Siemens DH 21400 - What to isolate the horny contacts in an electric heater?

Hello,

what to insulate the following defect? When connecting the heater in the instantaneous water heater (condition like in the pictures), the wire was blown. The cable has been replaced in its entirety and everything works perfectly, but here moisture appears. I suspect that it is the cause of earlier burnout.



Anyway - because it is long after the warranty, and the heater is simply expensive, I will ask you - what is the best thing to insulate? Which material? For example, some kind of hot glue? What do you propose? There is, of course, a high temperature here, because the heater provides water for a long distance, and voltage, because it is three-phase, and water. What will be the most reliable insulation material?

Thank you in advance and best regards!

Just in case, I'll describe what I did. Maybe someone will be useful. A bit stupid, I answer myself, feel as if I was sitting in the corner and talking to each other.

Anyway - after cleaning the burnt part thoroughly, removing the elements that seemed suspicious and delicate tarnish the whole covered everything with glue for engines that can withstand very high temperatures and which after hardening can be grinded. I gave it PLN 30. It works perfectly today, and it's been several months.

I will add only (again talking to himself) that he is working today without any problems. We're closing.