NEC article 240 tap conductors inside of an industrial control panel

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dawsez

Member
Location
USA
I have an enclosure with a disconnect inside with distribution lugs and I distributed the "tap conductors" to their overcurrent devices that are inside of the enclosure too, does this connection counts as the "point where the conductors receive their supply"?
what i mean is if I use wires to connect the tap overcurrent devices, do I need to follow the 3FT rule?
 

Smart $

Esteemed Member
Location
Ohio
240.21(B)(1)
3 meters (10 feet).

Your situation is in a gray area of the NEC... but the short answer is yes. The problem is how does one technically comply with tap conductors which do not leave the enclosure in which the tap is made. Keep this in mind as you read the conditional requirements.
 

dawsez

Member
Location
USA
3 meters (10 feet).

Your situation is in a gray area of the NEC... but the short answer is yes. The problem is how does one technically comply with tap conductors which do not leave the enclosure in which the tap is made. Keep this in mind as you read the conditional requirements.
Sorry... 10ft rule...
Well the problem is when I have, for example, a 300A feeder breaker, and I have branch circuits with 14 AWG, the rule say the ampacity of the tap conductors shall be at least 1/10 of the size of the overcurrent protection device, but if it counts as "point where the conductors receive their supply" i could avoid the 1/10 size.
 

Smart $

Esteemed Member
Location
Ohio
Sorry... 10ft rule...
Well the problem is when I have, for example, a 300A feeder breaker, and I have branch circuits with 14 AWG, the rule say the ampacity of the tap conductors shall be at least 1/10 of the size of the overcurrent protection device, but if it counts as "point where the conductors receive their supply" i could avoid the 1/10 size.
I don't have time to get into the particulars at present but you may find some resolve in a current (occurrence in time) parallel (very similar subject) thread...

http://forums.mikeholt.com/showthread.php?t=184732
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Sorry... 10ft rule...
Well the problem is when I have, for example, a 300A feeder breaker, and I have branch circuits with 14 AWG, the rule say the ampacity of the tap conductors shall be at least 1/10 of the size of the overcurrent protection device, but if it counts as "point where the conductors receive their supply" i could avoid the 1/10 size.

For field installations, if the tap conductors leave the
enclosure or vault in which the tap is made
, the ampacity
of the tap conductors is not less than one-tenth of
the rating of the overcurrent device protecting the
feeder conductors.

It seems to me that the 1/10 rule only applies if the tap conductors leave the enclosure where the tap is made.
 
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