Lighting Panel Feeder Switched by Contactor

[xguard]

I have a panel that will supply only lighting loads. Instead of having multiple smaller contactors on the load side of the branch circuits and having 5 or so individual circuits going in to each contactor enclosure, I would like to have a single contactor on the line side of the panel that will interupt or energize the feeder.

Is this type of installation specifically mentioned in the NEC? If so, where? I don't recall coming across it.

Any other good reference material for lighting controls circuits? Handbooks, etc.

Thank you for any help.

 

[iwire]

You describe a very common installation.

In fact if you have the time you can order a panel with a contactor built into it so it's all in one enclosure.

There is no specific NEC section regarding this.

When you choose a contactor for this I highly recommend using a mechanically held contactor for two reasons.

One is that other than when they switch states they are silent, they will never buzz

Two is that if they fail you can manually place them on or off until you repair them

 

[augie47]

I don't see it done as often as I do branch circuit contactors which makes me wonder about the cost comparison.
Two items I would mention is to make sure your contactor is rated for the type lighting load (they often have different ratings for different load types) and if the contactor is going to be in a noise sensitive area you might consider mechanically held contactors to reduce the "humming".
There may well be some electronic means of switching of which this old dinosaur is unaware.

 

[iwire]

I don't see it done as often as I do branch circuit contactors which makes me wonder about the cost comparison.

In my area a great many of the large store uses this panel contactor method to control lighting.

Most of our customers locations will have at least three contacted panels, one for site lighting, one for full inside lighting and the third for employee off hours lighting.

And as you suggest they often go mechanically held.

 

[david]

How do they handle unit equipment / egress lighting in this type of installation. Is there a normal night light circuit from a different panel run throughout the facility.

 

[iwire]

How do they handle unit equipment / egress lighting in this type of installation. Is there a normal night light circuit from a different panel run throughout the facility.

In many cases there is a genset for the emergency circuits, those circuits used to wired with normally closed, magnetically held contactors so they could shut down all the lighting and exits during unoccupied times. Now it is done with listed emergency relays.

In cases with no generator the battery units are feed with dedicated circuits as allowed in large open areas.

Some stores like Lowes, HD, large department stores also put panel contactors on panels or ceiling mounted bus ducts that supply sales floor receptacle outlets so that any displays shut down at night.

I did a large department store where every breaker was a Square D power link remote controlled breaker and there was a key switch at the employee exit, when the key was turned by the last person out almost every circuit would shut down. Receptacles, lighting, egress lighting, exit signs the only circuits left active where data room and management offices.

A power failure or fire alarm trip would restore the egress lighting.

 

[david]

In cases with no generator the battery units are feed with dedicated circuits as allowed in large open areas.

How would the dedicated circuit be supplied from the same panel if the whole panel is on a relay. you must be talking about a normal lighting circuit with battery back-up

 

[iwire]

How would the dedicated circuit be supplied from the same panel if the whole panel is on a relay. you must be talking about a normal lighting circuit with battery back-up

The EBUs and exits are not supplied from the same panel and they don't get locks either. I won't disagree about this being a violation, yet it is pretty much SOP in this area. I don't design them, I just follow the drawings.

Keep in mind no one area of the sales floor is supplied by a single lighting panel, there is always intermixing due to different lighting levels so the failure of a single lighting panel feeder will not place an area in darkness.

That said gensets with emergency circuits are the more common method.

 

[mgookin]

Egress illumination and exit sign illumination are only required when the building is occupied. It's perfectly legal to leave it dark if it's vacant. Those Fortune 500 companies use very good life safety consultants.