Kapton Tape

[fifty60]

I have a tytpe T thermocouple that is used to connect to the device under test (DUT) inside of an environmental test chamber. The temperature inside of the chamber can be between -70 to 190 C. The thermocouple wire is shielded. If I connect the non sensing end of the shield to ground, i have to clip the shield on the sensing end. My concern here is that the clipped shield on the sensing end can make contact with metal inside of the chamber causing ground loops.

Would I be better off just not grounding the non-sensing end, and just insulate it? The sensing end would be trimmed, but due to the conditions inside the chamber it is difficult to completely insulate the trimmed portion of the shield. What are the risks of having a shielded wire on a T/C and simply not using it?

I could continue to ground the non-sensing end, and use Kapton tape to insulate the shield at the sensing end of the cable. My concern here is that since the sensing end will be connected/disconnected multiple times to the DUT, that the tape will become disformed over time or fall off and require servicing just to re-apply the kapton tape.

Any opinions in regards to not grounding the shield vs grounding the sensing end of the shield and using kapton tape to insulate the shield on the non sensing end will be appreciated.

 

[Smart $]

Please elaborate on the products/materials used for the entire run. I'm at a loss in understanding why you would have to trim the shield if this is a single non-spliced. no-connector, no-intermediate-terminals run.

One approach is to use a kapton tube over hi-temp silicone rubber RTV. http://www.rectorseal.com/?s=rtv

 

[cadpoint]

Why don't you call some therm o coupling manufactures on Monday. I'm almost sure they have run into your problem before.

My Father use to do these types of tests on various electronic equipment for the military.

While we talked about some of these tests, I do know he conversed that all the units
were ready for the complete test and that no modification would be allowed from any
manufacture varying from the desired design.

So on you end you need to either design and apply that design to get your desired test results or test on your end that all aspects are met before you submit the actual assembly for secondary or be it testing by others.

MIL-STD-202G