Concept behind putting fluorescent lights on a contactor.

[Eddy Current]

Ive only ever put outside lights on a contactor. Where we are working now they have all their 4 foot fluorescent lights on contactors. I was told it was because you can put more lights on a circuit but how is that possible the lay in lights only pull a half an amp individually already.

 

[ActionDave]

Naahh, not buying it. The contactor would only make it easier to control more lights.

I remember a K-mart that had the panel with all lighting circuits tied to one contactor. The thing would bang like a small cannon and echo through the storeroom when it was energized.

 

[jumper]

I remember a K-mart that had the panel with all lighting circuits tied to one contactor. The thing would bang like a small cannon and echo through the storeroom when it was energized.

I had some at my old job that you could hear slam closed 2 floors up.

 

[ActionDave]

Depending on what one is doing at the moment the sphincter pucker factor might be quite high I imagine.

 

[infinity]

A contactor would not help with the number of lights on a circuit but it would help with the number of lights that you can control at one time when using multiple circuits.

 

[hillbilly1]

Naahh, not buying it. The contactor would only make it easier to control more lights.

I remember a K-mart that had the panel with all lighting circuits tied to one contactor. The thing would bang like a small cannon and echo through the storeroom when it was energized.

Home Depot does the same thing, two panels, two 200 amp latching contactors. Probably the one you heard was the GE "hammer" latching contactor. The coil is actually 70 volts, but run on 120. Massive arm on a pivot to a small unlatch coil. A few Home Depots have those too. Loved to scare the store manager by overriding it while there standing in the electrical room.

 

[Eddy Current]

A contactor would not help with the number of lights on a circuit but it would help with the number of lights that you can control at one time when using multiple circuits.

Ok i think ive got it. Does anybody know of a good schematic that would show a contractor wired this way?

 

[hillbilly1]

Ok i think ive got it. Does anybody know of a good schematic that would show a contractor wired this way?

Since you have done outside lights with a contactor, just substitute the photocell with a toggle switch or time clock in your wiring. No different.

 

[Eddy Current]

Since you have done outside lights with a contactor, just substitute the photocell with a toggle switch or time clock in your wiring. No different.

Well i should specify that the electrical foreman on the job did all the wiring inside the electrical room i just hooked up the parking lot lights, i was a helper at the time.

 

[broadgage]

There are two main ways by which a contactor may be used to control numerous lighting circuits.
Firstly, a number of lighting circuits may be wired through the same multipole contactor, for example take 8 standard lighting circuits, routing the hot wire of each through one pole of an 8 pole contactor. A single switch may then control all 8 circuits.

For larger installations it would be common to install a dedicated sub panel for the controlled lighting.
As many lighting subcircuits as desired may be run from this panel in the usual way, but the feed into the panel is controlled by a suitable contactor.

Either scheme not only allows numerous lamps to be controlled by one switch but also may save a lot of wire, since only one 2 wire plus EGC need be run to a distant switch. Contactor control may also allow smaller wire to be used for the lighting circuits, a long circuit via a distant switch may need upsized wire, but a shorter circuit from panel to lamp via a contactor might be OK in the code minimum.

As a design note, I consider it very poor practice to control all the lighting in a large office, factory, retail store, etc by a single switch and one or more contactors. Too much risk to life if the contactor coil fails or the cable to the switch is damaged.
I would regard TWO contactors on TWO switchs, each controlling half the lighting to be an absolute minimum, and then only with care taken to avoid any mishap affecting both circuits. Control circuits to the two contactors to be via seperate cables along different routes, to physicly seperated switches. NOT a multicore cable feeding a twin switch.

 

[iwire]

As a design note, I consider it very poor practice to control all the lighting in a large office, factory, retail store, etc by a single switch and one or more contactors. Too much risk to life if the contactor coil fails or the cable to the switch is damaged.

Use normally closed contactors so that they 'fail' on.

That is what we do with a percentage of the lighting in these large spaces

 

[hillbilly1]

Use normally closed contactors so that they 'fail' on.

That is what we do with a percentage of the lighting in these large spaces

That or latching type contactors. We have one customer though, that uses standard N/O contacts in a pre-fab manufactured cabinet. Not real fond of that setup, if the contactor control circuit fails due to shorted contactor coil, all of the contactors drop out. They maybe relying on the night lights, which are not switched, to keep the area from going totally dark.

 

[iwire]

That or latching type contactors.

Those can can and do fail to turn on. But those would be the kind we use for the fixtures we do not use NC contactors for.

And yeah we see the same thing here as well, redundant lighting circuits but all controlled by one control circuit. No a good plan.

 

[Eddy Current]

There are two main ways by which a contactor may be used to control numerous lighting circuits.
Firstly, a number of lighting circuits may be wired through the same multipole contactor, for example take 8 standard lighting circuits, routing the hot wire of each through one pole of an 8 pole contactor. A single switch may then control all 8 circuits.

For larger installations it would be common to install a dedicated sub panel for the controlled lighting.
As many lighting subcircuits as desired may be run from this panel in the usual way, but the feed into the panel is controlled by a suitable contactor.

Either scheme not only allows numerous lamps to be controlled by one switch but also may save a lot of wire, since only one 2 wire plus EGC need be run to a distant switch. Contactor control may also allow smaller wire to be used for the lighting circuits, a long circuit via a distant switch may need upsized wire, but a shorter circuit from panel to lamp via a contactor might be OK in the code minimum.

As a design note, I consider it very poor practice to control all the lighting in a large office, factory, retail store, etc by a single switch and one or more contactors. Too much risk to life if the contactor coil fails or the cable to the switch is damaged.
I would regard TWO contactors on TWO switchs, each controlling half the lighting to be an absolute minimum, and then only with care taken to avoid any mishap affecting both circuits. Control circuits to the two contactors to be via seperate cables along different routes, to physicly seperated switches. NOT a multicore cable feeding a twin switch.

I think in this case there are 3 circuits per contactor's and 2 contactor's.

 

[hillbilly1]

Those can can and do fail to turn on. But those would be the kind we use for the fixtures we do not use NC contactors for.

And yeah we see the same thing here as well, redundant lighting circuits but all controlled by one control circuit. No a good plan.

Yes they do, but they fail in the last position they were in, so if the store was already dark, then there's no change, if the control circuit fails while the store is open, the lights still stay on. Much easier to get than the N/C electrically held variety, plus no humming when energized.