How to tap a parallel feeder

Tank11

Member
Location
CO
Example scenario: 600-amp main service so parallel feeder conductors. Want to line side tap a PV inverter (10 KW in this example). Since there are parallel conductors to tap, is the best method to provide a parallel path from the PV inverter as well for continuity across the service feeder?
Or does it not matter, and just tap one of the two parallel feeds?
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Semi-Retired Electrical Engineer
Or does it not matter, and just tap one of the two parallel feeds?
It matters!

If you tap one conductor from a set of parallel conductors, you must install identical taps on all other conductors in the set.

A key requirement of successfully parallelling conductors is that each conductor in the set must have the same loading conditions.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
I believe it was in the 2020 NEC that wording was added to 300.3 to clarify that requirement.
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
Example scenario: 600-amp main service so parallel feeder conductors. Want to line side tap a PV inverter (10 KW in this example). Since there are parallel conductors to tap, is the best method to provide a parallel path from the PV inverter as well for continuity across the service feeder?
Or does it not matter, and just tap one of the two parallel feeds?

You _must_ tap all of the parallel feeds. All parallel feeds must be equivalent.

But you don't need to use parallel conductors between the PV inverter and the tap point. The tapping splice blocks could connect a single conductor from the PV inverter to the 2 parallel feeder conductors.

-Jonathan
 
Example scenario: 600-amp main service so parallel feeder conductors. Want to line side tap a PV inverter (10 KW in this example). Since there are parallel conductors to tap, is the best method to provide a parallel path from the PV inverter as well for continuity across the service feeder?
Or does it not matter, and just tap one of the two parallel feeds?

Note "service" and "feeder" are specific and different things, check the definitions. In this case the same rules would apply to either case, but for other issues you would need to be clear about which it is.
 
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