Requirements applicable to special installations and locations

Figure Q20 below summarizes the main requirements prescribed in many national and international standards.
Note: Section in brackets refer to sections of IEC 60364-7

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Locations	Protection principles	IP level	Wiring and cables	Switchgear	Socket-outlets	Installation materials
Domestic dwellings and other habitations	TT or TN-S systems Differential protection - 300 mA if the earth electrode resistance is ≤ 80 ohms instantaneous or short time delay (type S) - 30 mA if the earth electrode resistance is ≥ 500 ohms surge arrester at the origin of the installation if  - supply is from overhead line with bare conductors, and if - the keraunic level > 25 a protective earth (PE) conductor on all circuits	20		Switch operating handles and similar devices on distribution panels, to be mounted between 1 metre and 1.80 metre above the floor	Protection by 30 mA RCDs
Bathrooms or shower rooms (section 701)	Supplementary equipotential bonding in zones 0, 1, 2 and 3
Zone 0	SELV 12 V only	27	Class II limited to strict minimum			Special appliances
Zone 1	SELV 12 V	25	Class II limited to strict minimum			Special appliances Water heater
Zone 2	SELV 12 V or 30 mA RCD	24	Class II limited to strict minimum			Special appliances Water heater Class II luminaires
Zone 3		21		Only socket-outlets protected by : 30 mA RCD or Electrical separation or SELV 50 V
Swimming baths (section 702)	Supplementary equipotential bonding in zones 0, 1, and 2
Zone 0	SELV 12 V	28	Class II limited to strict minimum			Special appliances
Zone 1		25	Class II limited to strict minimum			Special appliances
Zone 2		22 (indoor) 24 (outdoor)		Only socket-outlets protected by : 30 mA RCD or electrical separation or SELV 50 V
Saunas (section 703)		24	Class II			Adapted to temperature
Work sites (section 704)	Conventional voltage limit UL reduced to 25 V	44	Mechanically protected		Protection by 30 mA RCDs
Agricultural and horticultural establishments (section 705)	Conventional voltage limit UL reduced to 25 V Protection against fire risks by 500 mA RCDs	35			Protection by 30 mA RCDs
Restricted  conductive locations (section 706)		2x				Protection of:                                 Portable tools by:  - SELV or  - Electrical separation Hand-held lamps   - By SELV Fixed equipement by   - SELV   - Electrical separation   - 30 mA RCDs      - Special      supplementary     equipotential bonding
Fountains (section 702)	Protection by 30 mA RCDs and equipotential bonding of all exposed and extraneous conductive parts
Data processing (section 707)	TN-S system recommended TT system if leakage current is limited. Protective conductor 10 mm2 minimum in aluminium. Smaller sizes (in copper) must be doubled.
Caravan park (section 708)		55	Flexible cable of 25 metres length		Socket-outlets shall be placed at a height of 0.80 m to 1.50 m from the ground. Protection of circuits by 30 mA RCDs (one per 6 socket-outlets)
Marinas and pleasure craft (section 709)	The cable length for connection to pleasure craft must not exceeded 25 m				Protection of circuits by 30 mA RCDs (one per 6 socket-outlets)
Medical locations Group 2 : Operating theatres and similar (section 710)	IT medical system equipotential grouding, limited to one operating theatre and not exceeding 10 kVA			Only magnetic protection for the primary of LV/LV transformer. Monitoring of secondary loads and transformer temperature	Protection of circuits by thermal-magnetic protection only. One to three per circuit.
Medical locations Group 1 : Hospitalization and similar (section 710)	TT or TNS				Protection by 30 mA RCDs
Exhibitions, shows and stands (section 711)	TT or TN-S systems	4x			Protection by 30 mA RCDs
Balneotherapy (cure-centre baths)	Individual: see section 701 (volumes 0 and 1) Collective: see section 702 (volumes 0 and 1)
Motor-fuel filling stations	Explosion risks in security zones		Limited to the necessary minimum
Motor vehicules	Protection by RCDs or by electrical separation
External lighting installations (section 714)		23			Protection by 30 mA RCDs
Mobile or transportable units (section 717)	The use of TN-C system is not permitted inside any unit				30 mA RCDs must be used for all socket-outlets  supplying  equipment  outside the unit

Fig. Q20: Main requirements prescribed in many national and international standards