Identifying which socket you need for a fluorescent installation can be rather difficult. The only thing that really divides the different types is the fact that they’re sized differently. Otherwise, they generally look the same if you’re not paying close attention.
Fortunately, there’s a few tricks that can make it much easier to spot the kind you need. That’s good news, because using the wrong socket can cause bulbs and ballasts to break down in a rather dramatic fashion.
The T12 and T8 sockets are probably among the most common. A bi-pin T8 socket will literally have two pins while a single pin T12 or T8 socket will feature a single central adapter that’s unmistakable. As long as you can get a good look at the midsection of the socket, you should be able to tell which one is which.
So-called conversion sockets feature more than one adapter on either end. You’ll normally see a T8/T5 socket when dealing with linear fluorescent tubes, but pay close attention to any legends that are carved into the housing. These should help you identify what two different types of connectors these jacks expect to interface with.
Keep in mind that just because the end of a light tube fits into a socket doesn’t necessarily mean it belongs in that particular socket. Most lamp manufacturers print a legend directly onto the glass of each tube they sell. This text should match anything carved into the socket for maximum compatibility and in order to ensure safety.