517.30(C)(1) Separation from Other Circuits

[DetroitEE]

I have a hospital application where I would like to control a contactor coil with a 120V critical branch circuit. The problem is that I would like this contactor to switch both normal power and critical power circuits, however it appears that 517.30(C)(1) prevents me from specifying such an installation:

(1) Separation from Other Circuits. The life safety branch and critical branch of the emergency system shall be kept entirely independent of all other wiring and equipment and shall not enter the same raceways, boxes, or cabinets with each other or other wiring.
Wiring of the life safety branch and the critical branch shall be permitted to occupy the same raceways, boxes, or cabinets of other circuits not part of the branch where such wiring complies with one of the following:
(1) Is in transfer equipment enclosures
(2) Is in exit or emergency luminaires supplied from two sources
(3) Is in a common junction box attached to exit or emergency luminaires supplied from two sources
(4) Is for two or more emergency circuits supplied from the same branch
The wiring of the equipment system shall be permitted to occupy the same raceways, boxes, or cabinets of other circuits that are not part of the emergency system.

Does anyone know of any way that this installation could be legal? I will be using a mechanically held contactor such as this one:
http://www.drillspot.com/products/147545/Square_D_8903LXO1200V02_Multipole_Lighting_Contactor

I am thinking that perhaps with an enclosure with some appropriately placed voltage barriers this is possible, but I'm not 100% sure.

I know that I could do this with separate contactors and separate circuits, but that is not desirable for this application. I would like the push of one button to switch these circuits from both normal and critical branches. Relay panels are not an option for this situation.

Any thoughts?

 

[Strife]

I could swear control circuits are exception to these/that rule. I think #1 bellow is your answer (IS IN TRANSFER equipment enclosure.)

I have a hospital application where I would like to control a contactor coil with a 120V critical branch circuit. The problem is that I would like this contactor to switch both normal power and critical power circuits, however it appears that 517.30(C)(1) prevents me from specifying such an installation:

(1) Separation from Other Circuits. The life safety branch and critical branch of the emergency system shall be kept entirely independent of all other wiring and equipment and shall not enter the same raceways, boxes, or cabinets with each other or other wiring.
Wiring of the life safety branch and the critical branch shall be permitted to occupy the same raceways, boxes, or cabinets of other circuits not part of the branch where such wiring complies with one of the following:
(1) Is in transfer equipment enclosures
(2) Is in exit or emergency luminaires supplied from two sources
(3) Is in a common junction box attached to exit or emergency luminaires supplied from two sources
(4) Is for two or more emergency circuits supplied from the same branch
The wiring of the equipment system shall be permitted to occupy the same raceways, boxes, or cabinets of other circuits that are not part of the emergency system.

Does anyone know of any way that this installation could be legal? I will be using a mechanically held contactor such as this one:
http://www.drillspot.com/products/147545/Square_D_8903LXO1200V02_Multipole_Lighting_Contactor

I am thinking that perhaps with an enclosure with some appropriately placed voltage barriers this is possible, but I'm not 100% sure.

I know that I could do this with separate contactors and separate circuits, but that is not desirable for this application. I would like the push of one button to switch these circuits from both normal and critical branches. Relay panels are not an option for this situation.

Any thoughts?

 

[DetroitEE]

I could swear control circuits are exception to these/that rule. I think #1 bellow is your answer (IS IN TRANSFER equipment enclosure.)

That's kind of what I was hoping....that this is somehow exempt from this requirement since it's a control circuit, though that code article doesn't make exceptions for control circuits. Is a critical branch circuit used as a control circuit still considered a critical circuit? I would assume so. Also, I don't think this application is considered in a transfer equipment enclosures, I'm pretty sure they are specifically talking about an ATS.

 

[stevebea]

I have a hospital application where I would like to control a contactor coil with a 120V critical branch circuit. The problem is that I would like this contactor to switch both normal power and critical power circuits, however it appears that 517.30(C)(1) prevents me from specifying such an installation:

(1) Separation from Other Circuits. The life safety branch and critical branch of the emergency system shall be kept entirely independent of all other wiring and equipment and shall not enter the same raceways, boxes, or cabinets with each other or other wiring.
Wiring of the life safety branch and the critical branch shall be permitted to occupy the same raceways, boxes, or cabinets of other circuits not part of the branch where such wiring complies with one of the following:
(1) Is in transfer equipment enclosures
(2) Is in exit or emergency luminaires supplied from two sources
(3) Is in a common junction box attached to exit or emergency luminaires supplied from two sources
(4) Is for two or more emergency circuits supplied from the same branch
The wiring of the equipment system shall be permitted to occupy the same raceways, boxes, or cabinets of other circuits that are not part of the emergency system.

Does anyone know of any way that this installation could be legal? I will be using a mechanically held contactor such as this one:
http://www.drillspot.com/products/147545/Square_D_8903LXO1200V02_Multipole_Lighting_Contactor

I am thinking that perhaps with an enclosure with some appropriately placed voltage barriers this is possible, but I'm not 100% sure.

I know that I could do this with separate contactors and separate circuits, but that is not desirable for this application. I would like the push of one button to switch these circuits from both normal and critical branches. Relay panels are not an option for this situation.

Any thoughts?

Why not use two contactors in two enclosures and parallel the coils? It's still one push to pull in both coils.

 

[DetroitEE]

Why not use two contactors in two enclosures and parallel the coils? It's still one push to pull in both coils.

True, I considered that also. What I want to know is for the enclosure that is switching the normal power circuits, if the circuiting feeding the coil is a critical branch circuit, isn't that a violation of the mentioned code section? Is there some exception for control circuits in this situation?

 

[steve66]

True, I considered that also. What I want to know is for the enclosure that is switching the normal power circuits, if the circuiting feeding the coil is a critical branch circuit, isn't that a violation of the mentioned code section? Is there some exception for control circuits in this situation?

In my opinion, if use a low voltage supply (say 12 volts or 24 volts) for the relays, you won't need a normal branch circuit in the relay enclosure for the LS circuit. (I believe the code requirement only applies to branch circuits, not low voltage circuits which would be much less likely to cause any problems that would affect the LS circuit).


Also, there are some emergency lighting relays that separate MIGHT work for this application. Bodine makes one. Its normally used to turn on an emergency circuit when a normal circuit fails, but it might be adaptable to your application.