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]

So that they can be switched by timers and or photo cells perhaps.
How many lights to each cct, relay/contactor?

 

[Pete999]

What he said^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

 

[Ken77]

Depending upon the classroom there are between 4 - 8 twin 5ft tubes per relay.

I can see any evidence of a timer, (not to ay one does not exist).

 

[Deleted member 72666]

Depending upon the classroom there are between 4 - 8 twin 5ft tubes per relay.

I can see any evidence of a timer, (not to ay one does not exist).

Are there any occupancy sensors?

 

[Ken77]

None that I can see.

 

[Jonspark]

isn't there anyone available to ask how there controlled?

 

[Ken77]

Currently controlled via a 1 gang switch - which is why I can't see the point of the relay.

 

[davesparks]

Are they all on the same circuit ?

 

[Jonspark]

its normally like that if the design current is too high for the switch, so this way the switch only carries the load of the relay

 

[Ken77]

I haven't yet determined if all the classrooms are on the same circuit, but there is a relay in each classroom. What where you thinking?

 

[Jonspark]

the load is distributed through the relay instead of the switch. how many channels on the relays are in use?

 

[Ken77]

1 channel

 

[Jonspark]

will the switch take the load?

relays could have been used for future expansion.

 

[Deleted member 9648]

Could be linked to an alarm system to switch on the lights if there is an alarm. ie the security alarm.

 

[Marvo]

Is the relay coil LV or ELV?

 

[Jonspark]

you can't be looking at more than a few amps per circuit and if their controlled by a suitably rated switch can't see the point in relays really

 

[Jonspark]

Could be linked to an alarm system to switch on the lights if there is an alarm.

is there another circuit that energisers the coil

 

[Ken77]

Nor can I. I was trying to understand why this may a have been done as I am not familiar with use of Relays. Thanks for all the help.

 

[Jonspark]

trace out what energisers the coil/whats connected to A1/A2