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


7.13.1 - Overhead wiring types

Most overhead wiring is carried out by the Electricity Supply Companies, and is not in the domain of the electrician. However, wiring between buildings is often necessary, and can be carried out using one or more of the following methods:

1. - rubber or p.v.c. insulated cables bound to a separate catenary wire,

2. - specialist cables with an integral catenary wire,

3. - p.v.c. Insulated and sheathed, or rubber insulated with an oil-resisting and flame retardant sheath, provided that precautions are taken to prevent chafing of the insulation or undue strain on the conductors,

4. and 5. bare or p.v.c. Insulated conductors on insulators. In this case, the height of the cables and their positions must ensure that protection against direct contact is prevented,

6. - cable sheathed and insulated as in 3) above enclosed in a single unjointed length of heavy-gauge steel conduit of at least 20 mm diameter.

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

 

 

 

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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