What is overload protection?

An overload protection device that prevents the main power line from overloading and causing the protector to overheat and damage.

The amount of current in an electrical circuit that allows continuous passage without overheating the wire, known as safe load flow or safe current. If the current passing through the wire exceeds the safe load flow, it is called a conductor overload. General conductor maximum allowable operating temperature of 65°c. overload, the temperature exceeds this temperature, will make the insulation rapidly aging and even the line burning.

In machinery, overload protection prevents damage to equipment caused by overloading when the shaft exceeds the load it can withstand.

The main cause of overload

The main cause of overload is improper selection of traverse section, the actual load has exceeded the safety current of the conductor;　　There are "small horse cart" phenomenon, that is, in the line of access to too many high-power equipment, more than the load power distribution lines. In important material warehouses, places of residence and public buildings, lighting lines, power lines that may cause long time overload of conductors or cables, as well as insulated conductors with a burnt sheath to be laid on flammable or refractory building elements, should be protected by overload. It is advisable to use automatic switch for overload protection of line. When running, the automatic switching long time delay action setting current should not be greater than the line long-term allowable load current. If the fuse is used as overload protection, the fuse current should not be larger than the current of the long line load. When an automatic switch is used as a protective device, its current release in the neutral grounding of the three-phase four-wire system, should be installed on the phase line, in the neutral point of ungrounded three-phase four-wire system, allowed to install in the two-phase, ungrounded binary two-phase system, allowed to be installed in a phase.