Load calculations/main OCPD/Solar 120%/subpanel

[ESolar]

One thing that is worth knowing is that Eaton Cutler-Hammer 150A - 225A panels all have the same 225A busbars.

What aboutthe Eaton BR2040? I have never been able to track down the busbar rating on that.

 

[ESolar]

One thing that is worth knowing is that Eaton Cutler-Hammer 150A - 225A panels all have the same 225A busbars.

I have been trying figure out if the eaton MBE 200A panels from the 1990s have 225A busbars. Even Eaton can't tell me.

 

[ESolar]

One thing that is worth knowing is that Eaton Cutler-Hammer 150A - 225A panels all have the same 225A busbars.

You might want to check that. I just called Eaton. They said that their busbars in the CH line panels are mostly paired withthe breaker amperage. They said that only their PV line has 225A busbars on a 200A panel.

 

[jaggedben]

BR is not CH, they are totally different busbars.

Given that Eaton has separate models of BR panels that are 225A rated instead of 200A, even if they use the same busbar I doubt they'd tell you because then they'd not be able to charge you the extra for the 225A.

 

[ggunn]

You might want to check that. I just called Eaton. They said that their busbars in the CH line panels are mostly paired withthe breaker amperage. They said that only their PV line has 225A busbars on a 200A panel.

We have it in writing and it's not specific to the PV line.

 

[ESolar]

We have it in writing and it's not specific to the PV line.

I wish that they were more helpful. Maybe one can compare crosssections to get to the truth of the matter.

 

[pv_n00b]

We have it in writing and it's not specific to the PV line.

I know people don't like to hear it but if we have a UL Listed panel and it's listed and labeled for 200A even if it has a 225A bus, or a 500A, or a 750A in it, it's still a 200A panel and has to be used like one. A letter from the manufacturer does not override the UL Listing requirements of the NEC. If the company wants people to be able to use the panel as a 225A panel then they can get it listed as a 225A panel. That being said some AHJs might just choose not to enforce this provision of the NEC and allow an alternative design using the 225A bus. But that's not guaranteed.

 

[ggunn]

I know people don't like to hear it but if we have a UL Listed panel and it's listed and labeled for 200A even if it has a 225A bus, or a 500A, or a 750A in it, it's still a 200A panel and has to be used like one. A letter from the manufacturer does not override the UL Listing requirements of the NEC. If the company wants people to be able to use the panel as a 225A panel then they can get it listed as a 225A panel. That being said some AHJs might just choose not to enforce this provision of the NEC and allow an alternative design using the 225A bus. But that's not guaranteed.

The NEC specifically addresses the ampacity of the busbar, so that is what we go by. More recent 200A CH panels show a 225A busbar rating on the inside sticker, but even with the older ones we have never been challenged by any AHJ on this, and some of them are real sticklers.

 

[pv_n00b]

The NEC specifically addresses the ampacity of the busbar, so that is what we go by. More recent 200A CH panels show a 225A busbar rating on the inside sticker, but even with the older ones we have never been challenged by any AHJ on this, and some of them are real sticklers.

The NEC specifically addresses the requirement to adhere to the listing, 110.3. Not being challenged by an AHJ does not equal NEC compliance. The old argument that goes, if the AHJ does not tell me I can't do it then it's approved, is often used and never valid. And like I said, people don't like to hear this. It's not something I would do, but by all means, if it works for you have at it. My objection is simply that it is not compliant with the NEC.

 

[ggunn]

The NEC specifically addresses the requirement to adhere to the listing, 110.3. Not being challenged by an AHJ does not equal NEC compliance. The old argument that goes, if the AHJ does not tell me I can't do it then it's approved, is often used and never valid. And like I said, people don't like to hear this. It's not something I would do, but by all means, if it works for you have at it. My objection is simply that it is not compliant with the NEC.

Well, then, we disagree. 'Sno biggie.

 

[jaggedben]

The NEC specifically addresses the requirement to adhere to the listing, 110.3. Not being challenged by an AHJ does not equal NEC compliance. The old argument that goes, if the AHJ does not tell me I can't do it then it's approved, is often used and never valid. And like I said, people don't like to hear this. It's not something I would do, but by all means, if it works for you have at it. My objection is simply that it is not compliant with the NEC.

If the panel label fails to clearly differentiate a busbar rating from and overall device rating, and additional documentation from the manufacturer clears it up, I don't see the problem.

 

[electrofelon]

The last time I had a residential project with over 100A of solar inverter output I used a 400A commercial panelboard, with commercial panels you can order all kinds of handy options, I got a 400A frame breaker with a 200A trip unit, so the service main was still 200A. Sure commercial panels cost allot more but they sure simplify things in the end, like having the proper size lugs for all your grounding wires etc..

Just out of curiosity, what is the purpose of the 400 AF 200AT breaker?

 

[tortuga]

Just out of curiosity, what is the purpose of the 400 AF 200AT breaker?

That was the main breaker, since its a 400A panel I think it came with a 400A breaker frame, or that whas what they gave me. It tied into an existing 200A meter so needed the 200A trip unit.

 

[tortuga]

The one line was like:
Utility <----->200A meter <------>3/0 CU<---->200A OCPD <---- 400A buss ---> 150A breaker (bottom frame spot) <----- 1/0 CU ---- combiner loadcenter <----- PV inverters (100A)
Or something like that.