Precautions for connecting high mast light poles cables

Since high mast light poles are usually located in high-altitude, open-air environments, cable connections need to cope with complex climatic conditions and mechanical stress, so technical specifications must be strictly followed during the construction process.

 

I. Preliminary design and material selection

1. Cable specification matching

According to the power, voltage level and line length of the high mast light poles, calculate the current carrying capacity of the cable to ensure that the cross-sectional area meets the load requirements (refer to "GB 50217-2018 Power Engineering Cable Design Standard").

Copper core cables are preferred because their conductivity and corrosion resistance are better than aluminum core cables. If aluminum core cables are used, copper-aluminum transition terminals must be used to avoid electrochemical corrosion.

Cross-linked polyethylene (YJV) or weather-resistant cables are recommended for outdoor environments to avoid aging of the insulation layer of ordinary PVC cables due to ultraviolet rays or temperature differences.

 

2. Connector quality requirements

The terminal should use crimped copper terminals, which are strictly matched with the cable cross-sectional area. It is prohibited to use winding or bolts for direct crimping.

The waterproof junction box must have a protection level of IP65 or above, and reserve cable bending space inside to avoid stress concentration.

 

3. Lightning protection and grounding design

The metal pole of the high pole lamp must be reliably connected to the grounding system, and the grounding resistance must be ≤10Ω (according to "GB 50057-2010 Building Lightning Protection Design Code").

The cable shielding layer must be grounded at both ends to prevent lightning-induced overvoltage from damaging the equipment.

 

II. Key points of construction technology

1. Cable laying specifications

Avoid excessive bending of the cable in the pole, and the minimum bending radius must be ≥15 times the outer diameter of the cable (such as the outer diameter of the YJV-3×25 cable is about 30mm, and the bending radius must be ≥450mm).

Use non-metallic cable ties or insulating clamps when fixing the cable to prevent metal parts from cutting the insulation layer.

 

2. Joint processing technology

Wire stripping accuracy: Use special wire strippers to ensure that the exposed length of the conductor is consistent with the terminal depth to avoid loose copper wire or residual insulation layer.

Crimping process: hydraulic pliers are used to crimp the terminals. The crimping sequence extends from the root of the terminal to the port. The indentation should be uniform and free of burrs. After completion, a tensile test is performed (≥50N without falling off).

Insulation protection: Double-layer insulation tape (inner waterproof tape + outer high-voltage self-adhesive tape) is wrapped around the crimping point, or heat-shrink tubing is used to heat and seal to ensure that there is no exposed conductor.

 

3. Waterproof and sealing measures

Waterproof locks or silicone sealing rings are used at the inlet of the junction box, and the outer sheath of the cable needs to extend into the box by at least 20mm.

Insulating waterproof glue (such as epoxy resin) can be filled in the junction box in humid areas, but heat dissipation space must be reserved.

 

III. Safety protection and environmental adaptability

1. Mechanical stress protection

The cable of the light pole lifting system needs to reserve sufficient margin (usually 1.2 times the lifting height), and spiral wiring or spring buffer devices are used to avoid frequent lifting and lowering causing cable breakage.

When the cable is passed through the pipe, a rubber sheath is added to the pipe mouth to prevent metal burrs from scratching the cable.

 

2. Extreme climate response

Low-temperature resistant cables (-40℃) are used in high-cold areas, and anti-salt spray cables are used in coastal areas.

Anti-condensation devices (such as silica gel desiccant) are installed in the junction box to prevent internal condensation from causing discharge failures.

 

3. Anti-biological damage

In areas where rodents are active frequently, the outer layer of the cable can be wrapped with a metal braided mesh or coated with rodent-proof paint.

IV. Test and acceptance standards

1. Continuity test

Use a multimeter to detect the continuity of the cable phase by phase to ensure that there is no false connection or short circuit.

Measure insulation resistance: Use a 500V megohmmeter to test the insulation resistance between phases and to the ground, and the requirement is ≥10MΩ (GB 50303-2015 Construction Quality Acceptance Code for Electrical Engineering).

 

2. Load test

 Run at full load for 4 hours, use an infrared thermometer to detect the temperature of the joint, and the temperature rise is ≤30℃ to be qualified.

 Repeat the lifting system 10 times to observe whether the cable is stuck or deformed.

 

3. Document retention

Record the cable model, connection point location, test data, and attach a wiring diagram for later maintenance.

 

V. Operation and maintenance and fault prevention

1. Regular inspections

Check the sealing of the junction box every quarter, clean the internal dust and insects; focus on testing the insulation resistance before and after the rainy season.

Immediately check whether the cable is deformed by force after a typhoon or earthquake.

 

2. Replacement of aging parts

When the cable insulation layer cracks, hardens, or the joints oxidize and turn black, they need to be replaced in time.

It is recommended to fully test the cable withstand voltage performance every 5 years.

 

3. Emergency plan

Equipped with spare cables and quick connectors to ensure that lighting is restored within 2 hours in the event of a sudden failure.

 

Conclusion

The cable connection of high mast light poles is a systematic project that requires full control of the entire chain from design selection, standardized construction to long-term maintenance. Only by strictly implementing technical standards and paying attention to detail processing can the safe operation of high mast light poles in complex environments be guaranteed, the life of equipment can be extended, and the operation and maintenance costs can be reduced. Construction personnel should receive professional training regularly and combine intelligent monitoring methods (such as online temperature sensors) to achieve fault warning and further improve system reliability.