work and design as the owner-builder, so you'd think they would be more suspicious of my claims that I did everything reasonably.

In your case, here are the failure modes I can imagine:
  • Incorrect information used for plans, so plans are drawn wrong
  • On-site contractors assumed that the plans are correct / the site survey was correct. And missed the fact that the plans did not match the existing conditions. In fact, they FOR A FACT missed that your service disconnect is 200A while the plans said 225A. They could have missed other things.
  • Your city and POCO are lax or only spot check things here and there.
With regard to solar and load side taps. Well I'm not an electrical contractor or a solar contractor, but I'm an engineer that's been micromanaging my own upcoming solar install and making sure the subpanels I'm getting installed are as future proof as possible. Seharper is an EC and knows the code quite well.

The only way to say load side taps are OK is to do a full calculation, and that requires having the full information as required by 705.12. That includes things requested already on this thread that I don't believe you've provided (this isn't an exhaustive list) -- the feeder conductor size, feeder conductor metal, busbar of both meter-main and subpanel, breaker size of both meter-main and subpanel. Out of these, the conductor size, metal, subpanel breaker could all have values that are not OK given the other facts you've provided. You will need to disambiguate that.

And if there is remaining ambiguity that could indicate a faulty design / installation, you can point out those ambiguities to a combination of your inspector and contractor.
Their "engineer" clearly understood your setup, because they drew it into the drawing reasonably correctly. They assumed your main subpanel has a 225A main breaker, when it actually has none at all, which makes overloading of the main feeder a serious problem. They still made a mistake; if you had in fact had a 225A breaker there, the main feeder would need to be upgraded to 3/0 (225A x 0.83 -> 187A, too much for 2/0Cu).

This kind of mistake just happens because of the "gold rush" of solar and the high production rate of too few qualified people doing too many solar jobs.

But @zanydroid is onto my line of thinking. If you can slap a 200A "main breaker" into the main subpanel, all problems are magically cured, and what's more, you get a free hand to put up to 200A of solar breakers in the main panel.

I have no earthly idea why they insisted on a solar fused disconnect instead of a CH breaker. Sales markup maybe? Conformance with their internal "cookie cutter" standards? Part of the solar salesman's job is to make the installations as "cookie cutter" repeatable as possible as it lowers the skill level needed by the staff they can barely find.



The taps are UL Listed, I can see the mark. ILSCO is a good vendor. However that "9.8" on the bolt indicates it is made of metal. What the...???? NEC 110.3(B) requires that the listed equipment must be installed according to its labeling and instructions which might be this. Hmm, don't see a problem but it is silent on the question of whether that bolt is energized. I would measure it with a meter.







That means nothing. The solar business is in "gold rush mode" so getting good staff is super hard. These big companies are subcontrating out to anyone who can fog a mirror.

The MAIN main breaker is 200A. Per NEC 310.15(B)(7) the service wire size must be 83% of that or 166A. 2/0 Copper is adequate for 200A service because of that.
Ok…so the only way to turn off the power to the breaker (in the garage) is at the main breaker outside on the meter.

Here’s the outside main breaker box. It has 200amps and the feeder wires feed through to the garage. If I turn off that 200amp breaker it cuts the power everywhere.

Product Electrical wiring Gas Machine Electronic engineering


Here’s the breaker box in the garage…the feeder wires at the bottom

Electronic device Machine Gas Electrical wiring Composite material

Electricity Circuit breaker Electrical wiring Cable Gas


With that being said, I only have 200 amps at the main breaker outside, right? And nothing at the breaker in the garage?

I see the bus rating and panel board rating in the garage is 225…but no breaker, right?

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Personal computer Netbook Computer Font Material property

So what exactly should I say to the company? That not only are their engineered plans showing the outside breaker incorrectly (it’s showing 225 when it’s 200) but also there’s no breaker in the sun panel (and they’re showing it as 225)?

And what they did…is the install now incorrect?
 
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