How To Change A Double-ended Halogen Bulb

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In some cases, improper use and installation may result in a breach of insurance. Even worse, you could be putting yourself or your family at risk as an incorrectly installed electrical device could start a fire. So, don’t risk it - seek the services of a fully licensed electrician instead.

A Double-ended halogen bulb has an R7S cap type. These are long bulbs which are commonly found in wall fittings, floor lamps, and garden flood lights.

They are available in 78 or 118mm sizes and in wattages ranging from 100W to 500W, although the latter is only really found outdoors in flood lights. These bulbs tend to last for at least 3,000 hours of usage. 

Double-ended Halogen bulb

They are known as double-ended bulbs as they have 2 spring loaded contact points to hold the bulb in place. This mechanism makes changing the bulb a breeze. The bulbs tend to have a T3 shape, meaning they are ⅜ inch in diameter.

They can also be found in T5 (⅝ inch diameter), T8 (1 inch diameter), and T12 (1 ½ inch diameter) shapes. They are also known as J- and T-type lamps. These are most suited to enclosed fixtures. 

How do halogen light bulbs work?

The electrical current travels through the light bulb and heats up the thin wire filament contained inside. The light given off is bright and white, meaning that they are very illuminating. 

Halogen light bulbs are filled with a special halogen gas, such as Bromine, and an inert gas. The inert gas acts to suppress the tungsten filament evaporation.

Simultaneously, the halogen gas reduces the quantity of tungsten plating the interior sides of the lamp. The tungsten is instead deposited back onto the filament, meaning that the lamps have a much longer lifespan and are more energy efficient.

What safety precautions should you take when changing a halogen bulb?

You must first switch off the power supply to the bulb, or unplug it from the electrical socket. Leaving the power supply on could lead to you getting electrocuted or otherwise injured. 

Allow it to cool completely before you even attempt to go near the light. You should wait for at least 10 minutes before giving the bulb a quick tap to check the temperature. If you need to unclip the bulb from metal prongs, you should wait at least 20 minutes to allow the metal to cool sufficiently. 

How To Change A Double-ended Halogen bulb

If your light fixture contains heat guards or protective coverings, we recommend taking a picture of them before removing. This ensures that you know where they are located and do not replace them in the wrong positions. 

We do not advise touching the outside of your halogen light bulb with your bare fingers. The exterior is made of quartz rather than standard glass, to ensure it can withstand the higher temperatures when the light is switched on.

The oils and salts that occur naturally on the surface of your fingers can cause damage to the bulb casing. They can force the heat to concentrate in specific locations, which can lead to the bulb shattering or breaking prematurely. We advise using a paper towel or glove to handle the bulb. 

When unscrewing the light bulb, use a gentle but firm grip to ensure you do not crack or smash the thin glass housing. If you are concerned, we recommend using a glove or cloth to further protect your hands. Unscrew the bulb in a counterclockwise motion if it is a screw fitting.

If it is a bayonet fitting push the end in and rotate. If you feel like you have to use a lot of force to change the position of the bulb, we do not recommend continuing. Instead, contact a qualified electrician to assist you. 

When disposing of halogen light bulbs, ensure you wrap them in a few layers of old newspaper. This means that if they smash, you and others around you are less likely to be injured. We advise contacting your local city to see whether you can recycle or dispose of your light bulbs with the rest of your trash. 

How do you clean a halogen bulb once it has been touched?

You should find a clean and lint free cloth as well as a small bowl of rubbing alcohol or methylated spirit. 

Dip the cloth into the liquid and use this to wipe the dirty section of the light bulb. 

Grab a second, dry cloth and use this to wipe any moisture off of the exterior of the light bulb. The bulb must be completely dry before you reinsert it into the fixture. 

How do you change a double ended halogen bulb?

The issue that people tend to find when changing a double ended bulb is that the socket cannot be moved. Pay attention to the springs found on either side of the lamp. 

Your first step is to take the glass out of the fixture before you attempt to touch or move the lightbulb. Grab a flathead screwdriver and use this to gently tap on one side of the bulb.

Press on the spring load using the head of the screwdriver. As you do this, gently and slowly pull out one side of the bulb. 

Repeat this process on the other side of the bulb. Snap out the second side of the bulb and remove it completely from the fixture. 

You will need to check the size and specifications of the old bulb to ensure that the new one will fit. Pay attention to the number after the T and ensure your new bulb matches.

When inserting the replacement bulb, attach one side first and then pop in the other. Switch on the light to test whether the bulb comes on. Once you are satisfied that it works, reattach the glass. Test once more and you are good to go. 

Why does my halogen light keep blowing?

This could be because you are purchasing low quality bulbs where the filament is much thinner and burns through faster. It may be because your light bulb has got wet, or has been touched with the oils on your fingers.

It may just be simply due to leaving the lights on for an extended period of time, causing them to overheat.