3. Photovoltaic connectors or photovoltaic cables are in a humid environment for a long time
Almost everyone believes that the conductive parts of photovoltaic cables and photovoltaic connectors are covered by other materials, and photovoltaic connectors are claimed to have waterproof functions. In fact, waterproof does not mean that it can be in water for a long time. Photovoltaic connector IP67 means that the pre-installed photovoltaic connector with wires is immersed in water, with the top 0.15~1 meter away from the water surface for 30 minutes, and the performance is not affected.
At present, photovoltaic cables on the market can also be soaked in water for a short time, such as a short period of watering, until water accumulates, but the time of water accumulation cannot be too long, and it must flow quickly and be ventilated and dried. A photovoltaic cable burned because the construction party buried the photovoltaic cable in a swamp. Due to long-term soaking in water, the photovoltaic cable was penetrated by water and caused arcing and burning. It is particularly emphasized here that photovoltaic cables laid in pipes are more prone to fire because of long-term water accumulation in the PVC pipe. If you need to lay it in a PVC pipe sleeve, remember to let the mouth of the PVC pipe face down, or make some holes at the lowest water level of the PVC pipe to prevent water accumulation.
4. Cable damage or excessive bending during laying
Scratching the cable skin greatly reduces the insulation and weather resistance of the cable. This is easy to understand and will not be repeated. In construction, cable bending is common. The standard stipulates that the minimum bending diameter must be greater than 4 times the cable diameter. The diameter of a 4-square photovoltaic cable is about 6MM. Therefore, the arc diameter at the bend must not be less than 24MM, which is equivalent to the size of a circle formed by the thumb and index finger.
The conditions that cause any point in the photovoltaic string circuit to be grounded or to form a path with the bridge are relatively complicated, including long-term immersion of photovoltaic cables in water, photovoltaic connectors on extended lines, damage to the cable surface during construction, cable skin bitten by mice during use, lightning strikes, etc.
5. Irregular crimping of photovoltaic connectors
Irregular crimping of photovoltaic connectors is mainly due to the gap between on-site tools and operating experience, resulting in poor crimping quality. The main problems are that the cable copper wire is bent, some copper wires are not crimped in, and the crimped part is the cable insulation layer.
When it comes to the crimping process, we also need to pay attention to the stripping process. The standard has strict regulations on the number of copper wires cut during stripping. If too many copper wires are cut, it will affect the crimping and flow quality, resulting in a higher temperature rise. It is recommended that installers with conditions can purchase professional tools, provide corresponding training to on-site installation personnel, and establish a random inspection mechanism.
