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

The April 2000 amendments to BS7671 (AMD 10983) have changed all of the Regulations relating to bath and shower rooms. Although the principles remain the same, much of the detail has been altered. For example, bath and shower rooms have now been split into zones, as was previously the case only for swimming pools and saunas.

The amended regulations Section 601 may be used at once,
but must be used for all installations after January 1st, 2002.

Up to that time either set of Regulations may be applied, but whichever is chosen must be used in its entirety. It is not permitted to mix the two versions of Section 601.

click here for amended Introduction.


7.2.1 - Introduction - prior to January 1st, 2002

People using a bathroom are often unclothed and wet. The absence of clothing (particularly shoes) will remove much of their protection from shock (see{3.4}), whilst the water on their skin will tend to short circuit its natural protection. Thus, such people are very vulnerable to electric shock due to their reduced body resistance, so special measures are needed to ensure that the possibility of contact (either direct or indirect) is much reduced. Guidance Note 7 (Special Locations) provides data on the impedance of the human body. However, the figures are complicated by the fact that values differ significantly from person to person; it would be sensible to assume a worst case possibility which suggests that the impedance of the human body from hand to foot is as low as 500 Ohms. Since this calculates to a body current of 460 mA at 230 V, we are considering a fatal shock situation. When the fact that the impedance figures assume a dry body are taken into account and may be halved for wet people, we come to a shock current approaching I A! Attention is drawn to the fact that a bath used for medical treatment may need special consideration, because the possible hazard is greater.

Appliances and sockets for use in these high-risk areas must be separated extra-low voltage (SELV) type, at a potential not exceeding 12 V; the exception is a shaver unit fed from a double wound transformer to BS EN 60742 (see {5.8.4}). Such equipment must be protected to level IP2X, which means that it must be impossible to touch live parts with a finger, and must have insulation capable of withstanding a voltage level of 500 V r.m,s. for one minute. Such socket outlets, or fused connection units in a bathroom or a bedroom containing a shower cubicle, must be protected by an RCD with an operating current no greater than 30 mA,

The special requirements of this section do not apply to rooms (such as bedrooms) containing an enclosed and prefabricated shower basin, provided that switches are not mounted within 0.6 m or sockets within 2.5 m of the door opening as indicated in {Fig 7.1}.

 

 

 

 

 

 

7.2.1 Introduction - ( - after to January 1st, 2002 )

People using a bathroom are often unclothed and wet. The absence of clothing (particularly shoes) will remove much of their protection from shock (see (3.4)), whilst the water on their skin will tend to short- circuit its natural protection. Thus, such people are very vulnerable to electric shock due to their reduced body resistance, so special measures are needed to ensure that the possibility of contact (either direct or indirect) is much reduced. Guidance note 7 (Special Locations) provides data on the impedance of the human body. However, the figures are complicated by the fact that values differ significantly from person to person; it would be sensible to assume a worst case possibility which suggests the impedance of the human body from hand to foot is as low as 500 ohms. Since this calculates to a body current of 460mA at 230V we are considering a fatal shock situation. When the fact that the impedance values assume a dry body are taken into account and may be halved for wet people, we come to a shock current approaching 1 A! Attention is drawn to the fact that a bath used for medical treatment or for disabled people may need special consideration, because the possible hazard is greater. The special requirements of this section do not apply to rooms (such as bedrooms) containing an enclosed and prefabricated shower basin, provided that switches are not mounted within 0.6m or sockets within 2.4m of the shower door opening as indicated in (Fig 7.1a) All socket outlets in such rooms must be protected by an RCD with a rating no higher than 30mA. The special requirements do not apply to emergency facilities in industrial areas and laboratories. Fig 7.1a) Permissible positions of switches and socket outlets in a room containing a shower cubicle but no bath.

 

 

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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