Main Disconnect before meters

[Zee]

I have a situation i do not understand.

I would like to tie in a (N) 2p50A PV breaker.
However the 100 AMP fused and rated, main switch is on the UTILITY side of all the meters.
The conductors then feed five meters in individual enclosures. The fifth meter is the relevant meter.
It feeds a MLO, 125 A rated panel, that has 9 breakers.....
6 of these feed 6 individual apt. units.

Is this a subpanel? OR MSP?
How does the 120% rule apply vis a vis the 100 A switch which is on the UTILITY side of the meter???
What are constructive suggestions to tie into such an existing scenario?
or
What would you replace, rewire etc to make it easy to add solar , and Code compliant?

 

[kwired]

I have a situation i do not understand.

I would like to tie in a (N) 2p50A PV breaker.
However the 100 AMP fused and rated, main switch is on the UTILITY side of all the meters.
The conductors then feed five meters in individual enclosures. The fifth meter is the relevant meter.
It feeds a MLO, 125 A rated panel, that has 9 breakers.....
6 of these feed 6 individual apt. units.

Is this a subpanel? OR MSP?
How does the 120% rule apply vis a vis the 100 A switch which is on the UTILITY side of the meter???
What are constructive suggestions to tie into such an existing scenario?
or
What would you replace, rewire etc to make it easy to add solar , and Code compliant?

View attachment 10088 View attachment 10089 View attachment 10091

I am not up to par on PV things, but if you connect ahead of meter(s) you will end up giving free power to the POCO, and will pay for every kWHr that passes through the meter even though some of it was produced by your PV system.

 

[GoldDigger]

POCO may provide a separate production meter to determine the PV output.

Tapatalk!

 

[jaggedben]

I would try to put a backfed main breaker into the load center so that I can call that my MSP and not violate the six handle rule. Hopefully the busbar is rated 125A so you can put in a 100A main breaker and have 50A of solar. You don't appear to have an EGC going back to the fused disco, so just bond the neutral to the box in the panel and call it a day on that item.

Hopefully you don't have to apply the same fix to all the other units to pass AHJ muster.

That would be my plan A. Alternatively you could replace the panel with something that would have room for two service disconnects (main and solar), and relocate the existing circuits to a new panel. Looks like you don't have a lot of room to work with though.

FWIW, I've seen this sort of thing a number of times. Always a little different from the last one.

 

[kwired]

I would try to put a backfed main breaker into the load center so that I can call that my MSP and not violate the six handle rule. Hopefully the busbar is rated 125A so you can put in a 100A main breaker and have 50A of solar. You don't appear to have an EGC going back to the fused disco, so just bond the neutral to the box in the panel and call it a day on that item.

Hopefully you don't have to apply the same fix to all the other units to pass AHJ muster.

That would be my plan A. Alternatively you could replace the panel with something that would have room for two service disconnects (main and solar), and relocate the existing circuits to a new panel. Looks like you don't have a lot of room to work with though.

FWIW, I've seen this sort of thing a number of times. Always a little different from the last one.

If I understand OP correctly there are 4 other meters - the 100 amp switch is the service disconnect - though it is ahead of the meters - usually not allowed by POCO's unless it is a meter center designed to limit accessibility to unmetered buss/conductors, but is not an NEC violation.

 

[Zee]

Thanks kwired Golddigger and jaggedben,
Kwired:
that was what i was wondering, is a disco switch before meters even allowed? Sounds like, then,
1. yes, per NEC
2. maybe per POCO.

Golddigger:
funny thing is that in this one city they do in fact require us to install a production meter (we do the socket; they add the meter) . Thanks for reminding me....I wonder if they will trust that alone. Let's see .....i would then feed the main switch ??(supply side tie and before the meters)

Jaggedben:
Exactly! That is brilliant.... install a 100A main breaker in the MLO load center....never thought of that. And it IS in fact, as you mentioned, a 125 A rated load center, so i would have exactly 50A.... all for moi and solar.
Now the one remaining problem (or not): How does that affect the 120% rule at the 100 rated and fused disco switch??

Where have you seen this set-up, and why would they do it like that?

 

[jaggedben]

Exactly! That is brilliant.... install a 100A main breaker in the MLO load center....never thought of that. And it IS in fact, as you mentioned, a 125 A rated load center, so i would have exactly 50A.... all for moi and solar.
Now the one remaining problem (or not): How does that affect the 120% rule at the 100 rated and fused disco switch??

I don't think the disco is 'capable of supplying multiple branch circuits or feeders or both', thus the 120% rule doesn't apply to it.

Now the conductors between the switch and the panel, not to mention the meter socket itself ... that might all have to be rated for 125A as well if the AHJ insists that the switch is the service disconnecting means.

Where have you seen this set-up, and why would they do it like that?

In apartment buildings with more than six separate meters, it makes sense. First responders need one switch.

The problem is that it makes it really confusing as to where your main bonding jumper(s) is supposed to be. I've never to my recollection seen separate equipment grounding through the meters, and sometimes you find the grounded conductors bonded to all the boxes on the load side of the meters, and the GEC at the main switch, and you're like... do I have to fix all that? And how?

As for other situations, I've seen single family residences and duplexes with this too, for whatever weird reasons. Sometimes it's because the service is at the back of the house, but there was no way to walk around the house so the meter was put at the front to be read (before smart meters). Sometimes it's evident that service went from overhead to underground, and the utility put in a switch where they made the transition. Sometimes the switch ahead of the meter has the GEC done there and there's only a sub after the meter. Sometimes there's a wholly adequate main panel after the meter and the switch ahead of it is just extra. Sometimes both of them have grounding electrodes connected. You never know with this crazy stuff.