Question 240.21(B)(2)

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codequestion

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I have a question regarding NEC 2014 240.21(B)(2). I have tap which is over 10' long and adding fused safety switch 400 amps off of existing wire way. The tap conductor size is 1 set of 600kcmil. I have following questions:

(A) Tap feeder conductors sizes are adequate per NEC 2014 240.21(B)(2)?
(B) Tap feeder conductors terminate in a single 400A fused safety switch is that per ENC 240.21(B)(2)?
(C) They are being contained in a 4" conduit. However, 240.21(B)(2) number 3 says in an approved raceway or by other approved means. Would 4" conduit be approved means to protect from protection? If not then what would be approved raceway?
 
codequestion said:
I have a question regarding NEC 2014 240.21(B)(2). I have tap which is over 10' long and adding fused safety switch 400 amps off of existing wire way. The tap conductor size is 1 set of 600kcmil. I have following questions:

(A) Tap feeder conductors sizes are adequate per NEC 2014 240.21(B)(2)?
(B) Tap feeder conductors terminate in a single 400A fused safety switch is that per ENC 240.21(B)(2)?
(C) They are being contained in a 4" conduit. However, 240.21(B)(2) number 3 says in an approved raceway or by other approved means. Would 4" conduit be approved means to protect from protection? If not then what would be approved raceway?
Click to expand...

A few questions: Is the tap under 25 feet? What is the size of the OCPD protecting the feeder?
 
electrofelon said:
Yes over ten feet, but how long? Can you use the 25' tap rule? What is the rating of the OCPD protecting the FEEDER, not the OCPD at the termination of the tap conductors.
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There are 2 fused disconnects one protecting OCPD 400 amps and the other 400 amps terminating at end of tap conductors.

I have to check regarding less than 25 feet or 25ft to 100ft.

Sent from my SM-G935U using Tapatalk
 
codequestion said:
There are 2 fused disconnects one protecting OCPD 400 amps and the other 400 amps terminating at end of tap conductors.

I have to check regarding less than 25 feet or 25ft to 100ft.

Sent from my SM-G935U using Tapatalk
Click to expand...

It sounds like you dont have a tap then? A tap would have a lesser ampacity than the circuit it is tapped from. Sounds like you are just splitting a feeder into two feeders and there is no need for the second 400 amp disco, they are already protected at 400 by the first one.

Note the over 25' tap rule is only for a certain occupancy and installation type. Do you meet those conditions?
 
electrofelon said:
It sounds like you dont have a tap then? A tap would have a lesser ampacity than the circuit it is tapped from. Sounds like you are just splitting a feeder into two feeders and there is no need for the second 400 amp disco, they are already protected at 400 by the first one.

Note the over 25' tap rule is only for a certain occupancy and installation type. Do you meet those conditions?
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Well tjeir is existing wireway from which i am tapping to 400 amps fused disconnect which then feeds another 400a fused disconnect at over 10 feet long. Would that not be tap?

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codequestion said:
Well tjeir is existing wireway from which i am tapping to 400 amps fused disconnect which then feeds another 400a fused disconnect at over 10 feet long. Would that not be tap?

Sent from my SM-G935U using Tapatalk
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No that is a splice. Tap has a narrow meaning in the NEC. You only have a tap when your overcurrent protection comes is at the end of your conductors rather than at their source.
 
ActionDave said:
No that is a splice. Tap has a narrow meaning in the NEC. You only have a tap when your overcurrent protection comes is at the end of your conductors rather than at their source.
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Wait so if I had one 400 amps fused disconnect at the end of conductors then its a tap? Otherwise if i have 2 fused 400 amp disconnect one at the wireway where feeder conductor is connected and other at the end then its splice?

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codequestion said:
Size of OCPD is 1200 amps peotrcting wireway.
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OK, so you tap the wireway with 600 kcmil copper conductors that are up to 25' long, no longer. These have to land on 400 amp OCPD. If you want to feed another disconnect after that, you have to feed it from the load side of the 400 amp OCPD. Or else separately tap the wireway conductors using 600 kcmil copper conductors that are up to 25' long.

Edit: In which case the answers to the 3 questions in your OP are all yes.

At least that is my understanding of the 25' tap rules. [OCPD could be smaller than 400 amp if desired for some reason, but tap conductors need an ampacity of at least 400 amps.]

Cheers, Wayne
 
codequestion said:
I thought i did says 1200 amps.
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Then why did you state the following? You are telling those responding to your question(s) different scenarios of what you have.


codequestion said:
There are 2 fused disconnects one protecting OCPD 400 amps and the other 400 amps terminating at end of tap conductors.

I have to check regarding less than 25 feet or 25ft to 100ft.
Click to expand...

Roger
 
Because all I know is tap conductor is over 10' long. Attached is what I meant best to draw pictures. But yea I guess you have caught my error :happysad::ashamed1::happysad::(
 

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codequestion said:
Because all I know is tap conductor is over 10' long. Attached is what I meant best to draw pictures. But yea I guess you have caught my error :happysad::ashamed1::happysad::(
Click to expand...
The best I can make of your drawing is not a tap, read the definition of "Tap Conductors" in 240.2

Roger
 
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