Tap conductor rule (240.21(B)(1))

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unsaint33

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Location
Minnesota
(240.21(B)(1)) says the tap conductors less than 10' shall not extend the equipment they supply, such as switchgear, panelboard. And the rule does not require terminating at a single breaker or set of fuses. Can someone tell me some examples of why a set of tap conductors would NOT terminate at a single breaker or set of fuses? And also why it would extend beyond the equipment it supplies? Supplying an equipment to me means it terminates at a breaker or fuses inside the equipment.
 

infinity

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Location
New Jersey
Occupation
Journeyman Electrician
The tap conductors are to only supplying one piece of equipment and cannot extend beyond that equipment. If it's a panelboard then a single OCPD may be required according to the Informational Note referenced at the end of the section. If have seen theater dimmer panels with individual branch circuit OCPD's and no single protection at the end of tap conductors.

240.21(B) Feeder Taps. Conductors shall be permitted to be
tapped, without overcurrent protection at the tap, to a feeder as
specified in 240.21(B)(1) through (B)(5). The provisions of
240.4(B) shall not be permitted for tap conductors.
(1) Taps Not over 3 m (10 ft) Long. If the length of the
tap conductors does not exceed 3 m (10 ft) and the tap
conductors comply with all of the following:
(1) The ampacity of the tap conductors is
a. Not less than the combined calculated loads on the
circuits supplied by the tap conductors, and
b. Not less than the rating of the equipment containing
an overcurrent device(s) supplied by the tap conduc-
tors or not less than the rating of the overcurrent
protective device at the termination of the tap con-
ductors.
Exception to b: Where listed equipment, such as a surge
protective device(s) [SPD(s)], is provided with specific in-
structions on minimum conductor sizing, the ampacity of
the tap conductors supplying that equipment shall be per-
mitted to be determined based on the manufacturer’s
instructions.
(2) The tap conductors do not extend beyond the switch-
board, switchgear, panelboard, disconnecting means, or
control devices they supply.
(3) Except at the point of connection to the feeder, the tap
conductors are enclosed in a raceway, which extends
from the tap to the enclosure of an enclosed switch-
board, switchgear, a panelboard, or control devices, or
to the back of an open switchboard.
(4) 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.
Informational Note: For overcurrent protection require-
ments for panelboards, see 408.36.
 
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