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If you require a new electricity connection please visit our connections pages to apply online or complete an application form.
If you are making significant changes to an existing installation, for example adding electrical equipment or altering earthing arrangements, please contact us prior to commencing the works to discuss.
We will undertake, on request, a small number of tasks on behalf of customers and their electrical installers. The tasks listed below are primarily for domestic connections but may also be applied to small commercial installations that utilise whole current metering.
Fixed charges apply to standard tasks. For a list of our current charges please click here.
It is sometimes necessary for the incoming electrical supply to be de-energised to allow works to be carried out safely on a customer’s wiring and equipment.
You can arrange for the supply to be de-energised and later re-energised by call the customer’s Electricity Supplier. The Electricity Supplier’s name, address and telephone number is shown on the customer’s electricity bill. If you have any difficulty arranging for this to be carried out please contact us although we may make a charge for this work.
We will provide an earth terminal at each new electricity connection provided it is safe to do so. We can also provide an earth terminal at an existing connection on request, provided it is safe to do so. We may, however, make a charge for this work.
Low voltage connections (up to 1000V)
We provide the following types of low voltage earthing:
Protective Multiple Earthing (PME)
PME (TN-C-S) is the most common form of earthing provided at new installations. We utilise a single conductor for the neutral and earthing functions within our network and provide a PME earth terminal at the customer’s installation. The customer’s earthing / bonding may be connected to this terminal providing the TN-C-S requirements within BS7671 (IET Wiring Regulations) and Engineering Recommendation G12 are satisfied.
Separate Neutral and Earth (SNE) derived from a Combined Neutral and Earth (CNE) Network SNE derived from a CNE Network
(TN-C-S) is commonly provided at existing connections and sometimes at new ones. In this case we utilise a single conductor for the neutral and earthing functions within all, or part of, our network, provide a separate neutral and earth service and make an earth terminal available at the customer’s installation. The customer’s earthing / bonding may be connected to this earthing terminal providing the TN-C-S requirements within the relevant edition of BS7671 (IET Wiring Regulations) and Engineering Recommendation G12 are satisfied.
Separate Neutral and Earth (SNE) derived from a Separate Neutral and Earth (SNE) Network
SNE derived from a SNE network (TN-S) used to be common in the past, however, as networks have been modified and sections of combined neutral and earth cable installed, it is now relatively rare. Where we do maintain a separate neutral and earth conductor along the whole circuit length and within all connected services, we may provide a TN-S earth terminal at the customer’s installation. The customers earthing / bonding may be connected to this earthing terminal providing the TN-S requirements within the relevant edition of BS7671 (IET Wiring Regulations) and Engineering Recommendation G12 are satisfied.
Protective Neutral Bonding (PNB)
PNB is common in rural locations where LV connections are made at just one point on our network, typically where a pole mounted transformer is dedicated to a single customer connection. It is also used at some large connections that have a dedicated substation. In these situations the substation’s buried LV earth electrode is installed at the point on the network where the customer connection/s are made. This type of earthing is normally considered to TN-S but is classified as TN-C-S if a combined neutral / earth conductor is installed between the earth electrode and the customer’s connection, as shown in the following diagrams. The customers earthing / bonding may be connected to this earthing terminal providing the appropriate sections of BS7671 (IET Wiring Regulations) and Engineering Recommendation G12 are satisfied.
Direct Earthing
Direct Earthing (TT) is common within older properties and is also used within installations that cannot be provided with a WPD earth terminal, e.g. on the grounds of safety. In this case we do not make our earth terminal available to the customer. If the installation requires an earth, which is invariably the case, the customer or their installer must provide and maintain a buried earth electrode (buried earth rods and/or buried conductor) and provide their own earthing terminal. Where Direct Earthing is employed the installation normally requires a residual current device (RCD) or residual current circuit breakers with overcurrent protection (RCBOs) in order to provide adequate protection. The customer’s installation must comply with the TT requirements of BS7671 (IET Wiring Regulations).
High voltage connections (above 1000V)
Information on earthing at high voltage connections can be provided on request.
The type of earthing that we provide will depend on the design of our existing network and the characteristics of the customer’s installation. Wherever possible we will install Protective Multiple Earth (PME) to domestic premises.
In some cases we are unable to provide an earthing terminal due to the installation type or due to particular equipment that the customer is proposing to use within the installation. For some installations, special criteria need to be satisfied by the customer/installer before we can provide an earth terminal.
Installations and equipment types that require careful consideration include:
Once we have provided an earthing terminal at an installation we will continue to maintain it for the life of the installation, as far as is practicable, unless changes are made to the customer’s installation or equipment that prevent this on the grounds of safety.
The customer / installer is under no obligation to use our earth terminal but they must ensure their installation meets the requirements of the relevant edition of BS7671 (IET Wiring Regulations).
We can install a 2 pole or 4 pole isolation switch that may be operated by the customer’s electrical installer, allowing them to de-energise and re-energise the customers’ installation themselves. However, we may make a charge for this work.
Where an external meter box is fitted, this is owned (and should be maintained) by the customer.
If a meter box door has been damaged and needs replacement, we can provide a replacement but we may make a charge for this work.
The electrical characteristics of an installation have to be considered when designing a new - or modifying an existing - electrical system. The following information is often required:
Low voltage connections (up to 1000V)
The following standard voltages apply:
The voltage should remain within +10% and –6% of these figures.
High voltage connections (above 1000V)
Large commercial or industrial installations are often connected at high voltage. A number of different standard voltages are in use within Western Power Distribution’s area, including:
The voltage should remain within ± 6% of the nominal connection voltage, with the exception of 132000V connections where the tolerance is ± 10%.
Low voltage connections (up to 1000V)
The number of phases provided at low voltage connections will vary depending on the capacity of connection and the nature of our electricity network. The following arrangements are typical:
Where more than one phase is provided load must be balanced, as far as possible, between each of the phases.
High voltage connections (above 1000V)
Three phases are provided at high voltage connections.
The statutory limit for frequency is 50 Hertz ± 1%.
The maximum prospective short circuit current is used to determine the short circuit rating requirement of electrical equipment.
Low voltage connections (up to 1000V)
The following values can be assumed at low voltage connections:
High voltage connections (above 1000V)
We can provide maximum prospective short circuit current information for high voltage connections upon request.
*Figures derived from ENA EREC P25/2 (2018)
The maximum Earth Fault Loop Impedance (ELI) is used to calculate the available earth fault current within an installation connected at low voltage (below 1000V).
The following are typical values for the Earth Fault Loop Impedence at the customer terminals, under normal network conditions:
| Earthing type | Maximum earth fault loop impedance |
|---|---|
| Protective multiple earthing (TN-C-S) | 0.34 ohms* (According to ENA EREC P23/2 (2018), 90% of premises will have an EFLI below this value) |
| Cable sheath earth / Separate continuous earth wire (TN-S) | 0.73 ohms* |
| Direct earth (TT) | Dependent on resistance of the customer’s earth electrode. Values exceeding 100 ohms can apply |
* These values are are typical maximums and may be exceeded where the connection is derived from a long overhead line network or from a pole mounted transformer. DNOs are under no obligation to design or maintain networks to provide a particular maximum value of Earth Fault Loop Impedence.
The type and rating of our fuse or circuit breaker installed at the point of connection can be provided on request. In some cases it will be necessary for us to carry out a site check, and to de-energise the supply for a short time in order to check the fuse size.
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