"It turned out that there was a seperate 240volt supply to the console for the Fire Emergency shutdown to control the main contactor in the console. "

I don't understand the whole concept of always on electricity in a fire situation. If I understand correctly, power to exit lights cannot be shut off, and there are other circuits, such as a fire alarm system, that may not be breakered, guaranteeing a serious fire if lightning hits that system.

I get the idea that exit lights should somehow be immune to tampering, but this idea seems more dangerous to me than the alternatives. I could maybe accept it more readily if there was a required day-glo insulation that could only be used on fire circuit wiring, but sheesh.

Buildings were in existance before indoor electricity, and water from fire hoses and electricity don't mix, fires in older exit lights must somehow be extinquished, etc. Surely there has to be a better and safer way to deal with this.

Comments? Convince me otherwise?

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I don't understand the whole concept of always on electricity in a fire situation. If I understand correctly, power to exit lights cannot be shut off, and there are other circuits, such as a fire alarm system, that may not be breakered, guaranteeing a serious fire if lightning hits that system.

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The question you have to ask is what is the bigger risk - that of lightning hitting that system or of staff and customers being trapped in a dark building, unable to escape?

In all the cinemas I worked in, power to the emergency (exit) lights could be turned off, but it was a different procedure to the general power supply. The emergency lights worked on a 'primary maintained' system, which was a low voltage supply fed from a bank of lead-acid batteries which, while the mains power remained on, was continuously trickle-charged at the rate needed to offset the discharge. In the event that the mains power failed, local council regulations (i.e. the cinema licence) said that the batteries had to be able to maintain the lights for a set period of time (usually three hours). This automatically kicked in if the mains failed or was switched off, and these systems are regularly tested by simply disconnecting the mains and letting the batteries discharge themselves.

You could turn those emergency lights off altogether, by disconnecting the supply from the batteries from the lighting circuit, but it was utterly verboten to do that when the public are on the premises. On the one occasion I ever had to (when the plant room containing the battery unit flooded), I had to go through a menu system on an LCD panel pressing OK to questions like 'Are you sure you want to do this?', 'Are you still sure?' 'If you do this and there are customers in the building, you are liable for the death penalty, so do you really really want to?' and so on and so forth. However it was never in any of our standard evacuation drills to do this.

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Leo Enticknap -- For auditorium air conditioning, I tended to kill the intakes but leave the extracts on, the thinking being that it would suck oxygen out of the room and help to starve any fire.

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In larger public buildings, like high-rise hotels, there are sets of large fans on the roof which lie dormant during normal conditions but are turned ON when the fire alarm is activated. The idea is to evacuate the (possible) smoke from the building, allowing the occupants to escape more safely. Smoke building up in confined spaces can also cause flash fires. Evacuating the smoke also helps prevent this.

AFAIK, all fire alarm wiring is supposed to be inside watertight conduit and painted red to differentiate it from the rest of the wiring. Except for the AC power to the panel, the majority of it is low voltage anyway, isn't it?

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