The importance of unplugging

[Radman]

Working on a practical lighting effect for the gum machine in Charlie and Chocolate Factory I had two different colored floodlamps in some old household flood fixtures, hooked up to a chase controller. I was having trouble with the chaser and one of the floodlights, something similar to one of these:

The lamp was wiggling around, so I turned off the chaser and took out the lamp. There was a loose screw, and I proceeded to tighten it. I touched the hood and ZAP! Owwww! The stupid chase controller was screwed up and didn't work right at all! It was sending juice even though it was off! Lesson learned: take precautions.

 

[Mayhem]

Not sure if I am reading this correctly or not but are you refering to a screw within the lamp base (i.e. a screw that secures a wire to the terminal) or the actual screw base on the lamp, as the picture looks like a PAR38 lamp to me.

Although, I am thinking that it is the former.

The second question that I have is related to the chase unit. When you say that you turned it off - did you turn of power to the unit or did you simply turn off the chase function?

If you just turned off the chase function, then it might be possible that the pre heat function was still activated, although I wouldn't imagine that you would get enough of a boot from that.

One possibility when people get a boot from a lamp base is when the hot and neutral have been switched over between the output and the lamp base.

Could be a faulty switch but if that were the case I would imagine that you would have noticed that the unit was still chasing the other lamp.

A bit more info from you with regards to the lamp base (and wheter the screw was inside or in fact the actual lamp) and also the chase unit might make it easier for someone to help you work out why juice was present at the lamp base when the unit was turned off.

Regardless of the cause, you have learned a valuable lesson. ALWAYS turn off the power and where ever possible, UNPLUG the device that is being worked on.

 

[mbenonis]

Sorry for the off-topic post, but you were able to get the rights to do Charlie and the Chocolate Factory?! We haven't been able to get them for two years running now, and it's the one show our entire department wants to do!