thermocouple wiring

[Richard M]

Rob,
You should use the correct thermocouple extension wire suited to the
thermocouple type you are using, to avoid errors occuring in the connection
junctions of the extension cable, the cable cores should be the same
material as the wires of your thermocouple. What you are aiming for is to
make sure each core of the wire run from your thermocouple is made of the
same material throughout it's run.
ie. for a 'K' type thermocouple the extension cable should be
nickel/chromium and nickel/aluminium (to match the thermocouple itself - the
wire insulation is usually colour coded to aid identification). Any
connections should also use correct thermocouple connectors, again suited to
the type of thermocouple you are using (same materials used throughout the
cable run).
If you use ordinary copper cable, you will incur a measurement error due to
the junction of the dissimilar materials forming a thermocouple junction of
their own, the error will be dependent on the temperature of these 'extra'
junctions.
Hope this makes sense.

Rich
----- Original Message -----
From: "Rob F" <rncfiles at hotmail.com>
To: <diy_efi at diy-efi.org>
Sent: Tuesday, January 01, 2002 4:41 AM
Subject: thermocouple wiring


> Hi all,
>
> I need to extend the wires on my EGT probe and I remember reading
somewhere
> that the wire has to be a certain ohms/foot for the thermocouple to be
read
> properly.  Did I just make this up in my sleep or is this real?  Can
anybody
> shed some light on this for me?
>
> Happy New Year!
> -Rob


----- End of forwarded message from owner-diy_efi at diy-efi.org -----
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