Tap Rule

[DCorby]

As I was reviewing a new installation, I found that there is a 70A Circuit breaker from an electrical panel feeding a 480 VAC Disconnect. Tapped off the bottom of the disconnect there is a feed for a 480VAC -400VAC transformer feeding a piece of equipment. This feed goes to the machine main panel. Also tapped off the bottom of the disconnect is a 12 gauge 480VAC 3 phase circuit that feeds the machine main panel as well. It goes to a set of fuses that someone put in to run a mist collector that has a different voltage. The distance from the disconnect to the machine panel is close to 25 feet. Without pulling the wire, I cannot tell for certain. I personally don't feel it is good practice, but is it legal by the NEC? I am co0nfused as part of the rule states that you can not tap a tap?? Any assistance would be greatly appreciated.
:?

 

[Dennis Alwon]

A tap usually implies change in conductor sizes. Is the # 12 the only conductor size that changes? The disconnect is feed with a 70 amp breaker and the 25' rule allows the follow. 1/3 of 70 is 23 amps so the breaker on the #12 would need to be 25 amps. Not exactly sure what you have there

(2) Taps Not over 7.5 m (25 ft) Long. Where the length of
the tap conductors does not exceed 7.5 m (25 ft) and the tap
conductors comply with all the following:
(1) The ampacity of the tap conductors is not less than
one-third of the rating of the overcurrent device protecting
the feeder conductors.
(2) The tap conductors terminate in a single circuit breaker
or a single set of fuses that limit the load to the ampacity
of the tap conductors. This device shall be permitted
to supply any number of additional overcurrent devices
on its load side.
(3) The tap conductors are protected from physical damage
by being enclosed in an approved raceway or by other
approved means.

Tap Conductors. As used in this article, a tap conductor is
defined as a conductor, other than a service conductor, that
has overcurrent protection ahead of its point of supply that
exceeds the value permitted for similar conductors that are
protected as described elsewhere in 240.4.

 

[augie47]

As far as compliance with the NEC is concerned, albeit a somewhat 'minor' infraction, in all probability the lugs on your disconnect are not rated to accept two conductors so you likely have a violation of NEC 110.14