5.3 Serviceability determination
Provisions of this code should be accompanied by responsibly developed and documented procedures for inspecting, assessing, marking and maintaining poles and structures that support overhead lines. Such procedures should be supported by appropriate work practices, and competency training and assessment.
The serviceability of a pole shall be determined by its:
- above ground condition;
- ground line and below condition; and
- strength in its "as is" condition.
An electricity entity should develop a periodic maintenance program to deliver the reliability level set out at the beginning of this section. This program should include an inspection system to verify structural integrity, both above and below ground.
Where appropriate for the supporting structure, the inspection should also determine the bending strength of a pole for comparison with its design load and an applied factor of safety.
Pole strength may be determined by:
- measuring physical dimensions and calculation;
- proof testing; or
- non-destructive evaluation
- the conductors and attachments should be capable of continuing to support the pole top loading conditions; and
- a minimum pole tip loading should be adopted to ensure the groundline shear strength of the pole is adequate.
Poles should be classified as either serviceable, suspect or unserviceable.
5.3.1 Frequency of inspection
An electricity entity’s inspection program should ensure the entity meets its safety obligations. Each pole should be inspected at intervals deemed appropriate by the entity. The intervals may be based on documented knowledge of the durability rating, preservation type, inspection procedures, age, performance of the poles, fungal decay, termite hazard and so on.
In the absence of documented knowledge of pole performance, poles should be inspected at least every five years.
Last updated June 7, 2005
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