2014 NEC 705.12(D)(2)(1)(b) - Inverter output connection made at a feeder.

[Kalyan]

I am trying to interconnect a PV system to a feeder at a location other than the opposite end of the feeder from its primary source overcurrent device. As per NEC 705.12(D)(2)(1)(b) i need to protect the feeders on the load side of the inverter output connection by having an overcurrent device on the load side of the inverter connection that is not greater than the ampacity of the feeder. It makes sense but the question i have is do i need to place this overcurrent device on the load side immediately after my inverter output connection or can the feeders run to a load center inside the house where there is an existing OCPD (main breaker of panel) that comes before any load connections? Please take a look at the image below to get a clear idea of my situation here. This link - https://www.jadelearning.com/jadele...2014-nec-705-12d2-pv-interconnections-part-2/ shows an interpretation of this part of the code that supports my situation. Let me know if anyone at the Mike holts forum group agrees.

 

[ggunn]

...can the feeders run to a load center inside the house where there is an existing OCPD (main breaker of panel) that comes before any load connections?

In most cases under the 2014 NEC, yes.

 

[jaggedben]

I think it's ultimately the AHJ's call, but whenever I've done it it's been with the a main breaker in the remote load center. I've done it a few times without having it questioned. From a safety point of view I don't think it should be questioned, because the purpose of the downstream OCPD is to protect against an operating overcurrent, rather than a fault that almost certainly would still trip the feeder breaker upstream of the tap.

For what it's worth, I think it would be a somewhat pointless provision, practically speaking, if the OCPD had to be near the tap. Because it most cases you're doing the tap because it's not practical to insert a panelboard or a second enclosure for an OCPD.

 

[Kalyan]

Thank you.

 

[Carultch]

I am trying to interconnect a PV system to a feeder at a location other than the opposite end of the feeder from its primary source overcurrent device. As per NEC 705.12(D)(2)(1)(b) i need to protect the feeders on the load side of the inverter output connection by having an overcurrent device on the load side of the inverter connection that is not greater than the ampacity of the feeder. It makes sense but the question i have is do i need to place this overcurrent device on the load side immediately after my inverter output connection or can the feeders run to a load center inside the house where there is an existing OCPD (main breaker of panel) that comes before any load connections? Please take a look at the image below to get a clear idea of my situation here. This link - https://www.jadelearning.com/jadele...2014-nec-705-12d2-pv-interconnections-part-2/ shows an interpretation of this part of the code that supports my situation. Let me know if anyone at the Mike holts forum group agrees. View attachment 17823

I have a concern with the way they depicted Option 1. If there is no main breaker in that panelboard, then it is theoretically possible for 250A worth of current from both the PV and the service to simultaneously feed it, should enough loads be active. Improbable that would happen, because the load calculations should indicate that exceeding 200A of loads is rare. But if it did happen, the busbar (which is likely 200A), would go unprotected. So if you were to build it that way, you would need 250A of both busbar and feeder downstream of the tap point, when 50A of PV interconnects to 200A of service in this manner.