Thermocouple Protection

does any body have experience how to avoid a thermocouple be accendently touching power line?

we had two cause looks like due to a thermocouple touch heating element (240VAC) and damaged temperrature controller

use a converter with a photocoupler in it.
when possible use a simple heatshrink tube around the sensor
ground the thermocouple on one side and use a groundfaultautomate of 30 mA. Still advisable when you can touch metal parts when machine is not double isolated this is mandatory.

Use an ungrounded thermocouple in a inconel sheath.

The inconel is conductive, but the thermocouple is isolated from the sheath by mineral insulation, MgO.

Ungrounded MgO thermocouples cost about $2-3 more than ungrounded.