36 Edison Screw Base Sizes

The Edison Screw base comes in four basic sizes, each operating under the same principle.

The smallest, the candelabra, is used for very low wattage lamps such as night lights and chandeliers.

The next size up is the intermediate base, which is sometimes used for appliance bulbs like one might find inside the fridge or oven.

You are already familiar with the next size up because it’s the standard size of lightbulb that is most commonly used. Almost every lightbulb you have ever changed was a standard-sized Edison bulb.

The next size up, the Mogul base, is commonly reserved for lamps rated 300W or higher.

Regardless of the size used, it is always important to connect the identified conductor to the identified screw terminal. A reversal of conductors wouldn’t impact the operation of the AC load but would increase the likelihood of a shock hazard when the lamp is changed.