Working clearance

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easymoney

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I am attempting to find out the area I need to keep clear in front of a service panel in a office storage room.
Is it correct to say I need to have 3 feet in front, the width shoule be 30 inches or the width of the panel whichever is greater.
So if i hold a 3 ft stick in front of tha panel and rotate it 90 degres it should touch nothing.
 
110.26(A)(1) requires minium of 36" space in front of panel.
110.26(A)(2) requires the width of equipment or 30" which ever is greater.
110.26(A)(3) requires this space to be from the floor to the structual cieling.
110.26(C)(1) requires a clear un obstructed pathway to the work space.

Did I miss anything?

Oh regarding 110.26(A)(2) the width can be offset to one side or the other as long as the door can be opened 90?;)
 
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I tell people that don't seem to understand the clearances required that you should be able to put a refrigerator box in front of the panel with no problem.
 
Picture a refrigerator box that is 30" wide 36" deep and 6 1/2' in height if the equipment does not exceed 6 1/2' these measurements would comply with 110.26(A)(1) condition 1, 110.26(A)(2) and 110.26(E). Now you should be able to place this box in front of the panel. It could be even with either side of the panel or centered on the panel.
 
easymoney said:
in the condtitons 1,2 and 3 when it says "exposed live parts on on side"
does that mean inside the panel?
Click to expand...

No this is for industrial type of equipment that would have access other then just through the front of the equipment, many who don't get into these types of installations wouldn't know about them, so it does confuse a few when they see this in the code book.

for a simple service panel with 120 volts to ground will follow what I posted above.;)
 
Will it make a difference if it was 3-p 120/208 does thay make it 3 1/2 ft.
or does it need to be 277/480 to make it 3 1/2
 
easymoney said:
Will it make a difference if it was 3-p 120/208 does thay make it 3 1/2 ft.
or does it need to be 277/480 to make it 3 1/2
Click to expand...

It would depend upon which condition you fall under?

Table 110.26(A)(1) gives you the distance, depending upon the condition, condition 2 is where you have the panel on one side of the room, and a block or concrete or other barrier that is considered grounded for the edge in front of the working space, many get this mixed up as to saying it there a concrete or block wall then for 277 it automatically goes to 3.5' but this is not the case, the grounded barrier has to be the other edge in front of the working space, this is only in the depth fo the working space where there is a grounded barrier 3.5' in front of the panel.

Condition 1 3' is all you need for either voltage.
 
easymoney said:
Will it make a difference if it was 3-p 120/208 does thay make it 3 1/2 ft. or does it need to be 277/480 to make it 3 1/2
Click to expand...
The value that makes the difference is the voltage to ground. In a 120/208V system, the voltage to ground is 120V, which is less than 150V, so you use the top row. In a 277/480V system, the voltage to ground is 277V, which is greater than 150V, so you use the bottom row.
 
easymoney said:
in the condtitons 1,2 and 3 when it says "exposed live parts on on side" does that mean inside the panel?
Click to expand...
I may have to take issue with Wayne's answer to this one. When I design the layouts for electric rooms, I treat the bus bars within a panel as being "exposed live parts on one side." If the opposite wall is empty, then I am in condition 2. If there is a panel on the opposite wall, I treat this as having "exposed live parts on both sides," so I am in condition 3. I provide working clearance under the presumption that a worker could be standing between two panels that are both open (front panel cover removed) for maintenance.
 
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