At home, there are several three sockets in the kitchen and balcony, and the ground wires are electr

It is a normal phenomenon of qualified electrical appliances, all electrical appliances have distributed capacitance to the metal shell of the induced electricity, (can not be measured with a pen, when measured with a pen, as long as the metal tip of the pen is touched with your hand at the same time, the pen lamp is immediately extinguished, proving that there is no electricity.) To use the multimeter AC 50 volts, measuring the electrical metal shell to the ground voltage below 30 volts is normal (when touching the meter pen head with your hand at the same time, the 30 volt voltage immediately drops to 2-6 volts), there is no danger, if you are worried when you use, as long as the power plug is inserted into the socket (or the socket live wire and the neutral wire are reversed), when the induced voltage can be eliminated (of course, according to the regulations should be in the socket ground post grounding wire). If the shell is measured to the ground, and the leakage voltage is higher than 50 volts (generally above 110 volts), it is really leakage and must be checked and repaired!