# Prep Garage Sub Panel For Future Grid-tie Solar



## backstay (Feb 3, 2011)

If you feed the garage from a breaker, you could put a 200 amp panel in. 150 amp cost more, so I wouldn't bother. Then your buss bar and wires would fit with with no problem.


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## Dennis Alwon (May 9, 2009)

GB are you doing this install?


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## Bootss (Dec 30, 2011)

Do you need to upgrade the panels on pretty much any solar installation? Or does it all depend on system load calculations?


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## backstay (Feb 3, 2011)

Think about the panel this way. If you have a 100 amp main breaker and your load was at 100 amps, it wouldn't trip. Now add 30 amps from a solar array and the buss is now at 130 amps, but the main still will not trip. So load calcs are important.


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## Bootss (Dec 30, 2011)

backstay said:


> Think about the panel this way. If you have a 100 amp main breaker and your load was at 100 amps, it wouldn't trip. Now add 30 amps from a solar array and the buss is now at 130 amps, but the main still will not trip. So load calcs are important.


I'm missing something here. What is the solar system go directly into the box lugs or something? I'll have to go to the slow learner row
:laughing::blink::laughing:


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## backstay (Feb 3, 2011)

Lep said:


> I'm missing something here. What is the solar system go directly into the box lugs or something? I'll have to go to the slow learner row
> :laughing::blink::laughing:


Some pocos allow you to back feed from the service(or subs). Grid tie inverters won't produce without utility power, so you can put the solar feed right in the panel or a sub panel.


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## gbowen1 (Sep 27, 2015)

Dennis - The boss's install when we get around to it, but its for a friend of mine so I am trying to get my head around it before hand.

Update - 182 ft. to detached garage - 2/0 2/0 #1 (net) #4 (grnd) USE-2/RHH/RHW-2 AL wire (40 amp continuous, 60 amp intermediate, 2.5% voltage drop. 2" conduit (tons of ground squirrels.....which probably is what killed the previous a shallow (15" depth) direct bury feed(s).

Backstay - Good suggestion. Will go with 200 amp load center for the garage (125 would have been ok) with 100 amp breaker on feed.

One oddity, we always put the solar inverter breaker(s) on the bottom end of the bus bar (future in this case). That is no problem for the garage sub. However, the garage feed breaker at the 200 amp meter/main which carries max 40 amp backfeed from the solar can also go in the bottom slot of the main's buss, but, that main buss is extended via the bar lugs at the bottom to a house subpanel on the opposite (indoor) side of the wall. So, I guess technically the garage backfeed, will be in the middle of the extended buss; anyone think we will get grief with that?


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## backstay (Feb 3, 2011)

gbowen1 said:


> Dennis - The boss's install when we get around to it, but its for a friend of mine so I am trying to get my head around it before hand.
> 
> Update - 182 ft. to detached garage - 2/0 2/0 #1 (net) #4 (grnd) USE-2/RHH/RHW-2 AL wire (40 amp continuous, 60 amp intermediate, 2.5% voltage drop. 2" conduit (tons of ground squirrels.....which probably is what killed the previous a shallow (15" depth) direct bury feed(s).
> 
> ...


I don't see a problem with that. Labeling is important.


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## Bootss (Dec 30, 2011)

backstay said:


> Some pocos allow you to back feed from the service(or subs). Grid tie inverters won't produce without utility power, so you can put the solar feed right in the panel or a sub panel.


Do you have any pictures of Solar set ups in the panel or main panel you can post? Or some sort of diagram?


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## Bootss (Dec 30, 2011)

Lep said:


> Do you have any pictures of Solar set ups in the panel or main panel you can post? Or some sort of diagram?


BACKSTAY

I know its a lot to ask but it would be cool if you could put a series of pictures up from start to finish of a Solar install. With maybe some explanation of what you did an how you laid it out, etc.
:thumbup::thumbup:


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## backstay (Feb 3, 2011)

Lep said:


> Do you have any pictures of Solar set ups in the panel or main panel you can post? Or some sort of diagram?


Here is two inverters back feeding into a main lug panel. From here the circuit goes to a 200 amp MB panel. I don't see any pictures on my phone of that. I will look and see on the laptop. See the GEC out of the bottom? You need to install a ground rod(2)at the array. Each inverter outputs 25 amps. I then ran #2 AL from this to the service panel. I'm not sure what size breaker I landed on. Most of my solar installs are off grid.


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## Bootss (Dec 30, 2011)

I think I'll have to read through that Mike Holt book you recommended what's it called again? Where are these off grid systems going? Cabins in the forest or something?

How are you setting up your batteries? You have any pics of your battery setups, controler, etc.?


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## backstay (Feb 3, 2011)

Lep said:


> I think I'll have to read through that Mike Holt book you recommended what's it called again? Where are these off grid systems going? Cabins in the forest or something?
> 
> How are you setting up your batteries? You have any pics of your battery setups, controler, etc.?


Understanding NEC Requirements for Solar Photovoltaic Systems

Cabins, homes, in the woods and on islands



picture is the combiner that takes the two strings(series wired) and sends DC to the charge controller.


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## backstay (Feb 3, 2011)

picture, batteries are 6 volt, four wired in series for 24 volts.


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## backstay (Feb 3, 2011)

inverter and charge controller, Outback 3500 watt, FX 60
inside the panels, main DC breaker, charge control breakers and AC output breakers.


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## backstay (Feb 3, 2011)

inverter and charge controller, Outback 3500 watt, FX 60


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## backstay (Feb 3, 2011)

Charge controller


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## Bootss (Dec 30, 2011)

How and where did you get your training for the stuff??


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## Bootss (Dec 30, 2011)

backstay said:


> picture, batteries are 6 volt, four wired in series for 24 volts.


Who does the maintenance on the batteries ?

Wonder if you can pick up that Mike Holt book used somewhere?


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## backstay (Feb 3, 2011)

Lep said:


> Who does the maintenance on the batteries ?
> 
> Wonder if you can pick up that Mike Holt book used somewhere?


The owners will check and clean the batteries. I will do a twice a year service call for $$$$. At that time I will check connections, water levels and state batteries. 



Lep said:


> How and where did you get your training for the stuff??


I have lived with an off grid solar system for over 20 years. Plus I've done some workshops, manufacture training...ect. It's just wires!


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## Bootss (Dec 30, 2011)

Here's some pics of some crap they did here around town.
:laughing::thumbup:


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## backstay (Feb 3, 2011)

Lep said:


> Here's some pics of some crap they did here around town.
> :laughing::thumbup:


Are those parking lot covers?


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## Bootss (Dec 30, 2011)

backstay said:


> Are those parking lot covers?


Yes, I guess they're feeding some buildings nearby or both. Local parks. What do you think of my pics?
:laughing::thumbup:

I don't know how to make them straight
:thumbup::laughing:


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## backstay (Feb 3, 2011)

Lep said:


> Yes, I guess they're feeding some buildings nearby or both. Local parks. What do you think of my pics?
> :laughing::thumbup:
> 
> I don't know how to make them straight
> :thumbup::laughing:


Photography isn't my strong suit.


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## Bootss (Dec 30, 2011)

backstay said:


> Photography isn't my strong suit.


I assume one of those is the inverter?


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## Bootss (Dec 30, 2011)

backstay said:


> picture, batteries are 6 volt, four wired in series for 24 volts.


Do you install solar /generator supported systems?


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## backstay (Feb 3, 2011)

Most of the inverters have a battery charger built in. So they will have a generator input on them. You just install a power inlet or hard wire a generator to them. Some also have generator starting wiring built in. When the batteries get to a programable level the generator is started.


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## IEC (Sep 20, 2015)

Lep said:


> Who does the maintenance on the batteries ?
> 
> Wonder if you can pick up that Mike Holt book used somewhere?


http://www.amazon.com/gp/offer-listing/1932685774/ref=dp_olp_all_mbc?ie=UTF8&condition=all

The new paperback is half the price of the used textbook.


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## Bootss (Dec 30, 2011)

Well it looks like I have a lot to learn concerning solar. And I'm not getting any younger but I read a few more books.


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