Conventional Fixtures A new (at least to me) failure mode

[JChenault]

Hanging a new plot for our next show today, and I want to move a pin plug that ended up resting on top of a fresnel. I can see the black side of the plug, but it appears to be stuck. Looking more closely, it looks like someone has glued the pin plug to the fresnel. Applying a bit of force, it turns out that the heat of the fresnel had melted the clear plastic cover piece of the pin plug.

Here is what was left of the clear plastic plug, with a good one for comparison.

I have never seen this failure mode before. Somehow I thought the plastic was more resistant to heat than this.

 

[BillESC]

Hanging a new plot for our next show today, and I want to move a pin plug that ended up resting on top of a fresnel. I can see the black side of the plug, but it appears to be stuck. Looking more closely, it looks like someone has glued the pin plug to the fresnel. Applying a bit of force, it turns out that the heat of the fresnel had melted the clear plastic cover piece of the pin plug.

Here is what was left of the clear plastic plug, with a good one for comparison.

I have never seen this failure mode before. Somehow I thought the plastic was more resistant to heat than this.

Plastic melts.

 

[jhdesynz]

Most of the 2P&G (stagepin) connectors can withstand the temperature for a few minutes to prevent temporary damage. That way if your focusing and it falls on top the fixture, no biggie. However, they are not designed to sit on top of a fresnel. Good rule of thumb, if it gets hot enough to take off your fingerprints, keep the power cables away too.

 

[SteveB]

Hanging a new plot for our next show today, and I want to move a pin plug that ended up resting on top of a fresnel. I can see the black side of the plug, but it appears to be stuck. Looking more closely, it looks like someone has glued the pin plug to the fresnel. Applying a bit of force, it turns out that the heat of the fresnel had melted the clear plastic cover piece of the pin plug.

Here is what was left of the clear plastic plug, with a good one for comparison.

I have never seen this failure mode before. Somehow I thought the plastic was more resistant to heat than this.

Had it happen as well. All my main electrics are raceways with 18" long pigtails and 2P&G. My S4/750w Pars and Zooms get VERY hot and can melt the connector and any rubber cable if the unit comes in contact, thus we use the very heavy duty tie-wraps (3/8" width ?) to tie up the pigtail with the connector against the pipe. Keeps all the rubber out of the way and the only thing that touches the unit is the fiberglass instrument lead.

 

[derekleffew]

Sadly, not all that uncommon, see melted pin connector?. But better to melt from contact with a hot light than from overheating internal terminations.

 

[MercyTech]

Re: A new ( at least to me ) failure mode

I am finding more and more people using zipties to keep cable looped, and plugs suspended etc... but too often I am smelling burning plastic in the theatre, and finding zipties too close to the business end of the instruments.

I concur... plastic melts. Learn it. Live it.