That Light Bulb Moment: An Idiots Guide to Light Bulbs

So, the extremely exhilarating topic of the technicalities of the light bulb. It may sound dull but since working for Kia Designs I finally had diffused my fear of light bulb shopping. I had always put off buying bulbs for that light that had blown, because, although I ended up with the right one in the end, the amount of codes and names always confused me. You go down the lightbulb isle in the supermarket and the amount of different, shapes, sizes, wattage etc glares back at you, and what makes it worse, many different places use differing names. And it turns out, many of our clients are the same, and we are often asked ‘what bulb do I need to get for my lamp, and where can I get it?’. I believe I am a step closer to becoming a light bulb pro. And I am here to share my knowledge, starting with the bayonet and the screw fitting… the excitement is palpable.


Screw Fittings – ES and SES bulbs

It’s easy to determine what type of fitting you need by looking at the fixture in the light itself. The difficulty is the size of the fitting. It may seem that there are hundreds of different sizes, but there are only really the two main sizes that you are most likely to need, the E27 and the E14. There are a number of other that can make things confusing but they are easily distinguishable as the ‘E’ numbers simply refer to the millimetre width of the screw/bulb cap.

The ES Bulb

ES (E27)

The ES bulb stands for the Edison Screw – this is the larger screw fitting, E27 would therefore be 27mm wide.

The SES Bulb

SES (E14)

The SES bulb stands for Small Edison Screw – with the E14 referring to its 14mm wide screw.


The GES stands for Giant Edison Screw – these are the largest screw fittings, however, usually aren’t used in domestic environments.


Bayonet Fittings – Often referred to as BC

Bayonets are the push and twist fitting, recognisable by the parallel slots on either side of the cap. Like Screw Fittings, the various numbers teamed with the ‘B’ at the beginning of the code refer to the size of the bulb cap.

The B22 Bulb

B22 – means the bayonet is 22mm

The B15 Bulb

B15 – means the bayonet is 15mm

You can find more info and buy the right bulb for you at many different retailers, click here to find out more.

Stay tuned for a guide for different types of bulbs regarding energy usage. More riveting stuff to come!

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