Making Tax Digital for Electricians —
Testing, Certification & CIS Explained
Testing, Certificates, and Materials All Add Up
Electrical work often bundles several chargeable elements into one job: the actual installation or repair labour, materials (cable, consumer units, fittings), and certification (EICRs, minor works certificates, NICEIC or NAPIT compliance paperwork). Every element combines into your total invoice, and your qualifying income is the full invoice amount, not just your labour or your margin on materials after what you paid a wholesaler.
CIS Contract Work Follows the Same Gross-Income Rule
Many electricians split their time between direct domestic and commercial clients, and CIS subcontract work for main contractors on larger builds. For the CIS portion, your MTD qualifying income is your gross invoiced amount before the 20% (or 30%) CIS deduction, not your net take-home after the contractor withholds tax. This is the single most common point of confusion for electricians checking their MTD position for the first time.
Certificates, Test Equipment and What to Keep
An electrician’s paperwork is already thorough, which makes digital records easier if you link it to your accounts. Each certificate is a record that a job was done and invoiced.
- Match each EICR, minor works or installation certificate to its invoice, so the work and the income can be traced together.
- Keep scheme fees (NICEIC, NAPIT or similar) and notification costs, which are normal business expenses.
- Keep calibration and replacement costs for test equipment, and treat larger purchases as capital items.
- Log materials from trade counters against the job, keeping the receipt.
- If you work under CIS, keep the monthly statements and record gross invoices separately from deductions.
Where Electricians Slip Up on MTD
- Counting profit instead of invoices. A £62,000 turnover with £22,000 of materials is still £62,000 for the threshold.
- Mixing domestic and commercial work. Commercial invoices are often paid 30 days or more later, so record them when paid and keep the invoice.
- Leaving out call-out premiums. Emergency and out-of-hours charges are income like any other.
- Ignoring van costs. Fuel, insurance, servicing and mileage need a log if the van has any private use.
- Assuming accreditation fees are personal. Scheme, qualification and testing course fees related to your work are allowable.
A Sample Quarter: What the Update Looks Like
A sample quarter for a self-employed electrician with a steady mix of work.
| Q2: 6 July to 5 October 2026 | Amount |
|---|---|
| Domestic rewires and installations | £13,900 |
| Commercial and landlord work | £8,400 |
| EICRs and call-outs | £3,100 |
| Total income | £25,400 |
| Materials from trade counters | £7,600 |
| Van, fuel and insurance | £2,750 |
| Scheme fees, test equipment and tools | £980 |
| Software and phone | £360 |
| Total expenses | £11,690 |
| Profit for the quarter | £13,710 |
Materials are an expense, but they never reduce the income used to test the threshold. Invoicing £25,400 puts this electrician on track for over £100,000 a year.
Worked Example
Domestic and commercial jobs (gross, including materials and certification): £31,400
CIS subcontract labour (gross, before 20% deduction): £13,600
Total qualifying income: £45,000 — above the £30,000 Phase 2 threshold, below £50,000. Freddie joins MTD from April 2027. The 20% CIS tax already deducted from his subcontract income is offset against his final tax bill, but it doesn't reduce the £45,000 qualifying income figure used to check his MTD position.
What You Can Claim
- Materials — cable, consumer units, fittings, fixings
- NICEIC or NAPIT membership and annual assessment fees
- Test equipment — multifunction testers, usually claimed in full
- Van costs — fuel, insurance, or the 55p/mile mileage rate
- Public liability and professional indemnity insurance
- CSCS card and CITB levy where applicable to CIS work
- Continuing training — 18th Edition updates, EV charging certification
Best MTD Software for Electricians
Software links are affiliate, help fund CheckMyMTD. Recommendations based on ease of use for self-employed income tracking.
Frequently Asked Questions
Is certification income (EICRs, minor works certs) separate from my labour income?
No, all of it combines into the same qualifying income total, however you itemise it on the invoice.
Is my CIS threshold based on income before or after the deduction?
Before. Your qualifying income is your gross invoiced amount, not the amount that actually reaches your bank account after the contractor's CIS deduction.
Can I claim my NICEIC membership fee?
Yes, professional body membership and assessment fees required for your work are a normal allowable business expense.
Do domestic and CIS income combine into one MTD threshold check?
Yes, all your self-employment income combines into a single qualifying income figure, regardless of the source.
Can I claim the full cost of a new multifunction tester?
In most cases yes, via the Annual Investment Allowance, letting you deduct the full cost against your profit in the year you buy it.