3 Wire RTD but only 2 connections at probe?

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Wolfairious

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I bought a 3 wire RTD off ebay that has the quick disconnect at the probe. I needed a longer cable so I took the quick connector apart that connects to the probe and inside the connector, both blue wires are soldered to 1 pin. Is this correct? That means there are only 2 connections at the probe. (one of which splits into 2 blue wires). Is this the way it is supposed to be or did I get "ebayed".
 
There are 2 wire, 3 wire, and 4 wire(rare) RTDs. The 3 or 4 wire have the advantage of letting the measuring device effectively subtract out the added resistance of a long wire run by using bridge circuitry.

If the connector is at the probe itself, then it's fine,as you aren't adding wire length resistance. All RTDs are just a special resistor inside - two wires.

Of course, some eBay vendors were confusing RTDs with thermocouples; hopefully that's not the case here.
 
Thanks. Yes, my extension cable is a 3 wire cable and I measured the resistance in each wire and they all pretty much match. Same wire gauge so expected as much. Now I made them a bit long, should I shorten them or does it not matter as long as the 3 match?
 
As long as the 3 match you should be OK though clearly there is going to be some practical limit - well beyond anything you would encounter practically though.
 
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