Need help installing an energy meter with two main breakers panels

[nofossil]

I just got my system installed last month. Like most people just getting their system installed, I didn't know that I would need a separate meter to measure import/export. Therefore I didn't write it into the contract. Now I am trying to install one myself. I bought a SolarEdge branded meter with 2 CTs. After going through documentations and YouTube videos, I am not so sure about the correct installation steps. All the documentations and videos that I have seen have only one main breaker panels. My house has two main breaker panels (200A each). Do I need two meters? because each meter can only monitor 2 legs; or do I just monitor the breaker panel which the solar AC side is tapped into? Thanks for any hep in advanced. Let me know more information is needed.

[blueman2]

My brother in Florida had the exact same issue. He had 2x 200A panels inside. He had to go to the incoming meter outside and put the CT clamps there. You do have just 1 incoming meter, right?

[nofossil]

Yes, I have one incoming meter. Does POCO (Dominion Energy) allow homeowner to do that? Or I need a licensed electrician?

[nofossil]

After talking to SolarEdge support, I just want circle back and let people know how this can be done. I know other people have asked this before but no clear solution. In short, you can install CTs in the 2nd panel and insert them into the same input in the meter. Just need to they are for the same phase.

More specifically, in my case, there are a total of 4 service wires coming into the house: let's call it panel 1 with leg A and B, and panel 2 with leg C and D. I would attach a CT to each leg, CT (A), CT (B), CT (C) and CT (D). I would then combine legs from CT (A) and CT (C) and CT (B) and CT (D) and connect them to L1 and L2 on the meter.

What blueman2 suggested would work too. However, I have a feeling that my POCO won't like that idea as they put a lock on the meter enclosure to prevent people from mucking with it.

[bob-n]

You may already know all of this, but please humor me as I go over some basics and then get to your situation.

If you want to measure the power used by your house, you need to measure all of the power, not just the power in one panel and not just the power in one line. Your power company (PoCo) meter does that.

Power comes into your house on two wires, commonly called Line1 and Line2, or L1 and L2. There is also a third wire called Neutral, which is connected to ground/earth. Line1 current is not the same as Line2 current. In the sketch below, I am assuming that there are two feeds coming out of your meter to two different panels. I am not showing neutral or ground.

TwoMeters.jpg
If you put current transformers in panel 2 as shown, you will measure all of the power going into panel 2 and all of the power coming out of panel 2 to the grid, but you won't measure any of the power going into panel 1. Likewise, if you put one CT in panel1 and one CT in panel2, you still won't be seeing all of the power.

To measure all of the power, you either need four current transformers or you need current transformers in the main feed, before it splits to two panels.

It could also be that panel 2 is fed from panel 1 and all of the energy goes through panel 1. In that case, you would only need two current transformers and would put them in panel 1. It all depends on what you have.
SubPanel.jpg

In your town, doing this may not require a licensed electrician. However, getting a licensed, qualified electrician to do the work may be a good idea. If you have any doubts in your abilities to do this correctly and safely, seek professional help.

[nofossil]

bob-n's response captured the issue and solution 100%. My situation is the first case. Instead of putting the CTs on the wires before they split, I am opting to use 4 CTs so that I can put everything inside my breaker panels instead of something owned by POCO. I didn't know that you can combine the CT output from the same phase to get a total current reading. Thanks for all those who chimed in and helped.

This link also further confirm what I need to do: "https: //help.ekmmetering.com/support/solutions/articles/6000131304-can-i-use-multiple-current-transformers-on-the-same-phase-"