How hot do inrush current limiters get when operating?

Green Socrates wrote:
How hot do inrush current limiters get when operating?

The short answer is they can get very hot, and in many cases, especially the higher power devices too hot to touch.

The final temperature of the device is affected by several factors: Lead length, ambient temperature and airflow, and of course, the amount of power the device is dissipating.

It is not unknown for these devices to exceed 180°C. However they are designed to work at these temperatures.

Good practice when using these is to mount the device off the board, either by forming the lead of the device, or by using a little ceramic spacer. It is also good practise not to put the device too close to other components or wiring looms that may be affected by the heat of the device.

Is it a good idea to mount these somehow on a heatsink to reduce the temperature of the component?

No cooling an inrush current limiter would be a little like cooling a lamp filament. The device will not work as well. Parts are designed to run hot in operation. If you cool the inrush current limiter you will push up its resistance and hence voltage drop across the device.