Latest updates

An RTD loop can show the wrong process temperature even when the sensing element is accurate: lead resistance, mismatched conductors, noise, poor grounding and unsuitable terminations all affect the final reading. By the end, you will be able to specify the sensor, cable, connection method and receiving instrument as one measurement system rather than buying a cable by insulation type alone.

How lead resistance changes a Pt100, Pt500 or Pt1000 reading

An RTD converts temperature into resistance, and the instrument converts that resistance back into temperature through a selected curve. Under IEC 60751, a Pt100 is 100 Ω at 0 °C with a nominal coefficient of 0.00385 Ω/Ω/°C. Pt500 and Pt1000 are 500 Ω and 1,000 Ω at 0 °C.

A thermocouple system can show a plausible number while measuring the wrong temperature because of cold-junction error, unsuitable alloys, poor cable selection, electrical noise, or heat conducted away through the probe. By the end, you will be able to select the thermocouple type, junction, cable, sheath, and controller interface as one measurement system and specify the checks needed for credible accuracy.

How a thermocouple produces a temperature reading

A thermocouple measures a temperature difference, not absolute temperature. Two dissimilar metal wires joined at the hot junction generate a small voltage through the Seebeck effect. The instrument reads that voltage and uses the known temperature of the reference junction to calculate the hot-junction temperature; it does not measure the hot temperature directly.

The reference junction is…

A furnace cable is selected by its actual route, heat exposure, electrical load, atmosphere, movement, and termination—not by a headline temperature rating. By the end, you will be able to separate power, sensor, and extension wiring, compare construction options, specify thermocouple cable correctly, and give a manufacturer a quotation brief that prevents avoidable failures.

Map Every Furnace Zone Before Choosing a Cable

Record every furnace location separately; furnace cable selection based on chamber temperature alone fails at the wall penetration or termination. Measure the continuous operating temperature, short-term exposure temperature, ambient temperature and conductor temperature at each point, including radiant heat from doors, elements and refractory surfaces.

A thermocouple cable can survive abrasion and crushing yet still deliver the wrong temperature because of moisture, incorrect alloy, poor grounding, or a termination rated below the process temperature. By the end, you will be able to define the thermocouple, armour, environmental, accuracy, installation, and verification requirements before comparing manufacturers or requesting a quotation.

Define the hazard before specifying thermocouple armour

A cable can survive abrasion and still report the wrong temperature. Chemical attack can alter thermocouple accuracy while leaving the cable mechanically intact, so cable protection in harsh industrial environments must begin with the actual failure hazard—not with a request for “armoured” cable.

1. Identify every exposure at the cable route: abrasion, crushing, impact, vibration, bending, moisture…

A cable that survives heat is not automatically suitable for movement, high voltage, chemicals, or repeated flexing. By separating insulation performance from conductor ampacity, mechanical durability, and installation conditions, you can choose a cable construction that will remain safe and functional in its actual service environment.

Why high-temperature flexibility requires a specialised cable construction

Flexible high temperature wiring is a specialty because heat resistance and repeated movement impose different demands on the same cable. Silicone insulation stays pliable across a wide temperature range, but its compound rating does not determine voltage rating, ampacity, abrasion life, or bend performance.

A thin lead using the same silicone as a thicker one can carry a lower voltage. Silicone cable manufacturers therefore select conductor…