Zero line and ground line they both lie in the firewire is a charged line, while the zero line and ground is not charged line, zero line and ground line is the difference between the d line directly to ground, if the leakage of electrical appliances through the ground release to the earth, and the zero line as a firewire and the return line, although ultimately also directly or indirectly grounded, but technically speaking, the zero line is the power supply end of the ground is also a part of the power transmission line. A part of it.