All electrical equipment housings of single girder bridge cranes should be grounded. If the trolley track is not welded to the main beam, the welding ground should be taken. The grounding wire may be a galvanized flat iron with a cross-sectional area of more than 75 mm2 or a bare copper wire of 10 mm2 or a galvanized round steel of more than 30 mm2.
There should be more than two grounding locations in the cab or crane body. The grounding resistance between any point on the crane to the neutral point of the power supply should be less than 4Ω. It is necessary to conduct safety technical inspections on a regular basis and do pre-review pre-repair work of single beam overhead crane.
In addition, there are other precautions that the overhead crane operator need to pay attention:
(1) Welding or hammering and work underneath the object (when supported) is not permitted on suspended objects.
(2) It is necessary to do inspections or perform maintenance work after a power outage and hanging signs of power outages on the power door. If it is necessary to carry out live work, it must be protected by safety measures and be provided with special care.
(3) Do not casually throw things from the car.
(4) Limit switch and interlock protection device, always check.
(5) It is not allowed to use limit switches as a means of parking.
(6) Lifting weights are not permitted when there is a problem with the lifting brake.
(7) Hanging objects must not be operated over people or equipment.
(8) When welding a certain part of a crane, it is necessary to set a special ground wire, and it is forbidden to use the fuselage as a ground wire.
(9) When the hook is in the lower limit position, more than two turns of safety rope must remain on the reel.
(10) Cranes are not allowed to collide with each other, and it is even more forbidden to use one crane to push another crane to work.
