7.13.2 - Maximum span
lengths and minimum heights
The required information is contained in
{Table 7.8} and {Fig 7.21}. Four special points are worth
noting here.
1. - in some locations where very
tall traffic may be expected (eg. yacht marinas, or where
tall cranes are moved) heights above ground must be increased,
2. - in agricultural situations,
the lower heights of 3.5 m and 3.0 m are not permitted,
3. - where caravan pitches are fed,
overhead cables must be at least 2 m outside the bounds
of each pitch,
4. - overhead supplies to caravan
pitches must have a minimum ground clearance of 6.0 m where
there will be moving vehicles, and 3.5 m elsewhere.
Fig 7.21 - Overhead lines.
Ground clearances shown are for places which are not accessible
to vehicular traffic - see {Table 7.8}
Table 7.8 - Maximum
span and minimum height for
----------------- overhead
wiring between buildings |
|
Type of system
|
Max. length
of span
|
Minimum height above ground
|
|
|
(m)
|
At road crossings (m)
|
Accessible to vehicles (m)
|
Not accessible to vehicles (m)
|
|
1
|
No limit
|
5.8
|
5.2
|
3.5
|
|
2
|
Consult manufacturer
|
5.8
|
5.2
|
3.5
|
|
3
|
3
|
5.8
|
5.2
|
3.5
|
|
4
|
30
|
5.8
|
5.2
|
3.5
|
|
5
|
Consult manufacturer
|
5.8
|
5.2
|
3.5
|
|
6
|
3
|
5.8
|
5.2
|
3.0
|
NB All ground clearances
are for positions not accessible to vehicular traffic
|
