Weird 1wire behaviour - heatup and damaging

This is not a real HA problem but more a weird hardware issue I’d like to share, maybe someone more experienced with this kind of devices will have a solution or an idea of what’s going on.

We made a custom board with a RPi, some relays and 230V power for lights and stuff. There are three sensors, two 1wire for temperature and one sht25 for temperature and humidity.
We had this board working perfectly in lab for days. As soon as we deployed in production the 1wire sensors started behaving weirdly, one measuring 20° more than the real temperature and the other one disappearing from the bus. One of the sensor was heating up a little bit, but we made sure there was no contact or short-circuit among the wires.

Nothing in the cabling or in the structure has been changed in the production environment. We just unplugged the sensor cables and put them in guides.

The only thing which came to our mind is that the 1wire cables are close to the 230V one. Could that interfere or damage the sensors? Any other behaviour which could damage the 1wire sensors?


How is your grounding done? Maybe you have a Ground loop from your Earth wire on the 230V side to the Ground of the RPi to the “core” of the sensor, to something that the sensor touches that is somehow “metally” and earth/ground connected?

Could this be an issue:

Counterfeit sensors.

We’re doing some tests on this, thank you for the suggestion