What is the insulation resistance of tower crane?
Two. Safety regulations for tower cranes GB 5144 - 20068.1.3 tower crane metal structure, track, all electrical equipment metal shell, metal line pipe, safety lighting transformer, low voltage side should be reliable grounding, grounding resistance is not more than 4 ohms. Repeated earthing resistance is not greater than l0. The selection and installation of the earthing device shall comply with the relevant requirements of the electrical safety.The insulation resistance of the 8.1.7 main circuit and control circuit shall not be less than 0.5M ohm.
Three. Technical specification for temporary power safety on construction site JGJ 46-20055.4.2 within the construction site crane, derrick and Longmen machinery equipment, metal structure and steel scaffolding and under construction in construction projects, when lightning protection devices in adjacent buildings, structures and other facilities outside the protect zone of lightning arrester, lightning protection device should be installed in accordance with the provisions of.5.4.7 lightning protection electrical equipment machinery, connected to the PE line must repeat grounding at the same time, with a repeat of the mechanical and electrical equipment grounding and lightning protection grounding machines can share the same grounding body, but should be consistent with the repeated grounding resistance of grounding resistance requirements.The electrical equipment of 9.2.1 tower crane shall comply with the requirements of the current national standard "safety regulations for tower cranes" GB5144.9.2.2 tower cranes shall be subjected to repeated earthing and lightning protection grounding as specified in Clause 5.4.7 of this code. The earthing device of the track type tower crane shall comply with the following requirements:L the two ends of the rail are respectively provided with a grounding device;The joint of the 2 track is electrically connected, and the ends of the two tracks are electrically connected in the loop;3 long track every is not more than 30m and a grounding device.
The lightning resistance of tower crane (tower crane) on the construction site shall be no more than 4 ohms.I. tower crane GB/T 5031--20085.5.5.9 lightning protectionIn order to avoid lightning stroke, the main structure of the tower crane, the motor frame and all the electrical equipment metal shell, wire metal protection tube should be reliable grounding, and its grounding resistance should be no more than 4 ohms. When multiple repetitive earthing is adopted, the grounding resistance shall be no more than 10 ohms.
