# Solar ready panel.



## ICE (Jun 1, 2015)

Residential

The mains are rated 125 amp max.  The bus is rated 225 amps max.  The meter socket is rated 125 amps max (100 amps continuous).

What is the minimum size service entrance conductors?

What is the maximum size solar contribution?


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## Five9 (Nov 22, 2015)

Would it be 2 awg & 145a?


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## ICE (Nov 22, 2015)

#2 is good for 125 amps on a dwelling service.  The maximum solar contribution is 100 amps because the meter socket is rated 100 amps continuous.


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## Five9 (Nov 22, 2015)

Isn't it based solely on the rating of the bussing?


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## Five9 (Nov 22, 2015)

Why make/endure the cost of a 225a buss if you aren't able to take advantage of it? Why not just make it a 188a rated buss in this case so we can use the 120% rule?


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## ICE (Nov 22, 2015)

I guess that they are being conservative.  There is a rule that a circuit should never be loaded past 80% and 100 amps is 80% of 125 amps.  The meter socket will carry the backfeed and the socket is only good for 100 amps.  For residential purposes this panel is overkill.  99% of the residential projects will not be more than 60 amps.

There is another panel out there that has a breaker slot at the top that is marked for an alternate power source.  It can be up to 60 amps for solar or wind but not a generator.  It might even be a split buss. Yet another panel has a statement that the top breaker can only be used for solar.


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## Five9 (Nov 22, 2015)

In the jurisdictions that fall under San Diego Gas & Electric as the utility. SDG&E will install something called an RMA adapter. This is installed at a cost to the homeowner and rather than upgrading their service the utility will install this device. It bypasses the bussing of the electrical panel and feeds straight into the meter socket doing away with the solar backfed breaker and allowing for a larger system on existing smaller panels.

http://www.sdge.com/environment/renewable-meter-adapter


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## ICE (Nov 22, 2015)

Five9 said:
			
		

> In the jurisdictions that fall under San Diego Gas & Electric as the utility. SDG&E will install something called an RMA adapter. This is installed at a cost to the homeowner and rather than upgrading their service the utility will install this device. It bypasses the bussing of the electrical panel and feeds straight into the meter socket doing away with the solar backfed breaker and allowing for a larger system on existing smaller panels.http://www.sdge.com/environment/renewable-meter-adapter


I have had one in my hands.  It is built well enough.  I'm not so sure about letting it out of the control of a utility company.

Solar City has come up with a line side tap at the service.  Supposedly UL will be there when it is installed (each time) because it is a field modification of the equipment.  I haven't encountered that yet.


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## Dennis (Nov 23, 2015)

So if your buss is rated 225 then you can go 120% more which means 270 amps.  If the breaker at the top is 125 that means my incoming solar overcurrent protective device can be as high as 270-125 = 145amps

I think that is the reason that they went with a larger bus and a smaller main.

This is something that is sometimes done in a 200 amp panel.  A 200 amp buss can have 40 amp load from the solar array (200*.20).  Sometimes the array can handle more so if the load permits the main breaker is dropped to 150 amps which allows the array to supply 90 amps  (240-150).

Remember the overcurrent protective device from the solar panels must be installed at the opposite end of the panel main-- usually the bottom of the panel.


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## steveray (Nov 23, 2015)

ICE said:
			
		

> I have had one in my hands.  It is built well enough.  I'm not so sure about letting it out of the control of a utility company.Solar City has come up with a line side tap at the service.  Supposedly UL will be there when it is installed (each time) because it is a field modification of the equipment.  I haven't encountered that yet.


Line side tap or supply side interconnections are done here all the time....Why would UL need to be present? Granted, they use those junk shark bite type connectors that are destined for failure, but they are listed so we have to approve....


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## steveray (Nov 23, 2015)

Dennis said:
			
		

> So if your buss is rated 225 then you can go 120% more which means 270 amps.  If the breaker at the top is 125 that means my incoming solar overcurrent protective device can be as high as 270-125 = 145ampsI think that is the reason that they went with a larger bus and a smaller main.
> 
> This is something that is sometimes done in a 200 amp panel.  A 200 amp buss can have 40 amp load from the solar array (200*.20).  Sometimes the array can handle more so if the load permits the main breaker is dropped to 150 amps which allows the array to supply 90 amps  (240-150).
> 
> Remember the overcurrent protective device from the solar panels must be installed at the opposite end of the panel main-- usually the bottom of the panel.


Just got a commercial ground mount where they are dropping the existing main from 600 to 500A to stuff in more backfeed...Without any calcs on the existing loads to see if it can go down to 500....


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## north star (Nov 23, 2015)

*& : &*





> "  Why would UL need to be present ?  "


Possibly, because the UL rated panel is being modified \ altered,and they want to ensure that it remains UL rated even after the

modification.



*& : &*


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