Thermocouple connectors
There are thermocouple connectors specifically for this, see link for an example:
https://au.rs-online.com/web/p/sensor-accessories/4559534
The thermocouples wires that pass through the fire wall in my A-22 do so via thermocouple connector plugs and sockets, leading to a Dynon D180. This works well, with the added convenience of being able to switch over a thermocouple for testing by swapping plugs between sockets.
From the product literature:
Product Details
Miniature Panel Sockets
The miniature thermocouple fascia mounting sockets with clip are available in types K, J, T, E, N, R/S and B. All fascia mounting sockets are polarised by means of unequally sized pins.
Panel mounting
Nylon clip for quick, simple fixing to panel
Colour coded in accordance with ANSI specification
Maximum operating temperature 220 °C
What is a Thermocouple Connector?
These miniature thermocouple connectors are an accurate and convenient way of interconnecting your temperature sensing components. Using thermocouple connectors allows a chain to be formed from the measuring tip of your temperature sensor to the host computer or meter. It is important that all the components in the chain are made from the same thermocouple material to prevent any alteration or distortion of the original signal. To achieve this, thermocouple connectors have contacts made from the same material as the thermocouple they are being used to connect or a compensating material. The connector housing has the thermocouple type clearly printed on it and is also colour-coded for easy identification. The thermocouple wires are simply screwed down into place using two captive screw clamps.
Features and Benefits
• Contacts made from true thermocouple alloys or a compensating material for accurate signal transmission
• Colour-coded for quick and easy identification
• Moulded fascia for flush fitting on front of panel
• Accepts polarized flat pin contacts for an accurate connection
• Made from rugged glass-filled thermoplastic
• Able to withstand temperatures of up to 120°C
• Will accept thermocouple cable up to 4mm in diameter
• Simple captive screw clamp connection for quick assembly
• Polarity and thermocouple type clearly marked on the socket housing
• Supplied with clip for quick and secure mounting to the panel
Applications
These miniature thermocouple connectors are used in any application where thermocouples are installed, extended or replaced. Their robust construction makes these thermocouple connectors ideal for use in demanding temperature measurement applications.
Accessories
Aluminium faceplates are available for use with these panel mount thermocouple connectors
Stock number 397-1674 (2 way)
Stock number 397-1703 (4 way)
Stock number 236-4132 (6 way)
Stock number 397-1719 (12 way)
Stock number 762-1156 (16 way)
Stock number 762-1165 (20 way)
Stock number 762-1168 (24 way)