PL Fluorescent Lamp

2 pin PL lamp

2 pin PL lamp

PL Fluorescent Lamp is quite a popular bulb choice for downlight use. Many of these bulbs can be seen in hotels, shopping centre, offices and household. There is various PL lamp socket available but the G24 socket is the standard in Singapore. The pins are 24mm apart.

Many building management teams use this type of 2 pins PL lamp because it is very easy to replace. Unlike the E27 bulb where the technician needs to screw the bulb in/out, PL lamp is a simple action of plug and unplug; bulb replacement is fast. Compare to the T8, T5 tube which is long and easy to break, PL lamp is small, compact and easy to store. PL lamp is small compact, suitable for designer lighting. This made PL lamp the number one choice for hotels, shopping centres, offices, etc…

2 pin PL Lamp

2 pin PL Lamp

4 pin PL Lamp

4 pin PL Lamp

Generally, there is 2 different type of PL lamp, the 2 pins and the 4 pins version. 4 pins PL lamp is not very common in Singapore. It is actually a raw fluorescent tube is like a T8 or T5 tube which has a pair of pins at both ends of the tube. This is the 4 pins of this PL lamp. Usually, this type of lamp is used as a dimmable bulb which has to be driven electronically by an electronic dimmer. Typical smart home/office setup uses this for controlling the lighting. This type of light is not commonly available which makes this simple bulb slightly more expensive. It is typically available in the specialised lighting store.

light starter

Light Starter

Most PL lamps available in Singapore today (2015) is using the 2 pins  PL lamp. The fluorescent tube is the same as the 4 pins version. It is integrated with a small light starter inside, with two of its pins. This is the reason why the tube has only 2 pins on the outside. When you switch on your light, you may see light flickering for a fraction of a second before it is switched on. During the flickering, you may also hear a soft clicking sound, from the starter, attempts to light up the lamp. Sometimes it can take a few seconds for the starter to strike up the tube. It is a brute force method to light up a bulb.


magnetic ballast

Magnetic Ballast

This 2 pins PL lamp operates in series with a magnetic ballast wired to our 230Vac supply. This setup is like the typical round fluorescent tube connected to a magnetic ballast and a starter used in many of the Singapore households. This is an old type of fluorescent configuration. Though it is a lot of energy saving compared to the incandescent bulbs, it is not compared to today’s standard. If you ever walk into our local stores, to buy the typical Philips PL Lamp, take a look at their product packaging. Claim 80% savings over the incandescent bulb. They are not wrong over the 80% claim, just that they are comparing with the very old incandescent light bulb. Instead of using the normal PL lamp available on the market, consider using newer fluorescent bulb or LED bulb which can easily reduce your electrical consumption further by about 50%.

 The lamp takes in higher current which makes the magnet ballast very very hot after operating for a couple of minutes. The lamp itself is also very hot. If your lamp is switched on 24hrs a day, 365 days a year (like hotels and shopping centre), you may notices that PL lamp’s fluorescent tube starts to detach itself from its base. This is especially obvious with PL lamp installed in a horizontal position. This is because of the heat generated from the ballast and the lamp. Energy is being converted to heat instead of light. The heat can also affect the lifespan of the fluorescent tube. Be sure to switch off and wait for the lamp to cool before any attempt to replacement the bulb.

For PL lamp, people buy it to replace their existing faulty bulb in their downlight. So which should you choose for your new bulb replacement? New energy saving electronic fluorescent or LED PL lamp?

In terms of energy consumption and generated heat, both electronic fluorescent and LED has a comparable performance. Both have similar brightness performance given the same wattage power. A significant advantage of using LED is that it does not have mercury content, and do not have a glass tube that may shatter. The lifespan of the LED is about 2-3 times the electronic fluorescent.



LED generate light in a single direction. They are best suited for new lamp design. To use LED in the limited tight space within your existing downlight reflective case can be challenging. In order to produce more light, it is best that the LED PL is designed to illuminate in an omnidirectional, just like a fluorescent tube. If not, it may not be able to provide enough light in the constraint downlight space.

Some LED PL lamp uses high power LED, which is able to generate more light from the smaller area. These LED can produce enough like equivalent to the normal PL lamp, however, the heat generated from high powered LED is more. If you notice a heat sink for the LED lamp, it is a clear sign that the LED inside is a high power type. High powered LED is commonly used in spotlight bulb. Tight space, high power. Comparing high powered LED, the low powered LED has much better energy efficiency because less power is converted to heat.

Note: You may like to check out a newer generation of LED PL lamp which produces lesser heat.

For a more effective replacement to LED, it is recommended to replace with the entire downlight with LED downlight instead of the PL lamp bulb.

saveOne PL Lamp

saveOne PL Lamp, G24 Electronic Energy Saving

Alternative to LED is the saveOne half spiral PL lamp (patent currently still held internationally by saveOne). It is the energy saving version designed to replace the old type of PL lamp. It looks quite similar to a typical PL lamp, except that it has a much larger base to house the electronic driver to control the fluorescent tube. The electronic driver helps optimise the power. Using less energy to provide more light. Most energy saving bulbs in the market are electronically driven now. The electronic driver replaces the magnetic ballast and the internal starter of the PL lamp. Besides energy saving, you will also notice that the lights get to turn on instantly. This is unlike the normal PL lamp where it will flicker itself for a fraction of a second to start up the light.

Replacement to this electronic PL lamp is as simple as the normal PL lamp for your existing lamp socket. The electronic PL lamp from saveOne is designed to work with existing ballast.

This PL lamp can also be wired directly to 230Vac power without the magnetic ballast, it works just as well. The energy saving is the same with or without the magnetic ballast. Compare to the old type of PL lamp, energy saving is about 40-50%. If the existing magnetic ballast is available, it is recommended not to remove it. In case someone is not aware and plug in a normal PL lamp. Operating a normal PL lamp without the ballast will blow out the PL lamp; it will not explode, but just a soft pop sound.

saveOne PL lamp has a high power factor of about 0.98 which is very near to 1.0. This mean that it will draw very little current. This is also the reason why no heat is generated from the magnetic ballast even when it is connected. You will not be able to feel a significant heat from the magnetic ballast after operating it for a few hours. Without the heat generated, it helps translate to a longer bulb lifespan. The reduced heat will also indirectly improve your air conditional energy consumption. This is especially significant in places like the hotel, and shopping centre where they operate lights and air-con 24 hours daily.

The saveOne PL lamp tube is also designed with a spiral shape which reduces light blockage and allows more light out. A spiral tube design also makes it less prone to crack when handling. Always hold near the base for PL lamp with straight U-tube design. Pulling the tube out by holding the end of the tube can crack the tube. This is due to the leverage force. A spiral structure is much robust and is less likely to crack during handling.

Do note that fluorescent tube contains mercury vapour. Although the mercury content level is low and probably not cause a serious health hazard, it is still important to clean the environment properly if the fluorescent tube is broken accidently.

saveOne PL lamp uses a new generation of tri phosphor coating on the tube which enables more lights to be generated. You may have seen it in some of the fluorescent product in the local market. They are usually marketed as “extra bright” and usually cost more than the other similar bulb family.

  saveOne PL Lamp LED PL Lamp 2 pin PL Lamp
Features Comparison saveOne
PL Lamp
PL Lamp
PL Lamp
Energy Saving X
Low Cost X ✔ ✔
Low Heat X
Longer Life Span X
Instant Light On X
 Faster ROI X   X
spiral design
no glass
 No Mercury  X    X
Electronic Ballast X
High Power Factor X