Re: Firewall electric thru connections

Rick Hole

For those who are using connectors not if thermocouple material: a difference in temperature on the two sides of the connection will induce an error.  It will be equal on each sensor so for EGT the error is harmless.
The thermocouple effect on this connector is much smaller than for a junction of the two thermocouple metals.  My tests at heating each side if the connection separately with hot air (hotter than engine compartment) showed a couple degrees of error, not enough to worry about.
With CHT we are concerned about red line and a couple degrees might be significant.  The error will be equal for all CHT channels so comparing cylinder temps will remain valid.
Rick Hole

On Thu, May 28, 2020, 6:20 AM Joe Hood <joe.hood@...> wrote:

I used to enjoy wiring up Canon plugs on A-4s. Had no idea on the dissimilar metals and "cold junctions." Can't the instrument be re-calibrated?


Found a pretty good primer on thermocouple extensions here (I learn something new every day):

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