Clarification on tap rules

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Brian Stoin

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Ran into an issue on a job. We have a 400 amp fused disconnect outside, next to the meter, and want to run two 3/0 feeder taps into two separate 200 amp main breaker panels in two separate raceways. The panels are inside the building, so the tap conductors will be originating outside and after entering the building will travel about 12-15 feet where they terminate in the main breaker panels. The overall length of these feeder taps would be well under 25'.

I have been told that these feeder taps must terminate at the nearest point of entrance according to 240.21(B)(5). This would mean that the panels would need to be relocated to where the feeder taps/raceway enter the building. Normally, would not be a problem, but the two panels are already made up and have all circuits landed, etc.

The 25' tap rule does not stipulate taps made inside, outside or entering inside from the outside.

Would the 25' tap rule apply to this installation, or am I required to locate those panels at the nearest point to where the feeder taps enter the building?

(We are considering removing the 400 amp disconnect and replacing it with two 200 amp disconnects to protect the 3/0 wires as normally done with feeders)
 
Brian Stoin said:
Ran into an issue on a job. We have a 400 amp fused disconnect outside, next to the meter, and want to run two 3/0 feeder taps into two separate 200 amp main breaker panels in two separate raceways. The panels are inside the building, so the tap conductors will be originating outside and after entering the building will travel about 12-15 feet where they terminate in the main breaker panels. The overall length of these feeder taps would be well under 25'.

I have been told that these feeder taps must terminate at the nearest point of entrance according to 240.21(B)(5). This would mean that the panels would need to be relocated to where the feeder taps/raceway enter the building. Normally, would not be a problem, but the two panels are already made up and have all circuits landed, etc.

The 25' tap rule does not stipulate taps made inside, outside or entering inside from the outside.

Would the 25' tap rule apply to this installation, or am I required to locate those panels at the nearest point to where the feeder taps enter the building?

(We are considering removing the 400 amp disconnect and replacing it with two 200 amp disconnects to protect the 3/0 wires as normally done with feeders)
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No limitation on how much tap conductor is run outside. Once you enter building though you need disconnect/overcurrent protection, but just how far can you enter is not clearly defined in NEC and varies from place to place - NEC just says nearest point of entry or something very close to that.

I do see one other problem with what you wish to do though. 225.30 only allows one feeder to supply a building or structure, your feeder tap is still a feeder, it just has it's overcurrent protection on the load end instead of the supply end.

I suggest you parallel the 3/0 conductors and make this a 400 amp feeder, then make taps at the building to the 200 amp panels.Your run is short, but if it were longer this may help with voltage drop as well.
 
kwired said:
I do see one other problem with what you wish to do though. 225.30 only allows one feeder to supply a building or structure, your feeder tap is still a feeder, it just has it's overcurrent protection on the load end instead of the supply end.

I suggest you parallel the 3/0 conductors and make this a 400 amp feeder, then make taps at the building to the 200 amp panels.Your run is short, but if it were longer this may help with voltage drop as well.
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This is in a multiple-occupancy building where it was not possible to increase the feeder size from the electric room so another service had been installed to increase available power to that space. This would mean that 225.30(B) would allow more than one feeder, correct?

I do, however like your idea of paralleling the 3/0 conductors and moving the taps near the 200 amp panels (less expensive than replacing the 400 amp disco with two 200 amp discos)
 
I don't see any code issues, or a requirement to have the disconnects "nearest the point of entrance". The building (service) disconnect is outside, and the only distance limitations on the location of the inside panels are those found in 240.21(B). 240.21(B)(5) is a special case and does not apply because the conductors continue past the nearest point of entrance. There is no need to look at (B)(5) where you are using (B)(2).

Part II of Article 225 does not apply here as this building is being fed by a service and not a feeder or branch circuit. 225.30 only applies where the service equipment is on a different building. It does not apply where the service equipment is on the building that the feeders are serving.
 
don_resqcapt19 said:
I don't see any code issues, or a requirement to have the disconnects "nearest the point of entrance". The building (service) disconnect is outside, and the only distance limitations on the location of the inside panels are those found in 240.21(B). 240.21(B)(5) is a special case and does not apply because the conductors continue past the nearest point of entrance. There is no need to look at (B)(5) where you are using (B)(2).

Part II of Article 225 does not apply here as this building is being fed by a service and not a feeder or branch circuit. 225.30 only applies where the service equipment is on a different building. It does not apply where the service equipment is on the building that the feeders are serving.
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Read OP again, my first reply was based on meter and 400 amp disconnect being on a separate structure - but apparently they are on the same structure, if so nothing wrong with what was mentioned in op, art 225 doesn't apply to the feeders either if the service is on the same building so no "nearest point of entry either" 10 foot and/or 25 foot feeder tap rules still apply to portion that are inside.
 
don_resqcapt19 said:
I don't see any code issues, or a requirement to have the disconnects "nearest the point of entrance". The building (service) disconnect is outside, and the only distance limitations on the location of the inside panels are those found in 240.21(B). 240.21(B)(5) is a special case and does not apply because the conductors continue past the nearest point of entrance. There is no need to look at (B)(5) where you are using (B)(2).

Part II of Article 225 does not apply here as this building is being fed by a service and not a feeder or branch circuit. 225.30 only applies where the service equipment is on a different building. It does not apply where the service equipment is on the building that the feeders are serving.
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I would agree that 240.21(B)(5) would not apply in this case. Unfortunately, the AHJ would disagree and is requiring us to make changes to the installation. I would maintain that 240.21(B)(2) would apply. That article makes no reference to whether the taps of 25' or less are presumed to be inside, outside or as in our case, tapped outside and entering the building. His argument is that since 240.21(B)(5) refers to outside taps, then that is the code I must apply. Therefore, I am expected to terminate these taps in my overcurrent device (panel) inside, nearest the point of entrance.

Thank you for clarifying article 225
 
don_resqcapt19 said:
I don't see any code issues, or a requirement to have the disconnects "nearest the point of entrance". The building (service) disconnect is outside, and the only distance limitations on the location of the inside panels are those found in 240.21(B). 240.21(B)(5) is a special case and does not apply because the conductors continue past the nearest point of entrance. There is no need to look at (B)(5) where you are using (B)(2).

Part II of Article 225 does not apply here as this building is being fed by a service and not a feeder or branch circuit. 225.30 only applies where the service equipment is on a different building. It does not apply where the service equipment is on the building that the feeders are serving.
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I agree. Since the taps are under 25' and the service disconnect (400 amp) is on the same structure the nearest point of entry does not apply.
 
Brian Stoin said:
I would agree that 240.21(B)(5) would not apply in this case. Unfortunately, the AHJ would disagree and is requiring us to make changes to the installation. I would maintain that 240.21(B)(2) would apply. That article makes no reference to whether the taps of 25' or less are presumed to be inside, outside or as in our case, tapped outside and entering the building. His argument is that since 240.21(B)(5) refers to outside taps, then that is the code I must apply. Therefore, I am expected to terminate these taps in my overcurrent device (panel) inside, nearest the point of entrance.

Thank you for clarifying article 225
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The key to that is that it applies to outside taps of "unlimited" length. It was put into the code to give relief from the much more restrictive rules as to the tap conductor length in (B)(1) or (B)(2) where the taps originate outside. It was never intended to restrict the use of (B)(1) or (B)(2) from originating at an outside location. One way around what he is incorrectly requiring would be to run 400 amp conductors to a box inside the wall, and make the 200 amp taps at that box. :)
 
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