Line Side tap and AC disconnect

[CO Solar]

The utility here requires a production meter (240V socket / 200A with lever bypass) to be installed for all PV systems along with a grouped lockable blade type AC disconnect. For a line side tap interconnection would it be possible to have the utilities production meter between the point of IC and the fused AC disconnect thus eliminating the need for 2 AC disconnects (one fused and the other non-fused) "sandwiching" the utility production meter?

Thanks.

 

[jaggedben]

Yes.

As far as the NEC is concerned, you could put the PV production meter on the line side or load side of the fused disco for the PV.

 

[ggunn]

The utility here requires a production meter (240V socket / 200A with lever bypass) to be installed for all PV systems along with a grouped lockable blade type AC disconnect. For a line side tap interconnection would it be possible to have the utilities production meter between the point of IC and the fused AC disconnect thus eliminating the need for 2 AC disconnects (one fused and the other non-fused) "sandwiching" the utility production meter?

Thanks.

The utility probably won't like it if the meter can is always hot.

 

[jaggedben]

The utility probably won't like it if the meter can is always hot.

Why not? Around here pretty much all meter cans are always hot. I don't believe utilities like it if it is easy to de-energize wiring on the line side of the meter, because then you can easily tap into it and use electricity you aren't charged for. (I'm talking regular meters here, not PV production meters.)

Here in Cali, where we can do 'Virtual Net Metering', I believe we are required to put the PV disconnecting means on the load side of the generating account meter.

 

[ggunn]

Why not? Around here pretty much all meter cans are always hot. I don't believe utilities like it if it is easy to de-energize wiring on the line side of the meter, because then you can easily tap into it and use electricity you aren't charged for. (I'm talking regular meters here, not PV production meters.)

Here in Cali, where we can do 'Virtual Net Metering', I believe we are required to put the PV disconnecting means on the load side of the generating account meter.

Here in Austin the meter shop does not want the meter can to be hot all the time, especially if the system is large enough to warrant CT metering. When they install a CT meter they must pierce the insulation on the conductors to get their reference voltage and they do not like to work hot.

 

[jaggedben]

Here in Austin the meter shop does not want the meter can to be hot all the time, especially if the system is large enough to warrant CT metering. When they install a CT meter they must pierce the insulation on the conductors to get their reference voltage and they do not like to work hot.

Well for a CT that makes sense, but the OP specifically mentioned that it wasn't that type.

I think the question of where the meter can go is for the utility. The NEC of course does not even require the meter and does not care, and regardless of where it goes, does not require a second disco.

 

[texie]

Well for a CT that makes sense, but the OP specifically mentioned that it wasn't that type.

I think the question of where the meter can go is for the utility. The NEC of course does not even require the meter and does not care, and regardless of where it goes, does not require a second disco.

I agree. One thing to consider though is that it will change the grounding and bonding requirements depending on where it is installed. Remember our discussion about bonding the neutral for PV connections?

 

[CO Solar]

Thanks for the input. I am going to give it a try as I don't see any NEC codes that state otherwise. The utility will sill service their production meter in the same manner as if the system were interconnected via a breaker anyway. Since they do not enter equipment that is not theirs, ie. the main panel, they will just throw the bypass lever on the production meter and throw the knife switch for the fused AC disco on the PV system.

Thanks again.

 

[ggunn]

This just in...

Austin Energy is getting ready to introduce a new Interconnection Guide, and for a 480VAC line side tap it will now require 2 AC discos, one on either side of the meter. In the AE contractors' meeting this morning where they unveiled the new IG I asked them why they want to see the disco between the meter and the inverter, since when the other disco is opened the conductors from the inverter are de-energized per UL1741. They told me it's because they don't want the meter ever to become de-energized after the system is commissioned.

 

[GoldDigger]

This just in...

Austin Energy is getting ready to introduce a new Interconnection Guide, and for a 480VAC line side tap it will now require 2 discos, one on either side of the meter. In the AE contractors' meeting this morning where they unveiled the new IG I asked them why they want to see the disco between the meter and the inverter, since when the other disco is opened the conductors from the inverter are de-energized per UL1741. They told me it's because they don't want the meter ever to become de-energized after the system is commissioned.

Hilarious, since opening the line side disco will de-energize the meter. I guess what they are saying is that the line side disco must be there, but they will never open it, so they require another one on the other side. :slaphead:
If I were Austin and were rational (never going to happen) I would just require the inverter side disconnect and install the meter hot wearing PPE.
At some point in the installation and commissioning process the service will have to be interrupted at the transformer anyway unless that work is done hot.