Distance in front of a disconnect

[sybrandy]

I work in a plant with a lot of 3 phase 480V disconnects. I have looked in the NEC and found in 110.26 that you have to have at least 3 ft. in front of the disconnect that is clear. Is there any provisions which would allow this to be less than 3 ft.?

 

[Dennis Alwon]

Is there any provisions which would allow this to be less than 3 ft.?

I don't think so except maybe a few bucks in the inspectors pocket.:grin:

 

[frenchelectrican]

not really just think one metre sqaure area [ simauir to the fridge size ] and i won't even temp to do something funny with inspectors lol

Merci,Marc

 

[jahrtrix]

I have never seen it any less, but if you have a grounded surface
on other side (opposite) to the disconnects its has to be 3.5 feet
or more. 2005 NEC 110.26(A)1

 

[Dennis Alwon]

I have never seen it any less, but if you have a grounded surface
on other side (opposite) to the disconnects its has to be 3.5 feet
or more. 2005 NEC 110.26(A)1

Come again.. Where is this-- you talking the table Condition 2???

 

[cadpoint]

You might get a visual inspection or read from local AHJ.

Only variable I can think of!
If new service is perpendicular and doesn't encroach on the existing opening the new device, One (might) be allowed to overlap the dedicated space, and only work on one panel, or one open at a time.

Maybe I'm totally wrong, but I've seen and applied this!

 

[ron]

Working space is not required if you can convince the inspector that the disconnect is not likely to require examination, adjustment, servicing, or maintenance while energized.
Some feel that a non-fused disconnect is not likely to require examination, adjustment, servicing, or maintenance while energized, so it doesn't require any working space. For example, this may occur in a non-fused disconnect for a condensate pump above a congested suspended ceiling.

 

[jahrtrix]

Dennis,
the NEC 2005 code lists the distances that have to be clear in front
of the panels. You were wondering if distances could be less. In
contradiction they could be more as shown in table 110(26)A1
condition 2. Hope this helps.

 

[Dennis Alwon]

Dennis,
the NEC 2005 code lists the distances that have to be clear in front
of the panels. You were wondering if distances could be less. In
contradiction they could be more as shown in table 110(26)A1
condition 2. Hope this helps.

I got you now but I wasn't wondering if the distance could be less , the op was... :smile:

 

[jerm]

we talking about panels, or disconnects? does it matter either way? I just put in four non-fused discos and the condensers were a lot closer than 3'. show me again what code I violated so the boss will let me move them before they get rejected by inspector...

 

[Jim W in Tampa]

110.26 read it all. you could easily be looking at 42 inches.You cant win this one with ahj

 

[tom baker]

I work in a plant with a lot of 3 phase 480V disconnects. I have looked in the NEC and found in 110.26 that you have to have at least 3 ft. in front of the disconnect that is clear. Is there any provisions which would allow this to be less than 3 ft.?

Its for your safety.The clearance for 480 is 3 ft to a non-grounded surface and 3 ft 6 in for a grounded surface.

 

[billsnuff]

i also work in a place with several 480vac 3 ph equipment. you may want to look at CFR 1910.3xx for general industry. The clearance rules may depend on the date of the installation. can be 24".

edit to add: not 24 but 30"

1910.303(g)(1)(vi)(B)
For installations built on or after August 13, 2007, 1.98 m (6.5 ft), except that where the electrical equipment exceeds 1.98 m (6.5 ft) in height, the minimum headroom may not be less than the height of the equipment.


Table S-1. -- Minimum Depth of Clear Working Space at
Electric Equipment, 600 V or Less


Nominal voltage to ground Minimum clear distance for condition2 3
Condition A Condition B Condition C
m ft m ft m ft
0-150
151-600 10.9
10.9 13.0
13.0 10.9
1.0 13.0
3.5 0.9
1.2 3.0
4.0
Notes to Table S-1:
1. Minimum clear distances may be 0.7 m (2.5 ft) for installations built before April 16, 1981.
2. Conditions A, B, and C are as follows:
Condition A -- Exposed live parts on one side and no live or grounded parts on the other side of the working space, or exposed live parts on both sides effectively guarded by suitable wood or other insulating material. Insulated wire or insulated busbars operating at not over 300 volts are not considered live parts.
Condition B -- Exposed live parts on one side and grounded parts on the other side.
Condition C -- Exposed live parts on both sides of the work space (not guarded as provided in Condition A) with the operator between.
3. Working space is not required in back of assemblies such as dead-front switchboards or motor control centers where there are no renewable or adjustable parts (such as fuses or switches) on the back and where all connections are accessible from locations other than the back. Where rear access is required to work on deenergized parts on the back of enclosed equipment, a minimum working space of 762 mm (30 in.) horizontally shall be provided.