Mogul base light bulbs tend to be bulbs with larger wattages than a typical bulb. Often referred to as an E39 compared to a normal sized screw in base which is an E26, Edison base, or medium base. The mogul base has four rotations around, just as a standard screw-in base has, only the mogul base is 39 millimeters across, while the medium base is 26 millimeters across. Obviously, it is important to measure and make sure which base your bulb has, since they are not interchangeable without a base reducer. Certain models of bulb are available in both base sizes, which contributes to mis-ordering and general confusion as to which base is needed. One example of this is the 175 watt metal halide bulb. You can order an M175/U or an M175/U/MED. Both are metal halide bulbs in 175 watts, but the one with /MED in the description has a medium or E26 base. The bulb with just a /U has a mogul or E39 base.
While there are smaller bases available than a standard base, such as candelabra, mini-candelabra, intermediate, and European or foreign base, there is only one that is larger, the mogul base. If your light bulb has a base noticeably larger than a normal everyday light bulb, then you have a mogul base bulb. As mentioned earlier, it is possible to get a base reducer, so you can use bulbs with an E26 base in sockets designed for an E39. The item number for the base converter on our website is AX22406. We do not have a converter, however, that will allow you to use a three-way medium base bulb in a three-way mogul socket. Since those bulbs need two connections to the electrical current, a normal socket converter won't work. Also, there is no converter available to use for putting a mogul base bulb in a standard sized socket.
Some of the most popular applications for mogul based bulbs are in metal halide or high pressure sodium fixtures. The main contributing factor is that many of those bulbs come in high wattages. These bulbs will be found in literally millions of businesses and organizations all over the country. Another popular application is old-style floor lamps. Many of those use Sylvania 14374, the 100-200-300 watt three way PS25 bulb or the Sylvania 15915, the 300 watt PS25 bulb.
We have over 340 different part numbers on our website with mogul bases of all different types and sizes, so we are sure to have the one you need listed. If we don't , we can almost always find a supplier to special order from, so whatever your needs, please don't hesitate to call us at 800.948.1063 and ask one of our helpful representatives to give you a hand. We've been in the lighting business for over 55 years, so believe us when we say we will be able to help you with almost any light bulb need.