2020 - Article 705.11 Supply Side Bus Connection

[cyriousn]

I'm working at an existing building where the service conductor feeders come into the building and terminate at the pull section of a switchboard. There are 6 existing service disconnects at the next section of the switchboard, thus the supply side connection.

There is room for one more set of feeders to lug on within this pull section which we plan on using as a connection point and then locate overcurrent protection within 16.5ft. of conductor length or 71ft if we used cable limiters per 705.11(C)

A lot of the language in 705.11talks about connections to the "service conductors", I'm assuming that the bus bar within the pull section is part of the service conductors. The bus is technically a bare conductor right?

If we couldn't connect at the bus we would have to somehow intercept the multiple sets of feeders with our single feeder set from our IEPPS which would require a piece of equipment before the switchboard which would pretty much kill this project from a financial standpoint. Maybe I'm just overthinking it.

 

[jaggedben]

Yes, busbars are conductors. And if they're on the supply side of the service disconnecting means then they're service conductors.

 

[cyriousn]

Yes, busbars are conductors. And if they're on the supply side of the service disconnecting means then they're service conductors.

Thanks for the sanity check.

 

[pv_n00b]

You can connect at the busbar. Keep in mind a small but important change in the language. Under the 2020 NEC the service conductors have to be rated for the PV system back feed, not the service.

 

[cyriousn]

You can connect at the busbar. Keep in mind a small but important change in the language. Under the 2020 NEC the service conductors have to be rated for the PV system back feed, not the service.

Not sure if I follow you on that one? Are you saying that the service conductors need to be sized so that it could handle the back feed if the service wasn't using any of the PV output? We have 3000A bus and 1200A PV connection so I would think we are good.

 

[ggunn]

Not sure if I follow you on that one? Are you saying that the service conductors need to be sized so that it could handle the back feed if the service wasn't using any of the PV output? We have 3000A bus and 1200A PV connection so I would think we are good.

Yes. In previous code versions it only said that the maximum PV system size was limited by the size of the service but it didn't explicitly say what defined the size of the service. This clears that up; it's the ampacity of the service conductors.