How to Design a Lifting High Mast Pole?
Oct 06, 2026
Designing a lifting high mast requires careful coordination of its structural, mechanical, and electrical systems. This guide outlines the key requirements for the luminaire carriage, mast, lifting system, lightning protection, electrical equipment, and foundation of Lifting High Mast Pole.
1. Luminaire Carriage of Lifting High Mast Pole
The figure below shows the structure of a lifting-type high mast. A lifting-type high-mast lighting installation consists of a luminaire carriage, mast, foundation, lifting system, power distribution system, lightning protection system, and other components. The luminaire carriage is the assembly on which the luminaires, light sources, and their electrical accessories are mounted. The weight of the carriage, including the luminaires and other accessories installed on it, is the main load on the lifting system.
The carriage should be designed primarily for functionality. Its luminaire brackets should be adjustable to make it easy to aim the light. The carriage should also have an attractive appearance and blend with the surrounding environment. However, the more decorative the carriage, the heavier it tends to be. This increases the strength requirements for the mast, foundation, flange, and lifting system, while potentially reducing the illuminance over the area being lit. A heavier carriage also reduces the safety margins of the associated braking and positioning devices and wire ropes. In addition, maintenance and cleaning become considerably more difficult.
Enclosed carriages should have adequate heat dissipation. If fibreglass is used, it must be made with flame-retardant resin. Carriages are commonly made from lightweight, corrosion-resistant materials such as steel or aluminium alloy, and must have sufficient mechanical strength. They may be designed as assemblies made up of multiple sections.
Flame-retardant wires should preferably be used inside the carriage. They should be arranged and secured with supports, and must not be subjected to excessive mechanical stress. For a multi-tier frame design, ensure that the light beams from the upper-tier luminaires are not obstructed by lower-tier luminaires or the frame, so that illumination levels are not reduced and shadows are avoided.
2. Mast Shaft of Lifting High Mast Pole
Mast shafts are generally divided into two types: conical and polygonal tapered. For conical poles, the cross-sectional roundness deviation should not exceed 5‰. Polygonal tapered poles generally have 12 to 18 sides; deviations in the across-flats and across-corners dimensions should each be less than 1%.
The mast shaft is assembled from multiple slip-jointed sections. The overlap length should be 1.7 times the outside diameter at the larger end of the joint. Once assembled, the clearance at each joint must not exceed 3 mm. To accommodate the length of hot-dip galvanizing baths and transportation requirements, individual shaft sections are generally less than 12 m long. The twist of each section should not exceed 7°. After erection, the pole's verticality deviation and the horizontal deviation at the top should each be less than 2‰ of the mast height. The mast shaft's axial alignment deviation should not exceed 1%.
Mast shafts are generally made from high-quality, high-strength low-carbon steel, low-alloy structural steel, or stainless steel. The steel properties should comply with ISO 630 and ISO 4950.
The pole surface should be hot-dip galvanized for corrosion protection. The zinc coating should be at least 70 μm thick when the shaft wall is less than 6 mm thick, and at least 85 μm thick when the wall is 6 mm or thicker. Where appearance is particularly important, a powder coating may be applied over the galvanized layer. The zinc coating should be uniform and smooth, with no burrs, runs, or excessive buildup. It must be firmly bonded to the steel substrate; in a hammer test, the coating must not peel or blister.
3. High Mast Pole Lifting System
The lifting system should support both manual and powered operation. Its transmission mechanism should operate smoothly, allowing the luminaire carriage to be raised and lowered steadily, safely, and reliably. The speed ratio should be selected appropriately, and the powered lifting speed of the carriage should not exceed 6 m/min.
The lifting system should use a single- or double-drum winch. The winch system should operate smoothly, be easy to handle, and have a self-locking function. A double-drum mechanism uses two main wire ropes and provides greater safety. The wire-rope safety factor should be greater than 6–8. The diameter of each wire-rope pulley should be at least 12 times the diameter of the wire rope.
The carriage's lifting travel must be controlled by both electrical and mechanical limit devices, with additional overtravel protection. This prevents impact damage to the head assembly if an operating error causes the carriage to continue rising after reaching its upper limit. Some systems are also equipped with a locking brake mechanism. If a main wire rope breaks and the carriage begins to descend, the mechanism can lock the carriage to the mast within a specified distance and stop its fall.
A maintenance support should be installed above the access door in the high-mast pole to support the carriage when it has been lowered to the bottom. Once the carriage reaches its raised position, an automatic latching and unlatching load-relief device should be provided. This securely supports the carriage on the mast and transfers the load away from the wire ropes, winch, and other load-bearing components.
4. Lightning Protection and Protective Earthing
A lightning protection system should be installed at the top of each high mast, with a protection zone covering the entire luminaire carriage and mast. The system should comply with the relevant requirements of IEC 62305. The lightning rod should be made of either 25 mm diameter hot-dip galvanized round steel or 40 mm diameter hot-dip galvanized steel pipe with a wall thickness of at least 2.75 mm.
In addition to the lightning protection system, the metal mast and the metal enclosures of electrical equipment must be effectively connected to protective earth. Connections between the earthing conductor, earthing body, and earth electrodes must be secure and fitted with anti-loosening devices.
Hot-dip galvanized steel pipes used as vertical earth electrodes should have a wall thickness of at least 3.5 mm; steel angles should be at least 4 mm thick. Each earth electrode should be at least 2.5 m long, and there should be at least three electrodes. The spacing between electrodes should preferably be twice their length. The top of each electrode should be buried at least 0.6 m below ground level. The earth resistance of the earthing system should not exceed 10 Ω.
Translator's note: The source gives "0.6 mm" for the electrode's burial depth and omits the unit after "10" for earth resistance. These have been rendered as 0.6 m and 10 Ω, respectively, as the likely intended technical values.
5. Electrical System of Lifting High Mast Pole
The electrical system of a lifting-type high mast includes power distribution and control equipment, providing lighting, lighting-control, and luminaire-carriage lifting functions. Cables routed through steel conduits and inside the pole must have no joints and should include an adequate allowance for movement. Conductors must have sufficient mechanical strength. The cross-sectional area of the copper conductors connected to the power supply must be at least 6 mm²; that of the copper conductors connected to each luminaire must be at least 1.5 mm². Flame-retardant cables should be used.
The distribution panel or cabinet should provide lighting-control and carriage-lifting functions. Lighting control should support both automatic and manual operation, and the three-phase load should be reasonably balanced. The carriage-lifting control buttons should be brought out from inside the pole using a cable longer than 10 m that meets the requirements for cables used with mobile electrical equipment.
The insulation resistance between the lighting power-supply conductors and earth must be at least 10 MΩ. The lighting circuit must withstand a dielectric test of 1,000 V AC at 50 Hz for 1 minute, with no breakdown or flashover. The power circuit must withstand a dielectric test of 2,000 V AC at 50 Hz for 1 minute, also with no breakdown or flashover.
6. High-Mast Foundation
The foundation requirements for high-mast lighting installations are stringent. The foundation must comply with the relevant requirements of ISO 4356 and ISO 3010. Design considerations should include the characteristic wind pressure and seismic effects, the ground conditions at the site, mast height, load, operational requirements, and the interaction with nearby buildings.
The stability of the excavation slopes must be checked, and the effects on adjacent structures must be considered. The assessment must account for adverse conditions such as loads placed near the top of the slope and surface water accumulation. Shoring should be provided where necessary. When excavating mechanically, take care to preserve the natural structure of the soil at the bottom of the excavation. Depending on soil hardness, leave a 20–40 cm layer of undisturbed soil above the formation level, then remove it manually or by another method that will not disturb the foundation soil. After the excavation has been inspected and accepted, foundation work should begin promptly.
Stress calculations for the reinforcing steel and the anchor bolts used to secure the pole must comply with applicable current national standards. Before pouring the concrete foundation, tighten nuts on both sides of the foundation template to secure the pole anchor bolts. Position the template level and weld the anchor bolts securely to the reinforcement. Reinforcing-steel welding must comply with the ISO 17660 series.
Before pouring the foundation, embed a steel or polyethylene conduit beneath the foundation template, running from the outer face of the foundation to the centre of the pole, to serve as a cable-entry duct. The source specifies "660 mm," which appears to be a formatting or transcription issue; it may have intended "Φ60 mm" (60 mm diameter).
Foundation concrete should preferably be poured in one operation. If a second pour is required, it must comply with the applicable current national concrete-construction standards, and the quality of the work must be ensured. Before continuing the pour, remove debris, thoroughly wash the surface, and ensure a sound bond between the pours. The concrete strength grade must be at least C20 and verified by a compressive-strength test. The lightning-protection earthing system must be completed before the foundation is poured, and the measured earth resistance must meet the applicable requirements.
Conclusion
A well-designed Lifting High Mast Pole balances lighting performance, structural strength, operational safety, and ease of maintenance. Verify all design details against applicable standards and site-specific conditions before manufacture and installation.
