to the 16th Edition IEE Regulations
   
   
   
 
 

chapter 5
Earthing

chapter 6
Circuits

Special Installations
  --1. - Introduction --2. - Bath tubs and shower basins
  --3. - Swimming pools --4. - Sauna rooms
  --5. - Installations on construction sites --6. - Agricultural & horticultural
--7. - Restrictive conductive locations --8. - Earthing for function & protection
--9. - Caravan, motor homes, caravan parks 10. - Highway power & street furniture
11. - Heating appliances & installations 12. - Discharge lighting
13. - Underground & overhead wiring 14. - Outdoor installations & garden buildings
15. - Installations of machines & transformers 16. - Reduced voltage systems
17. - Marinas 18. - Medical locations
19. - Exhibitions, shows and stands


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

 

 

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Extracted from The Electricians Guide Fifth Edition
by John Whitfield
Published by EPA Press Click Here to order your Copy

Click here for list of abbreviations