Line-Side Tap

[cdcengineer]

We are proposing a line-side (ahead of service disconnect) tap for a solar PV interconnection. The NEC allows this per 230.91 and 240.21. I was wondering though, the tap rule for taps shorter than 10' long still requires that the rating of the overcurrent protection on the line side of the tap does not exceed 10 times the ampacity of the tap conductor. In this case, there really is no overcurrent protection (aside from bayonet fusing on the utility primary) ahead of the tap. Our service disconnect is 1200 Amps at 480V, 3-Phase.

Input anyone?

 

[cdcengineer]

No takers?

 

[david luchini]

Your connection ahead of the service disconnecting means is not a "tap" per 240.21. They are service conductors. 240.21 would not apply.

 

[cdcengineer]

Good point. It's 230.82(6) & 241.21(D) that allows the supply side connection of the inverter. We just need to make sure the conductors are as short as possible, that the disconnect as next to the service disconnect (with placards/ directories) and that the conductors are sized for the PV inverter output at 125%.

This inverter doesn't require a neutral connection. But I'm thinking we'll still be required to run a neutral to the PV disconnect and bond at this location since it's essentially a second service disconnect.