Production meter connections.

[Dang old king]

I have a production meter, connected after the utility interactive inverter and before the back fed breaker in the load center.( working from inverter back to utility)
There is a stamp in the metal housing of the production meter that says "Line" on the top and Load on the bottom terminals.
My question is.
Where do the #12 AWG THHN Cu conductors that carry the 15A from the solor inverter terminate?
The meter is "Digital Bipolar" nondirectional.
thanks in advance,

 

[jaggedben]

The solar side needs to be connected to the 'Line' so that the meter counts up when the solar is producing. If the meter is truly 'non-directional' then it may not matter, but you can't go wrong doing it that way.

 

[ggunn]

The solar side needs to be connected to the 'Line' so that the meter counts up when the solar is producing. If the meter is truly 'non-directional' then it may not matter, but you can't go wrong doing it that way.

That's not to be confused with the orientation of an AC disconnect, if one is present. For an AC disco, the inverter goes on the load side of the switch.

 

[BillK-AZ]

The usual utility KWH meter is a Form 2S, 4-jaw meter. The line/load markings on the meter base are for the usual connection to the utility to measure energy from the utility.

As a second meter used to measure PV production, you have to ignore the line/load markings and connect the inverter output to the top terminals of the meter to measure PV output. Connected this way the meter will read positive (increasing) for PV energy.

 

[Dang old king]

As a second meter used to measure PV production, you have to ignore the line/load markings and connect the inverter output to the top terminals of the meter to measure PV output. Connected this way the meter will read positive (increasing) for PV energy.

I'm not trying to be difficult but,
110.3(b) kinda stops one from ignoring this requirement. As stated in the code and as a standard practice the Line side is considered Utility. A bi directional meter(Not Bi polar) will accomplish the same thing. The problem with the utility is it is "Not Cost Effective"
The production metering is for the utility anyway. We don't have jursidiction(90.2(B)(5)b&c) in the meter other than grounding & bonding, wire size termination limitations.

I have a secondary question that is not code but more of a point of concern.
Why would the utility need a production meter on the metered side of a service? How can they consider PV power theirs prior to it's entrance on to the Grid?
Hum?
As a safety concern for the technician that works on the inverter/array wring:If the power is secured at the inverter not the panel, the back feed thru the meter (which doesnt have to be identified because it is not a switch) could create havoc for the tech. If he has to do any work in the meter housing IE.. tightening of terminals, checking grounding continuity etc... Most if not all electricians are taught to check the top(LINE) side for power. Just me thinking out loud. Any way..
Thanks for your answers and input.
DOK

 

[BillK-AZ]

....
I have a secondary question that is not code but more of a point of concern.
Why would the utility need a production meter on the metered side of a service? How can they consider PV power theirs prior to it's entrance on to the Grid?
....
DOK

The second meter is generally required by utilities or others when a rebate is involved and there are Renewable Energy Credits (REC). For RECs the meter is to assure that the system produces the energy that was assumed. Some rebates are production based and require the second meter.

 

[ggunn]

The second meter is generally required by utilities or others when a rebate is involved and there are Renewable Energy Credits (REC). For RECs the meter is to assure that the system produces the energy that was assumed. Some rebates are production based and require the second meter.

Just to add... In many rebate/PBI/FIT situations, the utility retains possession of the RECs your system generates; that 's why they need to separately meter the production of your system.

 

[Zee]

1. Why not ask the utility? They require it and should have a way to deal with it.
2. The following does not address Code but does deal with concern over a tech's later confusion. I write (sharpie) on the back, behind terminals (where the LINE and LOAD Stamps are, i assume) "SOLAR" and "UTILITY" to clarify what is on top what is on bottom. (marking inside enclosure is important, as outside, "permanent" marker is legible for about 6 months....)
3. I have always wired separate solar generation meters as suggested by others here. Solar on LINE side. I had to, to get meter to count up.
4. Can you get a meter enclosure w/o line and load indications?

 

[Zee]

"

The solar side needs to be connected to the 'Line' so that the meter counts up when the solar is producing. If the meter is truly 'non-directional' then it may not matter, but you can't go wrong doing it that way.

Interesting point JBen.
What does "non directional" mean? It is new to me. That no matter which direction power is fed from the meter always counts up?
It is all Bi-directional meters (net-metering) here. ("Bi directional", on the other hand, AFAIK, means up when usage, down when solar)

 

[jaggedben]

"
Interesting point JBen.
What does "non directional" mean? It is new to me. That no matter which direction power is fed from the meter always counts up?

I've heard that some utilities' smart meters do exactly this, to prevent old school cheating by customers i.e. pulling the meter and sticking it in upside down for half the month. My impression is that digital meters can be programmed to count lots of ways, so when I see "nondirectional" I assume something similar to this. I have not (to my knowledge) encountered any meters that actually behave this way. It's just what I have heard on forums.

 

[tallgirl]

I've heard that some utilities' smart meters do exactly this, to prevent old school cheating by customers i.e. pulling the meter and sticking it in upside down for half the month. My impression is that digital meters can be programmed to count lots of ways, so when I see "nondirectional" I assume something similar to this. I have not (to my knowledge) encountered any meters that actually behave this way. It's just what I have heard on forums.

I've run across a lot of people who were screwed this way between the time their systems were powered on and the PoCo reprogrammed the meter to be bidirectional.

What fries my butt is meters like the Landis+Gyr meters Oncor installs that don't have a "net" register, only "delivered" and "received". Adding to my butt-fryage is that Oncor doesn't seem to report the daily "received" values, only "delivered", so it's impossible to look up daily production on the interwebs without getting up and walking outside.

 

[GoldDigger]

What fries my butt is meters like the Landis+Gyr meters Oncor installs that don't have a "net" register, only "delivered" and "received". Adding to my butt-fryage is that Oncor doesn't seem to report the daily "received" values, only "delivered", so it's impossible to look up daily production on the interwebs without getting up and walking outside.

So this is installed as a production-only meter, and the delivered will always be zero, but they do not give you online access to the received value?
Sounds like they should wire it the other way.
Or (really far out idea) fix their software?

 

[tallgirl]

So this is installed as a production-only meter, and the delivered will always be zero, but they do not give you online access to the received value?
Sounds like they should wire it the other way.
Or (really far out idea) fix their software?

No, it's the revenue meter. It has two registers, "delivered" and "received". Oncor only reports the "delivered" value to the Texas Smart Meter on-line website, and my monthly statements only show the "delivered" values -- the "received" energy shows up as a kWh count that's a "Grid Contribution Credit".

I have a Continental Control Systems WattNode between the main service panel and the inverter inputs, so I can measure net energy at that point, but I don't have a load-side WattNode to measure what's actually being consumed. I keep meaning to add one, but I also keep being busy working.

There's no production meter at all -- I paid for the entire system out of my pocket, no rebates, no SREC credits, no nothing. Even the Federal Tax Credit was pretty weak that year.

 

[Zee]

I have not (to my knowledge) encountered any meters that actually behave this way.

Once, just once, a memorable once, a meter counted the solar production and added it to the client's bill!
We finished install and happily turned it on, before the utility replaced meter...................
Next month their bill went up $3,000.
:rant:
It was a 36 KW system.....
They weren't happy.
The meter did in fact count the solar as extra usage!
Ever since, every meter I've seen spins backward. BUt i check.

 

[GoldDigger]

Ever since, every meter I've seen spins backward. BUt i check.

Even the old spinning disk meters could still attach the disk to the gear-driven unit dials in such a way that whichever way the disk spun the dials would still count up. Quite a shock at the end of the month.

 

[shortcircuit2]

No, it's the revenue meter. It has two registers, "delivered" and "received". Oncor only reports the "delivered" value to the Texas Smart Meter on-line website, and my monthly statements only show the "delivered" values -- the "received" energy shows up as a kWh count that's a "Grid Contribution Credit".

What is the dirfference between the "delivered" and "received" values?

Why would there be a difference between the 2 values?

 

[jaggedben]

What is the dirfference between the "delivered" and "received" values?

Why would there be a difference between the 2 values?

Both phrases refer to the utility's point of view. 'Delivered' means delivered by the utility and 'received' means received by the utility. From the customer's point of view they are imports and exports, respectively.

 

[GoldDigger]

Both phrases refer to the utility's point of view. 'Delivered' means delivered by the utility and 'received' means received by the utility. From the customer's point of view they are imports and exports, respectively.

Makes it easier for the math challenged (as well as more useful) than recording only a single net figure which could decrease or even go negative in some seasons.
Also relates to the fact that internally it is really keeping track of T.O.D and a bunch of other things too.

 

[GReed]

Hi everyone,
I have a questions regarding the placement of the production meter on my solar array.
The panels, Envoy and disconnect are on my barn and the service meter is on the house about 125 feet away. My utility wants a production meter installed and no clear advise on where they would like it. Would it be best to be next to the service meter or can it be on the barn with the panels and Envoy.
The next question is I have a 4 wire, L1,L2, ground and neutral. Can I use the L1, L2 and neutral only and pass the ground through the box?
Thanks Gary

 

[jaggedben]

First, if this is DIY we are not supposed to help you. Get an electrician on this if you don't have one.

Second, it would be better to start a new thread.

With that said, I'll offer a response to your questions.

The production meter needs to be on the solar output only. Only the utility can tell you if it's okay to have the Envoy on it too. And only the utility can tell you where it needs to be for them to read it. Finally, on a split phase system like you have, L1 and L2 land on the meter socket terminals and the neutral and ground pass through. Do not use the bonded lug on the socket for the neutral if the socket is on the load side of the service disconnect.