RTD Elements & Wires
RTD Products also provides Pt100 elements with lead wires attached.
There are a vast amount of lead wire options available to enable you to select the combination that best suits your application.
Lead Wire Configuration: Lead wires can be attached in 2, 3 or 4 wire configurations for both simplex and duplex elements.
RTD Products can provide customizable lead length dependent on your requirements.
Standard conductor size is 7/0.2 (7 strands, 0.2 mm). However larger sized cable can be provided if a more robust connection is required.
Standard wire plating is nickel. Silver and gold are also available.
as per IEC 60751:2008
2 wire =1 red/ 1 white
3 wire = 2 red /1 white
4 wire = 2 red /2 white
2 wire = 1 red/ 1 white, 1 yellow/ 1 black (grey)
3 wire = 2 red /1 white, 1 yellow/2 black (grey)
4 wire = 2 red /2 white, 2 yellow/2 black (grey)
Colour coding can be customized if required.
Lead Wire Insulation:
RTD Products offers customizable lead wire insulation material, however the most widespread are:
• PTFE (Polytetrafluoroethylene) a standard insulation material that is suitable for temperatures up to 260°C.
• PVC (Polyvinyl chloride) recommended for use with temperatures not exceeding 90°C.
• Bare wires (no insulation) suitable for high temperature assemblies.
If your application requires increased mechanical protection, the following insulation options are also available:
- PTFE /braided/ PTFE
- PTFE / PTFE /SS
Depending on the application, the correct choice of wire configuration, length, size, plating and insulation is crucial. If you are unsure as to which cable would be the right choice for your application, please do not hesitate to contact us and we will advise you on selecting the right configuration for your needs.
2-Wire Connection2 wire connection3 wire connection4 wire connection
This method allows NO compensation for lead resistance, which is effectively added to the thermometer resistance.
Only suitable for low accuracy applications such as domestic appliances, motor vehicles or where lead lengths are very short.
By far the most common configuration for industrial applications, the 3-wire system allows for effective compensation of lead resistance and also compensates for changes in lead resistance when wires pass through temperature variations (temperature coefficient of resistance of copper is greater than platinum).
Remaining errors with this system are mostly due to variations in resistance between the 3 wires.
This configuration must be used when the highest accuracy is needed, particularly where lead runs are long, providing almost total rejection of lead resistance and temperature effects.
This system is becoming more common as “Intelligent Transmitters” become more popular, as these almost always can use the 4-wire system.
Mineral insulated resistance sensors are becoming much more popular in recent years, for their robust, vibration resistant properties, these are normally made using 4 core MI cable, so there is no economic reason not to use all four.
It is recommended that all thermometers above tolerance class B should have a 3 or 4 wire configuration.