Defining Thermostats & Thermal Protectors

A question which can confuse the most seasoned engineering veteran involved with new product development. The terminology that is used for most thermal control devices is dependent on how it has been tested by one or more worldwide safety approval agencies.

The key question is what you need your thermal devices to do. In very simple terms, if a thermal control will continually make and break the circuit to maintain temperature control, or if they will need to cycle frequently, you will need a bimetallic Thermostat.

If your application requires a thermal control device to simply provide over-current or over-temperature protection, then you will need a Thermal Protector.

The basic mechanical difference between thermostats and thermal protectors is found in the internal spacings of the device. A thermostat requires additional spacing requirements so that there is more "through air" spacing to serve as additional electrical isolation. In most cases a Thermostat will be slightly larger than a Thermal Protector due to the greater internal spacings required to obtain safety agency approvals.