Technical requirements for safety protection line of Trolley Crane

Technical requirements for safety protection line of Trolley Crane: Protection of the Trolley Crane zero is the electrical equipment under normal circumstances without electricity of the metal shell or frame, with the wire and the power supply line directly connected.

Protection of Trolley Crane zero for power neutral ground directly to the three-phase four-wire or three-phase five-wire low-voltage grounding grid. Its role is when the electrical equipment is used to protect the Trolley Crane zero, once the equipment occurs short-circuit fault or electrical insulation damage, the electrical equipment shell live, because the neutral resistance is very small, the short-circuit current is greater than the rated current several times or even several times , Forcing the protection of electrical appliances in the circuit or so that the fuse in a very short period of time fuse, thus cutting off the power of the faulty equipment, protection equipment and personal safety.

Safety requirements for protection of connected wires:

(1) Trolley Crane zero line cross-sectional area should generally not be less than 1/2 of the cross-section of the phase line, the maximum cross-section, steel wire is not greater than 80 square millimeters, aluminum is not greater than 70 square millimeters, copper is not greater than 50 square millimeters. In order to ensure sufficient mechanical strength, the minimum cross-section shall not be less than the following values: bare copper wire 4 mm2, bare aluminum 6 mm square, insulated copper wire 1.5 mm2, insulated wire 2.5 mm2, general wire 12 mm2.

(2) The lines of the neutral and neutral lines should be secure and in good contact. The connection of the Trolley Crane zero line cable to the equipment is bolted with bolts and, if necessary, with spring washers. All electrical equipment connected to the Trolley Crane zero line, should be connected in parallel on the Trolley Crane zero line, not allowed in series.