10' tap rule

edward

Senior Member
240.21(b)(1)(4) .......the ampacity of the tap conductor is not less than 1/10th of the feeder OCPD protecting the feeder conductors.

The ampacity of the tap conductors is based on the 90 degree column or the 75 degree column?

300A OCPD protecting the feeder, tap conductors can not be less than 12 AWG or 10 AWG?

Thanks
 

david

Senior Member
Location
Pennsylvania
240.21(b)(1)(4) .......the ampacity of the tap conductor is not less than 1/10th of the feeder OCPD protecting the feeder conductors.

The ampacity of the tap conductors is based on the 90 degree column or the 75 degree column?

300A OCPD protecting the feeder, tap conductors can not be less than 12 AWG or 10 AWG?

Thanks
90 or 75 degree in most cases 75 degree sometimes 60 degree
10 AWG depending how 240.21(b) (1) (1) is a factor
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
240.21(b)(1)(4) .......the ampacity of the tap conductor is not less than 1/10th of the feeder OCPD protecting the feeder conductors.

The ampacity of the tap conductors is based on the 90 degree column or the 75 degree column?

300A OCPD protecting the feeder, tap conductors can not be less than 12 AWG or 10 AWG?

Thanks
This is something that has come up for me in the last day or so. In the case of a supply side tap for a PV system, there is no OCPD on the conductors being tapped; they come straight from the transformer. What then?
 

augie47

Moderator
Staff member
Location
Tennessee
IMO, in general the ampacity would be based on the insulation rating of the conductor.
In answer to the second part, the size would depend terminations. 110.14 would most likely limit you to the 75? rating thus a #10.
240.4(D) would also play a part and would also require a #10 under normal conditions.
 

david

Senior Member
Location
Pennsylvania
IMO, in general the ampacity would be based on the insulation rating of the conductor.
In answer to the second part, the size would depend terminations. 110.14 would most likely limit you to the 75? rating thus a #10.
240.4(D) would also play a part and would also require a #10 under normal conditions.
I made the assumption the tap would terminate to a rec. or terminals with a 75 deg. rating
 

kwired

Electron manager
Location
NE Nebraska
10' and 25' tap rule one of the most violated NEC rules I see. Had a job with a 100' tap :sick:
240.21(B) (4) allows up to 100 foot taps, but is fairly limited to where this can be used, and (B)(5) allows for unlimited tap length, but the tap must be outdoors.
 
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