FAQ's
- How close to a sink/basin can a socket outlet be located?
- Can I certify other contractors' work if I am a member of a Competent Persons' scheme?
- Does the connection of equipment, i.e. cookers/boilers, etc. require notification under Part P?
- Can I install a spur off an existing circuit without being registered on a Competent Person scheme?
- Do I need to provide protection for cables buried in walls?
- Where pipework in a bathroom is plastic, do I need to supplementary bond the bath/radiator, etc?
- Do I need to provide RCD protection on a shower circuit?
- Can a PME supply be used to supply a swimming pool?
- Do I need to provide supplementary bonding in a commercial kitchen?
- Do I need to install main bonding if it is missing or undersized if I am installing a new circuit?
- Can equipment such as washing machines be installed in a bathroom?
- Do caravans come under the scope of Part P?
- When using a 3-core cable in the new harmonised colours on a single-phase installation, which core can I use for the CPC and which for the Neutral?
- Do I need to install fire hoods/fire rated downlighters in every situation?
How close to a sink/basin can a socket outlet be located?
BS 7671 does not specify any minimum distance for socket-outlets to be from a sink. Regulation 512-06-01 requires external influences be considered when selecting equipment for a particular location. The Regulation requires all equipment to be of a design appropriate to the situation in which it is to be used. Accessories used in domestic installations are not designed to be splashed and therefore not suitable for installation close to a sink or draining board. It is recommended that socket-outlets and other accessories should be located at least 300 mm, measured horizontally, from a sink or draining board, where they are unlikely to be splashed.
TopCan I certify other contractors' work if I am a member of a Competent Persons' scheme?
No; the Competent Person schemes are self-certification schemes. You cannot certify somebody else's work through your scheme provider. You can, however, provide a Periodic Inspection Report or complete the testing section of an Electrical Installation Certificate provided that you have inspected the work during the construction phase.
Does the connection of equipment, i.e. cookers/boilers, etc. require notification under Part P?
No; connection of equipment to an existing point is not notifiable work even in a special location or a kitchen.
Can I install a spur off an existing circuit without being registered on a Competent Person scheme?
You can install a new spur from an existing circuit without being registered on a Competent Person scheme provided it is not in a special location or a kitchen.
Do I need to provide protection for cables buried in walls?
Mechanical protection of cables directly buried in a wall is not required if it is installed in one of the following zones:
- Within 150 mm from the top of the wall or partition;
- Within 150 mm of an angle formed by two adjoining walls or partitions;
- The cable is running either horizontally or vertically to an accessory or switchgear on the wall. This zone now extends to the reverse side of a wall or partition 100 mm thickness or less if the location of the accessory or switchgear can be determined from that reverse side.
If installed outside of these zones, the cable must have an earthed metallic sheath or be enclosed in earthed earthed metallic conduit/trunking or be buried at a depth of more than 50 mm or be mechanically protected from penetration by nails/screws etc.
Where pipework in a bathroom is plastic, do I need to supplementary bond the bath/radiator, etc?
No; if the pipework is substantially plastic with only short metal stubs connecting the taps/radiators, etc. these can be treated as isolated pieces of metalwork and do not need to be bonded.
On metal pipework installations, under the 17th Edition, provided all the circuits of the location are protected by a 30mA RCD and there is continuity between the extraneous conductive parts and the protective (main) equipotential bonding, then supplementary bonding is not required.
Do I need to provide RCD protection on a shower circuit?
BS 7671 (16th Edition) does not require RCD protection on circuits supplying instantaneous showers, shower pumps or water heaters. However, if it is a requirement of the manufacturer's instructions, RCD protection should be fitted. Under the 17th Edition, all circuits in a bath/shower room will require 30mA RCD protection.
Can a PME supply be used to supply a swimming pool?
If a swimming pool forms part of an installation and the supply to that installation is PME, then all metalwork and pipes should be separated from the rest of the installation and connected to an earth electrode. If this is not practical, then a metal grid will need to be installed in the floor around the pool and shower areas and supplementary bonded. In either case, the installation should be protected with an RCD.
Do I need to provide supplementary bonding in a commercial kitchen?
Supplementary bonding of metal work surfaces, etc, is not a specific requirement of BS 7671. The designer of the electrical installation may, however, perceive there to be an increased shock risk in that particular location and specify additional bonding.
Do I need to install main bonding if it is missing or undersized if I am installing a new circuit?
If you are installing a new circuit and you are relying on automatic disconnection in the event of an earth fault, it follows that you are relying on there being an equipotential zone. To ensure there is an equipotential zone, main bonding to incoming services must be carried out.
If the main incoming services, etc, are bonded but the conductor is undersized in relation to the current BS 7671 Regulations, you should bring it to the customer's attention and upgrade it if requested.
Can equipment such as washing machines be installed in a bathroom?
Washing machines, etc, are classed as transportable equipment and are allowed provided they are sited outside of Zone 2, permanently connected and protected by a 30mA RCD.
Do caravans come under the scope of Part P?
No; providing it is a proper caravan, i.e. it meets the requirements for the construction and use of road vehicles, it does not come under the scope of Part P regardless of whether it actually moves or not.
When using a 3-core cable in the new harmonised colours on a single-phase installation, which core can I use for the CPC and which for the Neutral?
Technically, when any cable is over-sleeved or marked (with the exception of single-core green/yellow which must not be over-sleeved or marked), the over-sleeving or marking takes precedence over any colour underneath and therefore any combination can be used. However, a convention has been generally accepted of over-sleeving or marking the black with green/yellow (CPC) and the grey with blue (Neutral). This has been done with the aim of helping to disassociate the colour Black with Neutral.
Do I need to install fire hoods/fire rated downlighters in every situation?
It really depends on whether the ceiling forms part of a fire compartment, its type of construction, its load-bearing capacity or if it has been specified by the client/contract.
Generally speaking, a dwelling is considered to be a single compartment with regards to fire (Part B of the Building Regulations) unless it has an integral garage or has a protected stairway leading to a third floor. In the case of 3-storey dwellings, it is advisable to fit fire protection to downlighters installed in intermediate floors, especially where the integrity of flooring above has been compromised (e.g. gaps between floor boards, etc.).
Where recessed downlighters are installed in ceilings that are not fire compartments such as the intermediate floors of 2-storey dwellings, the ceiling needs to have a minimum fire rating of 30 minutes.
Research was commissioned in 1996 to look into the effect on the fire resistance of plasterboard ceilings with conventional rectangular joists having recessed downlighters installed (with no boxing in or fire hoods). The results of the tests were published in the July 1996 edition of Building Control Magazine. These results confirmed that the installation of downlighters, without being boxed in and with no fire hoods in plasterboard/timber joist ceilings, have little significant effect on fire resistance ratings up to 30 minutes. It must be inferred from these tests, therefore, that with ceilings of robust type construction (plasterboard with conventional rectangular timber joists at not more than 450 mm centres), it is not necessary to 'box in' downlighters or to use fire hoods for the purpose of restoring the fire resistance capability of ceilings that do not form part of fire compartment construction.