Entrance to working space

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Jolly

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What constitutes Unobstructed Exit? I have a switchboard 25 feet long with front and back access only,and it is sitting in the middle of room with 42 inch clearance on both front and back sides.One end of the switchboard is against the side wall and has a 30 inch clearance on the other end.As allowed for unobstucted exit,one exit is planned on both front and back side of switchgear. Does the code define as to where along the length of the gear this exit has to be situated?If I look at Exhibit 110.17 of NEC handbook and situate the switchgear in the middle of room with required working space both in front and back of 480 Gear,my interpretation of 110.26C would be to have an exit door both in front and back, Please comment
 
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entrance to working space

entrance to working space

Gear Voltage is 277/489V. Can't get exact interpretation of unobstructed exit.If you look at Exhibit 110.17 in NEC handbook,and slide switchgear into middle of room with required clearances for working space,my interpretation is that a door at the front as shown and adoor at the back woud meet the requirement. Please comment
 
Pierre C Belarge said:
what is the voltage of this gear?

Take a peek at 110.26(c)
Click to expand...
The voltage is 277/480. If you look at Exhibit 110.17 and have a situation where the gear is in the middle of room with required working space at both front and back,my interpretation of unobstructed exit would be to have exit at both front and back. Is that correct?
 
There is no hard and fast rule as to what constitutes an unobstructed exit. This is one of those areas where the AHJ is expected to make a judgement call. What is aceptable in one area may not be acceptable in others.
 
There is some controversy as to whether the intent of this article is to provide two exits from the room. The words say two entrances to the working space. I believe that you are talking about two working spaces, and wondering if you need two entrances for each of the two spaces. Lacking the ability to put four exit doors in the room, you are trying to take credit for one exit door in the front working space, and one exit door in the rear working space, with each of these being ?unobstructed,? as allowed in 110.26(C)(2)(a). Have I correctly interpreted your question?

To my way of thinking, if you have a door to the front of the gear, and another door to the rear of the gear, then you have ?two entrances,? and you are done. You don?t need to ask about the entrances being unobstructed, because you have the required two. Others, including some AsHJ, would disagree.

My take on ?unobstructed? is that if you have your hands in the gear, and if you took your hands out and turned your head, you must be able to see the exit door. If you have to close the panel cover before you can see the exit door, then that counts as an obstruction.
 
The AHJ has the final word for "unobstructed" exit. The IBC has requirements for egress pathways and exit access. If this is a secured area, i.e. only qualified personnel have access to this area, then I agree with dab and exits near the end of the gear is good.
 
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