‘We have been asked to convert from a normal light fitting to an emergency light fitting. The fixture is a wall-mounted well-glass bulkhead that uses a GLS lamp. Is there any way of making this an emergency fixture, even if the batteries were not actually attached to this fitting but within a separate enclosure?’
The first thing to remember is that there are special obligations surrounding emergency lighting, and it is always best to have any conversion work done by a company that is competent in such work and can provide suitable guarantees for the work undertaken.
There is no problem in having a remote conversion pack located near to the fixture. However, if the emergency pack is more than one metre away, the interconnecting cable would have to be in a fire-rated containment, such as MICC cable or suitable conduit. The cable size would need to be a minimum of 1.5mm².
It is essential that the batteries in the converter pack are permanently connected to the mains supply. This may require new cabling to be installed to the converter pack. This does not alter the usual switching arrangement of the fixture.
There is a wide range of LED GLS lamps, and they all have different operating characteristics. The lamp used should be tested to ensure it is suitable to run as an emergency light source, and what sort of emergency pack it should operate from.
An important note: Traditionally, emergency conversions would be carried out by breaking into the secondary, extra-low voltage part of the circuit between the driver and the load, thus reducing the amount of power required from the batteries to run the load at a lower output for three hours.
In this case, the lamps that would be used would require a 240Vac input. In effect, you would be powering the primary side of the driver at full power. There are LED GLS lamps available that could be used in this scenario, run from smaller emergency packs and delivering a lower light output than normal. But, generally, LED GLS lamps require a pure sine wave AC voltage for them to work. it would be an extremely expensive option to power a small load like this.
Your emergency lighting supplier should have data on which LED GLS 240V lamps will work from smaller emergency kits. If not, please speak with the Liteplan technical office who will be able to advise you.
To read other questions answered by Jonathan Bell at Liteplan Limited click here.