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 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 can, however, provide a periodic inspection report or complete the testing section of an electrical installation certificate for other contractors' work if you are asked to do so, but you cannot certify it for Part P of the Building Regulations.
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 steel conduit or be buried at a depth of more than 50 mm.
Where pipework in a bathroom is plastic, do I need to bond the bath/radiator, etc?
No, if the pipework is substantially plastic these are isolated pieces of metalwork and do not need to be bonded.
Do I need to provide RCD protection on a shower circuit?
No, BS 7671 does not require RCD protection on circuits supplying instantaneous showers, shower pumps or water heaters.
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 in Zone 3 provided they are 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 compartmention, its construction and 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 floor that is above 4.5 m from the ground (3-storey). In the case of 3-storey dwellings, fire protection should be fitted to downlighters between the upper 2 floors unless the first and second floors are served by a protected stairway leading to two fire separated routes on the ground floor or directly to an exit door (no fire separating floors in this situation).
Where recessed downlighters are installed in ceilings that are not fire compartments such as the intermediate floor of a 2-storey dwelling, 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 downlighters, even without being boxed in and with no fire hoods in plasterboard ceilings, have little significant effect on fire resistance ratings up to 30 minutes. It must be inferred from these tests, therefore, that at least with plasterboard ceilings with conventional rectangular joists, 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 are not of fire compartment construction.