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Thermocouple, grounded or ungrounded check

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slepax

New Member
Hello,

I am wondering if there's a way to know whether the thermocouple I have is grounded or ungrounded? Would it be fair to assume the ungrounded type would have zero resistance from the negative connector to the shield?

Thanks!
 

MaxHeadRoom78

Well-Known Member
I would expect a shielded device may be have a the shield separate to conductors, this leaves the option open whether to earth ground a device conductor or not, the shield is usually connected to GND at the source end.
Max.
 

KeepItSimpleStupid

Well-Known Member
Most Helpful Member
"grounded" thermocouples are a "special case" of the rule your citing. Yes, there will be a connection to the "sheath" as it's normally called from both wires. "zero resistance" is hard to achieve.

Grounded thermocouples have a much better response time. Ungrounded ones play better with instrumentation.
 

KeepItSimpleStupid

Well-Known Member
Most Helpful Member
Depends on your definition of zero - 0.000000000 (infinite number of zeros)

The point, I was trying to make is that wire has finite resistance, likely in mlilliohms. I had to worry at both extremes with currents from about 2 pA to 3000 A and I had to worry about mV drops near say 400 mV.
 
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