Entrance to and Egress From Working Space

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ron

ron

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This is large equipment - 110.26(C)(2) because it is for equipment rated 1200 amperes or more and over 6 ft wide that contains overcurrent devices, so there needs to be one entrance to and egress from the required working space not less than 24 in. wide 6-1⁄2 ft high at each end of the working space.

One end of the working space for the 4000A SWBD is mostly against the column and a small portion extends past the column at that end. Of course this is an interpretation for the local AHJ, but I'm curious if anyone would have trouble saying that there is still an one entrance to and egress from that end of working space not less than 24 in. wide 6-1⁄2 ft high, since you can go around the column?

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ron said:
... I'm curious if anyone would have trouble saying that there is still an one entrance to and egress from that end of working space not less than 24 in. wide 6-1⁄2 ft high, since you can go around the column?
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Isn't double the working depth counted as an exit?
 
You don't have double the working depth. This is Condition 3 (live part on both sides), and the minimum is 4 feet. Double that would be 8 feet, and you only have 7'-8".

I would not accept this layout. I believe the 24 inch exit has to be outside the working space itself. A person working on either panel in the area where they face each other would not be able to step away from the working space on the panel being worked (i.e., step 4 feet away from that panel), and still have 24 inches of walking room on the way towards the top of the drawing.
 
charlie b said:
You don't have double the working depth. This is Condition 3 (live part on both sides), and the minimum is 4 feet. Double that would be 8 feet, and you only have 7'-8".
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It may be a condition 3 only if 'live parts' are exposed in both pieces of gear, unless this is a new building.
 
I would agree that it should be condition 3 (4' instead of 3'-6"), but I have trouble with the 2' path not being allowed to overlap the working space of the "other" SWBD.

I was concerned with the path "starting" within the working space, and it sounds like some opinions are that it starts outside of the working space (not crashing into the column), and so if it is allowed to overlap with the "other" working space, then I feel comfortable with there being one entrance to and egress from the required working space not less than 24 in. wide 6-1⁄2 ft high at each end of the working space.
 
I understand your point, Ron. But there are two things unknown. Let's dismiss one of them by assuming that a worker standing between the two switchboards can walk in a direction that is "downwards" as shown in the sketch, and leave the area. That would give us one of the two required exits from the working space.

The other unknown is the size of the column. Simple math tells me that the area between the two working spaces, as shown in the sketch, is 8 inches wide. But since the required working space is 48", and not the 42" shown, the two working spaces will overlap by 4 inches. That is acceptable. But now if you work on the board to the left, and need to leave quickly, and first step away from the board on the left far enough to be past its working space, and turn in the direction of the top of the page, will you have 24" of space between the edge of the left-hand board's 48" working space and the column? If the column is drawn to scale, I would say no. The column looks like it is more than half the width of the 42" working clearance shown on the right hand board.

Here's the math: There is 7'-8" between the boards. 4' of that is the left-hand working space. That leaves 3'-8", or 44", between the end of the left-hand working space and the right-hand board. The column appears to take up at least 21" of that space. This leaves only 23", and probably less, of clear space to walk past the column. It is close to being compliant. But as drawn, without more detailed measurements, I would not accept it.
 
Charlie;

It sounds like you are requiring working space and a 2' wide path of egress in front of the large panel. If that were the case, it seems like every switchboard that qualifies as large equipment would need a minimum of 5' of clear space in front of it. (3' working space +2' egress space).

I hope that's not really the case.

I don't have any of the latest NEC books with me to check for any recent changes to the working space requirements, but I personally don't think I see anything wrong with the diagram.
 
charlie b said:
Here's the math: There is 7'-8" between the boards. 4' of that is the left-hand working space. That leaves 3'-8", or 44", between the end of the left-hand working space and the right-hand board. The column appears to take up at least 21" of that space. This leaves only 23", and probably less, of clear space to walk past the column. It is close to being compliant. But as drawn, without more detailed measurements, I would not accept it.
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So it sounds like your position is that at any point along the 4' working clearance of the 3000A SWBD, a worker should be able to egress from the required working space, then head away without re-entering the working space.

I guess I was reading it a little different, in that along the 4' working clearance of the 3000A SWBD, a worker should be able to egress from the required working space at each end of the working space, not exit the working space then find a path out without re-entering. That's why the original question was about the end of the working space of 4000A SWBD and the column obstruction that I was concerned about not being "able" to go around before the egress process were to start.
 
steve66 said:
I don't have any of the latest NEC books with me to check for any recent changes to the working space requirements, but I personally don't think I see anything wrong with the diagram.
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Actually after the 2020 code gets adopted in a jurisdiction, the cubicle or section doors will not be allowed to cause an obstruction, so it will end up being 4' working clearance plus the distance for the hinged door to be swung open. The Architects are going to love it. Let the arm wrestling begin!
 
Ron, I get that this is not an easy call. I can see a different point of view as follows: You are working somewhere in the middle of the 3000A board, and need to leave in a hurry. You walk in the direction of "plan north" while remaining within 4 feet of the board (i.e., you are still within its working space). You walk past the column and you are still within the working space of the 300A board. When you get to the end of the working space, you can leave the working space and have at least 2 feet of room in the exit path in that direction. One could call that compliant, and I could not prove that it is not. I just can't imagine a worker not wanting to walk away from the 3000A board first, and then figure out how to leave the area.
 
ron said:
Actually after the 2020 code gets adopted in a jurisdiction, the cubicle or section doors will not be allowed to cause an obstruction, so it will end up being 4' working clearance plus the distance for the hinged door to be swung open.
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I don't think that is what it says, and I think it is a clarification and not a new requirement. What it tells me is that if you wish to take credit for the ability to leave the working space by walking in one direction (e.g., "plan north" in your sketch), then that direction cannot be used if the cubicle doors swing open (i.e., cannot be entirely taken off) so as to block your movement. You would need two other exits from the working space, or you would need to be able to use the double-working space alternative.
 
charlie b said:
I don't think that is what it says, and I think it is a clarification and not a new requirement. What it tells me is that if you wish to take credit for the ability to leave the working space by walking in one direction (e.g., "plan north" in your sketch), then that direction cannot be used if the cubicle doors swing open (i.e., cannot be entirely taken off) so as to block your movement. You would need two other exits from the working space, or you would need to be able to use the double-working space alternative.
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I have a similar situation, and trying to work out the impact of door swing to and from the working space. Does the attached layout meet the requirements for the 2020 NEC?
 

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Tim Davies said:
I have a similar situation, and trying to work out the impact of door swing to and from the working space. Does the attached layout meet the requirements for the 2020 NEC?
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On the top of your line-up you are ok, because there is at least 2' between door swings, which offers the egress from the working space with the doors open.
On the bottom, you have some bigger doors where there is essentially 0 egress available with the doors open which is a problem.
 
ron said:
On the top of your line-up you are ok, because there is at least 2' between door swings, which offers the egress from the working space with the doors open.
On the bottom, you have some bigger doors where there is essentially 0 egress available with the doors open which is a problem.
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Kirk key interlock to open doors???


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