Yes it does. 200A SquareD Breaker built in. Sounds like this is the best approach.
Solar Inverter tie to house system - 120% Rule help
- Thread starter huronengr
- Start date
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
If the OP were to decide on this approach he should check with the POCO to see if they will allow it; some will not. That said, I think that the OP has a plan that will work fine, which is to add a two port lug to the load side of the service disconnect.
PWDickerson
Senior Member
- Location
- Clinton, WA
- Occupation
- Solar Contractor
The utilities in our area absolutely will not let us in to their meter equipment to install line-side interconnection lugs, and I can't say I blame them. There are some pretty crappy solar installers out there, and I sure wouldn't want them working in my equipment. I also believe that a load-side interconnection is always preferred unless there is a good reason not to. In this case, the site is just asking for a feeder tap interconnection. We get charged over $500 for a utility disconnect. Avoiding those charges is an added bonus.
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
The reason usually being that the PV system output is too much to fit into a panel when the panel main breaker is the service disconnect. That, or when there is an ATS ahead of the panel where its OCPD is the service disco.
Thats exactly what I don't do. That trips up some utility staff and they get all confused.
What I do is pull a my own permit with a scope of work to a 2nd 60A service disconnect, I treat it like any other service disconnect, its grouped with the other service disconnect or what the OP is calling a 'isolation switch'. The most the utility asks is if there is any additional loads and I say no additional loads, just a reconfiguration. Its often done for a detached garage or mother-in law cottage, utilities are quite used to double lug mater-bases around here anyway.
I would have to go out of my way to get a single lug class 320 meterbase.
Utility pulls the meter for free here, I put in the double lugs and the disco.
I will update the grounding electrode system, usually a larger GEC to a water pipe etc. and get a final inspection on the disconnect.
Then later the solar company comes back and now has a brand new shiny spare service disconnect to use, no weird taps to squeeze in a old panel etc.
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
Yeah, you're not doing a supply side connection in "utility's' equipment" if it's just in a meter socket owned by the customer.
In the OP's particular case I would do the lugs on the load side of the disconnect cause I don't even need to call the utility. But I agree with your point for the general case.
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
- Occupation
- Electrician
Around here, none of the utilities look at residential PV systems. The only utility person that steps foot on the property is the guy who changes the meter out and he just asks where do I put the meter.
I come out of class 320 socket all the time with a second set to feed solar, but I usually call it 230.40 ex #2 or #3 and not a supply side connection. I don't know if they would have an issue if I said "PV tap inside meter socket". It's just about knowing how to state and diagram things in a way that gets it through the process and gets you what you want I think I might try those add-on lugs in a 200 amp socket next time, but I'll just call it "two sets of service conductors".
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
It depends on the rules being enforced by the POCO. When I was doing resi PV design the two cities I was doing most of my work in were Austin (Austin Energy) and San Antonio (CPS). Nether allowed any branching of service conductors in the meter can or CT enclosure. AE would allow adding lugs to the line side of the service disconnect for a supply side PV connection, but in CPS' jurisdiction, all line side PV connections had to be done in a separate gutter or tap box between the meter and the service disconnect. As as I know those rules are still in place.
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
- Occupation
- Electrician
They must allow 230.40 ex #2 installs. You could do it that way.
Last one I did, I simply used an entire 2nd 125A or 100A main breaker loadcenter totally reserved for solar, its tapped off a 200a Milbank meterbase. Nither Utility nor inspector said anything, the I think the solar guy was a little unsure until the moment it passed.
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
They do, just not connected in the meter can or CT enclosure, although a POCO does not necessarily have to allow something that is allowed by the NEC.
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
- Occupation
- Electrician
They do not allow two sets of conductors off a 320 base or a CT cabinet to two (or more) service disconnects?
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
What they (CPS and AE) do not allow is anyone other than themselves making any changes to or in the utility revenue metering equipment. FWIW, every 320A metering base I encountered in their jurisdictions already had two sets of service conductors installed by the POCO. Every CT cabinet or meter that had more than one set of service conductors had them split out in a seperate enclosure of some kind.
There were two projects I designed (in other states) where the POCO allowed a PV interconnection in a CT cabinet, but in both cases they made me prove that there was no other practical way to interconnect it and they sent out their own guys to land the conductors after we had installed the discos.
Of course, everyone has their own set of experiences; I do not mean to say that what I encountered is universal or even predominant. YMMV.
Last edited:
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
The POCO really installs the service conductors in your area?
- Location
- Illinois
- Occupation
- retired electrician
Our utility would only allow that if the meter can on their approved list had more than one set of lugs installed by the manufacturer of the meter can. Additional field installed lugs are not permitted.
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
- Occupation
- Electrician
That pretty odd, to me. Around here the 320 sockets do not come with lugs, just studs. CT mounting bases I usually order with studs because I am using crimp lugs. What if you want to use crimp lugs?
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
All the systems I worked on or with were already installed, so I don't know. What I do know is that I was not allowed to interconnect a PV system in a meter enclosure or CT can in Austin or San Antonio. CPS (San Antonio) was more restrictive than AE (Austin).
Absolutely I would probably get that same response here all day long if I asked that.
For sure I make sure its a meter or CT can that is on the approved list and use dual lugs approved by the manufacturer for two sets of service entrance conductors to two service disconnects.
Then I proceed to install the 2nd service disconnect, and get a final inspection.
Having two service disconnects off a meter is something familiar and common they deal with every day.
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
It wouldn't make any difference whether you asked or not. Both utilities (AE and CPS) inspect every PV system that gets installed in their jurisdiction, and if a system is not installed in accordance with their rules it fails the inspection even if it is NEC compliant. There are many AHJs in Texas that are difficult to deal with in varying aspects; things are apparently different in Oregon.