How to Identify Halogen and Xenon Bi-Pin Bulbs

Jan 11, 13 How to Identify Halogen and Xenon Bi-Pin Bulbs

So one of the bulbs in those little “puck” lights under your kitchen cabinets or the light in your desk lamp has burned out. You may have even had a burn-out with a landscape bullet light. Once you figure out how to get the fixture apart, you find a tiny bulb with two pins you don’t recognize. Now what?

Sure, you can throw the entire fixture out and just get a new one. That may be easier, but it definitely won’t be cheaper. What happens when the bulb burns out again (which it certainly will)? Are you going to just keep buying replacement fixtures?

Relax. We at 1000Bulbs.com have you covered. Identifying and replacing your existing bi-pin xenon bulb (sometimes called ’2-pin bulbs’ or ‘T-bulbs’) is easier than you think. Just follow these five simple steps:

Step 1: Measure the Pin Spacing

How far apart are the pins from each other? You can figure this out by getting a ruler and measuring the space between the pins. The space between the pins is measured in millimeters. Write this measurement down as it will help you find the right base type.

Step 2: Determine the Bulb Voltage

Check the fixture housing or socket and see if there is a label that tells you the voltage of the original bulb. The label will most likely have a UL or CSA symbol. If it’s not on the fixture, try to find it on the bulb itself. When you find the voltage, write it down. If you can’t find the label or the label doesn’t list the voltage, don’t worry. You may still find the correct bulb with some tips coming up in step 4.

Step 3: Check the Pin Type

Now check the pins on your existing bulbs. Are they straight or looped? Most bi-pin bulbs will have straight pins, but there are also bi-pin bulbs that have looped pins. Knowing if the pins are straight or looped will help you to further narrow down your bulb selection. Along with your pin measurements and voltage, make sure to jot down if your pins are looped or straight.

Step 4: Find Your Bulb

Now that you’ve got the bulb spacing, pin type, and (hopefully) voltage, it’s time to find your bulb. If you measured 4 millimeters between pins, that means you have a G4 base bulb, which comes in 6, 12, or 24 volts. If your measurement is just a hair wider than 6 millimeters, you have a bulb with a G6.35 base, which comes in 12, 24, or 120 volts. A measurement of 8 millimeters means you have a G8 base xenon bulb, which only comes in 120 volts. Looped pins spaced 9 millimeters apart means you have a G9 base bulb, which also only comes in 120 volts.

Step 5: Install Your Bulb

After you’ve figured out what bulb you need, installing it is simple. Your fixture has a glass lens that fits over the bulb. After you remove the lens, insert the new bulb into the socket and replace the lens. Be careful not to touch the bulb itself, as the oils on your fingers will damage the bulb, shortening its life and maybe even causing it to melt. Some bulbs come with a wrapping around the bulb to prevent damage when installing them. If your bulb didn’t come with a wrapping, wear gloves or use something to wrap around the bulb, but be sure to remove the wrapping after you install the bulb.

That’s all there is to it. Remember, replacing your bulb is much cheaper than replacing the whole fixture. While replacing the bulb may not be as easy, after a few times, you’ll get the hang of it. If you have any questions about these bulbs or just questions in general, don’t be shy! Drop us a comment in the box below or reach out to us Facebook, Twitter, or Google Plus.

Jordan Loa

Jordan is a copywriter at 1000Bulbs.com. Check back often for new entries in his "Light Post" series of happenings in the world of lighting.

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4 Comments

  1. I need halogen 10 watt 12 volt g4, for outside lighting

    • Jordan Loa /

      L.W.,

      We thank you for reaching out to us! In order to recommend a bulb that fits your needs, we’ll need to know specifically what kind of bulb you’re looking for, such as base type, and what application it’ll be used for. Thanks!

  2. I am just discovering your articles on lights and lighting. They’re so informative! As Director of Operations for my church I must keep up on changes in technology and EISA so that the building will continue to be properly lit in a comfortable and appropriate ambiance. Thank you, and please keep the information coming!

    • Thanks for the kind words, Bob! We’re glad you’re finding our posts to be useful. Let us know if there’s anything else we can answer for you or help you with!

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