Electricity capacity enquiries and connection costs

Electricity connection cost development budgets fail for one reason more than any other: the distance to the nearest cable is not what drives the price. What drives it is the point of connection the distribution network operator nominates, and whether the network between that point and the substation needs reinforcing to carry your load. A site 30m from a low voltage main can be more expensive than one 300m away if the local feeder is already at capacity.

The only way to find out is to ask, and the asking is free or close to it. A budget estimate enquiry costs a small administrative fee and takes a few weeks, and it should be made before you fix the layout, not after permission.

What a budget estimate enquiry gives you

A budget estimate is an indicative, non-binding figure from the network operator based on your stated load and site location. It is not an offer and you cannot accept it. What it gives you is a number to put in the appraisal and an early warning if the site is constrained.

To get a useful one you need to tell the operator:

• The site address and a plan with the boundary and the proposed connection point marked.
• The number and type of units, or the floor area and use for commercial schemes.
• The maximum demand in kVA or kW, with the basis stated.
• Whether heat pumps, electric vehicle charging or electric cooking are proposed, and at what diversity.
• Any generation or battery storage, with export capacity.
• The anticipated programme, including phasing.

A formal connection offer is the next stage and it is binding. It carries a statutory determination period, a quoted price and an acceptance window, and once accepted it locks in capacity. The gap between a budget estimate and the formal offer is where most of the surprises live, because the operator does detailed design in between.

Keep both documents. A planning application for a scheme with an energy strategy will often be asked for evidence of the connection position.

Point of connection and reinforcement

The operator nominates the point of connection, usually the nearest point on the network with capacity, and that choice drives the cost. There are three cost components to understand.

The connection assets themselves: the cable from your site to the point of connection, any new substation, switchgear, metering and the service cables within the site.

Network reinforcement: work needed further back on the network to create capacity for your load. That can mean upgrading a transformer, laying a larger feeder, or in the worst case works at the primary substation. Reinforcement is the component that produces the alarming numbers.

Diversions: moving existing apparatus that crosses the site, which is chargeable and frequently forgotten. An overhead line across a field or a low voltage main under a proposed building footprint both need moving, and both have long lead times.

Charging for reinforcement follows the industry's common connection charging methodology, and the balance between what the connecting customer pays and what is socialised across all users has changed in recent years. The detail is set out in the Distribution Connection and Use of System Agreement and in each operator's published connection charging statement, so check the current statement rather than relying on a figure from an earlier scheme.

Load assumptions and heat pump schemes

Load assumptions are where developers over-order and under-order in equal measure. Over-ordering buys capacity you pay for and do not use. Under-ordering means a second application later, usually at a worse point in the queue.

The variable that has moved most is heating. A gas-heated house drew a modest electrical load. A house with an air source heat pump, an electric hob, a hot water cylinder and a 7kW charge point draws considerably more, and the diversity assumptions that applied to gas-heated estates do not transfer. The Future Homes Standard direction of travel makes this the default case rather than the exception, so a scheme designed now should assume all-electric unless there is a reason not to.

Three things to get right in the assumption:

1. Use the operator's own diversity guidance for the house type and the technology mix, and state which version you used.
2. Allow for charge point load at the number of spaces Building Regulations Part S requires rather than at today's uptake.
3. Where the scheme is phased, declare the whole-site load at the first enquiry even if you only connect phase one, because retrospective capacity is the expensive route.

The electrical strategy and the heating strategy are the same conversation. That is why an Energy Statement and the connection enquiry should be prepared together rather than sequentially.

Timescales for an offer and for works

The regulated timescales for a connection offer are measured in weeks and vary by connection type and complexity. The construction programme afterwards is measured in months, and where reinforcement is needed it can run well beyond a year.

Realistic planning assumptions:

Wayleaves and easements over third party land are the single most common cause of delay, because they depend on a landowner who has no reason to hurry. Where the cable route crosses land you do not control, start that negotiation at the same time as the planning application.

Check the current offer timescales and charging statement with your operator rather than relying on these indications. The figures above are planning assumptions, not commitments.

Contestable and non-contestable works

Part of a connection can be carried out by an independent connection provider rather than the network operator, and that is where a real saving sometimes sits.

Contestable works are those open to competition: the site cable route, excavation and reinstatement, ducting, and in many cases the substation civils and the cable installation up to the point of connection. An independent provider or an accredited contractor can price these.

Non-contestable works are reserved to the network operator: the final jointing and energisation onto the live network, and most reinforcement works on the existing network. You cannot shop around for those.

The practical route is to ask the operator to split the quotation into contestable and non-contestable elements, then price the contestable part with an independent connection provider. Compare like for like, including the adoption arrangements and who holds the design liability. An independent provider route also needs the operator's agreement on the point of connection, so it does not remove the operator from the conversation.

Where the strategy changes the cost

Design decisions move the number more than negotiation does.

• Putting the substation at the site boundary nearest the point of connection rather than in the middle of the layout shortens the chargeable cable run and avoids a long private route.
• Reducing peak demand with a balanced heat pump and hot water strategy, or with smart charge point management, can drop the scheme below a reinforcement threshold.
• A flexible or timed connection, where the operator can curtail at peak, can avoid reinforcement entirely on a constrained network.
• On-site generation and storage reduce import capacity but add an export application, which has its own process.
• Phasing the connection in line with the build programme spreads cost but risks losing capacity between phases.

Keep the substation location on the planning layout from the first drawing. Adding a 3m by 4m enclosure after permission means a non-material amendment at best and a fresh application at worst, and it usually lands in the worst possible spot for the street scene. A Utilities Assessment is the document that pulls the electricity, water, gas and telecoms positions into one place for the application, and the same early-enquiry logic applies to water and drainage connection costs.

Making the enquiry early

The sequence that saves money on a small or medium scheme:

1. Make the budget estimate enquiry as soon as you have a unit mix, before the layout is fixed.
2. Record the point of connection and any reinforcement warning in the appraisal as a line item with a contingency.
3. Fix the substation position and cable route on the layout before the planning application goes in.
4. Start wayleave negotiations for any third party land in parallel with the application.
5. Apply for the formal offer once the scheme is settled enough that the load will not change.
6. Price the contestable works independently before accepting.

A connection problem found after permission is a design change. Found before, it is a layout decision. PlanScope's pricing covers the drafting side of the application at a fixed cost, which makes the infrastructure lines in a budget easier to read against the rest.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. This is general guidance rather than legal advice. Connection charges and timescales are set by each network operator and change, so check the current published charging statement before relying on any figure.