IBEW Electrical Practice Test 2025 – Complete Exam Preparation

Inrush current refers to the surge of current that occurs when an electrical device is turned on, which can be significantly higher than the normal operating current. The scenario of plugging in an electronic device typically causes inrush current because, upon connecting the device to the power supply, all the capacitors and coils within the device attempt to charge up quickly. This sudden demand for current can lead to a brief spike in electrical current that can be several times higher than the device's usual operating current.

When an electronic device is plugged in, especially if it contains motors or large capacitive components, the instantaneous load can draw a large amount of current as those components transition into operation. It's important to account for this inrush current in circuit design and protection to avoid tripping circuit breakers or damaging equipment.

Other scenarios such as turning off a light switch, disconnecting a battery, or switching off power to a circuit do not typically create an inrush current situation since they involve the interruption of current flow rather than the initiation of it.