High-Mast, H-Pole & 4 Pole Structure
- Prior to lifting the structure, any slipover joint below the crane attachment point should be securely lashed to prevent any possibility of separation during lifting. For additional safety, a hook capable of supporting the entire weight can be attached to the handhole opening and connected to the crane attachment point.
- The lifting crane must be attached:
- to the main pole member, not to appurtenances such as pole step lugs, the top flange, etc.
- above the center of gravity of the entire assembly including the weight of all equipment mounted on the structure before erection.
- as high as possible since higher attachment will result in more nearly vertical alignment of the assembly while suspended above the foundations.
- Care should be taken to operate the crane very smoothly since jerkiness will cause impact loads which could damage some portion of the assembly.
- At least a few anchor bolt nuts should be installed as quickly as possible after the base plate is in place. If the pole is eccentrically loaded, the nuts on the side opposite the direction of eccentricity should be installed first. Lighting structure components may be affected by vibrations induced aerodynamically or from other sources. Although rare, these vibrations can be severe enough to cause damage. This is believed to be more likely to happen when a structure is installed without the equipment which it is intended to support. All such equipment contributes damping to the system. It is considered good practice for installers to attach at least some equipment at the time of installation of the structure.
‘H’ Structure poles shall be located to within 50 mm of their design plan position. They shall be oriented such that the through bolts can be inserted without forcing. Care shall be exercised in the lifting of and splicing of poles, by using the manufacturer’s recommended lifting slings and lifting procedure to minimise any damage to the surface of the poles. Poles shall not be lifted from the pole tip unless the pole design Engineer so approves. Poles shall be located to within 50 mm of the pegged pole position and centralised in holes with a minimum clearance of 150 mm between the pole and the edge of the hole for the total buried length. Suspension type insulator strings that are supported by a crossarm may be attached to the crossarm before the structure is erected. These insulator strings shall be securely tied to the crossarms prior to pole erection to prevent insulator damage. Ladders and ladder stiles shall be erected straight to within ±10 mm of bow. Stayed poles shall have all stays connected to them and anchored securely as soon as the poles are stood. Staywires on poles with counterbalancing (opposing) stays shall be pretensioned to 5 - 10 kN. Care shall be exercised in the application of load and sequence of loading of stays so that erection stresses are not built into the structure
- 'Four' Pole Structure shall be mounted in substation area, comprising of DO/GO Insulators, V-Shape arm, angles and channels for devices support, nut bots, tightening screws. Taking care of wiring direction to make suitable and hindrances identify during the erection.
- Pole direction shall be decided by location during site survey.
- Taking care of safety terms while erecting poles
- Stringing and Installation of line with Bare Conductors
- Insulators Fixing
- Running out of the conductor/Stringing
- Jointing, Tensioning & Sagging Operations
- At the time of Testing-
- Continuity of messenger wire and conductors
- Absence of cross phasing
- Insulation resistance to earth iv) Insulation resistance between conductors
- DC Resistance
- Inspection Approvals: The material to be supplied will be subject to inspection and approval by the Procurement dept. representative before dispatch and/or on arrival at the destination.
Keys to Perform:
- Raw Material, their Chemical and mechanical composition.
- Earth wire
- Insulator strings
- Transformer specifications
- Connection properly
- Check list workout
- Site Clearance
- Line energising
- Handling over