What is electrical overload?
An electrical overload is an excessive current relative to the normal operating current, but one which is confined to the normal conductive paths of the circuit. Overloads are often between 1,35 and 6 times the normal current level. When a circuit is overloaded, the plasticizers in the insulation are vaporized over a long period and the insulation becomes brittle.
Continuous overloads can result from too many loads connected to one circuit or from defective equipment. An overload must be cut off by protection devices before they damage the circuit. Fuses and circuit breakers protect a circuit against current overloads.
Overloads are most often between 1.35 and 6 times the nominal current level. Overloads are usually caused by temporary starting currents that occur during the motor start-up or transformer energization. Temporary overloads or transients are not harmful to circuit components as the associated temperature rise is minimal. They are not harmful.
Continous overloads can result from defective motors (worn bearings) or when too many loads are on a single circuit and must not be permitted to last long enough to damage electrical system components such as conductors. This damage may eventually lead to severe fault events such as fires if the overload is not interrupted. Due to the overload’s inherent low magnitude nature, removing them within seconds or even minutes will generally prevent thermal damage.
Causes of overload
The main causes of an overload in the circuit are:
- Inrush currents when starting a motor.
- Worn bearings of a motor.
- Too many loads in a single circuit.
- Overloaded machine tools.
- Damaged material and products.
How can you prevent having an overloaded circuit?
Fuses, overload relays, and circuit breakers are protective devices used to protect circuits against overloads. In the event of an overload, a properly sized fuse, overload relay or circuit breaker will immediately open the circuit. Each device, however, has different time characteristics and must be used and applied according to the appropriate standards and manufacturer’s recommendations for the individual application. Failure to select the properly rated overcurrent protective device can result in fires, explosions, and death.
Is an overloaded circuit dangerous?
The overloaded circuit in an electrical system is dangerous because it can produce heat. Wires and other components in an electrical system have a maximum amount of current they can carry safely. When an overload occurs the electrical current will heat the wires and it could cause a fire.
What are the warning signs of an overloaded electrical circuit?
The obvious sign of an overloaded electrical circuit is a breaker tripping. Other signs can be:
- Dimming lights.
- Buzzing outlets or switches.
- Warm outlet or switch.
- Very hot appliances or motors.
- Burning smells.
- Sluggish electronics.
- Power outage in a room or whole house.
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