What should an extension electrical quote include?

Start with a drawing and a written schedule

Give every contractor the same dated plan and a room-by-room list of what you want. Mark socket and switch positions, lighting groups, appliances and any outdoor equipment. If the kitchen designer changes an appliance or island layout, issue the revision to the electrician and builder together.

Our extension planning guide covers the early design decisions. This checklist is for the next stage: turning those decisions into a scope that you can compare, approve and hand over.

What belongs in the quote?

• Existing installation assessment. State what must be checked before the proposed additions can be confirmed, and how any necessary remedial work will be priced.
• Circuits and connections. Identify new circuits, alterations and the equipment being connected. Do not assume ‘electrics included’ covers every appliance, fan, heating control or outdoor point.
• Fittings and controls. Record quantities, specifications, finishes and who supplies them. Separate a basic fitting allowance from your selected decorative product.
• Installation stages. Include first fix, second fix, testing and any planned return visits. Agree the conditions needed for each stage to start.
• Building work. Allocate openings, fire stopping where required, boxing-in, plaster repairs and decoration rather than leaving these between trades.
• Handover. List certification, applicable Building Regulations notification, circuit identification and a demonstration of controls.

This is a scope checklist, not an electrical design. The electrician must assess what is appropriate for the installation.

Does an extension automatically need a new consumer unit?

No automatic replacement decision should be made from the word ‘extension’. Ask the electrician to explain whether the existing equipment and protection are adequate for the proposed work, what has been inspected or tested, and what remains provisional. A spare space alone is not the whole assessment.

The IET explains that additions and alterations require assessment of the existing installation’s suitability for the changed circumstances. See its discussion of additions, alterations and protective measures. If an upgrade is proposed, ask for its reason and scope on a separate line.

Who coordinates the electrician and builder?

Decide who owns the programme and who can approve changes. The following is an example allocation to agree, not a statement of what your contract already includes.

• Before first fix: the client approves the current drawing; the builder confirms access and construction details; the electrician confirms the agreed electrical scope and outstanding survey questions.
• Before walls or ceilings close: the builder checks with the electrician that the relevant work and inspections are complete. Agree how that confirmation is recorded.
• Before second fix: the named supplier confirms the correct fittings are available and the electrician confirms the areas are ready.
• At handover: the electrician explains the work and supplies the agreed documents; the client records remaining items and who will resolve them.

For example, if a kitchen plan adds an induction hob after the quote, send the exact appliance information before ordering or covering cable routes. Ask for the design and price implications to be assessed. Do not assume the original cooker allowance covers the change.

Which certificates should you expect in England?

Agree the appropriate electrical installation certification for the work and the Building Regulations notification route where required. These serve different purposes. Under England’s Approved Document P, new circuits and consumer unit replacement are examples of notifiable work. The exact route should be agreed before work starts, rather than assuming another trade will arrange it.

Check Approved Document P and Electrical Safety First’s explanation. Ask who will issue each document and when. An invoice is not a substitute for the appropriate certification.

Send a useful brief for your extension

Crest Electrical Contractors handles extension and renovation enquiries across Buckinghamshire, Bedfordshire, Hertfordshire and Northamptonshire. Send the site address, current plans, proposed start date, appliance schedule and details of who is managing the build. We can then discuss the survey and information needed to quote. Request an extension electrical quote.

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