What are the environmental requirements for cable laying?

Today's wire and cable are used for power transmission (magnetic), which can realize electromagnetic energy conversion, information, wire products. Let's take a look at the laying of wires and cables.

1. Ambient temperature. Since the weather temperature is variable, the ambient temperature at selected points above ground, underground (eg indoors and outdoors) takes different values in different settings. Partially buried underwater heat source equipment plant tunnel, indoor cable tunnel, indoor cable duct or outdoor Mingfu There is no heat source as shading equipment Factory poor ventilation or mechanical ventilation The ground temperature and the highest average water temperature are the hottest, plus 5°C, the highest temperature, the average value when the number of tunnel cables is large, and the cable thermal effect should also be included in the hot daily average maximum temperature.

2. Laying method. Exposed laying, dark laying, pipe laying, bridge laying, trough laying, different laying methods, different cooling conditions.

3. Lay the area. Ground, underground, water, cable trench, electrical shaft, etc.

4. Power cord and application. Not only will cooling conditions be affected, but many cable heating will also affect each other. 5. Another medium pipeline. Such as hot water pipes, steam pipes, etc.

The actual allowable carrying capacity of the cable.

In the actual project, the fixed wiring system has set the laying conditions of each cable, so the actual allowable bearing capacity and the traffic load change mentioned in the table depend on the actual installation situation.

Conditions and tables are based on installation conditions.

The engineering correction factor "to" allows for variations in load-carrying capacity due to the conditions imposed by different laying cables. Typical correction factors are: temperature correction factor, application correction factor, soil thermal resistance correction factor, etc. Essentially, the correction factor is a correction to the cooling conditions.