110.26 Working Space and Egress requirements

[Andy Tischendorf]

I am the manager of a controls group responsible for designing custom electrical control and distribution equipment to support our capital equipment. We recently took on a very large project that requires 11 different electrical enclosures to control and power our equipment. The space we have been given at the installation site is fairly limited, so we are trying to layout the placement of the enclosures to comply with NFPA 70 Sect. 110.26. The enclosures come in different sizes with 7 enclosures 8' long and the remaining enclosures 6' long. If we place the enclosures in an arrangement where exposed live parts are directly across from one another when the enclosure doors are open, we would need to adhere to condition 3 and place our equipment 4 feet apart (our operating voltage is 480V 3p) (see attachment). The problem we have interpreting this section is with respect to egress. Do I need to move the enclosures further apart to create a 2 foot egress if someone decides to open doors on opposing electrical enclosures simultaneously? We have envisioned a scenario where an electrician may open all the enclosure doors around him/her and effectively trap themselves. The section is not clear on how to deal with this scenario.
Some additional information: the enclosures are over 6 feet tall; the door width is roughly 36"; each cabinet will be under 1200A.
In the worst case scenario, I would need to space the cabinets 8' apart to account for the 3' doors on opposing sides and still leave a 2 foot egress path. 8' is a lot of wasted space, but I do not want to design an unsafe environment.
Any guidance would be appreciated.

 

[charlie b]

Can you build your enclosures with doors that open nearly 180 degrees, so that they won't be in the egress path? If not, can the doors be completely removable?

 

[ron]

You don't have to worry about the electrical equipment doors being open for the depth measurement. The measurement begins from the exposed live parts, unless the live parts are enclosed. If they are enclosed, the measurement begins from the enclosure or opening.

 

[qcroanoke]

You don't have to worry about the electrical equipment doors being open for the depth measurement. The measurement begins from the exposed live parts, unless the live parts are enclosed. If they are enclosed, the measurement begins from the enclosure or opening.

Yep