Tapping a tap violation.

[darekelec]

Can anybody explain or write a code section prohibiting install like one in a picture.
At work I have to prove I am innocent that I do not want to perform an install like that.
I feel it is not right but can't put it in words.

 

[iwire]

Can anybody explain or write a code section prohibiting install like one in a picture.
At work I have to prove I am innocent that I do not want to perform an install like that.
I feel it is not right but can't put it in words.

Need more info, how long would the tap(s) be?

 

[darekelec]

Let's suppose less than 10 ft each conductor. I thought one can not tap a tap regardless of the distance of conductor.


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[GoldDigger]

Let's suppose less than 10 ft each conductor. I thought one can not tap a tap regardless of the distance of conductor.


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Is this a field assembly or the interior of a listed panelboard?

 

[infinity]

What about this?

240.21 Location in Circuit. Overcurrent protection shall
be provided in each ungrounded circuit conductor and shall
be located at the point where the conductors receive their
supply except as specified in 240.21(A) through (H). Conduc-
tors supplied under the provisions of 240.21(A) through (H)
shall not supply another conductor except through an overcur-
rent protective device meeting the requirements of 240.4.

 

[iwire]

Let's suppose less than 10 ft each conductor. I thought one can not tap a tap regardless of the distance of conductor.

I believe you are correct but you are asking for a code section supporting that and the tap rule sections are different for different lengths.

I want to give you the right code section. It turns out it did not matter.




2011 NEC

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 device supplied by
the tap conductors or not less than the rating of the
overcurrent protective device at the termination of
the tap conductors.

(2) The tap conductors do not extend beyond the switchboard,
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 shall extend
from the tap to the enclosure of an enclosed
switchboard, 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.

I would point out that this tap rule allows taps from feeders, it does not allow a tap from a tap.

 

[iwire]

What about this?

Sounds better than my suggestion.

 

[hurk27]

Beside not being able to tap a tap, if the 4/0 is 10' and the 1awg is even 3' it would put it over the 10' tap rule and the 1awg would not be allowed as now it would have to meet the 1/3rd rule which would require 400 amp conductors, the second thing that jumps out is the 10awg tap doesn't even meet the 1/10th rule at 10' at 2.9%of the 1200 amp OCPD it would most likely burn up and start a fire, for 1200 amp feeders, 120 amp rated conductors are the smallest conductors allowed up to 10' after 10' you need at least 400 amp conductors.

A tap must land in some kind of OCPD at the end of the tap before they can be tapped again, the best way to do this is to install a small panel that will handle both the 125 amp circuit and the 30 amp circuit.

My question is what does the 1200 amp breaker feed?

 

[Smart $]

Beside not being able to tap a tap, if the 4/0 is 10' and the 1awg is even 3' it would put it over the 10' tap rule and the 1awg would not be allowed as now it would have to meet the 1/3rd rule which would require 400 amp conductors, the second thing that jumps out is the 10awg tap doesn't even meet the 1/10th rule at 10' at 2.9%of the 1200 amp OCPD it would most likely burn up and start a fire, for 1200 amp feeders, 120 amp rated conductors are the smallest conductors allowed up to 10' after 10' you need at least 400 amp conductors.

...

The one-tenth for 10' or less tap length condition is rendered moot where all the depicted connections occur in the same enclosure... which is a possibility given the OP'er wanted us to speculate on 10' or less.

 

[petersonra]

Let's suppose less than 10 ft each conductor. I thought one can not tap a tap regardless of the distance of conductor.


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you can't as a practical matter, but it is not worded that way.