What is the indication of 30mA & 40A?

What is the indication of 30mA & 40A?

The values of 30mA and 40A are typically associated with different electrical parameters and devices:


This measurement often signifies the sensitivity of a Residual Current Device (RCD/RCCB) or Ground Fault Circuit Interrupter (GFCI). A 30mA RCD/GFCI is intended to trip and disconnect the circuit upon detecting a leakage current of 30 milliamperes or higher. This level of sensitivity is selected for protection against electrical shock, as 30mA is considered a threshold below which the risk of a harmful electric shock is significantly reduced.


This value commonly represents the current rating of a circuit breaker or fuse. A 40A circuit breaker or fuse is designed to manage up to 40 amperes of current. If the current surpasses this value, the circuit breaker will trip, or the fuse will blow, to safeguard the electrical circuit from damage caused by overcurrent, which can occur due to short circuits or overloads.

In short term, 30mA indicates the sensitivity of a protective device to leakage current for safety purposes, while 40A indicates a device’s current carrying capacity for safeguarding electrical circuits from excessive current.

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