After the cable is in the water, under the action of the electric field, the phenomenon of water tree aging will occur, this phenomenon may lead to cable breakdown.
The water tree refers to a collection of water-filled voids with a diameter of 0.1m to a few microns. The presence of impurities in the insulation, air holes, and uneven locations where the insulation is combined with the inner and outer semi-conducting layers can become a hatching ground for water trees.
The water tree development process is long, generally more than 8 years, the higher the humidity, temperature, and voltage, the more ions contained in the water, the faster the development of water trees.
Water directly into the low-voltage power cable, causing corrosion of steel and copper strip and other metals, insulation performance decline. Water through the insulation will cause cable breakdown, and even explosions and injuries.
1. When storing
Newly bought into the cylinder cable, its two ends are sealed with a plastic sealing sleeve, but after using a section, the rest of the plastic paper is wrapped in a rope outside a tie, the seal is not good, a long time, moisture will seep into the cable.
2. When laying the cable
When the cable is laid, the cable head wrapped with plastic paper is sometimes immersed in water, so that water enters the cable.
When pulling and threading, sometimes the outer sheath will be broken.
3. After laying
After laying, cable head production is not carried out in time, so the unsealed cable port is exposed to the air for a long time, or even immersed in water, so that water vapor enters the cable in large quantities.
4. When making cable head
When the cable head is made, including the terminal head and intermediate joints, the cable end sometimes slips into the cable well with water accumulation due to the intention of the production personnel.
5. When the cable is in operation
When a fault such as a breakdown of an intermediate joint occurs during cable operation, the water in the cable well will enter the cable along the gap.
In construction sites, external forces causing cable breakage or breakdown can also occur when the cable enters the water.
Wire and cable into the water is a very tricky thing, so far, there is no effective way to solve it.
The usual treatment is the intermediate joint and is to replace the entire cable, the more effective method is still based on prevention.
As everyone in the power cable industry knows, in most cases, cables are kept away from water sources. Once the cable enters the water, it will be a very troublesome thing.
It is very difficult to solve.
So in order to help young people who are new to the cable industry, ZMS Power Cable Co., Ltd. summed up a few experiences about cable waterproofing.
1. Pay attention to storage. The power cables that have just been purchased are generally well-sealed, but after a period of use, if you do not pay attention to storage, moisture will infiltrate.
2. When laying the cable, avoid the place close to the water source, and at the same time, be careful to avoid damage to the cable sheath.
3. After laying, install cable heads in time to avoid long-term exposure to the air and moisture infiltration of the cable opening in an unsealed state.
1. The cable head is sealed, and there is a professional cable sealing sleeve to seal the cable head to prevent water vapor from entering.
2. After laying the cable, install the cable joints in time to prevent problems before they happen.
3. Long-distance cables should be equipped with cable branch boxes to minimize the risk of water ingress by dispersing hazards.
In short: the danger of water in the wire and cable is still very large, and you need to prevent it in advance, if the water is really in, to a large extent, need to replace the cable, if you take a chance will bring unnecessary waste to the enterprise!