Tap Conductors?

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minesh21

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CA USA
  1. If you splice a conductor to re-route a feed to a new location and install the same size wire at the splice - is it considered a tap? I'm assuming no because the overcurrent protection required for the "tapped" portion is the same as the original feed.
  2. I have a set of spare #4/0 conductors fed from a 200A breaker and abandoned in a j-box. I wanted to tap these conductors to feed a new 100A panelboard. If I splice and install #1 conductors I have to abide by the tap rule (NEC 240.21) correct?
  3. What if I install a MCB (where the tap conductor terminates) in the panelboard rated for 100A, does the tap rule still apply? I would think the MCB protects the upstream conductors from burning up. And since nothing else is on the feed the MCB should be sufficient.
  4. If I install the same #4/0 conductors as the original feed then the tap rule doesn't apply correct?
 
  1. If you splice a conductor to re-route a feed to a new location and install the same size wire at the splice - is it considered a tap? I'm assuming no because the overcurrent protection required for the "tapped" portion is the same as the original feed.
  2. I have a set of spare #4/0 conductors fed from a 200A breaker and abandoned in a j-box. I wanted to tap these conductors to feed a new 100A panelboard. If I splice and install #1 conductors I have to abide by the tap rule (NEC 240.21) correct?
  3. What if I install a MCB (where the tap conductor terminates) in the panelboard rated for 100A, does the tap rule still apply? I would think the MCB protects the upstream conductors from burning up. And since nothing else is on the feed the MCB should be sufficient.
  4. If I install the same #4/0 conductors as the original feed then the tap rule doesn't apply correct?

1. Not a tap
2. Yes, tap rule applies
3. Yes, tap rule applies. You will need an OCPD at the end of the tap conductors in scenario #2 as well.
4. Correct.
 
Your Code reference , 240.21 is the correct p-lace to look for details.
In addition, look at 240.2 for the definition of a "tap conductor"
I did not follow what you asked 100% but, yes, if the conductor you install has the ampacity of the breaker protecting it then it is not a "tap", merely an extension of the circuit.
Once you reduce the wire size to one with an ampacity less than the supply side device protecting it then you need to follow the tap rules.
 
  1. If you splice a conductor to re-route a feed to a new location and install the same size wire at the splice - is it considered a tap? I'm assuming no because the overcurrent protection required for the "tapped" portion is the same as the original feed? Correct it is not a tap, just a splice
  2. I have a set of spare #4/0 conductors fed from a 200A breaker and abandoned in a j-box. I wanted to tap these conductors to feed a new 100A panelboard. If I splice and install #1 conductors I have to abide by the tap rule (NEC 240.21) correct? Correct
  3. What if I install a MCB (where the tap conductor terminates) in the panelboard rated for 100A, does the tap rule still apply? I would think the MCB protects the upstream conductors from burning up. And since nothing else is on the feed the MCB should be sufficient. The tap rule will apply once you change the wire size. If you install a 100 amp breaker at the origin of the feeder than you are okay-- not a tap anymore.
  4. If I install the same #4/0 conductors as the original feed then the tap rule doesn't apply correct? Not sure what this means
 
Your Code reference , 240.21 is the correct p-lace to look for details.
In addition, look at 240.2 for the definition of a "tap conductor"
I did not follow what you asked 100% but, yes, if the conductor you install has the ampacity of the breaker protecting it then it is not a "tap", merely an extension of the circuit.
Once you reduce the wire size to one with an ampacity less than the supply side device protecting it then you need to follow the tap rules.

So technically I can install 3/0 conductors and it's not considered a tap even though the main conductors or 4/0 (since it's a 200A breaker).
 
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