72 Pole Panel with a main breaker

[shroominator]

I have a design with a 120/208V, 3PH, 4W, 72-pole, 225A panelboard with a 225A main breaker on the secondary side of a 75KVA transformer. A question has come up regarding the maximum number of poles allowed in this panel on the basis of Article 408.36 (Exception 2), limiting this panel to 42-poles because of the 3-pole main breaker. I do not think this applies at all. I believe they are just misinterpreting the definition of 2 or 3 pole breakers counting as 2 or 3 overcurrent devices.

I appreciate all comments.

 

[iwire]

The 42 circuit limit has been removed from the NEC.

 

[augie47]

To me the exception applies to panel such as the older "split buss" type and what you have is Code compliant.

 

[petersonra]

I have a design with a 120/208V, 3PH, 4W, 72-pole, 225A panelboard with a 225A main breaker on the secondary side of a 75KVA transformer. A question has come up regarding the maximum number of poles allowed in this panel on the basis of Article 408.36 (Exception 2), limiting this panel to 42-poles because of the 3-pole main breaker. I do not think this applies at all. I believe they are just misinterpreting the definition of 2 or 3 pole breakers counting as 2 or 3 overcurrent devices.

I appreciate all comments.

I think each individual OC device counts. a 3 pole is 3 OC devices.

In any case, the article cited does not limit the number of OC devices in a PB, it only allows some fudging on the PB OCPD if you have 42 or fewer OC devices.

 

[shroominator]

Is it within code to have a 3-pole main on a 72-pole panelboard? I think so, or why remove the 42-pole limit at all.

 

[dicklaxt]

Is it within code to have a 3-pole main on a 72-pole panelboard? I think so, or why remove the 42-pole limit at all.

That makes sense to me ,if the 42 circuit limitation has been removed then Exception 2 doesn't apply or maybe it should have been removed too.

dick

 

[shroominator]

Thanks a lot everyone. I have my answer. Again, I appreciate all the help. Have a good weekend!

 

[Ragin Cajun]

I think each individual OC device counts. a 3 pole is 3 OC devices.

That's not right. Six, three pole disconnects is not unusual.

RC