I’m having trouble interpreting requirements of the neutral (both the location and the sizing) for Enphase IQ series systems with line side connections.
As per the Enphase manual, no neutral is required (or provided) from the inverters, so there is obviously no neutral from the roof to the point where those branch circuits terminate.
But 250.24(C) says “the grounded conductor(s) shall be routed with the ungrounded conductors to each service disconnecting means and shall be connected to each disconnecting means grounded conductor(s) terminal or bus. A main bonding jumper shall connect the grounded conductor(s) to each service disconnecting means enclosure”
I’m confused by the words “each service disconnecting means” as opposed to just saying “each service disconnect”. Does this mean we only have to bring the neutral to the service disconnect (ie the fused disco prior to the point of POI) and it can terminate there? Or does it mean it needs to continue on to any additional AC disconnects in the system (ie a rapid shutdown initiation device, a dedicated combo panel for Enphase branch circuits, etc)? I realize that the Envoy requires a neutral, but if no Envoy was involved, I’m unclear what the code is requiring.
And in terms of sizing the neutral, do we just use the minimum acceptable size as per 250.102(C)(1), based on the largest conductor in the PV system? or is there somewhere else we should be looking for sizing?
Finally, if the ungrounded conductors are tapped in the MSP, would you also tap the grounded (neutral) conductor or just land it on the neutral bar in the MSP?
As per the Enphase manual, no neutral is required (or provided) from the inverters, so there is obviously no neutral from the roof to the point where those branch circuits terminate.
But 250.24(C) says “the grounded conductor(s) shall be routed with the ungrounded conductors to each service disconnecting means and shall be connected to each disconnecting means grounded conductor(s) terminal or bus. A main bonding jumper shall connect the grounded conductor(s) to each service disconnecting means enclosure”
I’m confused by the words “each service disconnecting means” as opposed to just saying “each service disconnect”. Does this mean we only have to bring the neutral to the service disconnect (ie the fused disco prior to the point of POI) and it can terminate there? Or does it mean it needs to continue on to any additional AC disconnects in the system (ie a rapid shutdown initiation device, a dedicated combo panel for Enphase branch circuits, etc)? I realize that the Envoy requires a neutral, but if no Envoy was involved, I’m unclear what the code is requiring.
And in terms of sizing the neutral, do we just use the minimum acceptable size as per 250.102(C)(1), based on the largest conductor in the PV system? or is there somewhere else we should be looking for sizing?
Finally, if the ungrounded conductors are tapped in the MSP, would you also tap the grounded (neutral) conductor or just land it on the neutral bar in the MSP?