Junction type box

[ban-all-sheds]

Indeed they do.

And if this system has been neglected the management company should be prosecuted.

Emergency lighting did not arise out of the goodness of property-owners' hearts, it became mandated because people had died through lack of it.

 

[333rocky333]

When/how would it light up?

They work as simon said, the OP has often referred to a battery as if theres only one, these systems are old and they confuse some, the panel has 1 or more batteries dependant on load, when the panel loses power, then it outputs a voltage often only about 50 volt to light the fittings.
Bigger systems have 3 phase sensing.
Systems are only really good for a total supply loss rather than a local circuit failure.
The fittings are 8watt T5 and look similar to mains units but have no indicator light and inside is a small electronic circuit that runs at 50 volt, they should be labelled such if they are, only a couple of weeks ago I found a 240 volt fitting put where a 50 volt unit once was, obviously never tested.
Some panels have a switch that toggles between Maintained and non maintained, to extend lamplife.
Before the self contained units become popular they were used a lot in Licenced premises and it was a condition that the lights had to be switched to Maintained whilst trading.

 

[SUNRAY]

They work as simon said, the OP has often referred to a battery as if theres only one, these systems are old and they confuse some, the panel has 1 or more batteries dependant on load, when the panel loses power, then it outputs a voltage often only about 50 volt to light the fittings.
Bigger systems have 3 phase sensing.
Systems are only really good for a total supply loss rather than a local circuit failure.
The fittings are 8watt T5 and look similar to mains units but have no indicator light and inside is a small electronic circuit that runs at 50 volt, they should be labelled such if they are, only a couple of weeks ago I found a 240 volt fitting put where a 50 volt unit once was, obviously never tested.
Some panels have a switch that toggles between Maintained and non maintained, to extend lamplife.
Before the self contained units become popular they were used a lot in Licenced premises and it was a condition that the lights had to be switched to Maintained whilst trading.

I had often worked on a system that originally had had a central NIFe battery and around the building were cast iron boxes containing a permanently operated mains relay and a 24V lamp which sat inside a clear dome (think Morris 1000 side lamp) mounted on the lid. It was installed before the war and around 1972 I helped remove and re-install it in another building (small theatre), in use until about 10 years ago and finally removed completely several years later.

 

[333rocky333]

I had often worked on a system that originally had had a central NIFe battery and around the building were cast iron boxes containing a permanently operated mains relay and a 24V lamp which sat inside a clear dome (think Morris 1000 side lamp) mounted on the lid. It was installed before the war and around 1972 I helped remove and re-install it in another building (small theatre), in use until about 10 years ago and finally removed completely several years later.

That would be better for localised failure than sensing the buildings supply, though wouldn't the relays get hot and eventually destroy themselves.
I love finding wacky old systems like that we do a lot of old bingo halls and occasionally find old redundant set ups that never got removed, i like the fittings with 1 Mains voltage BC holder and another Sbc holder with a Lower voltage lamp

 

[JohnW2]

That would be better for localised failure than sensing the buildings supply, though wouldn't the relays get hot and eventually destroy themselves.

Relays should be rated for continuous powering of the coil.

I have small 'power failure' relays in my house (which switch on lights powered by other phases in the event of a single-phase failure) which, give or take the occasional very brief power cut or power-down for maintenance, have been 'powered up' continuously for nearly 30 years. None has needed to be replaced, and all still 'open' satisfactorily if the power to the coil is removed.

Kind Regards, John

 

[SUNRAY]

That would be better for localised failure than sensing the buildings supply, though wouldn't the relays get hot and eventually destroy themselves.
I love finding wacky old systems like that we do a lot of old bingo halls and occasionally find old redundant set ups that never got removed, i like the fittings with 1 Mains voltage BC holder and another Sbc holder with a Lower voltage lamp

In the time I had any dealings only one failed, but it was the spring went soft, not the coil. Fortunately there were a number of spare units. The bigger problem was the charger.

The post office in Chatham used to have big opaque glass lampshades and I remember as a youngster wondering why several of them had the shadow of a second bulb.