Supplementary Protectors is a manually resettable device which is designed in such a way that it opens the circuit automatically on predetermined value of time versus voltage or current in electrical equipment or within the appliance.  Supplementary protectors may also be provided means for closing or opening the circuit. The primary function of supplementary is to protect the equipment from excess voltage or current. Owing to the contrast with branch circuit breaker that is applied with at 75% of the rated current value, the supplementary protector can be applied at 100% of the rated current values, unless marked differently on the device. Supplementary protectors are used for electrical equipment or within appliances such as control power transformers, control circuits, relays, lighting circuits and PLC I/O points. Supplementary protectors have three different types of tripping characteristic such as type B, type C, type D. These characteristics or tripping defines the speed of the devices in response to the various level of overcurrent. The tripping characteristic is applied on the basis of the application, for instance, type B supplementary protectors are developed primarily...