LOTO clip on breaker

[jaggedben]

I'm pretty sure a disconnecting means within sight is required for an air handler. I'm less clear if it's required to be lockable. Between Articles 424, 430, and 440, it's pretty hard to figure out what applies to modern HVAC systems. FWIW in residential I usually see a disconnect next to the unit but it's usually not lockable.

 

[kwired]

I'm pretty sure a disconnecting means within sight is required for an air handler. I'm less clear if it's required to be lockable. Between Articles 424, 430, and 440, it's pretty hard to figure out what applies to modern HVAC systems. FWIW in residential I usually see a disconnect next to the unit but it's usually not lockable.

If is an air handler and no compressor art 440 doesn't apply. 424 possibly a little questionable, I would think their intention would been if the heat source were via electric elements of some type though it doesn't really say that. Otherwise a simple fan coil with some other heat source could fall under 424 as well. I think art 422 is what typically would apply to most air handlers without electric heat source in them.

With the mini splits there is no compressor in the air handling unit. The unit is normally less than 300VA or 1/8 HP and would not require a local disconnect at the unit per 422.31(A). Does that allow the disconnect at the compressor unit that these usually are also powered from to serve as that disconnect if it is lockable since it isn't necessarily the branch circuit device? Maybe not. I think many AHJ's do allow it that way though.

 

[kwired]

All of the facilities that follow strict LOTO procedures, that I have worked in provide a 110.25 device on all breakers. Can't tell you how many thousands of the breaker devices that we installed in one facility.

Larger commercial/industrial facilities typically do have LOTO provisions on about anything imaginable. Could possibly still run into some lighting or general purpose circuits where one may need to put a temporary locking mechanism on when working on those.

Other thing would be some contractor that has rather strict LOTO policies and goes into some facility (big, small, commercial, residential, doesn't matter) that doesn't have locking provisions on anything other than what NEC required it at initial install and they would likely put temp locking mechanisms on anything they happen to be working on.