Construction Skills Certification Scheme (CSCS) Practice Test

To protect yourself from electric shock when using a 230 volt tool, what device should you use?

1. Standard plug

2. Fuse box

3. Portable residual current device (RCD)

4. None, it's safe without protection

The correct answer is: Portable residual current device (RCD)

Using a portable residual current device (RCD) is essential for protecting yourself from electric shock when operating a tool that runs on 230 volts. An RCD works by constantly monitoring the electric current flowing through the circuit. If it detects any imbalance, which may occur if current escapes through a fault (for example, through a person), the device rapidly disconnects the electrical supply, minimizing the risk of severe electric shock or electrocution. In contrast, a standard plug does not provide any additional protection against faults; it is simply a means to connect a device to a power source. The fuse box is important for broader electrical protection by interrupting the circuit in the event of an overload or short circuit but does not respond quickly enough to prevent shock from smaller imbalances. Finally, operating a tool without any protective device is highly unsafe and increases the risk of electric shock, making it unadvisable. Thus, using an RCD is a proactive safety measure that can make a significant difference in ensuring electrical safety.