Here, probably 75W incandescent. It was never very common, I think we've only got two or three in the collection, and at least one of them is 110V..!

We also didn't have many 50W MV lamps, there were a few, but not many. And I've never seen a 175W MV here either, although I'm told they did exist.

Yes 75w incandescent are really quite rare, I'm also not sure how common 200w was when compared with 150w I haven't seen as many of them about.

100w SON also seems fairly uncommon compared to 70w & 150w, its only really used in street lighting.

Interesting what you both said about 75w incandescent.
While once readily available here in the "A" shape the way I remember it people generally used either 60w or 100w.
75w always seemed to be lost in a gray area so to speak.
I guess that's why when I look for incandescents online I find so many 75w and why I now have to many of them
However 75w was the standard in the common R30 but I'm not sure what the European counterpart is to the R30.

The unusual HID wattages for otherwise common use sound to me like an attempt for vendor lock-in. Because usually the only supplier of lamps in the area is the one the lanterns came from. And cost way more than the common wattages. Because with technology varying in output easily by +/-30% among individual lanterns in a really random way, there is no practical technical difference between e.g. the 200W vs 250W, both are a good match for that 400W MV. Or when factoring in the more efficient modern optics, 150W, another common wattage, would be good match for road illumination yet provide even more power saving, yet still staying with wattages where parts were (at the time this was the topic) abundant.

75w incandescent was never really commonly sold here even before incandescents got phased out. People would either use 60w or 100w and I'm pretty sure most household incandescent luminaires were rated for a maximum wattage of 60w or 100w too.

15w A15s I find useful in things like exit signs (the vintage exit signs took two medium based lamps) or light marquees although the 10w S11 sign lamp was probably more widely used and had a longer life rating.

25w A19s I used to use a lot in desk lamps, still enough light but not as hot as running 40w or 60w lamps in them.

Another oddball wattage is 30w A15. I have a few of these in one of my traffic signals to cut down the brightness from using the typical 60w bulbs for them.


The story behind the 200w lamp according to James is it was developed by Sylvania on request from the US Federal Highway Administration as a retrofit for the thousands of 400w mercury lamps that were used to light Interstate highways at the time. It later on more or less became an official standard with all of the big 3 making lamps in that power rating. 275w HPS got derated to 250w as there was trouble with short lamp life ealry on in it's lifespan. 

The odd PSMH wattages from Venture I'm pretty sure are an attempt at vendor lock in, namely the 125w PSMH and 200w PSMH which I'm pretty sure only they make. Reminds of the odd wattage and sometimes voltage of halogen lamps used in overhead projectors back in the day.

It is also good to know that 1000w H34 mercury vapor lamps are pretty obscure in North America as of now since the lamps and ballasts are extremely hard to find and it is also good to know that European 1000w mercury vapor lamps designed for a 380v-440v OCV are also pretty hard to find since most European 1000w mercury vapor lamps are designed for a 220v-240v OCV.