Lighting Contactor

[mull982]

I am wanting to use a lighting contactor to control a number of 480V lights in the field. I do not have a 480V panel avaliable to take multiple branch circuits through a lighting contactor then out to the field. I do have the option of installing a 480V molded case breaker, so my question was weather or not I can come off of the load side of this breaker to the line side of my lighting contacor and jumper all of the line side contacts, and then pull the multiple lighting circuits off the load side contacts of the lighting contactor.

In other words as long as my branch circuit from the 480V breaker to the lighting contactor is large enough to handle multiple lighting feeds can I use this arrangement to power multiple lights in the field?

 

[teco]

IMO you still have to provide overcurrent protection for the lighting branch circuits. I guess it depends on what the amp rating of the 480 volt breaker would be. I would use a small circuit panel and control the panel with a contactor using the molded case breaker. Say a 40 or 60 amp contactor.

 

[480sparky]

What would be the point of coming off one breaker, then breaking them up across several contactors?

If you only have one 480v circuit, you only need a 2-pole contactor.

 

[teco]

I'm assuming from your post you have more than one branch circuit. If not then what sparky said.

 

[480sparky]

OK. I'm gonna ask for a bit more information. You say you have a 'number of lights'. What is the amp draw of these lights? Is each one 'home-runed' to where the contactor will be, or are there several on each circuit?

My fear is you are going to feed a bunch of 20-amp ciruits with one large (say, 50- or 60-amp) breaker.

 

[augie47]

I would think the installation you desire would call for the contactor and associated circuit to be sized according to the size (ampere) of your molded case breaker. You could run a feeder from your breaker, thru the conatactor and then provide branch circuit protection at the lighting (taps).
Depending on your lighting, you might be ble to use the provisions of 210.24 and a 50 amp circuit, however, I would think, keeping troubleshooting in mind, you would be beter to split the loads up on individual protection;

 

[nakulak]

I have seen contactors that had built in fuses, didn't pay any mind though (never installed in the manner you describe). You might want to see if someone makes one with overload protection that meets your criteria though (might not be something normal but its worth a shot I guess)

 

[jim dungar]

Another problem to consider with a single breaker feeding a large amount of lighting is the inrush current of all of the ballasts.

For example: a 60A breaker may trip when it sees 1450A of inrush current = 24x, given that HID ballasts may have inrush currents of 14x this breaker could be fully loaded. But a 200A breaker might trip at only 2000A = 10x so this breaker could not be fully loaded with ballasts that draw 14X on inrush.

 

[benaround]

If you can install a 480vac MCB then you can install a lighting contactor and

a panel to protect the branch circuits.

 

[mull982]

I have decided that I am going to use 240V branch circuits that I have avaliable and run them through a lighting contactor. I want to use 4 branch circuits, so I am assuming that I want to use a 4 pole lighting contactor? I am going to use 240V lighting, so for each lighting circuit I'm assuming that I am going to take one leg straight to the light, and run the other leg through the lighting contactor?

Is this the correct setup for this application?

 

[Dennis Alwon]

I have decided that I am going to use 240V branch circuits that I have avaliable and run them through a lighting contactor. I want to use 4 branch circuits, so I am assuming that I want to use a 4 pole lighting contactor? I am going to use 240V lighting, so for each lighting circuit I'm assuming that I am going to take one leg straight to the light, and run the other leg through the lighting contactor?

Is this the correct setup for this application?

Get yourself an 8 pole contactor and you will be a much happier person. At least I will be. :smile:

 

[augie47]

Get yourself an 8 pole contactor and you will be a much happier person. At least I will be. :smile:

so will the dummy who decides to work on the lights and fails to check for voltage since they are "off"

 

[SiddMartin]

don't split it at the contactor, you'll have voltage goin in one leg and through the ballast onto the other leg... sux to work on that ...(IMO the breakers would be locked out to work on them anyway) but still, thats like havin a SP t-stat on a 240 BB HTR, buy 2 4P contactors