NEC 110-26 history

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Fedders

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Pueblo, CO, USA
I assume that NEC 110-26(A) (Working Space) wasn't always part of the electrical code. We have a building in our facility that was built in the 1940's that doesn't have 3' clearance in front of some panels. Does anyone know when the present 'working space' requirements were added to the electrical code?
 

Carultch

Senior Member
Location
Massachusetts
I assume that NEC 110-26(A) (Working Space) wasn't always part of the electrical code. We have a building in our facility that was built in the 1940's that doesn't have 3' clearance in front of some panels. Does anyone know when the present 'working space' requirements were added to the electrical code?

I'm sure 110.26 is overlooked and cheated all the time. It is probably the most common section of the code violated by other trades, who don't understand it. I know in my house, the panelboard is in the pantry was located properly when the house was built the first time. Then the closet shelf installers decreased the width of the work space from 30" to 25".
 

cowboyjwc

Moderator
Staff member
Location
Simi Valley, CA
If I remember correctly it wasn't always 36" in front. It's in the 1984 NEC as three feet, but I don't even see clearances mentioned in the 1965 Uniform Wiring Code. Someone threw out all of my code books in between during a move so I don't have any other references.
 

480sparky

Senior Member
Location
Iowegia
110.26 started out as Art. 1111 in the 1940 NEC. It changed to 1112 in 1947, 1116 in 1956, 110-16 in 1959, 110-15 in 1962, moved back to 110-16 in 1965, then 110-26 in 1999. In 2002, the - was replaced by a . and it became 110.26.
 

Carultch

Senior Member
Location
Massachusetts
110.26 started out as Art. 1111 in the 1940 NEC. It changed to 1112 in 1947, 1116 in 1956, 110-16 in 1959, 110-15 in 1962, moved back to 110-16 in 1965, then 110-26 in 1999. In 2002, the - was replaced by a . and it became 110.26.


Regardless of its address, how has its content evolved over the code cycles?

Has it always specified min 3 ft depth, and a depth that may be larger for higher voltages?
Has it always specified min 30" width?
Has it always specified min 78" height?
 

kwired

Electron manager
Location
NE Nebraska
If I remember correctly it wasn't always 36" in front. It's in the 1984 NEC as three feet, but I don't even see clearances mentioned in the 1965 Uniform Wiring Code. Someone threw out all of my code books in between during a move so I don't have any other references.
2014 NEC says 914mm and is followed by (3 ft) for all 0-150 volt conditions and condition 1 for 151-600 volts.

151-600 volt condition 2 says 1.07m (3 ft 6 in) and condition 3 says 1.22m (4 ft).

Width and height are also metric measurement first but width is followed in parenthesis with 30 inches height says 6-1/2 feet.

Add: but I believe there is an error there, seem to recall max height of a breaker/switch handle was changed a few years ago from 6 foot 6 inches to 6 foot 7 inches only because 6-7 is equal (or much closer anyway) to 2.0 meters:blink:
 
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480sparky

Senior Member
Location
Iowegia
Regardless of its address, how has its content evolved over the code cycles?

Has it always specified min 3 ft depth, and a depth that may be larger for higher voltages?
Has it always specified min 30" width?
Has it always specified min 78" height?



No.

1947%201111.jpg
 

mwm1752

Senior Member
Location
Aspen, Colo
NEC 1965 has a horizontal dimension that refers to the face of the equipment (basically a tunnel of area) 2'6" thru 4'-- so the dimensions of the panel HXW was the determine working space -- no 30" width min -- does have headroom though -- clear space was not allowed in as passageway --
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
It may have been.

It definitely was.
The posted NEC text (from the 60's) says 2-1/2ft which equals 30".

This constantly gives us fits, as 40 year old equipment is retired and the new stuff cannot be put into the same space.
 

480sparky

Senior Member
Location
Iowegia
It definitely was.
The posted NEC text (from the 60's) says 2-1/2ft which equals 30".

This constantly gives us fits, as 40 year old equipment is retired and the new stuff cannot be put into the same space.

Or the old stuff was installed without permits or inspections. Common back the the old days.
 

mwm1752

Senior Member
Location
Aspen, Colo
It definitely was.
The posted NEC text (from the 60's) says 2-1/2ft which equals 30".

This constantly gives us fits, as 40 year old equipment is retired and the new stuff cannot be put into the same space.

The 2'6" is reference to depth not width -- used to be 30" deep instead of the 36" now as a min.
 

Carultch

Senior Member
Location
Massachusetts
This constantly gives us fits, as 40 year old equipment is retired and the new stuff cannot be put into the same space.

Yup...annoying as hell.I wonder if you can get a "things can remain compliant with the codes they were once compliant with" interpretation by the AHJ.

With any luck, new equipment might be slightly smaller, and could somehow fit by luck.

Such as, it was built in the 40's with 30" of depth. That's existing, and it was OK then. Now you've gotta replace it, and you aren't increasing the safety hazard by doing so...it's simply the standard that changed to increase the safety requirement.

However, if its working space was not OK at the time it was built, there is a problem allowing you to continue it.
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
I wonder if you can get a "things can remain compliant with the codes they were once compliant with" interpretation by the AHJ.
Let me know if you get one.:D

With any luck, new equipment might be slightly smaller, and could somehow fit by luck. Such as, it was built in the 40's with 30" of depth.
Where do you find this stuff? Everything I run into seems to be from the 70-80's which was built 20" deep instead of today's 24".:weeping:
 
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