# Solar Meter Socket Wiring



## Hal260 (May 17, 2012)

My question is, is there really a right or wrong way to wire an AC solar meter socket? I've seen where they say the top wires should be from the solar array (inverter actually) and the bottom wires are supposed to be connected to the load side of the main service panel (through the AC disconnect typically). This is opposite of the way the service entrance meter socket is wired. However, if AC current alternates back and forth (unlike DC which flows in only one direction) then isn't the top / bottom wiring scheme irrelevant (as long as it is wired in series as it should be)? In other words, if I wired a solar meter socket the same way the service entrance meter socket is wired would it work properly or not?


----------



## Black Dog (Oct 16, 2011)

Hal260 said:


> My question is, is there really a right or wrong way to wire an AC solar meter socket? I've seen where they say the top wires should be from the solar array (inverter actually) and the bottom wires are supposed to be connected to the load side of the main service panel (through the AC disconnect typically). This is opposite of the way the service entrance meter socket is wired. However, if AC current alternates back and forth (unlike DC which flows in only one direction) then isn't the top / bottom wiring scheme irrelevant (as long as it is wired in series as it should be)? In other words, if I wired a solar meter socket the same way the service entrance meter socket is wired would it work properly or not?


The solar meter scocket should be marked line load.


----------



## Hal260 (May 17, 2012)

Thanks, but your reply really does not answer my question. As I indicated, the same meter is wired one way at the service entrance (utility / line at the top) and the opposite way when installed as a solar meter (utility-side at the bottom). This is not a net metering meter (bi-directional) it is merely a power production meter (uni-directional) power comes out of the inverter toward the main service panel and the inverter does not consume any (utility) AC power. I think "line" and "Load" is irrevelant if current is alternating; isn't the meter just measuring current through it? Said another way, if I wired it backwards would it work just fine?


----------



## Maple_Syrup25 (Nov 20, 2012)

Here in ontario we just use a regular meter base. The poco uses a bi directional meter. Line load is wired the same as a consumption service


----------



## Hal260 (May 17, 2012)

Molson, Moosehead, Carlsberg ... all good beers, but my question is more of a theoretical one and remains unanswered. Thanks for the comment anyway.


----------



## cabletie (Feb 12, 2011)

My inverter is tied into my panel through a back fed 30A breaker and also through a meter. The inverter is on the top lugs (line), the breaker is on the bottom lugs (load side). It is a four jaw meter and the neutral is wired through without going to ground. 

If you wire it the other way the meter will run backwards. As you are producing electricity you don't want your solar meter tuning backwards. The solar meter here is used for your SREC credits.


----------



## Hal260 (May 17, 2012)

Thanks, you did address the issue directly and I appreciate that; however, I am skeptical about the meter "running backwards" assertion. Afterall, the meter measures current flow right? And, AC current flow alternates (bi-directional). So, how are you going to run backwards in such a scenario? I suspect there is no "backwards." This suspicion of mine is supported by the fact that the same meter if installed at the service entrance is wired one way and is wired the opposite way when wired at the inverter. True, in both cases the "source" is tied into the same place (top), but I suspect that is more "convention" (it answers which wire goes where even if it does not matter) than requirement.


----------



## cabletie (Feb 12, 2011)

It is a watt hour meter, not a current meter. If you put your power company meter upside down you can go to jail.


----------



## Hal260 (May 17, 2012)

You got my attention with the jail comment. Want to avoid that! The watt-hour meter comment starts to make more sense for me, but then I say to myself: "Well, voltage is a constant in this scenario, so the only other variable is current flow (P = I x E)." Which brings me back to it being a current meter. Yes / No? Am I missing something here?


----------



## cabletie (Feb 12, 2011)

It has been a while since I had to study the inner workings of a watt hour meter, but they only spin on one direction. It Works off of a magnetic field. All the current does pass through the meter. When you get into larger services the current won't go through the meter. It will go through "current transformers" called "CT's".


----------



## Hal260 (May 17, 2012)

I am doing some other "outside" internet research, and it appears from what I've found so far that the older "analog" meters that spin and ran off a magnetic field would run backwards, but it appears that the newer "digital" (smart) meters do not run backwards. If that is true, then, wouldn't it be possible to wire it backwards and have the solar power production meter run just fine? I am dealing with a digital meter.


----------



## btharmy (Jan 17, 2009)

Power in the top and out the bottom. Where or what the source is does not matter. Whether it is solar power from an inverter or utility power, it doesn't care. Treat it like a disconnect. Line in the top and load out the bottom.


----------



## Hal260 (May 17, 2012)

Ok, I understand how it should be wired. That is not the question. What I want to know is, if I have a digital meter installed and the meter socket was wired opposite (load-side) top and (line-side) bottom will it operate just fine as is or does it need to be rewired?


----------



## cabletie (Feb 12, 2011)

It more than likely needs to be re-wired. I don't know what digital meter you have, or even how many diferent types there are. 

My digital utility meter is bi-directional. It has two readings. One for power in and one for power out. The readings (numbers) always increase. The power company says that a normal meter tuning backwards may not be as accurate as when it is running forward. That is why they have the digital meters that always count up. 

If I take the digital meter and reverse it, both numbers will still go up. But the power consumed will look like power produced, and vice versa.


----------



## Hal260 (May 17, 2012)

The meter I am dealing with is not a net metering (bi-directional) meter, and as such, I believe it will, as you indicate, "count up" whether it is wired correctly or wired opposite. With that said, I will rewire the meter socket appropriately.


----------



## JasonH (Dec 30, 2020)

If your utility requires a sperate meter for the solar then they likely are using meters that only read one direction and the generation meter gets wired in reverse to the consumption meter. Your utility company should provide you a SLD to show how it should be wired for the meters they are using.


----------



## HertzHound (Jan 22, 2019)

Whatever happened to that Cabletie dude? He was very modest. He was by far the most handsome electrician, but he never bragged about it.


----------

