The importance of being well-lit.

Posted on October 19th, 2003 in Opinion by Julian Edgar

Inevitably anyone who works (in paid employment) and also works on their own car (for fun) will spend a lot of time twirling the spanners in the middle of the night. And that means that – again inevitably – they’re going to have invest in some decent lighting. (It always puzzles me when I go into poorly-lit workshops – you can literally see the mechanics feeling around for things that – with decent lighting – would be obvious.)

As with most houses around here, mine is built on stilts and so the de facto workshop is located under the house. It’s dim under there, even in the middle of the day. The lighting that came with the house comprises two double fluorescent battens – for an area of about 60 square metres. Not good. I rigged some Portaflood-style 150W directional incandescent bulbs over my workbench, but the rest of the space remained pretty dark.

So what to do? I was undecided… so did nothing for two-and-a-half years.

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Then I was at a household goods auction and stumbled across several boxes of lighting fittings and assorted accoutrements. The lighting looked highly industrial – a good start. There were seven ceramic light sockets, each using a Giant Edison Screw (GES), which is like any other screw-type light bulb fitting but much bigger. The bulb holders were empty, but together with the holders were seven white control boxes, each marked ‘600W HPS’, the ‘HPS’ standing for High Pressure Sodium. And there were also hundreds of metres of 3-core cable connecting the lot together.

I pored over this collection before the auction started, also discovering the matching aluminium reflectors. The reflectors – tall and narrow – indicated that the lights were designed to be mounted high on a factory ceiling – anything less than about 10 metres installation height and the shape of the reflector would cause just a pool of light to be thrown beneath it.

Hmm, what to pay? The light bulbs were all missing, but I figured that they couldn’t be more than about AUD$10-20 each – after all, the control gear was all included and so the bulbs could be relatively dumb in their abilities. I was still undecided when the bidding started, but when the dust had settled, I’d got the lot for AUD$70.

I dragged it all home (amazed at the weight of the control boxes, which later inspection showed contained huge transformers amongst other parts) and dumped it all in a corner. It stayed there for a month or so, then I got motivated. Separating out the bits showed that each light socket came with at least 10 metres of flex, so it would be possible to mount all seven bulb holders under the house, evenly spaced – and still get power to them without having to extend the leads. Perhaps the control boxes could all be mounted along one of the floor bearers, next to their respective switches?

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I made brackets and screwed four of the lamp holders into place, neatly running the wiring along beams. But after about an hour of doing this, a thought occurred. Perhaps I’d better price those bulbs….

I jumped onto the phone and received my first shock. A 600W HPS bulb was apparently a HUGE power rating. I knew it’d be bright (and obviously draw a lot of power – more than the 600W bulb rating when transformer losses are taken into account) but I wanted bloody bright lights. But bulbs of this rating were rare – and incredibly expensive. How much then? Well, try over AUD$200 each at wholesale prices! And they’d need to be specially ordered in. I told the bloke at the other end of the phone that I’d think about it, and walked downstairs to admire my painstakingly-installed ceramic GES bulb holders… which now looked like they’d be useless.

There was simply no way in the world that I was going to spend that much money on my new lighting system. But did I have to use the High Pressure Sodium approach, anyway? The light bulb holders were labelled as ‘general purpose’, so presumably other designs of bulb could also be screwed in. From inquiries I already knew that I couldn’t just use a lower-powered HPS bulb with the control gear – but what about a bulb that could be connected straight to power? Just discard the control boxes – even at seventy bucks for the lot, the seven ceramic bulb holders and their long cables were still good value for money.

I got back onto the phone and asked the electrical wholesaler to go through his catalogs. I wanted a bulb that would screw straight into a GES holder, have a rating of (say) 250W, and have a high efficacy. (That is, produce lots of light for this power input. More than an incandescent lamp, for example). And much to my surprise he found a suitable design – a mercury vapour lamp with on-board control gear. The lamps cost AUD$30 each and while they also needed to be ordered, they could be available the next day.

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This looked promising, so I finished installing the rest of the lamp holders and put in some switches so that I could operate them in groups. The bulbs arrived and I screwed them into the holders. A flick of some switches and bingo!, I finally had excellent lighting under which I could work on cars. And it is good: not so bright that you lose vision when entering a darker area but still bright enough that the light reflects off surfaces so that you can clearly see into shadows.

But talking about reflection, I wondered if I was getting as much out of the bulbs as I could. Because of the low mounting height, I’d had to leave off the big aluminium reflectors, but that also meant that lots of light was being directed up to the dark wooden panelling (the floorboards) above each light. Not much came back reflected off that… What I needed was some large discs (or better still, some shallow cones) of shiny aluminium positioned above and around the pear-shaped bulbs. Like traditional light bulb reflectors – but bigger.

More time passed, then I was at a place where there was a huge variety of goods on tender. And there were my “reflectors” – a collection of large shiny stainless steel lids off commercial saucepans. I put in my tender – AUD$12 – and got them. At this stage I’ve mounted only one of the reflectors – on the light above my workbench – but it seems very effective.

The complete lighting system cost about AUD$320.

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As this tale has shown, the way in which I’ve ended up with 1.5kW of mercury vapour lighting in my work area is not something that someone else could easily follow. Even if they wanted to. But it does show that it’s worth exploring a range of alternatives to traditional household luminaries when installing workshop lighting.

Another approach would have been to use double fluorescents – although I think that realistically, 20 battens would have been needed to provide the same level of light. In a high-roof galvanized iron shed of similar size (where the shiny walls and roof make good reflectors), perhaps three of the mercury vapour lights would have been sufficient – in fact, in a 10 x 7 metre shed I previously owned, I used two high-mounted 250-watt mercury vapour lamps with great success.

But look, if you’re fiddling around in the dark when you’re working on your car, think for a moment about how that decreases your performance. When you can’t clearly see what you’re doing, it’s easy to make mistakes, and is also much more tiring.

The first project that I did with the new lights working – fitting the auto trans cooler to my Maxima (see “Cooling the Trans”) – was simply so much easier than when working under the previous lighting…

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