424.19 VAV Disconnects

[Sandlapper]

I am working on a project where our client will be installing about 40 or so VAV boxes in the ceiling of an office building. Each VAV utilizes electric heater coils that is protected by supplementary fusing and according to the manufacturer's literature is isolated by a "factory provided interlocking door disconnect switch located on the electric heater control panel". There are no motors/fans or compressors in these VAV units. The disconnecting means provided does isolate the the fuses on the supply side, but there is no provision for locking out. Does this factory provided interlocking door disconnect switch meet the conditions set forth in 424.19(A)(1)(1) as referencing to 424.19(C)? Appreciate your responses in advance and look forward to the thoughts generated by them.

 

[augie47]

In my opinion, yes. A common install practice in this area.

 

[iwire]

Is it 'indicating' as required?

 

[Sandlapper]

Iwire,

Are you referring to a "marked "off" position as referenced in 424.19(C).
If so, I'm not sure. The diagram I have is woefully lacking in such details.

 

[stevenj76]

The heater section should come pre-done, and the controller low voltage section should be empty. The disconnect is in the high voltage section, and will be the typical ABB 600v 3-pole disconnect. It won't let you open the hinged cover unless it is either off or the safety is bypassed with a tweaker screwdriver.

For the 480, you could put a 2-pole swith in an IR cover, nippled to the can, with a red plastic switch cover, yes?