110.26 Question

[Jimmy7]

I have a set of drawings where the engineer is putting a 480V Switchboard facing a fire alarm terminal cabinet and a fire alarm control panel. The engineer states that the working clearance between the equipment will be 42", so I'm guessing that it's not 48" because of the voltage of the fire alarm equipment. Is the engineer correct if that is the reason?

110.26 (A)(1)
Condition 2 at 480V grounded parts one side is 42"
Condition 3 at 480V live parts on both sides is 48"

 

[charlie b]

My answer is that the engineer is right, but that the voltage level of the fire alarm components is not the reason. I don't consider the FACP to fall under 110.26 at all, and the FATC even less so. I don't believe that either would be likely to require maintenance while energized. So I would treat them as merely a conductive surface, and that puts us into Condition 2. When I lay out a room that has these items, I don't go out of my way to make sure the area in front of them is depicted on the plans as having the 30x36 clear space. I leave room to gain access for future connections or replace components, but not necessarily enough room for live work.

(Aside - I suspect there is likely to be some dissention on this point.)

 

[nhee2]

My answer is that the engineer is right, but that the voltage level of the fire alarm components is not the reason. I don't consider the FACP to fall under 110.26 at all, and the FATC even less so. I don't believe that either would be likely to require maintenance while energized. So I would treat them as merely a conductive surface, and that puts us into Condition 2. When I lay out a room that has these items, I don't go out of my way to make sure the area in front of them is depicted on the plans as having the 30x36 clear space. I leave room to gain access for future connections or replace components, but not necessarily enough room for live work.

(Aside - I suspect there is likely to be some dissention on this point.)

Do you assume a fire alarm tech is going to deenergize power to the FACP prior to performing any diagnostics/troubleshooting or other maintenance? I'd think energized troubleshooting on the FACP would be more likely than energized work on the panelboard?

 

[kwired]

The fire alarm may be low voltage, could still be a 120 volt main supply circuit in the control panel though, but 110.26(A)(1)(b) Low voltage does say by special permission. I would confirm that special permission with the AHJ before just assuming you can consider less working clearance than the table says.

The table applies to anything between 0 and 600 volts.