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How this is calculated#

The tool looks up two things for an aerial conductor. Table 3.8 of AS/NZS 3000:2018 gives the minimum clearances. Table 3.10 gives the gap between conductors where they meet a support.

1. Conductor type. You pick bare live conductors, insulated and unsheathed live conductors, or neutral-screened cable.
2. Span. You enter the span in metres. Table 3.10 reads it.
3. Spacing at supports. The tool reads the spacing from Table 3.10 for the type and span. This is the primary result.
4. Vertical clearances. From Table 3.8 it gives the clearance over areas used by vehicles, areas not used by vehicles, and roofs.
5. Horizontal clearances. From Table 3.8 it gives the clearance from walls, clothes lines, aerials and telecommunications lines.
6. Special areas. It gives the clearance over swimming pools and over sailing craft or irrigation pipes. Some types are not permitted there.

Worked example#

Bare conductors over a 30 m span. The spacing at supports is 0.6 m. The clearance over areas used by vehicles is 5.5 m. The clearance from walls is 2 m. A bare conductor is not permitted above a swimming pool.

Limits#

• The clearance is not the whole requirement. Read Note 1 to Table 3.8 and Clause 3.12.3.
• The tool does not apply Table 3.9. Check the span against Table 3.9 and Clause 3.12.4.
• It does not check pole strength, sag or tension.
• It does not cover supply authority overhead lines.

See also: Minimum conductor size, Underground cables and civil interfaces and the cable size calculator.