Mechanical expanding cardboard lamp - This way up!

Step 14 Wiring

The final cut is the last:
Right, you need to put some holes in your innermost struts to thread the lamp holder's wires through. Turn your lamp so the upright 1OUT is facing you. Mark which struts are to receive a punching. Have a look at the picture below which has notes on the struts to pierce. The holes should be at the mid-point on that half of the strut. Cut a paper template the length of the short strut, mark the centre of it and use that to measure where to mark the struts. Make a hole through the middle of the each marked strut, big enough for the trailing lead from your lamp-holders to fit through.

Add the lamp-holders:
Thread each lamp-holder lead through one of the holes in the strut, so that each parallelogram "cell" has one lamp-holder suspended diagonally in it. Trim the lamp-holder leads, the insulation (pic), and put a screw terminal on the outside to hold them in place (pic).

I decided to use two 35W lamps and two 20W lamps. Lamps bigger than 20W use a larger base size, usually GY6.35, so I installed two GY6.35 lamp-holders in the middle two cells of the lamp, and G4 ones in the top and the bottom. Some lamp-holders have slots instead of holes in them and can take both sizes.

Thread your wires:
This wiring plan makes the second top lamp come on first, followed by the top lamp, then the second bottom one, then the bottom one. The reason for the second top one being the first instead of the top one, is so that there is some space between the top bulb (hot!) and the operators hand when it's being pulled up. There is also an issue that any shade on the top of the lamp will be close to the top bulb when the lamp is down.

Thicker wires are better than thinner. The ones I used here are about 1mm square. The instructions for you transformer will probably give you some directions about minimum wire gauge - Mine says use 1.5mm square for runs of the maximum of 2m, so I'm pushing it a little, but none of my wires are 2m long, so I'm safe I think.

I got my wires from some lamp cable and just stripped the outer insulation off. It was only two core, so it means I only have two colours, which is a bit confusing, but be careful and you'll be ok.
Wires can be managed by sliding them along the tubes in the corrugated struts to keep them neat, but for any routing that doesn't go through the full length of a strut (like direction change for instance) a small segment of corrugated board threaded onto on of the skewers can often be used, or just glued onto a strut if needs be. If you are feeling lazy you can just wind them round the skewers as you go, but it'll be untidy.

I found this bit to be something of an exercise in frustration. You would think there's only so many ways to get the wiring wrong, but I kept on finding new ones. By the power of Greyskull... Follow the diagram for the big directions, and then look at the photos for how I did the corners and things. I think these are reasonably neat, and keep all the wires pretty much inboard. Doesn't matter a jot if you don't do it, but just make sure you leave enough slack at any direction changes so that the wires don't get pulled tight when the lamp is extended or squashed.

Once you've done this, you're done! More or less. You can certainly put your tools away and tidy up. I probably don't need to mention tea. I've opened a tin of Kopparberg. It is dangerously drinkable.

Finishing touches:
The four screw connectors on the outside at the bottom are where the positive lines exit the lamp. You should also have four trailing leads that are the negative lines. The lamp is big enough that you can fasten the transformer to it somehow. I used some adhesive pads. Trim all the wires and use the tubes in the structure of the lamp to keep the wires organised and feed them into your transformer output terminals, paying very careful attention to the polarity. Use a continuity or ohm-meter to check your connections again. Add the mains cable.