Understanding common household light bulb shapes, sizes, and styles is important whether you’re converting outdated incandescent fixtures into energy-efficient ones or using LED bulbs for new-construction applications. Every light bulb has identifying characteristics that are represented by a letter or series of letters and a number; these are known as light bulb codes. The letter or letters in a bulb code indicate either shape or special features such as reflector type. Numbers in a bulb code indicate size in millimeters or eighths of an inch. These codes will tell you if a bulb will fit in your fixture and if it’s the right shape.

For every light fixture or application, there’s going to be a specific bulb or light bulb shape that will fit best and provide the right type of light. If you understand bulb codes, it’s easy to look at a light fixture and know right away what kind of bulb you’ll need.

Let’s talk about light bulb groups, their bulb codes, and what applications those bulbs are typically used for.

Standard/arbitrary (A) bulbs are the most widely used and thought of when it comes to household lighting. These bulbs work well for a variety of applications, such as ceiling lights, lamps, vanity lights, kitchen lights, closet lights, porch light fixtures, and so many more.

Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.

A15 bulb: 15/8 = 1-7/8″ diameter

A19 bulb: 19/8 = 2-3/8″ diameter

A21 bulb: 21/8 = 2-5/8″ diameter

A25 bulb: 25/8 = 3-1/8″ diameter

Most common base types:

Globe (G) bulbs have a full, round shape and are available in various sizes. They can be used for many applications throughout the home, such as foyer lights, kitchen lights, chandeliers, and ornamental fixtures. The most common type is the large G30 bulb, which is used in bathroom and makeup vanities.

Depending on the bulb, numbers in each code can refer to the bulb’s diameter in one-eighths of an inch or in millimeters.

G11 bulb: 11/8 = 1-3/8″ diameter

G14 bulb: 14/8 = 1-3/4″ diameter

G16/G50: 16/8 = 2″ diameter

G60: 60 millimeters = 2-3/8″ diameter

G25/G80: 80 millimeters = 3-9/64″ diameter

G30: 30/8 = 3-3/4″ diameter

Most common base types:

All of the bulbs in these groups resemble the shape of a candle flame and are often referred to as candle bulbs. Conical (C) bulbs are shaped like a cone. Conical angular (CA) bulbs are shaped like a cone but have a bent tip. Blunt-tip (B) bulbs are very similar to C-type bulbs but have more of a torpedo or bullet shape. These bulbs can be used in chandeliers, wall sconces, pendant lights, night lights, decorative light strands, holiday light strands, and other decorative home lighting applications.

Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.

B10 bulb: 10/8 = 1-1/4″ diameter

CA10 bulb: 10/8 = 1-1/4″ diameter

C7 bulb: 7/8 = 7/8″ diameter

C9 bulb: 9/8 = 1-1/8″ diameter

C15 bulb: 15/8 = 1-7/8″ diameter

Most common base types:

BR stands for bulged reflector. Traditionally, the inside surface of an incandescent BR bulb is covered in reflector material that is used to gather and cast a wide beam of light away from the bulb. LED BR bulbs don’t require the reflector material. These bulbs can have a frosted, clear, or patterned dome-shaped lens that diffuses light and provides a gradual fade into nonilluminated areas. BR bulbs also produce less shadows when compared to PAR bulbs. They’re a bit longer than PAR bulbs and tend to protrude from light housings but are used in similar applications, such as track lights, recessed lights, display lights, or can lights.

BR20 bulbs are often referred to as R20 but have the same characteristics of other BR bulb types. The R stands for reflector.

Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.

BR20/R20 bulb: 20/8 = 2-1/2″ diameter

BR30 bulb: 30/8 = 3-3/4″ diameter

BR40 bulb: 40/8 = 5″ diameter

Most common base type:

Multifaceted reflector (MR) bulbs are small in size with a reflective, faceted interior. The facets create a concentrated beam of light that can be displayed in a narrow spot or wide flood beam pattern. Because of the directional light they provide, MR LED bulbs don’t require the facets but often still have them. These bulbs are available in a variety of colors and can be used for many applications, including track lighting, recessed lighting, desk lights, and display case lighting. Many MR bulbs operate on low-voltage wiring systems, which makes them great for outdoor and landscape applications such as driveway lights, path lights, gazebo lights, paver lights, and malibu lights that have weatherproof housings.

Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.

MR11 bulb: 11/8 = 1-3/8″ diameter

MR16 bulb: 16/8 = 2″ diameter

Most common base types:

Tubular (T) bulbs come in a variety of lengths and widths. Depending on their size, these bulbs can be used in applications ranging from chandeliers, wall sconces, and pendant lights to basement and garage troffer light fixtures.

Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.

T7 bulb: 7/8 = 7/8″ diameter

T8 bulb: 8/8 = 1″ diameter

T10 bulb: 10/8 = 1-1/4″ diameter

T14 bulb: 14/8 = 1-3/4″ diameter

Most common base types:

A good number of the calls I get during an average day at work fall into two categories;   customers who call to have something installed in their electrical system, and customers who tried to install it themselves and are calling me to come and fix the mistakes they made.  There’s certainly nothing wrong with trying to perform basic electrical work yourself if you have a good grasp on proper electrical safety techniques and what you’re doing.  On the other hand, there’s nothing wrong with calling a top Dallas electrician to do the work for you either.  The best way to ensure the job is done right every time is to hire an honest, hardworking professional electrician who’ll stand behind his work.

Even tasks that can seem quite simple can be treacherous if you’re not sure what you’re doing.  This comes into play a lot when a homeowner is trying to perform a three-way switch installation.  It seems a lot easier to install than it really is; I generally recommend homeowners not attempt to install three-way switches without at least a electrician on the phone to walk you through the process.  Keep the following in mind:

There are tasks well suited for the do-it-yourself minded homeowner, though.  The easiest is wall outlet replacement, which is usually a very simple, straightforward procedure.   That doesn’t mean the haystack isn’t free of the odd needle that you can hurt yourself on, though.  Here are some of the more common problems I run into, along with some typical solutions or hints to keep them from happening to you: 

By Kristin Waites

Warm weather makes it more appealing to be outside after the sun goes down, and do-it-yourself lighting projects can add a distinctive flair to outdoor gatherings. Mr. Electric® has ways to power your tomorrow and help make your backyard the place to be on summer evenings with these great DIY backyard lighting ideas.

This inventive project uses a small can, a thrift-shop vase and a wooden stick to create outdoor lighting that looks store-bought. It requires a few simple tools, but is very quick to put together. Real or battery-operated candles inside the vase will cast a dreamlike glow across your yard. Try making a few of these and lining a sidewalk or porch with them.

Recycle old wine bottles by making a mosquito-repelling torch. All you need is a bottle, washer, wick, and citronella oil. You can add decorative stones or rocks to the bottom of the bottle to decrease the amount of oil you need. This can also help weigh the bottle down if you are worried about stability. Place the torches around the backyard where the flame won’t be blown out.

This project turns recycled cans into lanterns that can be painted and hung outside. Some of the steps require extra time, so plan ahead. Lanterns are a simple way to add color and light to your backyard or porch. Not only are they fun and easy to make, you can customize the paint colors and design to fit the atmosphere you want.

This is a simple project that can add lots of character to your yard. All you need is an opaque glass light shade and a string of lights. The string lights can be coiled inside of the shade and when placed around the yard, add a muted glow. They are also simple but striking decorations during the daytime. A benefit to this project is that the orbs are easy to reposition throughout the yard. Invest in a few extension cords to make sure you can put the lights exactly where you want them.

With winter descending full force, residents of northern states are bracing for the potential of major blizzards. Of course, other extreme weather events like hurricanes, tornadoes and floods can strike throughout the year, putting life and property. Wise homeowners make sure they prepare in advance so their homes have a better chance of surviving disaster. The good news is that many of the steps that help disaster-proof a home also serve to make it more energy efficient.

Do what you can to help your home and belongings make it through the next big storm:

Use Surge Protectors: You spent a lot of money on your electronics, so why leave them vulnerable to a sudden power surge due to a lightning strike or disruption in the power grid? If you have advance notice that a storm is coming, you should unplug unnecessary devices, but sometimes disasters arrive without warning, so make sure everything goes through a surge protector, or better yet, an uninterruptible power supply.

Solar is Your Friend: One unfortunate result of extreme weather can be power outages that last for days, even if your house doesn't suffer a direct strike. Be prepared with solar panels so you can get by before the power comes back. Note that most home solar setups are tied into the power grid and therefore won't power your house independently if the rest of the electricity is out, but some systems do allow you to charge a battery directly so you can keep the lights on. Another option is to keep a generator on hand for emergencies. They aren't as eco-friendly as solar power but don't rely on the sunlight for fuel so tend to be more reliable.

Walls Matter: The latest in building wind-proof houses is using insulated concrete forms, or ICFs, to make a mold for quick and easy concrete construction. Not only are concrete walls far stronger than wood, making them more likely to survive extreme winds, they are much more fire resistant than standard construction as well. What's more, concrete usually costs a bit more than wood framing, but over the life of your house you should see big energy savings. The superior insulation provided by the concrete walls and foam molds means you spend less for heating and air conditioning. Estimates range from a few hundreds dollars per year in savings to as much as an 80 percent reduction in heating costs. You can also find cheaper insurance rates for concrete houses than for wood.

Let the Experts Help: Have a trusted professional inspect your house to make sure that your roof and foundation are in good shape and your HVAC and electrical equipment is all functioning correctly. You can resolve any issues in advance to increase your chances of weathering a bad storm, and if disaster never does strike you still know you made a good investment. Call local Mister Sparky for a check of your electrical system and any necessary repairs as a part of your disaster preparedness plan.

Super Bright LEDs employs skilled engineers and experts to test LED lights before they’re sold. Our in-house test lab is stocked with numerous pieces of equipment that provide important specifications about each product, such as brightness, color temperature, and operating temperature. Testing methods include the use of integrating spheres, spectrometers, Forward-Looking Infrared (FLIR) cameras, and an environmental chamber. In addition to this equipment, our technicians perform burn-in tests and durability tests that can last anywhere from two weeks to several months.

CCT, and

Our state-of-the-art environmental testing chamber utilizes a 30-cubic-foot enclosure to reproduce the full ranges of temperature and relative humidity found within commercial and industrial LED lighting applications. Data collection (photometric & electrical) occurs while a device-under-test cycles through specified environmental extremes. Chamber temperature ranges from negative 35° C (negative 31° F)  to 200° C (392° F), and humidity ranges from 10 to 95 percent.

To ensure that our products will perform under normal and extreme conditions—and to have a little fun—our technicians put them through a round of applicable tests. A selection of LED lights is time tested in the environment that each product is designed for. For example, waterproof boat lights are submerged in water, and weather-resistant landscape lights are installed outside. Depending on the type of product and its impact/weather rating, our technicians might drop, run over, freeze, burn, or even saw it in half to test the product’s durability.