Working Clearances in NEC 1956 edition?

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winslowfam

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VA
Hi...we have a client who would like to take advantage of the current NEC exception for working clearances where, if a panel is being replaced in place, and it's existing working clearance was code compliant in the year when it was installed but now it would not be compliant, that it is allowed to be replaced in place without needing to modify the working clearance to meet the current code's requirements in front of that panel. His existing panel was installed in 1956. Does anyone know what the NEC working clearance requirements were in that year? Panel face to panel face...480 volts AC, in particular. Thanks.
 
don_resqcapt19

don_resqcapt19

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Location
Illinois
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retired electrician
Can you cite the exception that would permit that? The only thing that I can think of is 110.26(A)(1)(c) that permits a "condition 2" workspace where the current code requires a "condition 3" work space.
 
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winslowfam

Senior Member
Location
VA
The client has now asked if we can determine if the existing installation violated the NEC when it was installed, or if it is just not compliant in later issues? The Motor Control Centers are 480 volts and face each other an are 36" apart. Today, 48" are required for Condition 3...or if using (c) of that section, Condition 2 is allowed, but that still requiers 42" between the faces of these MCC's. Did the 1956-era NEC allow only 36" for live front to live front spacing of 480 volt panels?
 
cowboyjwc

cowboyjwc

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Simi Valley, CA
What it used to say was, that if it was installed under a certain code, then it was compliant as long as it was not modified or changed.

Uniformed Administrative Code 102.3 (1997) Building service equipment lawfully in existence at the time of the adoption of the technical codes may have their use, maintenance or repair continued if the use, maintenance or repair is in acordance with the original design and a hazard to life, health or property has not been created by such building service equipment.
 
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winslowfam

Senior Member
Location
VA
That's what we had thought...just didn't know where it said that.

Now, I need to know if that 36" working clearance, face to face at 480 volts, was code compliant in 1956...
 
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