Could I have some advice please on connecting a K type thermocouple to a temp reader. The reader came with the basic thin flexible temperature probe but can I use the old yellow connector for the new k type or would I be better buying a more suitable one, in which case, any suggestions please? Thanks
The colours are wrong for a K type thermocouple, usually they are Red and Yellow. The wore colours you have indicate a Type R thermocouple??
Also the Red wire is always the negative (which seems unusual, but that’s the convention.
This is a good site to cover the wire colours of the different type https://www.thermocoupleinfo.com/type-r-thermocouple.htm
If you do have have a K Type there, then you can remove the terminals and connect them as Red -ve and black +ve.
Different countries use different colour standards but it’s not unusual for some manufacturers to just use black and red, in which case black is normally negative.
In the UK K-type are normally blue and brown, brown being +ve. In the US, red and yellow as Dave mentioned.
Use a magnet and which ever wire (not connector) is attracted, that’s the -ve wire.
All of our k types at work are green/white with green plugs, N types pink, J types brown. Just to throw some new colour combos into the ring :)
If you have an accurate dc mV multimeter you can check if its J type with ref to the table in daves link
And k type, also starting from daves link
Ade Smith. ACS Evo Leva v2. Kafatek Flat max 2, ssw 2024. Mazzer Philos, Craig Lyn HG-1 prime.
DavecUK Use a magnet and which ever wire (not connector) is attracted, that’s the -ve wire.
J-type (Iron / Copper-Nickel): The positive iron wire is magnetic, making J-type thermocouples easily identifiable with a magnet.
K-type and N-type (Nickel-Chromium / Nickel-Silicon): These materials are generally non-magnetic, so K-type and N-type wires won’t attract a magnet.
T-type (Copper / Copper-Nickel): Copper is non-magnetic, and the copper-nickel alloy has weak magnetic properties, making magnetism an unreliable identifier for T-type wires.
Ade Smith. ACS Evo Leva v2. Kafatek Flat max 2, ssw 2024. Mazzer Philos, Craig Lyn HG-1 prime.
Adrianmsmith K-type and N-type (Nickel-Chromium / Nickel-Silicon): These materials are generally non-magnetic, so K-type and N-type wires won’t attract a magnet.
No that’s not actually correct…when you alloy Nickel and Chromium (Chromel), Nickel which is ferromagnetic loses this property as the molecular structure is randomised by the Chromium content.
When you alloy 95% Nickel with 2% Aluminium, Maganese and 1% silicon (Alumel), it remains magnetic.
I guess my information just goes to show you cannot believe every fact you read on the internet this seemed to be In good detail but it just goes to show 🤔
My k type thermocouples are all sealed both ends and encapsulated. I can confirm the whole “wire” is magnetic but obviously I can’t check which core.
In my past life, one of my jobs was setting the offsets and calibrating various temperature displays using a certified millivolt source. …. In reverse…. It is worth checking any unknown thermocouples at room temperature with a multimeter assuming it’s accurate enough and referring to the tables for the various thermocouple types. It is also relatively easy to check at near 0 and 100C.
I must try and source Some of those very thick polystyrene cups we used to use in the science lab back in the school days 😎
Ade Smith. ACS Evo Leva v2. Kafatek Flat max 2, ssw 2024. Mazzer Philos, Craig Lyn HG-1 prime.
