2D Lamps

[The Medway Handyman]

These 16w and 28w lamps come in either 2 pin or 4 pin - I wondered why? Seems daft having 2 configurations for 1 lamp.

Will a 2 pin lamp work in a 4 pin holder?

[Harry Bloomfield]

The Medway Handyman was thinking very hard :

I think - not sure on this....

The 2 pins have (most of the control gear inside them, where as the 4 pin jobs all of the control is outside.

No!

[Peter Andrews]

I'm not quite sure which ones you are referring to, but, if the following 2 and 4 pin:

will find that they are not interchangeable as the base has different lugs on it. The 4 pin ones I use are for lights that have an emergency battery supply. Although they appear identical apart from a small red LED and that doesn't stop people forcing the wrong one in though!

Peter

[The Medway Handyman]

Hmmm. 2 pin & 4 pin lamps are the same price at TLC. I would have thought if 2 pin had more inside they would cost more?

[The Medway Handyman]

I meant these (at the top)

[Andrew Gabriel]

No.

The 2-pin ones have a built-in fluorescent tube starter in the base, and will only run using a series magnetic ballast. They aren't dimmable.

The 4-pin ones are usually used with electronic control gear and so have no fluorescent tube starter in the base, and dimmable electronic control gear is available. They can in theory be used with a series magnetic ballast and separate fluorescent tube starter, but that would be most unusual and I've never seen it done.

Note that both the 16W and 28W have another power rating which is the same physical size - 21W and 38W respectively. (Actually, the higher power ones have larger diameter tubes, but the overal lamp size is the same.)

[John Rumm]

I have a couple of portable work lights that use these - mag ballast and separate starter...

[The Medway Handyman]

Thanks Andrew.

[James Salisbury]

My bathroom light has a 4 pin, mag ballast and an electronic starter. The electronic starter made the flicker at turn on a little better.