How to set up the lightning protection device of the tower crane, and whether the tower crane is equ

1. The top of the tower cap should be equipped with a lightning rod.

The joints should be clearly painted. The cable of the lightning protection grounding protection device can be bolted to any of the main chords, and the paint on the bolts, nuts and sleeves is clear. The chassis anchored to the foundation should never be used as a grounding electrode for lightning protection devices.

A lightning protection grounding device must be set up outside the tower crane foundation.

2. The resistance of the lightning protection grounding protection device does not exceed 4 ohms. Even if other safety protection devices can be used, such as highly sensitive differential relays, such grounding protection devices must be installed according to the regulations. The grounding device should be installed by a special person, because the grounding resistivity time and local conditions vary greatly, and high-precision instruments should be used to determine the resistance.

3. The installation and maintenance of materials and equipment for lightning protection facilities are not provided by the tower crane manufacturer. The lightning protection grounding device must be made according to the provisions of the following figure.

According to the provisions of the national standard GB5144-94 "Tower Crane Safety Regulations", the metal structure of the crane, the metal shell of all electrical equipment, and the metal wire pipe must be reliably grounded. The ground resistance is not more than 4 ohms.

a.The joints should be cleared of paint.

b.The cable of the lightning protection grounding protection device can be bolted to any main chord and the paint on the bolts, nuts and sleeves can be removed.

c.The chassis that is riveted with the foundation must not be used as the grounding electrode of the lightning protection device, and a lightning protection grounding device must be set up outside the tower crane foundation.

d.The resistance of the lightning protection grounding protection device does not exceed 20 ohms.

e.Even if other safety devices can be used, such as highly sensitive differential relays (automatic circuit breakers), they must be installed according to the regulations.

f.The grounding device should be installed by a special person, because the grounding resistivity varies greatly depending on the time and local conditions, and high-precision instruments are required to determine the resistance.

Make a grounding electrode around the tower crane and connect it with the tower crane.

Article 1 of the Technical Code for Temporary Electricity Safety on the Construction Site (JGJ46-2005) stipulates: tower cranes.

There is no need for a lightning rod.

Although the tower crane can not be equipped with a lightning rod, it must be a lightning protection grounding device. The grounding wire for each grounding device.

Two or more conductors should be used to make electrical connections with the grounding body at different points. Aluminum conductors shall not be used as grounding bodies or underground grounding wires. Angle steel should be used for vertical ground.

Steel bucket trillion tube or light such as pin surface round steel.

Rebar shall not be used.

The ground resistance value is not more than 4 ohms, and the repeated ground resistance value is not more than 10 ohms.

Tower crane foundation and hoisting precautions:

1. The tower crane should be inspected in time after the rain, and the empty vehicle should be operated to determine that there is no problem before it can be officially hoisted.

2. Observe the subsidence of the foundation, and make a good observation record, if there is a settlement, it should be dealt with immediately to ensure the safety of the tower crane when it is used. In case of heavy rain, heavy rain and strong wind, the hoisting operation should be stopped.

3. High-altitude operators should pay attention to anti-slip when working after rain, wear rubber-soled shoes, and are not allowed to wear hard-soled shoes for high-altitude operation. The grounding resistance value of the tower crane should be measured, and the resistance value is not greater than 4.

4, the tower crane foundation around the digging 200mm 300mm drainage ditch and the site temporary drainage ditch connection, the inner plastering, the bottom of the ditch to the temporary drainage ditch direction set 5 water slope.

5. Set up 4 sediment trapping observation points on the tower base, conduct settlement observation regularly and after rain, and deal with problems in time.

The construction site temporary electricity code JGJ46-2005 states that the tower crane can not be a lightning rod, but must be reliably grounded. Because of the airlift, the tower crane can not be equipped with a lightning rod.

A complete set of "lightning protection" devices needs to have three elements: "lightning receiver", "down lead", and "grounding device".

Lightning rods, lightning belts, lightning nets, etc. are all special "lightning receivers", round steel or flat steel and other metal conductors can be "down wire", buried in the soil of the metal grounding body and the grounding wire used for connection constitute a "grounding device bucket orange old" attack.

Therefore, in the case that the tower crane is not equipped with lightning rods, it is necessary to pay attention to lightning protection grounding and repeated grounding, and ensure that the impact grounding resistance is not greater than 30 ohms.

The basic requirements and protection devices of the tower crane distribution box 1, the basic requirements for the tower crane distribution box a, the distribution box of large equipment such as the tower crane should be dedicated to the box, and one machine and one gate, with obvious identification; B, the distribution box should be installed within 5 meters from the tower crane, high meters, easy to operate the position. c. The distribution box should be rainproof and dustproof, with doors and locks, and the wires should enter and exit from under the box, and the box should be reliably connected to zero and grounded. 2. The protection device of the tower crane distribution box a, the distribution box should be installed with a four-wire air circuit breaker with leakage protection device, the working zero line should enter the four-wire air break circuit, and the fuse should be installed.

b. The leakage protection current should be 50-80mA, and the test is sensitive and reliable. c. When there is a short circuit and over-interception of electrical appliances, the air break trip device should act immediately, and the fuse should be blown quickly. d. Reasonable selection of the melting capacity of the total fuse of the tower crane, generally using the following formula:

The total melting capacity of the total fuse = (the rated current of the largest motor + the sum of the rated current of the other motors.) Example: The total melting capacity of the fuse of the 63tm tower crane is.

First, the tower crane due to its height, should be designed grounding grid, but do not install lightning rod (lightning rod), ground grid resistance value below 4 ohms, the ground grid to temporary 10 centimeter round steel and vertical angle steel, steel pipe piling as the main material, the grounding wire must be connected to the top of the tower crane control room, the control room should be laid insulating mats, in order to ensure the safety of indoor personnel!!

Second, the power supply lightning protector should be installed in the distribution box;

3. Signal arresters should be installed on its industrial bus, such as 485 232 lines.