The third amendment

Section 601 of BS 7671 has been virtually unchanged since it was first published in the 16th Edition of the IEE Wiring Regulations in 1991.

The reason that the section was left untouched during the 1990s is that a complete revision was being carried out by European standards body CENELEC, but the committee failed to reach agreement, even after five attempts.

Now the CENELEC board has taken the decision that standardisation cannot be achieved. And so, the national committees can create their own standard for the area without having to harmonise with the appropriate European Standard.

One of the major items of disagreement has been the provision of socket outlets supplied directly from the main supply network, at 230 V. Many countries already permit their use; some countries legally prohibit the use of such equipment in bathrooms.

In the UK there was a strong lobby, particularly by manufacturers, who can already sell plug-in equipment in some countries, to provide for 13 A sockets in bathrooms; others objected on the grounds of safety.

Do not mix Amendments 2 and 3

Enough of the history: what exactly does the new Section 601 contain and when does it come into force? The introduction says that the new section may be used from 15 April 2000 and that design and construction may be to either Amendment 2 or Amendment 3, but it is not permitted to mix the two versions. Amendment 2 may not be used after 31 December 2001. It is intended that by this date Amendment 4 will have been published and will replace 2 and 3.

So, now we have two substantially different documents running in parallel for 20 months at least. This will cause confusion to say nothing about the possibility of disputes and litigation. The only valid reason for the advanced publication of Amendment 3 is that the old Section 601 was due for change.

601-01 Scope

The scope has been expanded to include cabinets containing a shower and/or bath and the surrounding zones. It states that it does not include emergency facilities in industrial areas and laboratories, and advises that special requirements may be necessary in rooms containing baths and showers for medical treatment and for use by disabled persons.

601-02 Classification of zones

The latest amendment adopts the zoning concept similar to swimming pools. The UK has agreed that the use of defined zones helps to make the regulations more understandable. There are four zones:

• Zone 0 is the interior of the bath or shower basin. If there is a flat floor it extends to 600 mm horizontally and 50 mm vertically if the shower head is fixed, and 1·2 m horizontally if the shower head is demountable.
• Zone 1 is the upper plane of Zone 0 to a height of 2·25 m above the floor. It includes the area under the bath, if it is accessible without the use of a tool. This poses the question: is a key a tool? It is quite common practice to form a cupboard with a locked door within the bath housing to accommodate shower and Jacuzzi pumps and equipment.

  Again, if there is a flat floor the zone extends 600 mm horizontally if the showerhead is fixed, and 1·2 mm horizontally if the head is demountable.

• Zone 2 extends Zone 1 by 600 mm and includes the area of Zone 1 that is above 2·25m up to 3·0 m, if the ceiling is that high.
• Zone 3 extends Zone 2 by 2·4 m and includes the area of Zone 2 that is above 2·25 m up to 3·0 m, again if the ceiling is that high.

601-03 protection against shocks

References to direct contact and indirect contact have disappeared. PELV is not permitted within any of the Zones. If SELV or PELV are used within the vicinity but outside the zones then barriers to IP2x or IPXXB or insulation capable of withstanding 500 V ac for one minute must be used. There should be no bare wires or live parts.

601-04 Supplementary bonding

The 400 ms disconnection time for all circuits in bathrooms has disappeared. A 5 s disconnection time is permitted for all circuits.

Supplementary bonding in compliance with 547-03 is to be applied between the terminals of protective conductors of both Class 1 and Class 2 equipment and all other metal pipe work, ductwork, baths and shower basins, and any other accessible structural parts of the building. Class 1 and 2 presumably includes shaver sockets, meaning that the earth terminal will need to be bonded.

Non-structural parts (metal door architraves, window frames etc) are explained and are not considered to be extraneous conductive parts. It also allows the bonding to be attached in close proximity to the location.

This regulation appears to override 547-03-05, which permits the core of a flex between an accessory and an item of fixed equipment to be used as a bonding conductor.

It also indicates that a bathroom with only a single Class 2 lighting fitting must have the earth terminal within the fitting bonded to pipes, the bath etc. But unlike the previous edition, if there is no electrical equipment and no light in the bathroom, there is no bonding required. This is, however, unlikely to occur.

601-05 Application of protective measures for safety

Where SELV is used it must be limited to 12 V ac or 30 V ripple free dc and the safety source must be sited outside Zones 0, 1, and 2. Protection by obstacles, placing out of reach, non-conducting locations and earth free equipotential bonding, cannot be used.

601-06 Selection and erection of equipment

The degrees of protection of equipment are stated for the various zones. It appears that 230 V equipment can be used anywhere except Zone 0, providing that the correct degree of protection is provided and maintained.

Within the zones, the minimum IP rating is IPX4, or one drop if the equipment is not IP coded. Where water jets are likely to be used it is IPX5 or two drops.

601-07 Wiring systems

These rules apply to surface cabling and cables buried in walls up to a depth of 50 mm. In zones 0, 1 and 2 cables are permitted to supply only equipment within the respective zone or the adjacent lower referenced zone, ie a cable supplying equipment in Zone 1 can pass through Zone 2.

Gone is the prohibition on the use of steel conduit, trunking and metal sheathed cables fixed to the surface of walls and buried to a depth of 50 mm.

601-08 Switchgear and control gear

This section states that these regulations do not apply to switches and controls incorporated in equipment suitable for the zones in which they are fitted. Gone is the regulation that allows switches and controls to be inaccessible to a person using the bath or shower.

In zone 0, no switches or control gear are permitted. In zone 1, only SELV switches 12 V rms ac or 30 V dc ripple free are permitted. In zone 2, only switches and sockets of SELV systems are permitted provided the safety source is outside zones 0, 1 & 2. Shaver sockets are permitted in zone 2.

In zone 3, no sockets are permitted except SELV and shaver sockets. No provision can be provided for portable appliances except for SELV appliances and shavers, equipment, other than that listed in regulation 601-09 (see later), must be protected by an rcd having a tripping current of 30 mA or less.

Cord switches are permitted in zones 1, 2 and 3.

Where a shower cubicle is fitted in a room other than a bath or shower room, socket outlets installed outside of the zones must be provided with rcd protection of 30 mA or less.

This new requirement is unlike previous editions that required rcd protection for sockets within 2·5 m of the shower cubicle. The On-Site Guide has always indicated that this is a regulation.

The requirement for lamp holders to be shrouded or fitted with protective shields if sited within 2.5 m of the bath has disappeared. All luminaires now have to be suitable for the zone of use.

601-09 Other fixed current-using equipment

Generally equipment must only be used within the zones for which it is specifically intended and suitable. In Zone 1 water heaters and shower pumps can be used without rcd protection, other suitable equipment must be rcd protected (30 mA or less) or SELV.

In Zone 2 the following equipment may be used provided that it is suitable for the zone: water heaters; shower pumps; luminaires, fans, heating appliances and whirlpool units, complying with relevant standards. Suitable equipment that can only reasonably be sited in Zone 2 can be used; and SELV equipment.

So going back to 601-08: in Zone 3 an rcd is required for any equipment that is not listed above.

Gone is the requirement for exposed elements of heaters to be out of reach of a person using the bath. These heaters will now have to be classified for the zone of use.

Electrical floor heating units may be installed below any zone provided that they are covered with an earthed metallic grid or have an earthed metallic sheath that is connected to the supplementary equipotential bonding.

Conclusion

There is little doubt that bathroom installations will cost more in the future due to the higher cost of specifically rated equipment and the increased bonding requirements. Manufacturers will need to address the capacity of earthing terminals in accessories to enable bonding conductors to be accommodated.

I urge contractors to grasp the nettle straight away and work to this amendment. There is little doubt that there will be disputes, so the sooner the amendment is adopted the lesser the opportunity for dispute.

I would remind contractors that when completing the Installation Certificate they must state which amendment to BS 7671 applies.