Installing a breaker panel between inverter and production meter

[Gregda]

I'm designing a 10kw grid tie solar system for a new house. I plan on putting the solar array next to my workshop and installing the inverter in the shop. When the house was being built, I told the builder what I was planning and they ran a 1/3 cable from my meter by the road to the shop.
My question is in regards to wiring the shop. Will I be able to install a breaker panel to service my shop after the inverter? Would this require the added expense of a hybrid inverter? If I have to run a separate line from my main panel by my meter, the distance is about 100'and if have to bury it 3'.
Thanks for any help.

 

[Bkord]

Draw a pic.

 

[Gregda]

Here's a sketch

 

[Gregda]

I forgot to draw solar array. Here's an updated sketch

 

[DIYrich]

Input to inverter from 1/3 wire.
Load panel on output of inverter.
Your choice if you want a grid inverter (can export) or off-grid (can't export).

Others will have to weigh in on grounding issue (what is considered first service panel).

 

[Gregda]

I'm looking at a fronius inverter (but open to others if they're more compatible to my situation). The input would be from the array and the export would go through the 1/3 wire to my production meter. See attached sketch

 

[Gregda]

Sorry, I'm not good at labeling I guess. Here's that last drawing with labels

 

[Bkord]

Dose the 1/3 cable have 3 #1 wires and a ground?

 

[Gregda]

Yep. Here's a pic

 

[Bkord]

I’m not familiar with a 2 meter system. I would run the shop from the main breaker pannel. Dose the power company have a drawing on how things need to be hooked up. Or from the house.

 

[Jbird2000]

=

 

[Gregda]

Here's what they require. I was hoping to be able to tie in after the inverter to power my shop. That would save having to bury another line

 

[zanydroid]

Grid tie will be fine here and there really doesn't need to be much overthinking put into this if you are net metered with no export limit.

If you need to do self consumption (EG to manage export, to comply with an export limit, or to optimize for time of use), then you need to think about where consumption monitoring CTs are going to go. If you have no batteries then this too is academic because all you can do is YOLO out the power (apart from export limit).

Hybrid powering the house also requires more careful thinking because the ATS for disconnecting grid needs to be placed in the right place.

 

[Gregda]

I have a Fronius 6kw. Feeds from my array on my garage to the garage subpanel and back to the main panel, then off to the mother ship. I am not sure if that is to code. Mothership is aware of the net meter and would have had to see the plans. FYI I have a 125Amp subpanel with just 4 15A breakers and my Inverter on a 50A breaker. inverter and subpanel are 10 feet apart. Used #4 aluminum

 

[zanydroid]

Here's what they require. I was hoping to be able to tie in after the inverter to power my shop. That would save having to bury another line

So this is a question that will be hard to answer esp if solar users are few/far between where you are. Options include:

1. get answer in writing from the POCO
2. get an approved SLD of a neighbor from AHJ and POCO that has config that you want to do, showing that it is possible
3. find a local installer or local forum member to provide (2) or explain why (2) is doable based on the POCO rules book
4. read the POCO rules book yourself or find someone you trust to parse the the lawyer-speak
5. post the rules book and hope someone you trust on the forum can read it and write a legal analysis

For my area I know the answer but it's not applicable to your area.

 

[Gregda]

Thanks for those responses. My POCO seems pretty reasonable. Jbird, any chance you could send a picture or sketch of your setup? I'm still a bit confused as to the correct way to wire. Would I just run the output from the inverter into my shop breaker panel then put in a 50amp breaker to feed my production meter through the existing 1/3 wire?

 

[zanydroid]

(Assuming you get POCO approval. This will work electrically, and a smart production meter will correctly bill. While a dumb production meter will not. It's therefore an administrative/legal question if you have a smart production meter, whether they'll be cool with this. Maybe if they offer you to pay more for a smart meter go for that, it'll be cheaper than trenching)

Shop panel will have
1/3 feeder wire into the top. May require a main breaker at the top (no big deal). Some combination of my designer/POCO/AHJ wanted this.
Inverter backfeed breaker at the bottom. This and the wire are sized to 125% of the AC output of the inverter.

With this, the main breaker and inverter backfeed breaker must respect this math to be code compliant (well, you can choose from a few clauses to qualify, this is the most common).
Main Amps + Backfeed Amps <= 120% * subpanel busbar

The other breakers don't matter under this rule. (there are other code clauses you can choose from, where the other breakers do matter)

If you exceed the 120% rule then there are other solutions possible. Generally involving adding subpanels or upgrading your shop panel.

 

[Gregda]

Thanks for all that. I'll play around with the numbers and see what I come up with

 

[hwy17]

You usually aren't allowed to put loads on the solar side of a dual meter solar.

 

[Bkord]

You usually aren't allowed to put loads on the solar side of a dual meter solar.

That makes sense. If the shop was pulling more then the solar produces. The meter would not turn.