After the tax year ends on 5 April, on your tax return. For 2026-27 a sole trader electrician can file from 6 April 2027. Under Making Tax Digital, the refund is requested separately through HMRC online services.
Under the Construction Industry Scheme (CIS), the 20% a contractor takes from the labour part of your invoice is an advance payment towards your Income Tax and National Insurance. It is 30% if the contractor cannot verify you. Many electricians mix CIS work for contractors with jobs paid by homeowners, so the refund depends on the whole year, not just the CIS side. Over-deducted CIS is claimed back through your tax return. The sooner after 5 April you file, the sooner HMRC can repay you. This page is for sole traders and follows GOV.UK as checked on 18 October 2026. A limited company uses its deductions through its payroll instead, as our guide on whether a limited company can claim back CIS deductions explains.
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Which of your jobs have a deduction
| Job | Paid by | CIS deduction? |
|---|---|---|
| Full rewire or new installation | A main contractor or electrical firm | Yes, on the labour part |
| Wiring extra sockets or an extension to a circuit on its own | A contractor | Usually no; HMRC's manual treats extending a system as outside CIS |
| Consumer unit change, rewire or repairs | A homeowner directly | No; householders are not contractors |
| Testing and inspection on its own | Anyone | Our guide to CIS for electricians covers the edge cases |
Only the jobs with a deduction add to what HMRC holds for you. Every job's profit goes on the return. The more of your income comes from homeowners, the smaller the refund, and it can turn into tax to pay.
A worked example for an electrician
Leah is a self-employed electrician outside Scotland with no other income. In 2026-27 contractors pay her £30,000 for labour before deductions and take 20%, which is £6,000. She also earns £12,000 from homeowners, with no deduction. Her van, tools, test equipment, scheme fees and phone come to £7,000.
| Item | Amount |
|---|---|
| Turnover: CIS pay before deductions plus homeowner work | £42,000.00 |
| Business costs | £7,000.00 |
| Taxable profit | £35,000.00 |
| Income Tax: 20% of £22,430 (profit above the £12,570 personal allowance) | £4,486.00 |
| Class 4 National Insurance: 6% of £22,430 | £1,345.80 |
| Total tax and National Insurance owed | £5,831.80 |
| Deducted by contractors at 20% | £6,000.00 |
| Overpaid through CIS, repayable | £168.20 |
Without the homeowner work, and with the same costs, her refund would be about £3,300. With it, the deductions only just cover her bill. These are 2026-27 rates. Class 2 National Insurance is treated as paid because her profit is above £7,105. This is an example only.
Steps to claim your CIS refund
- Collect every payment and deduction statement for the tax year, 6 April to 5 April. A contractor who takes a deduction must give you one within 14 days of the end of that tax month.
- Ask for copies of any that are missing. If a contractor has closed, write to HMRC with your details, the contractor's details, the dates you were paid and why you have no statements.
- Check each statement against your bank account, and that the deduction was taken from the labour, not the cable, fittings and other materials you supplied.
- Total your domestic income for the year, including cash jobs, and your business costs.
- If you are not in Making Tax Digital for the year, put your total turnover and your CIS deductions on your Self Assessment return, give your bank details and file online.
- If you are in Making Tax Digital, check the CIS deductions HMRC has added to your MTD tax return, correct them in your software if needed, submit, then request the refund through your HMRC online services account.
What this means for you
Making Tax Digital for Income Tax (MTD) started on 6 April 2026 for sole traders whose 2024-25 return showed over £50,000 of self-employed and rental income before costs, and starts on 6 April 2027 above £30,000 on the 2025-26 return. Leah's £42,000 is for 2026-27. If her 2025-26 return also showed over £30,000, she joins in April 2027. Her 2026-27 return is an ordinary Self Assessment return, so she claims the £168.20 in it. From 2027-28, HMRC adds her deductions to her MTD tax return and she requests any refund separately.
The deadline for a 2026-27 return is 31 January 2028. Your deductions sit with HMRC until your return is in, so filing in April rather than January gets your money back sooner. If your homeowner work is growing, expect a smaller refund. Set money aside from domestic jobs as you go, because CIS will not cover that tax for you.
If something looks wrong
- A contractor took 30%. GOV.UK says the details you give a contractor must match your registration exactly. Speak to the contractor, and the extra still counts on your return.
- HMRC's figures differ from your statements. Our guide on checking your CIS deductions with HMRC explains what to do.
Use the free MTD check to see when MTD starts for you, and the trades section for more guides for electricians.
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Questions people ask
Can I get my CIS refund during the year?
Not while you are trading as a sole trader. Over-deducted CIS comes back through your tax return after the tax year ends on 5 April. If you stop trading, GOV.UK says form CIS40 may let you claim that year's deductions early.
Do my domestic jobs affect the refund?
Yes. A consumer unit change or rewire paid for by a homeowner has no CIS deduction, because CIS 340 says private householders are not contractors. The profit is still taxed on the same return, so it uses up some or all of the refund.
Does the VAT reverse charge change my CIS refund?
No. The reverse charge decides who accounts for VAT on your invoice. The CIS deduction is worked out on the amount before VAT, and the refund is about Income Tax and National Insurance only.
How do I claim once I am in Making Tax Digital?
HMRC adds your CIS deductions to your MTD tax return and you check them before you submit. GOV.UK says you cannot claim the refund in that return. You request it through your HMRC online services account, or your main agent requests it through its agent services account.
How long will HMRC take to pay?
HMRC does not publish a timescale for CIS refunds, and checks can make it longer. The sooner after 5 April you file, the sooner HMRC can repay you.
Sources
- What you must do as a CIS subcontractor: Pay tax and claim back deductions (GOV.UK)
- What you must do as a CIS subcontractor: Get paid (GOV.UK)
- Use Making Tax Digital for Income Tax: Submit your tax return (GOV.UK)
- Use Making Tax Digital for Income Tax: Help and support (GOV.UK)
- Construction Industry Scheme: a guide for contractors and subcontractors, CIS 340 (GOV.UK)
- CISR14090: construction operations: building service systems (HMRC manual)
- Claim repayment of subcontractor deductions, form CIS40 (GOV.UK)
- Income Tax rates and Personal Allowances (GOV.UK)
- Self-employed National Insurance rates (GOV.UK)
- Choose agents for Making Tax Digital for Income Tax (GOV.UK)
- Find out if and when you need to use Making Tax Digital for Income Tax (GOV.UK)
- Work out your qualifying income for Making Tax Digital for Income Tax (GOV.UK)
This is general information to help you understand the rules. It isn't tailored to your circumstances, so check your own position before acting on it.
Righto Tax is a trading name of NJG Consultancy Ltd, registered in England and Wales, company number 16095900. Registered office: Jubilee House, East Beach, Lytham St Annes, FY8 5FT.
All CIS guides for subcontractors
What happens next
- Use the free Making Tax Digital checker to see your own start date and deadlines.
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- Questions about this page? Email hello@rightotax.co.uk.