Is a Disconnect Required?

[njtrombley]

Hello all, I have a question that came up out in the field that I need some other interpretations on. We are wiring a nuro-care facility, 39 bed, and at each bed there is a medical gas panel that mounts in the wall and it comes complete with 3 - Hospital grade receptacles fed with normal power and 3 - Hospital grade receptacles on a generator panel. Also in the medical gas panel is medical gas (surprising I know). There are gas lines that patients get hooked up to for oxygen etc. These lines are pressurized by a compressor and a vacuum pump. Both the compressor and the vacuum pump are on the generator circuit. The generator is sequenced so that all the loads don't come on at once and stall the generator. The compressor and vacuum pump are part of the generator sequencing process and are delayed to be energized 15 seconds after the generator starts up. The way we did this is we put the compressor and vacuum pump on contactors and we are controlling the coil off the transfer switch because the transfer switch has control wiring that can be delayed. So the generator turns on, the vacuum pump and compressor are off until the transfer switch contacts close which pulls in the contactors for the vacuum pump and compressor.

Now, to make a long story longer. The electrical room where the breakers are located for the vacuum pump and compressor are about 200' away from the mechanical room where the vacuum pump and comressor actually sit. We are putting the contactors in the mechanical room where the pump and compressor sit, but do we need a disconnect in front of the contactors in the mechanical room? The equipment has disconnects on them from the factory, but it's not a typical disconnect that would come with a gear package for instance (I will attach a picture). I know that the obvious answer is ask the AHJ, but I would like to know the facts before I do so.

 

[iwire]

The compressor and vacuum pump are part of the generator sequencing process and are delayed to be energized 15 seconds after the generator starts up. The way we did this is we put the compressor and vacuum pump on contactors and we are controlling the coil off the transfer switch because the transfer switch has control wiring that can be delayed.

The transfer switch control contacts can be delayed independently of the transfer switch itself?

 

[njtrombley]

Yes they can. There is a control area in the transfer switch (by Kohler) and it will close or open contacts for you and intervals you select. It's pretty cool actually, it took me a while to wrap my head around it, but it will work. I talked to the factory and our sales reps about it in lenght. We are stepping the generator 4 times on start up after power is lost.

 

[cadpoint]

I was only going to comment on the Box and not what Iwire is asking, and I'll assume that this delayed sequencing is not in this Box - that’s in question! But having re-read your own quote below, and your additional response you've answered it yourself.

If you where to put additional contacts inside this listed product then I believe you've altered it's listing and it is then an error to your install.

…The electrical room where the breakers are located for the vacuum pump and compressor are about 200' away from the mechanical room where the vacuum pump and compressor actually sit. We are putting the contactors in the mechanical room where the pump and compressor sit, but do we need a disconnect in front of the contactors in the mechanical room?.

Your breaker in the electrical room is protecting your circuit to the mechanical room. I also belive you'd understand this!

The equipment has disconnects on them from the factory, but it's not a typical disconnect that would come with a gear package for instance.

(my comment on the Box alone)

Based on the this statement, I believe your ok with your location of this equipment in the mechanical room. As I can see it -IF (and I‘m questioning the OP?) there are lockable tabs on the switches of the main and to the individual pumps of this industrial control panel then they qualify for a means of disconnect that are required by Code including that the disconnect be with-in sight and repeating, lockable.

Look here for UL standards descriptions of "Industrial Control Panels (NITW)".

As long as the panel is UL Listed, you should will be fine.

 

[njtrombley]

I know it's a confusing question so I'll try to answer your comments and I do appreciate your help on this. We are not altering anything inside the box of the picture shown. We wouldn't want to void the UL listing. The controls for sequencing are in the Kohler transfer switch that we don't have yet as we are waiting for the factory to ship it. The question boils down to whether or not the factory disconnect switches shown on the control board will be an acceptable means of disconnect.

What do you mean by lockable tabs on the switches of the main?

 

[earlejohnson]

What do you mean by lockable tabs on the switches of the main?[/QUOTE]

I think he is talking about a breaker lock. 422.31

 

[Strife]

Looking at the picture there doesn't seem to be a main "switch" for the panel other than control switches. Keep in mind control (like contactor controls) who could energize a circuit automatically are not considered means of disconnect). IE The "Auto", "Manual", 'OFF" switch that you find on any starter IS NOT means of disconnect. They wouldn't make combos if it was otherwise, would they?

View attachment 5337Hello all, I have a question that came up out in the field that I need some other interpretations on. We are wiring a nuro-care facility, 39 bed, and at each bed there is a medical gas panel that mounts in the wall and it comes complete with 3 - Hospital grade receptacles fed with normal power and 3 - Hospital grade receptacles on a generator panel. Also in the medical gas panel is medical gas (surprising I know). There are gas lines that patients get hooked up to for oxygen etc. These lines are pressurized by a compressor and a vacuum pump. Both the compressor and the vacuum pump are on the generator circuit. The generator is sequenced so that all the loads don't come on at once and stall the generator. The compressor and vacuum pump are part of the generator sequencing process and are delayed to be energized 15 seconds after the generator starts up. The way we did this is we put the compressor and vacuum pump on contactors and we are controlling the coil off the transfer switch because the transfer switch has control wiring that can be delayed. So the generator turns on, the vacuum pump and compressor are off until the transfer switch contacts close which pulls in the contactors for the vacuum pump and compressor.

Now, to make a long story longer. The electrical room where the breakers are located for the vacuum pump and compressor are about 200' away from the mechanical room where the vacuum pump and comressor actually sit. We are putting the contactors in the mechanical room where the pump and compressor sit, but do we need a disconnect in front of the contactors in the mechanical room? The equipment has disconnects on them from the factory, but it's not a typical disconnect that would come with a gear package for instance (I will attach a picture). I know that the obvious answer is ask the AHJ, but I would like to know the facts before I do so.

[]

 

[cadpoint]

Since this a known brand name manufacture, I'm sure they have manufactured this with all the considerations that need to be met and addressed it in respects to this matter.

I'm sure that the supplier knows what thier doing, if it's listed I beleive your fine.

...

What do you mean by lockable tabs on the switches of the main?

I think he is talking about a breaker lock. 422.31

Exactly!

In the picture it's the white insert that are on the knobs themselves, they flip out and either match to an existing hole or allows this piece to be locked in place, IE flipped out.

This knob design requires both pieces to work together to allow for the knob operation. It can only happen with the two parts together, if the white is extended out and locked out, well it's just that.

Some of us might get use to so much steel runs and hard fasten construction that were looking for a steel thrown arm, "Where the lever arm?!" Nope it just a little piece of plastic in a motor rated switch...