Fluorescent lights and relays

[Ken77]

Hi all,

I've just been to test a number of faults and have found a number of classrooms have relays on fluorescent lights? Can anyone think of a logical reason why someone would have installed them like this?

Thanks in advance.

 

[Deleted member 72666]

It could be that there's a gang of master/key switches near the entrance so the caretaker can make sure none of the lighting is accidently left on.

 

[GEOFF S]

Surely that will depend on the contactor?

To a degree, i doubt they would be vastly different.

Cheers

 

[Charlie_]

Specific lighting contactors are good for their ratings..
i.e. A 20 amp lighting contactor is rated to 20 amps for resistive, magnetic and tungsten

 

[davesparks]

To a degree, i doubt they would be vastly different.

Cheers

They can be vastly different, the switching duty will make a big difference, one which can handle heavy inductive loads will cope with a lot more fluorescents than one only rated for resistive/light inductive loads.

 

[GEOFF S]

They can be vastly different, the switching duty will make a big difference, one which can handle heavy inductive loads will cope with a lot more fluorescents than one only rated for resistive/light inductive loads.

Well the schneider 16amp contactor states 10 x 58w fluorescent, do you have an example?

cheers

 

[GEOFF S]

Abb do a contactor A26 45amp (high rating than the schneider) with a 25amp CB, and that can handle 35 X 65W. I was referencing a 16 amp, do you have one in mind Dave?

Cheers

 

[Marvo]

Check out the IEC utilisation code on the device. It will usually rate the switch contacts AC-1 linear load to AC-4 motor load, the ratings will be between AC-1 and AC-23. http://support.automationdirect.com/docs/iec_contactors.pdf