It is a common question many have in mind. It is always important to ensure your safety by checking whether your house, office or workplace is properly earthed or not.
The three-pin female plug pin present in the circuit board has three holes in it called as Phase (P), neutral (N) and Earth (E), as shown in the following picture.
Take a light bulb holder, connected with two wires i.e., for positive and negative terminals of the bulb. Now insert one of the wires in phase and the other in neutral. The bulb glows indicating the power supply.
Take out the wire from neutral and insert it into the Earth’s hole. The bulb glows with a bit lesser brightness than before. During Summer season, the Earth’s resistance is more and hence the light glows with lesser brightness. But during Rainy and Winter seasons, the Earth’s resistance is less and the light glows brightly. However, this brightness is lesser than what is observed between neutral and phase.
If the bulb does not glow when you insert the wire between phase and earth, then it does mean that there is no proper earthing provided for that circuit board. This could be very dangerous as the electricity might pass through any metallic substance in the room or the floor itself. This could lead to death by electrocution.
If the neutral and earth are shorted, even then the bulb glows with the same brightness as it glowed when connected between neutral and phase. Even this is not a safe condition as this method doesn’t provide proper earthing. Check if your electrician laid a safe connection for you. Otherwise, ask him to connect it properly.