Using a Contactor

Broadsword · Feb 21, 2013

Have been advised by the Fire Officer that the supply to the stage area of our large club ( which supplies amplifiers etc for musicians) must be automatically isolated in the event of a fire alarm. At present they use a couple of 13A sockets which are on a ring main. I have no experience of this type of installation and will consult the people who service our fire alarm for advice what I would like would be some advice regarding placement of the contactor and also cable size for the radial which I imagine will be required to supply those two sockets, as I said this is a large club and the sockets in question are around 27 meters from the C/U, the fire alarm panel is only around 5 meters from C/U

Any advice gratefully received.

Des 56 · Feb 21, 2013

You are best to get a contactor to fit the distribution board
You may also need a manually operated emergency stop button wired into the contactor control circuit situated remote from the stage area,perhaps behind the Bar?
You would also need a switch on that control circuit to reset the sockets fed by the contactor

Broadsword · Feb 21, 2013

No room in the Dis board for the contactor I'm afraid so will have to be stand alone.

Des 56 · Feb 21, 2013

I would also add that the reseting of the contactor manually after its been triggered would best be restricted,perhaps by using a key or lockable switch

Knobhead · Feb 21, 2013

As Des has rightly said, as it's an safety circuit it should be wired so it has to be manually reset.
Do you know how to wire a latching circuit?

Broadsword · Feb 21, 2013

Tony said:
As Des has rightly said, as it's an safety circuit it should be wired so it has to be manually reset.
Do you know how to wire a latching circuit?

I shall not be doing this job myself I should imagine that the alarm engineer will be doing it, I am asking just out of general interest

Rockingit · Feb 21, 2013

Might be better to bring the whole circuit out to a new small box (so take a feed from the main CU > cable to a new 4 way enclosure (Gewiss do one for about £10 with a clear lid would be perfect for this) > CPD ) and then just fit a 12V activated shunt trip to knock the circuit off. That way you can just take an aux straight off the alarm panel at 12v and it knocks the whole thing off, rather than having a contactor permanently latched. You have to manually reset them anyway. Hager do a nice one.

tazz · Feb 21, 2013

Standard request from fire officer, usually request house lights to be turn on aswell. For most small clubs, pubs we box up a contactor with reset switch. Contactors used have 24v coil, so straight into fire alarm, emergency buttons are twist rest type, diagram my help your spark.

[ElectriciansForums.net] Using a Contactor

Broadsword · Feb 22, 2013

Thanks to all for the replies. Tazz would I be right in thinking that the emergency buttons on your diagram should be wired in series?

tazz · Feb 22, 2013

Broadswood, they are wired in parallel using normally closed buttons, therefore when they go open the contactor is de energised

Broadsword · Feb 22, 2013

tazz said:
Broadswood, they are wired in parallel using normally closed buttons, therefore when they go open the contactor is de energised

Thanks for that TAZZ, forgive my ignorance but as far as I can see BOTH of those emergency buttons would need to be operated in order to de energise the contactor...............no?

Bobster · Feb 22, 2013

Would a fireman's switch not be easier?

tazz · Feb 22, 2013

Broadsword said:
Thanks for that TAZZ, forgive my ignorance but as far as I can see BOTH of those emergency buttons would need to be operated in order to de energise the contactor...............no?

Sorry your correct, was late when i drew this for you. They do need to be wired in series to de energise,