Adjusting Old ParCan Fixtures


Active Member
I read here what a long time ago about some law that may have been up in place about adding a little knob to the backs of parcans so you could adjust them w/o electicuting yourself.

Well, stupid me, I didn't actually realize that you could adjust the bulbs (and thus the relation of hte beam). How is it that you do it (the unsafe way)? I don't see it possible to get those little knobs in my school, but I figure that if I simply plug in the parcan, see where it's beam is at that moment, unplug it, then adjust it and then plug it in again and see i should be fine. I tried it to a fixture on the ground and I couldn't figure it out (we have those old Altman pars) so I was just curious. Maybe I'm stupid :p

Thanks for you help guys!


Well-Known Member
You grab the ceramic lamp base and spin it, the beams are kindof rectangular so you can adjust which way it is spun.


Senior Team
Senior Team
Premium Member
If the par is properly maintained you will not get shocked. Simply make sure that all the connections to the lamp are solid and the leads are not fraid and you will be ok. You run more of a risk while adjusting the bottle from a burn then from being shocked.


Well-Known Member
Here are two tricks that make adjusting a Par can easier.

1. After hanging the fixture, open up the lamp house and loosen the retaining ring a bit. This will allow the bulb to spin quite easily.

2. The wide axis of the bulb is in parallel with the porcelean. This way you can practically pre-focus (orient) the pars before turning them on.


Senior Team Emeritus
Premium Member
Way back when Colortran used to sell a PAR 64 fixture that had a handle on it’s rear so as to adjust the beam. ISU had them and I remember having used them and liking the thought.

Kupo otherwise sells a attachment that might or might not work for your fixture in being a add on handle/cap assembly that grabs the lamp base and allows you to spin it without reaching your hand into the cap. It's a handle and a ring that is sold as a seperate item that clips to the lamp base and spins in the hole in the back of the can. Good product, very good design idea for solving this problem. Should list price in around the $10.00 each range.

In some discussions with their rep, it would seem that they had two choices in getting their version of the PAR 64 UL listed. Either they could screen the back of the can so nobody could reach their hand into it and get shocked which they do for the normal fixture. Or sell it with a adjustment knob they also sell. The screen otherwise is easily removable in using the now no longer UL listed fixture. Not sure how other sources such as Penn, American DJ, TMB or TomCat (much less Altman with their own steel or aluminum versions) get away with non-screened or handled fixtures but for at least the Kupo version, it was screening it off so you could not reach your hand into it or use of the after market adjustment knob.

Tried the Adjustment knob on some TMB fixtures, didn’t work so well. Worked some but not as well as might be expected in being just slightly off in use on another brand. The handle for adjusting the bottle might or might not work so well on other fixtures but would also be a good solution no matter if stiff in use or free working.

Otherwise there is solutions that can be done in ensuring that you won’t get shocked. First is the splice or doing away with it in converting the heat wire off the lamp base to the fixture cord. No cord means longer heat wire whip and no splice to fail. After that better splicing methods also ensure wires don’t come loose from a terminal block, grounds stay tight and it’s safe inside the can. Further still is better quality than the off the shelf lamp bases. The Osram PAR 1 lamp base for instance is of highest quality. Still further is fiberglass spaghetti tubing inserted over the heat wire next to the lamp base. Should the conductor melt down you still have a outer coating over it. There is options, mostly in doing your own wiring instead of wiring from no matter who is supplying the can.

Used to be where I work, you were not worth your salt unless you at one point were shocked by attempting to spin a bottle. I would be surprised by anyone shocked by one of my upgrades to the cans in recent years. No reason to be shocked by properly maintained gear, much less a well thought out wiring system for them.
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