Do electricians on CIS still do Self Assessment?

Yes. CIS is a deduction, not a full tax return.

Can I claim NICEIC or NAPIT fees?

Yes if you need the membership to trade.

Is a tester allowable?

Yes, as equipment, plus calibration each year.

Mileage or actual van costs?

Either, not both, for that vehicle. 55p a mile for the first 10,000 business miles in 2026/27 if you use simplified expenses.

What if I am employed Monday to Friday and do domestics at weekends?

The weekends are self-employment if clients pay you. Register once that income is over £1,000 in the year.

Self-employed electrician tax UK (2026/27)

Expenses list · Self Assessment · Tax calculator · Deadlines

Who this is for

Sole-trader electricians: domestic, industrial, or subcontracting. Also sparks who hold scheme memberships in their own name and invoice clients directly.

Employed maintenance electricians on PAYE are not this page. If you moonlight domestics at weekends, those jobs can still be a self-employment once they pass £1,000.

What is the same for every sole trader

If you work for yourself you register with HMRC, keep a record of what came in and what you spent to earn it, and file a Self Assessment return. Tax is on profit, not turnover. The 2026/27 personal allowance is £12,570. Class 4 National Insurance is 6% between £12,570 and £50,270, then 2% above that. The online filing and payment deadline for the 2025/26 return is 31 January 2027.

What is different if you are a electrician

CIS works the same as for plumbers: deduction towards your tax, not a cost of sales. Keep the monthly statements.

What is different is the kit and the badges. A calibrated tester is equipment. NICEIC, NAPIT or equivalent membership, if you need it to trade, is a professional cost. Failed calibration you have to redo is still a business cost. A course to keep your 18th edition current is training in this trade.

Part P / building control fees you pay and recharge should appear as turnover when billed and as expenses when paid, or net consistently. Do not lose them in a drawer because “the customer paid the council”. If it went through your books, put it through your books.

Worked example

An electrician invoices £58,000. Materials £6,200. Van mileage 8,000 miles at 55p = £4,400. Test kit and calibration £1,900. Scheme membership £650. Insurance £980. Phone and software £370. PPE £200. Accountant £500. Other job costs £1,600. Total expenses £16,800.

Typical year	Amount
Turnover	£58,000
Materials	£6,200
Van mileage	£4,400
Test kit and calibration	£1,900
Other job costs	£1,600
Insurance	£980
Scheme membership	£650
Accountant	£500
Phone and software	£370
PPE	£200
Total expenses	£16,800
Taxable profit	£41,200
Income Tax	£5,726
Class 4 NI	£1,717.80
Estimated bill	£7,443.80

Figures use 2026/27 England, Wales and Northern Ireland rates, full personal allowance, no other income. Scotland uses different bands. Run the calculator with your own numbers.

Mix of domestic and CIS, England. CIS deducted not included in expenses.

Making Tax Digital

Gross labour plus materials on invoices is the MTD number. A subcontract spark on CIS can be in MTD while taking home far less than £50,000. Check qualifying income, not drawings.

See does Making Tax Digital apply to me? and the sole trader MTD guide.

Next steps

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