Cover exposed live metal

Use insulating barriers or shields to cover live parts. Plexiglas plates can be usefull. If the voltage of the system is less than 50V for AC supplies or less than 120V for DC supplies then it is known as extra low voltage and it is considered to be low enough that it is not going to cause a fatal electric shock. If the source of supply is made so that, even in a fault condition, mains voltages cannot appear on the system then it is safety extra low voltage (SELV) other protection measures may not be required.