Rewiring a used Desisti Magis light head
Lighting is expensive. Consequently, I am always open to buying decent used lighting. So recently I jumped on a deal at B&H on a "clean" used Desisti Magis light head. Great price with a used barn door- not sharing how much exactly here- for an item listed as little or no signs of wear. Cool!
When it arrived I was excited as I unpacked it! Then I see the catch... There are bare wires sticking out of the head with maybe two feet of wire and NO on/off switch. They did thoughtfully include an off the hardware store shelf Edison grounded plug adapter. Gee thanks, a-- holes... They did not say this anywhere in the listing on their website. So buyer beware I guess... The picture below shows the new light on the left and my old one which is complete on the right.
OK then, what should I do. It is Friday night, B&H is closed, and I have a shoot on Sunday I planned to use the light for. Further they are closed for some sort of week long holiday we don't seem to have here in the Pacific Northwest. great...
Now I have replaced switches before on my lights before, it's not hard. Further two feet of cable from a light head is completely useless. Grrrrrrrrr....
Quick disclaimer: I am not an electrician, and this is a post to give general guidance and to explain what I did only. If you are unsure of your self consult a lighting specialist or electrician. In other words don’t sue me if you thy this and cause yourself a problem, this is just what I did to solve my problem! This is all based on my experience as a Grip/Gaffer.
My solution: I pull out an extension cord from my electrical bag with 14 gauge wiring, same as the Desisti, and then to visit a pro lighting store in Seattle to pick up a Lowel switch for the Tota/Omni lights. The Lowel switch will easily handle the 650 watt max this light head will pull and is roughly $10. Alternately you could buy a 10-16 foot extension cord from the hardware store for $20-30 depending on the gauge, length, and quality. See the parts below: The yellow Edison plug adapter they thoughtfully threw in, the black Lowel switch, and the end of the wire from the light head itself.
Below is my replacement extension cord, again something I already had in my electrical bag.
The actual work to fix all this was pretty easy. Compare the size of the wire and open up the ends of the switch. I used my Dremel, but a knife will also work. Just be sure the edges are smooth or they will bite into the outer insulation of the wire and possibly expose the wires beneath and cause a short which could be a fire hazard.
Now you will need to strip back the outer insulation to expose wires beneath. Next take that wire and place it into the opening of the switch then lock it down with the provided parts and screws, see the picture below. Now line up the wires to the holes where you will be attaching them and trim them to fit with a short amount of the actual wires exposed to push into the openings in the switch. You can see below I am stripping back the insulation on the neutral lead, and the other half of the wiring is already locked in place and the wires are screwed down into their places in the switch.
This is really all there is to do. Just be sure that everything is securely locked down and there are no bare wires exposed or any wires pinched by the switch case coming together. Below is my finished wiring, note that I tucked the neutral lead on the right side next to the mounting hole for the switch case to avoid pinching.
This was done with the Lowel switch, and you could certainly use other switches. I actually prefer the original Desisti on/off switches or even the Arri ones, but this is what I found in a pinch. Do be aware of the wattage you are sending through the switch and be sure it can handle the load. This switch works with lights ranging from 500 to 1000 watts so my Magis head and its 300/500/650 watt bulbs do not exceed the switches capacity. In general what I have found is that #14 gauge wire is rated at 1440 watts at a 12 amp load, this is not set in stone, but that fits this scenario quite well as the length of the wire is only about 12 feet long.
You could also use off the shelf switches and boxes from the hardware store, but they are not meant to be used this way and are nowhere near as clean in appearance and are much heavier so that may stress the end of the wire where it exits the light head.
This can also work for other brands of lights- Altman, Mole Richardson, Arri or whatever. The Lowel Tota T1-80 power cable is another great option, and costs roughly $32-45. You would have to cut off the light head end and wire it into the light head in the same manner as I did with the switch.
Good luck if you are finding yourself in this position and need to make a fast fix!