Emergency lighting

The ones in our factory are (b).

The lights during SEB (or any other power supply) are general lighting. The energencies are off unless the absence of the input voltage triggers the light.

However there are no problems as far as (a) is concerned, just a bit costly that's all.

The normal lighting for the factory is high power gas lamps, and you will need special circuits for the UPS, Additionally these are a bit focussed lights.

Where as the emergencies being at larger spacing should have more spread. Usually these are the flouroscent or similar. It gives lower lux, but spread out.

Emergency lights are self contained lighting packages designed with internal battery power. Main power is routed through a relay, through the relay you charge the battery with one set of contacts keeping the other set open. when power is lost to the relay the relay turns off and allows the n/c contacts to close and turn the emergency light on, at the same time the contacts to the charging unit are opened.

Emergency lighting should be wired directly into the main lighting system and should be used for lighting a safe path through, and out of, your facility for easy egress. It is not used as replacement lighting to work by.

Emergency lights usually only last for a very short time, depending on charge and the condition of the battery. Sometimes they fail after only a few minutes while at other times you may get a couple of hours out of them.

You should have at least a monthly maintenance schedule for your emergency lighting system to test battery strength and lighting. All emergency light units come with a "press to test" button for just this purpose.

I am not familiar with any emergency lighting standards so this maybe an incorrect opinion. I believe that running house lights with a UPS misses one critical scenario of power outage. If the wiring to the house lighting gets shorted a circuit breaker should trip to prevent fire. Without self contained lighting that senses this power loss, people can now be sitting in the dark.

HUH!?

In normal conditions emergency lighting is industrial. We don't typically see this in residential use. Although there is no reason not to use it for home safety.

There is not a UPS, just a back-up battery. A UPS would negate the entire purpose of the lighting. The lights ONLY come on if supply voltage is lost. Or if the "press to test" button is pressed. These lights are not used as normal every day lighting.

Typically, emergency lighting is battery powered and comes on when it detects main power failure. Standards usually dictate a minimum 90 minute life (although that was off an older standard - can't guarantee that's still valid)

However, I have seen installations in office buildings where every fourth or fifth luminaire was designated as "emergency lighting". These would be dual-supplied with main power and UPS (or generator) and acted as both "normal" and "emergency" lighting.

Grae