How to Spot a Psychopath

I used to have a really big light bulb hanging in the junk-storage/photo-studio/emergency-guest-accommodation room.

I wrote about it here, very early in the life of this blog.

Unfortunately, that 85-watt compact fluorescent lamp, which we came to affectionately call "the skylight", only lasted a couple of years. That might have been because it wasn't very well-made, but I suspect it just didn't like being turned on and off so often. I wasn't in and out of the junk room a dozen times every day, but CFLs only have so many on/off cycles in them.

After the eighty-five-watter died, I sighed and put a standard boring "100W-equivalent" bulb in the dangly hacked-together socket I'd used for the big lamp. And there that boring bulb stayed, for about another year.

But then, the other day, I noticed that this eBay seller had some new-old-stock Y-adapters, for Australian light-bulb sockets.

(In the USA, the most common light-bulb socket is the "E27", a 27mm Edison screw. Here in Australia, though, the large majority of our light bulbs use a 22mm bayonet mount, a.k.a. "BC".)

The eBay seller turned out to have a total of nine double-adapters, some with a switch for one of their branches, some without.

I don't like to miss a chance to go beyond the usual and construct something that'd make a home inspector turn pale and need to sit down for a little while. (The Cable that Should Not Be was the third post on this blog!)

So I bought all of the adapters.

And now I have this!

Nine double-adapters, ten sockets.

In case you're wondering: No, this is not a good idea. Do not do it.

What you see in that picture is actually my third attempt to get everything working at once. I first tried a couple of "bushier" layouts, but the leverage of greater bulb-weight on the wider branches produced broken or, worse, arcing connections between the adapters. So I reconfigured the motley convocation into this vaguely Christmas-tree-ish shape.

The less bushy configuration puts the bottom bulb only about 204 centimetres (six feet, eight inches) above the floor. And this many stacked bayonet connectors becomes sort of... floppy. So a tall person bumping their head on the bottom bulb might manage to unplug half of the assembly. And I don't trust all of the connections to really be free of slow-overheating-causing extra resistance or tiny arcs. So I wouldn't leave this Photonic Agglomeration Mark I turned on when I left the house.

But, dodgy though this preposterous bricolage of brightness is, it's actually not as dreadful as you might think.

Light-bulb double-adapters were, in the olden days, a way to buy several tickets in that special lottery where the grand prize is burning your house down.

A light-bulb socket should remain safe, you see, even if you run a few hundred watts from it. But there are plenty of ceiling lamps that're blessed with cack-handed amateur wiring, old cables chewed by rats, old connections corroded by possum pee, ancient insecure aluminium wiring, flammable insulation batts installed right across the top of hot areas, or some combination of the above.

If you double-adapt a light-bulb socket that's hanging down from the ceiling on a cable, then you at least shouldn't be able to dangerously increase the temperature of the ceiling above the bulbs. But it's still perfectly possible that you'll overheat some wiring.

The whole point of compact fluorescent bulbs, though, is that they consume a lot less power than incandescents, for a given brightness. A "100-watt equivalent" CFL will probably draw only 18 or 20 watts. So you can double-adapt a whole bunch of CFLs onto one standard socket and run no more risk of disaster - from excess current, anyway - than you would if you'd plugged in only three or four incandescent bulbs.

In my illuminative monstrosity, there's one 23-watt CFL, five 18-watt, one 14-watt and three 10-watt, for a total of a mere 157 watts. You can buy single incandescent bulbs that draw that much - or 200 watts, even - if they've not yet been banned where you live. Those big bulbs will usually work fine in normal ceiling fixtures if they physically fit, and they also often have an extremely long lifespan. That's because they're built for toughness, not efficiency, though, which brings us back to the subject of light-bulb bans.

(Most standard incandescents are now effectively banned here in Australia, but there are specific exceptions for bulbs for which high-efficiency replacements do not yet exist, like the little lamps in fridges and microwaves. So nobody seems to have been terribly inconvenienced. In a few years, immortal LED bulbs ought to have stepped up to fill pretty much every niche that doesn't actually require a lamp that wastes power.)

157 watts of compact-fluorescent light is getting on for twice the power of my old 85-watt single bulb. It ought to add up to an incandescent-equivalent figure of more than 800 watts. So I whipped out the light-meter to see how the new fluorescence excrescence did.

Compact fluorescents don't give their full brightness until they've warmed up, and that can take a minute or three. Some CFLs are really dim when they're at even a comfortable room temperature, and all of them will be very dim if they're very cold (which can be annoying if you want to use them as a porch light in a cold climate, or to illuminate your meat-locker). So I measured the brightness of the new Lamp That Should Not Be at turn-on at the ambient temperature of about 20°C (68°F), and then again ten minutes later. I taped my light-meter's sensor to the wall about 195 centimetres from the middle of the array, looking at it from a bit below, but broadside-on. (A flat array of bulbs like this will, of course, be dimmer if you look at it edge-on.)

At turn-on, the multi-lamp managed a brightness of about 125 lux over there on the wall - already more than twice the usual brightness of domestic indoor lighting. Ten minutes later, it was 344 lux. Left to warm up even longer, it plateaued at 360 lux.

At the front of my photo-tent area (located, since the kitchen table is not available, in the second-most-traditional location for professional Web-site photography, a spare bed), the old 85W CFL managed about 205 lux. The new array manages about 345!

That's still not bright enough for general photographic use. It's more than enough for large-aperture portraiture, but for product shots you'll find yourself needing one-second tripod exposures. It's a really good light level for a workroom, though; bright enough for fine work, without the actinic glare of a 7-Eleven at two in the morning. (Which is exactly the same brightness as a 7-Eleven at ten at night, but always seems a lot brighter.)

At the standard measuring distance of one metre, by the way, the warmed-up ten-bulb Chandelier of Uncertainty manages better than 900 lux - overcast daylight brightness - when measured from a perfect broadside-on location. An edge-on view of the lamps one metre from the middle of the whole array is still about 900 lux, because the lamps at the near side of the array are now rather closer than one metre. Moving back to take that into account drops the brightness to around 700 lux.

The ten bulbs cast a rather pleasant light, too. Because the light comes from so many sources - and the sources themselves are the tubes of CFLs, not the little filaments of clear incandescent bulbs - the light casts the soft shadows that you can normally only get from efficiency-reducing lampshades or indirect lighting. And the random mix of colour temperatures from ten supermarket bulbs might drive pro photographers to distraction (because all shadows will have multiple soft fringes of subtly different colours...), but I think it makes the room look sort of sunset-ish, without actually being very yellow. The only problem is that when I come out of the junk room into the normally-lit house, I can't see where I'm going any more.

Early compact fluorescent lamps were widely hated, for good reason. They were quite expensive, and they gave light that was qualitatively inferior to that from incandescent bulbs. Their mains-frequency ballasts gave them noticeable flicker, which in turn gave people noticeable headaches, and early CFLS also often used the cheap high-efficiency "triphosphor" coatings. Triphosphor gives lots of light per watt - it's still pretty much ubiquitous in the cheap-straight-fluoro-tube market - but it has lousy colour rendering, so people look like corpses and you can't tell your jelly beans apart.

But modern CFLs, even cheap supermarket ones, now have high-frequency ballasts and pretty decent colour rendering. Especially if you combine lots of different lamps into one fitting!

(Current CFLs even have a good power factor now. So my irradiative congerie shouldn't be doing funny things to the mains waveform. They do still have mercury in them, but this is not actually a very big deal.)

Oh, here's another way in which a Dumb Light-Bulb Trick like this could go horribly wrong: The monstrosity weighs about 1.38 kilograms (three pounds), versus maybe 85 grams (three ounces) for a single "100W-equivalent" CFL. 85 grams is already heavy for a, ahem, light bulb; I just weighed a standard incandescent hundred-watter, and it was only 31 grams.

If I'd just hung 1.4 kilos from the poor horizontal socket of the old ceiling oyster-light in the junk room, like I did with the huge 85W CFL before, I wouldn't be at all surprised if the ten-lamp contraption yanked the socket bodily off the ceiling.

So, instead, I rigged up an extender that connects a standard "batten" bulb socket to the oyster-light socket. The extender, and the rest of the luminaceous imbroglio, hangs from the threaded rod that's meant to retain the ceiling-light's glass lamp-shade. You shouldn't assume that any particular fastener coming out of your ceiling is retained by more than a Rawlplug and hopeful thoughts, but this one seems pretty solid to me.

(I should probably put some tape over contacts on the top of the batten socket, seeing as it's not screwed onto a batten and they're just sitting there proudly naked. Nah - what could possibly go wrong?)

In case you haven't got the message yet: Don't do this. If you feel the need to run a ton of CFLs from one ceiling socket with a home-made contraption, make it a proper permanently-connected fitting, like a white-painted plywood circle with a bunch of parallel-wired batten sockets on it, and anchor it to the ceiling properly. "Properly", in case you're wondering, means "not with coat-hanger wire, sticky tape, picture-hooks or occy straps".

And all of my usual disclaimers also apply: Don't fool with mains-powered circuits as your first venture into amateur electronics. Don't make your own mains gear if it's not legal to do that where you live. Bear in mind that gimcrack electrics may not only set your house on fire, but also invalidate your insurance.

Bulb-socket double adapters are, I think, very acceptably safe if you only use one of them at a time. With CFLs, they'll let you easily get the equivalent of 200 to 250 watts of incandescent light into a room, with only about 40 watts of actual power consumption. There are probably cheesy light-bulb double adapters from scary Chinese factories that're unsafe at any speed, but the old-stock ones I got are all sturdy Bakelite and spotless heavy-gauge metal inside. They only become dodgy when you... iterate.

I think I'll stick with my illumination conglomeration for a little longer, then whip up something more solid, perhaps in the Hollywood-makeup-mirror form factor.

But then again, I did also buy a lot of in-line bayonet plugs and sockets from that guy on eBay.

Perhaps I should develop something based on the classic Australian cork hat.