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


7.16.1 - Types of reduced voltage

Most installations operate at low voltage, which is defined as up to 1000 V ac or 1500 V dc between conductors, and up to 600 V ac or 900 V dc between conductors and earth. Extra-low voltage is defined as not exceeding 50 V ac or 120 V dc between conductors or from conductors to earth. Four types of reduced voltage system, all intended to improve safety, are recognised by the Regulations. They are:

1. - separated extra-low voltage or SELV {7.16.2},

2. - functional extra-low voltage or FELV {7.16.3},

3. - reduced voltage {7.16.4},

4. - voltages at values lower than the maximum for ELV may be required to ensure the safety
----- of people and of livestock in areas where body resistance is likely to be very low {7.6}.

 

 

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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