Interconnection application help - One-line diagram issue

[skizzlez]

All,
I'm not sure if this is the correct method to ask questions around here, but i'm newer to the solar game, and have been trying to find someone who can review my one-line diagram and discuss the site plan w/ me.

I've submitted my interconnection application here in minnesota with Xcel energy - and they are brutally slow and not helpful in the process. No one monitors their email box, and there is no phone number to call a human. Just a 'chatter' box on the side of your application, which again, is not monitored.

Here is the deal..

On my property, I have 2 meters. One for the main panel on the house, and one for the detached pole building. Each building has its own 200a panel. They are billed as two separate meters, but on the same Xcel account and on the same parcel ID.. good so far! everything should be possible!

My detached building has a large roof facing directly south, which is where I want to place the PV array. This array is large enough to suit my needs (70 REC panels). I've filled out the application and have been rejected due to the following quote:

----------

One-Line:
3.2 - Application case number assigned to the project. Missing. Failure to include case numbers in future applications may lead to rejection.
3.7 - Main service protection between DER and the utility. There must be protection in the form of a breaker or fused AC disconnect between the DER and utility located immediately after the main service meter, before the production meter.
3.7 - Note - Protective device shall be provided immediately after the main service meter. Per requirement 3.7 the protective device must be located immediately after main service meter. This design does not satisfy the requirement. See 3.21.2 when correcting to help avoid additional rejections.

Site Plan:
4.4 - Application OID, SRC, or case number assigned to the project. Missing. Failure to include case numbers in future applications may lead to rejection.
4.7 - Main service entrance, all meter locations, disconnects, transformers, proposed and existing DER systems. Please ensure all changes made to the oneline are made on the site plan.Approver 3 Comment: Approved.Application OID, SRC, or case number assigned to the projectMain service protection between DER and the utilityApplication OID, SRC, or case number assigned to the project
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3.2 and 4.4 are easy fix.

4.7 will be updated once I know how to fix 3.7... (which, there is indeed a protective device/disconnect immediately after the production meter, before the PV system.

Attached is my one-line... maybe someone can explain in more detail what needs to be done? I want to connect on the supply side of the electrical panel -- not on the load side. But I guess if that isn't possible - i can connect post the main panel... Also, if I connect on the supply side, i'm wondering how it will be billed / net metered? Seems like they should be able to spin the production meter backwards, while the two other property meters spin forward... then sum the two -- thats the bill?

Thanks all
Jason


https://flic.kr/p/2pz5WfP

 

[electrofelon]

IMO, you need to investigate the rules for applying DG to two meters. I would just hate it to have it end up not working the way you thought it was going to work. For example here DG can only apply be applied to 1 meter.

 

[Elect117]

3.7 sounds like they want a fused disco upsteam of the solar meter. so just (where wire marking 10 is). Some utilitys require disconnecting means on both sides of the solar meter. It sounds like they want it physically located near the MSP so they can disconnect the solar at the main board. Assuming it isn't already right next to each other. It also sounds like they want that disconnect located between the main meter and the main service panel.

 

[skizzlez]

Great comment - and yes, i've done a bunch of digging on this. Here is the legal detail for MN:

Meter Aggregation​

Minnesota law allows customers to aggregate the consumption of multiple meters and apply the electricity produced by their DG system to those meters in the order they choose; however, the meters must be on contiguous property owned by the same customer. Some utilities also require the meters to be either all Time-of-Day rates or not Time-of-Day rates. (Minn. Stat. 216B.164; Subd. 4a)

 

[skizzlez]

3.7 sounds like they want a fused disco upsteam of the solar meter. so just (where wire marking 10 is). Some utilitys require disconnecting means on both sides of the solar meter. It sounds like they want it physically located near the MSP so they can disconnect the solar at the main board. Assuming it isn't already right next to each other. It also sounds like they want that disconnect located between the main meter and the main service panel.

Yeah, physically the existing meter and the proposed production meter would be 2-3 feet apart. The disconnect I have marked as 8, would be directly next to the production meter.

I guess I don't fully understand why they would need a disconnect on both sides of the production meter, as their main utility meter doesn't have a disconnect on either side -- (not including the main service panel breaker)

 

[ggunn]

I guess I don't fully understand why they would need a disconnect on both sides of the production meter, as their main utility meter doesn't have a disconnect on either side -- (not including the main service panel breaker)

I have seen this in some jurisdictions. It doesn't necessarily make sense electrically, but if they say do it, I do it.

 

[Elect117]

When we did our review of the solar requirements for the Utility I work for, the metering guys required it. This was their train of thought:

If you want to work on the metering section for the solar cold (no power), and didn't want to have an outage on the customer, then you would need a disconnect on both sides of the meter. If you want to work on the house's electric meter cold, you need an outage and will disconnect at their transformer, or secondary, or wherever.

They wanted a way to work the solar meter section cold without an outage. I personally argued that if the section doesn't have CTs (less than 400A) then that is foolish, plus we have work procedures for working those sections hot.

 

[skizzlez]

When we did our review of the solar requirements for the Utility I work for, the metering guys required it. This was their train of thought:

If you want to work on the metering section for the solar cold (no power), and didn't want to have an outage on the customer, then you would need a disconnect on both sides of the meter. If you want to work on the house's electric meter cold, you need an outage and will disconnect at their transformer, or secondary, or wherever.

They wanted a way to work the solar meter section cold without an outage. I personally argued that if the section doesn't have CTs (less than 400A) then that is foolish, plus we have work procedures for working those sections hot.

I understand their logic here, and also your argument. But seems silly to require it on both sides of that meter, but not the other one...

I can make that edit and then re-submit, but would be nice to see if any others have thoughts? For sure not discounting your opinion!! just want to have a few others agree/disagree/tell me i'm clueless. Whatever works.

And thanks again!

 

[ggunn]

I understand their logic here, and also your argument. But seems silly to require it on both sides of that meter, but not the other one...

I can make that edit and then re-submit, but would be nice to see if any others have thoughts? For sure not discounting your opinion!! just want to have a few others agree/disagree/tell me i'm clueless. Whatever works.

And thanks again!

If the AHJ is requiring it then you really have no choice but to comply. I think that going up against the AHJ to try to get them to change their policy is not likely go your way.

 

[skizzlez]

If the AHJ is requiring it then you really have no choice but to comply. I think that going up against the AHJ to try to get them to change their policy is not likely go your way.

Yeah, not trying to go against them. But simply don't understand exactly what they want - I just don't read that line as clearly as they expect me to.

I'll drop a disconnect on the other side of the meter, and resubmit. See what they say!

And again, thanks for the help - i'll report back when I get rejected again lol.

 

[ggunn]

Yeah, not trying to go against them. But simply don't understand exactly what they want - I just don't read that line as clearly as they expect me to.

I feel your pain. There is an AHJ I have dealt with a lot that requires a disco on both sides of the PV meter - sometimes - and the rules for when they do and when they don't are not that easy to interpret. If this, or if not this, and if this other thing... There are even instances where they require three discos. I do the best I can and then depend on their plan review to tell me when I get it wrong.

 

[jaggedben]

@skizzlez It looks to me like you just need to swap the positions of your generation meter and your fused disconnect for your supply side connection. They want the meter on the load side of the disconnect so it can be de-energized.

 

[skizzlez]

@ggunn + @jaggedben - yeah, if you look down stream towards the array, I have disconnects at each combiner box too. so theoretically, the one directly after the meter is unnecessary. MAYBE they would be OK with just flipping it as jaggedben suggests, but I really don't want to drag this out another month. If the guy would just respond to the emails or give me his office phone number, we could figure it out like reasonable humans.

But what do I know =)

 

[jaggedben]

I think you are overthinking it. "Protective device shall be provided immediately after the main service meter." Your design "does not satisfy the requirement" because the generation meter is immediately after the main service meter, not the protective device. Switch them and your design meets their requirement. Despite all their boiler plate this is the only thing they objected to. Fix it and I'll bet a sandwich you're good to go.

I deal with these sorts of e-mails a lot in my job.

 

[skizzlez]

I think you are overthinking it. "Protective device shall be provided immediately after the main service meter." Your design "does not satisfy the requirement" because the generation meter is immediately after the main service meter, not the protective device. Switch them and your design meets their requirement. Despite all their boiler plate this is the only thing they objected to. Fix it and I'll bet a sandwich you're good to go.

I deal with these sorts of e-mails a lot in my job.

I'll give it a go.

The thing that threw me was the comment about reading the following..."This design does not satisfy the requirement. See 3.21.2 when correcting to help avoid additional rejections."

AC Disconnect
3.21 A visible‐open type, lockable, and readily accessible AC disconnect for purposes of isolating the DER from the utility source labeled “Utility AC Disconnect,” “Photovoltaic Utility AC Disconnect,” or similar shall be shown
3.21.1 Other AC Disconnects shall not be labeled or identified as a “Utility” AC Disconnect, if applicable Note: The “Utility AC Disconnect” must be accessible to Xcel Energy’s personnel 24/7 without escort, hindrance, or delay. Rack‐out/draw‐out breakers5 do not qualify as a “Utility” AC Disconnect.
3.21.2 For installations that require a Production Meter, the Utility AC Disconnect shall be located between the DER and production meter
3.21.3 For installations not requiring a Production Meter, the Utility AC Disconnect shall be located between the DER and main service

Again, appreciate the feedback, going to resub now.
=)

 

[ggunn]

Again, appreciate the feedback, going to resub now.
=)

Best of luck to ya'!

@ggunn + @jaggedben - yeah, if you look down stream towards the array, I have disconnects at each combiner box too. so theoretically, the one directly after the meter is unnecessary. MAYBE they would be OK with just flipping it as jaggedben suggests, but I really don't want to drag this out another month. If the guy would just respond to the emails or give me his office phone number, we could figure it out like reasonable humans.

But what do I know =)

With the AHJ to which I was referring, the physical location of the components is a factor. If they require a disco adjacent to and on the line (PV system side) of the PV meter, unless the combiner is grouped with the rest of the gear, a disco at the combiner does not comply.

 

[skizzlez]

Best of luck to ya'!

With the AHJ to which I was referring, the physical location of the components is a factor. If they require a disco adjacent to and on the line (PV system side) of the PV meter, unless the combiner is grouped with the rest of the gear, a disco at the combiner does not comply.

Totally valid argument.

seems reasonable that they want to be able to isolate your system from the grid. But to isolate the meter specifically, seems a bit excessive. At the end of the day, its an extra disconnect and some connectors. I have a feeling that the billing of aggregate meters is where they are going to make this a no-go.

 

[BackCountry]

Yeah, physically the existing meter and the proposed production meter would be 2-3 feet apart. The disconnect I have marked as 8, would be directly next to the production meter.

I guess I don't fully understand why they would need a disconnect on both sides of the production meter, as their main utility meter doesn't have a disconnect on either side -- (not including the main service panel breaker)

If I’m reading your SLD right, you’re doing a line side tap off of your MSP. They’re going to want a fused disconnect ahead of the meter. The disconnect after the meter can just be a non fused disconnect since the OCPD has already been handled. They want to be able to service the meter disconnected.

 

[jaggedben]

If I’m reading your SLD right, you’re doing a line side tap off of your MSP. They’re going to want a fused disconnect ahead of the meter. The disconnect after the meter can just be a non fused disconnect since the OCPD has already been handled. They want to be able to service the meter disconnected.

I don't see why a disconnect on both sides of the meter is necessary. It would be really stupid of the utility to require one on the load (solar) side of the meter if there is already one on the line (utility) side, but that's not to say utilities are never that stupid. The NEC only requires one fused disconnect. I guess if one is unsure how many total disconnects the utility requires, and if the goal is to avoid another round of back and forth on the interconnection app no matter the cost or ugliness of the installation, then resubmitting with two disconnects might be the choice.

 

[ggunn]

I don't see why a disconnect on both sides of the meter is necessary. It would be really stupid of the utility to require one on the load (solar) side of the meter if there is already one on the line (utility) side, but that's not to say utilities are never that stupid. The NEC only requires one fused disconnect. I guess if one is unsure how many total disconnects the utility requires, and if the goal is to avoid another round of back and forth on the interconnection app no matter the cost or ugliness of the installation, then resubmitting with two disconnects might be the choice.

But stupid or not, some AHJs (CPS Energy in San Antonio, for example) do indeed require it in at least some situations; I have experienced it myself.