On Distribution Box And Its Connection
Analysis of distribution box and its wiring:
The temporary power system shall adopt "three-level control, two pole protection" system, i.e. three-level control of general distribution box, distribution box and switch box shall be adopted. At the same time, leakage protector shall be installed in the general distribution box and switch box respectively to protect the power equipment under normal circumstances, which can only be connected from the switch box in practice, It is not safe for some construction units to directly use the wiring in the cluster distribution box because the electrical equipment is close to the distribution box.
In addition, according to the safety code, when the conductor is led down from the pole into the distribution box, it shall be protected by passing through the pipe and led in from the bottom of the box. The upper end of the protection pipe shall be made with waterproof elbow. On the construction site, however, the cross arm shall be directly added under the pole, and the conductor shall be led down directly from the top by using the porcelain bottle wiring.
No sheath and waterproof elbow shall be provided for the lead in and out of the box. At the same time, on the construction site, we often see that the distribution box with strong randomness of wiring is not locked or locked at ordinary times, but the key is not managed by specially assigned person, the incoming and outgoing lines are in disorder, not divided into bundles, without protective pipe, the length is not neat, the power supply is connected in disorder, the power line is directly hooked on the knife switch = the wiring in the box is not standardized, the wire cutting head is too long, and the conductor is exposed, “ The phenomenon of chicken claw line "is serious. The wiring in the box and the arrangement of electrical switches do not meet the requirements. The porcelain cover of the knife switch is lost or the nuts are not complete. The knife switch is connected directly over the leakage protector. The upper leakage protector is equipped with multiple residual wire heads, residual melt gadgets, etc. in the socket box. Even the load lines that have been removed for stacking shoes, hats, food and other sundries are still left in the box, and the exposed wire heads are against each other In addition, the lighting and wiring problems in the distribution box of the near switchgear are characterized by many points, wide area, strong mobility and temporariness, which makes the management of the power consumption of the on-site lighting difficult. The electric pressure of the lighting power supply in the humid place and the place easy to touch the electrified body shall not be more than, and the power voltage in the place where the mobile lighting is used shall not be more than and shall not use the self coupling type Transformer transformer voltage, another wet place should also use closed type waterproof and dustproof.
However, what we see is that in the stage of foundation plastering, the ground is extremely humid. If the workers do not cut off the power supply, they will take the iodine tungsten lamp tied to the wooden strip randomly to hang or tilt it, and then they will start to work. The hand-held lighting line is not laid off from the ground, and it will be put on the ground randomly, and it will be dragged and dragged along the aisle without any pipe protection. Some wires and lighting lamps used as power lines are bound to wire, iron frame and tree right. In addition, the lighting lines are seriously aged and the insulation layer is damaged= There is a joint in the middle of the lighting line, and there is no protection at the joint. The lighting line is not equipped with a switch box or a knife switch. Instead, the lighting line is directly hung on the knife switch of other equipment, or the lighting line is connected to the knife switch by skipping the leakage protector. The lighting line in the temporary facilities of the construction site is set too low, and the joint is broken at will, like a spider's web, and even some people hang on it Clothes, etc. These illegal phenomena are common and there are many hidden dangers, which urgently need to be paid attention to by the person in charge of the construction unit.
