![]() ![]() Generally, when the supply voltage increases up to 1.1 (which is 110%) of the rated voltage of a device is known the overvoltage unless specified by the manufactures.įor instance, if the rated voltage printed on the nameplate data rating of a machine is 230V AC ☑0%. In short, voltage higher than the permissible voltage is known as overvoltage. Overvoltage is the condition where the operating or supply voltage is higher than the rated voltage of the system specified by the manufacturer.Īs the name suggests, overvoltage is the higher supply voltage to a device than its nominal rated voltage. Typically, overload protection circuit activated when 120% – 160% greater current starts to flow in the circuit than the rated current by power supply. the tripping time becomes less when current increases. The “magnetic” element provides protection against overcurrent and “thermal” element protects the circuit from “overload” where it operate on inverse time curve i.e. Slow blow fuses and overload relays are used against overload protection whereas, thermal magnetic circuit breaker are used for both overcurrent and overload protection. Overload protection is actually a protection against overheat due to the flow of overcurrent in the circuit for specific time. Overload is the overcurrent flow in the circuit which causes overheating in the connected device hence, overload is a type of overcurrent. In this case, the wires may heats up and caught fire or damage the circuit and connected appliances while the breaker won’t trip as we didn’t use the proper size and rating of circuit breaker for protection.Īnother example of overload is connecting a 1.5kW load to the 1kW alternator, inverter or transformer etc or when up to 1.5 times higher current flows through the circuit rather than the rated current. In other words, the circuit breaker may allow more current than the nominal current which can only handle up to 20A. Now if we use 30A – 35A circuit breaker instead of the rated CB, it means the circuit breaker will allow about 30 to 35 amperes current to the load circuit which flows in the wires rated for 20A. In this case, we must use maximum of 25A circuit breaker for protection. The circuit can be protected by minimum of 20A or 125% of load amperage i.e. ![]() What is Overload?Īn electrical overload is the condition where the load takes more current than the normal or rated current.įor example, a #12 gauge wire can safely carry 20 amperes current. In addition, a thermal magnetic circuit breaker is used for both overcurrent and overload protection. Overcurrent protection is generally a protection against short circuit where excessive current starts to flow in the circuit which leads to damage the connected equipment.įuses, circuit breakers, overcurrent relays, current limiters, temperature sensors and solid state power switches are used against overcurrent protection devices. ![]()
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