PV System Supply-Side Connection

[MurphyLuth]

For PV system installations, the county of Ventura, CA requires:

Photovoltaic drawings and installations using a Supply-Side Connection per CEC 705.12(A) and 230.82(6) shall either:

i. Provide third-party certification of field altered service panels modified to accept the supply-side connection per CEC 90.7 and 110.3(a) & (b), or
ii. Replace the main service-panel with one that is listed to accept a supply-side connection without field alteration

Can someone explain what this means? I was going to tap into the existing Service Disconnect and attach the Utility AC disconnect for the PV system similar to adding another branch circuit. Does the above requirement pertain to that?

 

[SolarPro]

That's the way I read the requirement. The AHJ seems to be saying that you need to prove to them that making a supply-side connection inside existing equipment does not violate the terms of that product's listing.

 

[GoldDigger]

In particular, I suspect they are worried about double tapping lugs or otherwise doing stupid things, but instead of inspecting for that they have gone all formal on you.

 

[ggunn]

I have run into this several times, where we want to land on empty existing holes in the bus bars on the supply side of the main breaker of the MDP. The AHJ's wanted to get some documentation from the MDP manufacturer saying it was OK with them if we did that. I never had an MDP manufacturer say that we couldn't, but sometimes it was hard to find someone there to answer the question. Don't rely on customer service to answer the question; they may tell you no because they don't know and they want to cover their hineys. Get someone from tech support to talk to you. Once I've gotten through to those guys it's never been a problem.

One thing, though, in my case it's always been about using existing holes.

 

[jaggedben]

For PV system installations, the county of Ventura, CA requires:

Photovoltaic drawings and installations using a Supply-Side Connection per CEC 705.12(A) and 230.82(6) shall either:

i. Provide third-party certification of field altered service panels modified to accept the supply-side connection per CEC 90.7 and 110.3(a) & (b), or
ii. Replace the main service-panel with one that is listed to accept a supply-side connection without field alteration

Can someone explain what this means? I was going to tap into the existing Service Disconnect and attach the Utility AC disconnect for the PV system similar to adding another branch circuit. Does the above requirement pertain to that?

i. ... means having a representative of UL or a similar organization come out and perform a field inspection and certification. You pay them a lot (thousands) and it's a time consuming process, probably involving a pre-install visit and post install visit. It's not an approach that should be taken unless replacing the service equipment would be much more time consuming and expensive. OIW, for residential up to 400A you probably wouldn't want to go this way.

ii. ... A panel that has factory-configured space for more than one service disconnecting means should meet this requirement. There are plenty of those out there. (Many homes already have them, so when they imply that you have to 'replace' they are not being very precise.)

To respond to your final question...
Exactly how were you planning to perform the tap?

Performing a supply side connection at the service equipment should not be the only option. If your plan is to to put a tap box ahead of the existing service panel and tap the service entrance conductors to your PV disconnect, then in my opinion the requirements you quoted are not pertinent. However, you should probably see if this AHJ agrees.

Alternatively, if you are planning to tap a field-installed conductor that didn't come shipped as part of the disconnect, then you ought to be okay (provided you are complying with various code requirements for fill and wire bending space). But again, ask the AHJ...

 

[ggunn]

To respond to your final question...
Exactly how were you planning to perform the tap?

My question as well. If you are landing on existing busbar perforations on the line side of the main breaker in the MDP, it isn't a field alteration according to all (three, I believe) the MDP manufacturers' tech support guys I have contacted about this.

A tap box can be messy if the service you are tapping has parallel conductors coming in.

 

[Smart $]

A question I'd have is whether changing disconnect supply-side lugs (with listed for the device/panel) is considered field alteration as far as the AHJ is concerned...