Tap Rule

Status
Not open for further replies.

buccs407

Inactive, Email Never Verified
Location
Orlando
I have a 400A fused disconnect on the exterior feeding a 200A enclosed brkr just inside on the opposite side of the wall. I would like to tap onto the lugs of this service disconnect to feed a 200A MCB panel on the interior (within 10ft). Is this an allowable application of the tap rule under NEC 240.21?
 

buccs407

Inactive, Email Never Verified
Location
Orlando
I would tap the load side lugs with (3)#3/0,#6gnd, 2" conduit (same as the existing set feeding the other 200A enclosed brkr).
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
It would appear that you would have 3 service disconnects that are not grouped as required by 230.72(A). If I understand your installation correctly, it is already in violation of this section.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
I believe that the 400 amp disconnect is the service disconnect and the taps are on the load side. Would that make the other two feeders, feeder taps?
 

buccs407

Inactive, Email Never Verified
Location
Orlando
Yes, the exterior 400A disconnect is the service disconnect for the building. If this is allowable, Would each set of tap conductors be able to be sized for 200A, or should they be sized for 400A? I know the NEC states that the ampacity of the tap conductors must not be less than the combined calculated loads on the circuits to be supplied.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Will you installation fall under the 10' tap rule? If so, your tap condcutors can be from 40 to 399 amps. If they're 400 amps they're no longer tap conductors.
 

buccs407

Inactive, Email Never Verified
Location
Orlando
I feel that it is allowed under the 10' tap rule, but i have a plans reviewer that disagrees, I do not understand why. Is it a problem that I tap in the main disconnect and then the tap conductors enter the building (within conduit)?
 

Volta

Senior Member
Location
Columbus, Ohio
I feel that it is allowed under the 10' tap rule, but i have a plans reviewer that disagrees, I do not understand why. Is it a problem that I tap in the main disconnect and then the tap conductors enter the building (within conduit)?

No, you're right, they do not need to be adjacent, on in sight from.

The EGC has to be no smaller than a #3, as the circuit is protected at 400 amps.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
I feel that it is allowed under the 10' tap rule, but i have a plans reviewer that disagrees, I do not understand why. Is it a problem that I tap in the main disconnect and then the tap conductors enter the building (within conduit)?

Since your using tap conductors with an ampacity 1/3 or larger than the 400 amps you could use the 25' tap rule even for taps that enter the building. If the tap conductors are on the outside of the building then their length is unlimited.
 
Status
Not open for further replies.
Top