TN-S neutral protection system is adopted; 3.
The n-line in the incoming and outgoing lines must be connected through the n-line terminal board; The PE line must be connected through the PE line terminal board.
When TN system is used as protective zero connection, the working zero line (N line) must pass through the general leakage protector, and the protective zero line (PE line) must be led out from the repeated grounding of the incoming zero line of the power supply or the zero line on the power side of the general leakage protector to form a local TN-S zero connection protection system.
It is not allowed to make protective neutral connection for some equipment and protective grounding for others.
6.2.3 the power supply of the generator set must be interlocked with the power supply of the external power line, and parallel operation is strictly prohibited.
1.0.3 220 / 380V three-phase four wire low-voltage power system with power neutral directly grounded for temporary power engineering on the construction site must comply with the following provisions: 1 Adopt three-level power distribution system; 2.
5.4.7 for electrical equipment on lightning protection grounding machinery, the connected PE line must be repeatedly grounded at the same time.
5.3.2 in addition to repeated grounding at the distribution room or general distribution box, the protective zero line in TN system must also be repeatedly grounded at the middle and end of the distribution system.
8.2.15 it is forbidden to use plugs and sockets for movable connection at the power inlet of distribution box and switch box..
Five core cables must be used for cable lines requiring three-phase four wire distribution.
The leakage protector used in wet or corrosive medium places shall be splash proof products, and its rated leakage action current shall not be greater than 15mA, and the rated leakage action time shall not be greater than 0.1s.
3.3.4 the regular inspection of temporary power utilization works shall be carried out according to divisional and subdivisional works, the potential safety hazards must be handled in time, and the review and acceptance procedures shall be performed.
According to technical code for safety of temporary electricity use on construction site JGJ46-2005, articles 1.0.3, 3.1.4, 3.1.5, 3.3.4, 5.1.1, 5.1.2, 5.1.10, 5.3.2, 5.4.7, 6.1.6, 6.1.8, 6.2.3, 6.2.7, 7.2.1, 7.2.3, 8.1.3, 8.1.11, 8.2.10, 8.2.11, 8.2.15, 8.3.4, 9.7.3, 10.2.2, 10.2.5 and 10.3.11 are mandatory and must be strictly implemented.
The repeated grounding of the same mechanical electrical equipment and the lightning protection grounding of machinery can share the same grounding body, but the grounding resistance shall meet the requirements of repeated grounding resistance value.
There shall be obvious breakpoints when the power disconnector is disconnected.
Five core cables must contain light blue and green / yellow insulated core wires.
The preparation shall be organized by electrical engineering technicians and implemented after being reviewed by relevant departments and approved by the technical director of the enterprise with legal personality.
Adopt secondary leakage protection system.
A specially assigned person must be responsible for power off and transmission.
8.2.11 the rated leakage action current of the leakage protector in the main distribution box shall be greater than 30mA, and the rated leakage action time shall be greater than 0.1s, but the product of the rated leakage action current and the rated leakage action time shall not be greater than 30mA · s.
Exposed laying along the ground is strictly prohibited, and mechanical damage and medium corrosion shall be avoided.
3.1.5 the temporary power use project must be jointly accepted by the preparation, review and approval department and the user, and can be put into use only after passing the acceptance.
6.2.7 when the generator units operate in parallel, the synchronization device must be installed, and the load shall be supplied with power after the unit operates synchronously.
8.1.11 n-wire terminal board and PE wire terminal board must be set on the electrical installation board of the distribution box.
Light blue core wire must be used as n wire; Green / yellow core wire must be used as PE wire, and mixing is strictly prohibited.
The n-wire terminal board must be insulated from the metal electrical installation board; The PE line terminal board must be electrically connected with the metal electrical installation board.
The protective zero line shall be led out from the working grounding wire, the zero line at the power side of the distribution room (general distribution box) or the zero line at the power side of the general leakage protector.
5.1.1 in TN-S neutral protection system for power supply of special transformer on construction site, the metal shell of electrical equipment must be connected with the protection zero line.
7.2.1 the cable must contain all working cores and cores used as protective zero wires or protective wires.
6.1.6 the power distribution cabinet shall be equipped with power isolation switch and short circuit, overload and leakage protection appliances.
In TN system, the grounding resistance of each repeated grounding device of the protective zero line shall not be greater than 10 Ω.
It is strictly prohibited to use the same switch box to directly control 2 or more electric equipment (including sockets).
7.2.3 cable lines shall be laid underground or overhead.
8.1.3 each electric equipment must have its own special switch box.
The buried cable path shall be provided with orientation marks.
3.1.4 during the design and change of temporary electricity organization, the procedure of “preparation, review and approval” must be performed.
In the power system where the working grounding resistance value is allowed to reach 10 Ω, the equivalent resistance value of all repeated grounding shall not be greater than 10 Ω.
6.1.8 when the distribution cabinet or distribution line is powered off for maintenance, the grounding wire shall be hung, and the power-off sign board of “no switching on, someone working” shall be hung.
5.1.2 when the construction site shares the same power supply system with external power lines, the grounding and neutral protection of electrical equipment shall be consistent with the original system.
8.2.10 the rated leakage action current of the leakage protector in the switch box shall not be greater than 30mA, and the rated leakage action time shall not be greater than 0.1s.
5.1.10 it is strictly prohibited to install switches or fuses on PE lines, to pass working current, and to break lines.
When changing the power consumption organization design, relevant drawings and data shall be supplemented.
