G24 PL lamp base, pin to pin distance is 24mm
G24 is the bulb base type for PL fluorescent lamp. The G24 base for the lighting tube is square, with a protruding rectangular base as a support. PL lamp is typically used as a downlight. They are usually installed in either vertical or horizontal position, housed in a reflective lamp case which can hold 1 or 2 PL lamps. They can easily be seen up the ceiling in household, offices, hotels and shopping centre. Generally, in Singapore, we can find two type of PL lamp, 2 & 4 pins.
The most common type is the 2 pins PL lamp which integrate a mechanical light starter inside. When you switch on this PL lamp, you can easily notice that the light take a fraction of a second to strike the light on. You may also hear some soft clicking sound from the starter inside the lamp. Installed closely together with this PL lamp is a magnetic ballast which is hidden inside the lamp casing or above the false ceiling. A magnetic ballast helps to regulate the current to the PL lamp. It looks like a bar of heavy metal on a flat mounting plate. This magnetic ballast can be very very hot, operating the PL for only a couple of minutes. The PL tube itself will also become very hot after some time. Allows the PL lamp to cool down for at least about 10min, before attempting to change the PL lamp. The heat is the main reason why PL fluorescent tube starts to detach from its base after operating for a period of time. This is especially obvious for the horizontal mounted PL lamp where you can often see the tube falling off.
Though there are many disadvantages using the PL lamp, many building maintenance offices still prefer to use PL lamp because the pin plug design makes it a breeze to change the lamp. Simply pull to unplug the lamp and push to replace a new PL lamp. For the maintenance technician who needs to replace hundreds of bulbs every day, this help saves them a lot of time, compare to the E27 screw base.
With the advance in electronic and lighting technology, the replacement for these PL lamps is slowly emerging from the market. LED is currently a well know replacement for these old magnetic ballast PL lamp. The other less known is the electronic PL lamp (international patent still held by saveOne), which is an improve version of a fluorescent lamp. The new PL lamp generates much less heat and draws much lower current from the power line. The lower heat helps improve the lifespan of the lighting tube. It can work with or without the magnetic ballast. Energy consumption is close to the LED version, but the cost is lower. This makes it a better return on investment for building management point of view.
G24 lamp base is still a very popular bulb base used in Singapore. It is definitely still available off the shelve for the next few decades