6 Service Switches

[Grouch1980]

Just a question out of curiosity... where did the limit of 6 service switches per incoming service for a building come from? I've actually been asked twice, but I have no answer.

 

[rc/retired]

As near as I can recollect it has something to do with the time it takes to kill the power of the building..
Other than that I have no idea.

Ron

 

[Phil Timmons]

Was looking for a joke version . . . found what is supposed to be real -- that is about like typical work day . . . .

The Six Disconnect Rule: The 2020 NEC revision has major impacts on electrical installations

Sometime between the 1925 and 1933 National Electrical Codes , the maximum number of service disconnects changed from one or two disconnects to a maximum of six. I cannot verify the exact edition where the change occurred. I have original copies of the 1925 and 1933 NEC books and the 1933...

www.ecmag.com

 

[LarryFine]

I remember back when it was referred to as "six throws of the hand."

We also had 110/220v w/190v high leg, and a neutral was called the identified conductor.

 

[Grouch1980]

Was looking for a joke version . . . found what is supposed to be real -- that is about like typical work day . . . .

The Six Disconnect Rule: The 2020 NEC revision has major impacts on electrical installations

Sometime between the 1925 and 1933 National Electrical Codes , the maximum number of service disconnects changed from one or two disconnects to a maximum of six. I cannot verify the exact edition where the change occurred. I have original copies of the 1925 and 1933 NEC books and the 1933...

www.ecmag.com

Nice article

 

[Grouch1980]

Was looking for a joke version . . . found what is supposed to be real -- that is about like typical work day . . . .

The Six Disconnect Rule: The 2020 NEC revision has major impacts on electrical installations

Sometime between the 1925 and 1933 National Electrical Codes , the maximum number of service disconnects changed from one or two disconnects to a maximum of six. I cannot verify the exact edition where the change occurred. I have original copies of the 1925 and 1933 NEC books and the 1933...

www.ecmag.com

I read through the article again. During the 1920's, the Chrysler building in NYC was built... I'm guessing skyscrapers back then only had 2 service disconnects, until they came up with the 6 disconnect max in 1937 for all occupancies.