hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
I have the attached installation in which transformer secondary conductors 2 sets of 4#41/0+1#1/0AWG Gnd are in wire trough. The trough is tapped*with: 4#1/0AWG+1#1/0AWG Gnd to P1, 4#1/0AWG+1#1/0AWG Gnd to P2, 4#1/0AWG+1#1/0AWG Gnd to P3.*
The furthest distance from transformer to panel P3 is 15 feet and Panels P1, P2,P3 are grouped each with 150A main circuit breaker.
I am trying to make inspector understand how I got 2 sets of 4/0AWG which is if I take each secondary conductor back to transformer that's each 1/0AWG to transformer and 1/0AWG ampacity is 150A and three of them would be 3x150 = 450A. 2 sets of 4/0AWG is equivalent*to 450A and same as taking conductors back individually.
However the inspector is telling me that it does not comply per NEC 2014 Article 240.21 cannot tap a tap and also that secondary tap conductors are not suppose to extend beyond panel or overcurrent protection served. Inspector is telling me either add secondary*450A breaker between trough and transformer to make them in feeders load side of breaker.
Am I correct in my explanation and don't need to provide anything or inspector is correct and need to add secondary 450A breaker between trough and transformer?
*
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The furthest distance from transformer to panel P3 is 15 feet and Panels P1, P2,P3 are grouped each with 150A main circuit breaker.
I am trying to make inspector understand how I got 2 sets of 4/0AWG which is if I take each secondary conductor back to transformer that's each 1/0AWG to transformer and 1/0AWG ampacity is 150A and three of them would be 3x150 = 450A. 2 sets of 4/0AWG is equivalent*to 450A and same as taking conductors back individually.
However the inspector is telling me that it does not comply per NEC 2014 Article 240.21 cannot tap a tap and also that secondary tap conductors are not suppose to extend beyond panel or overcurrent protection served. Inspector is telling me either add secondary*450A breaker between trough and transformer to make them in feeders load side of breaker.
Am I correct in my explanation and don't need to provide anything or inspector is correct and need to add secondary 450A breaker between trough and transformer?
*
Sent from my SM-G935U using Tapatalk