Working Clearance

[charlie b]

Make it 2 + 22 + 4 + 22 = 50 then.

The (2 + 22 + 4) only gives you 28 inches of width, before running into the deeper panel. That won?t work either.

Nonetheless, the standard panelboard width I am used to dealing with is 20" wide.

In that case, you can do 5 + 20 + 5 + 20 = 50, and the panel on the left would have the required 30 inches.

 

[pete m.]

It would be physically impossible for it to be " within the 30" without extending into the working clearance demanded by 110.26 (a) (1)

Again, we agree. The commentary doesn't agree with us.


The 30-in. measurement can be made from either the left or the right edge of the equipment and can overlap other electrical equipment, provided the other equipment does not extend beyond the clearance required by Table 110.26(A)(1)

Pete

 

[charlie b]

If I am reading this commentary correctly, using the same 50" wide wall space, I could have a section of switchgear that is 34" deep next to either of the panelboards and not have a violation

I can't answer without knowing wide your proposed switchgear is. If, for example, you have a 20 inch wide, 6 inch deep panel at the left edge of the wall, and a 20 inch wide, 34 inch deep panel at the right edge of the wall, with 10 inches of space between them, then both will have at least the minimum required clearance.

 

[WastefulMiser]

The (2 + 22 + 4) only gives you 28 inches of width, before running into the deeper panel. That won’t work either.
In that case, you can do 5 + 20 + 5 + 20 = 50, and the panel on the left would have the required 30 inches.

Thank you for the corrections. If it is not differential equations I cannot do it apparently. I'm blessed to have AutoCAD verify my dimensions for me.

The 8" deep panelboard would have to be directly next to the wall and 20" wide in order for it to work without making the 6" deep panelboard flush in front. I wouldn't (try to) put anything directly next to a wall as I feel it is bad practice.

 

[charlie b]

The 30-in. measurement can be made from either the left or the right edge of the equipment and can overlap other electrical equipment, provided the other equipment does not extend beyond the clearance required by Table 110.26(A)(1).

This commentary is badly written, at best, and downright wrong, at worst. It appears after sub paragraph 110.26(A)(2), and is talking about width. But it refers to a table that it itself talking about depth. So the table is irrelevant to the discussion.

I think that it is trying to address the very situation presented in this thread. Here you have two panels side by side, and if they were the same depth there would be no problems. The working clearance for each would begin at the level of their front faces. The 30 inch width required to be in front of the one would include some of the space that is in front of the other. The handbook has a drawing that illustrates this type of overlap. But in this thread, the two panels are not the same depth. So the working clearance for the 6 inch deep panel can't take credit for space in front of the of the 8 inch deep panel, because their respective working clearance areas do not begin at the same plane.

 

[pete m.]

This commentary is badly written, at best, and downright wrong, at worst.

Agreed.

As written, the commentary would lead one to believe that the disparity in depth is irrelevant as long as the depth of one piece of equipment does not extend beyond the minimum required working depth of the other even when the working widths are overlapping.:roll:

Pete