How do I register for CIS as an electrician?

If builders or main contractors pay you for installation work, register for the Construction Industry Scheme (CIS) online with your Unique Taxpayer Reference (UTR). Registered and verified, they deduct 20%; otherwise 30% (GOV.UK, October 2026).

Not every electrical job is in the scheme, and that is where electricians differ from most trades. The law covers installing systems of lighting and power supply in a building. HMRC's CIS manual says that means installing a system, not repairing, altering or extending one. So the same electrician can be inside CIS on Monday's rewire and outside it on Tuesday's fault call.

Which electrical work is under CIS

HMRC looks at the contract, not the invoice. If one contract mixes covered and excluded work, such as a rewire and a burglar alarm, CIS 340 says every payment under it is in the scheme.

HMRC's A to Z index of construction operations does not mention portable appliance (PAT) testing or electric vehicle chargers. In our reading, PAT testing is testing, not installing, so it is outside CIS on its own. A charger fitted to an existing supply looks closest to extending a system, while one wired in as part of a new installation is likely to be inside. Check the contract each time. Our guide to whether CIS applies to electricians goes through the lines in more detail.

Homeowner jobs

CIS 340 says private householders are not contractors, so a homeowner who pays you direct deducts nothing. But if you wire a homeowner's extension for a builder, the builder is your contractor and deducts CIS from what they pay you. The homeowner guide explains both sides.

Steps to register as a subcontractor

1. Check you are self-employed. GOV.UK says employees do not register for CIS.
2. If you have no UTR, register as a new business for Self Assessment and choose "working as a subcontractor". GOV.UK says this registers you for Self Assessment and CIS at the same time.
3. If you have a UTR, use HMRC's online CIS registration. You need your legal business name (and trading name if different), your UTR, your VAT number if registered, the date you started trading and, depending on your circumstances, your National Insurance number.
4. Give every contractor the exact name and UTR you registered with, and your National Insurance number, so they can verify you at 20%.
5. Keep the payment and deduction statement each contractor must give you within 14 days of the end of each tax month.

If you cannot register online, the postal form for sole traders is CIS301. The subcontractor registration guide covers the details.

Paying a mate or another sparky

If you pay a self-employed electrician or labourer to help on CIS work, you are their contractor. GOV.UK says you must register as a contractor before you take on your first subcontractor, through HMRC's process for setting up as a new employer, and check they should not be your employee instead. CIS 340 says that when a builder is working for a homeowner, the builder operates the scheme on payments to you, and in our reading the same applies to you when you pay a mate on your own homeowner job. The guide to registering as a contractor explains the monthly returns that follow.

What this means for you

Deductions come off your labour, and any expenses such as fuel the contractor pays you, but not your materials. GOV.UK says contractors do not deduct CIS from VAT, plant hired for the job or materials you paid for directly. For an electrician who buys cable, consumer units and fittings, that matters. Keep the receipts, because the contractor may ask for evidence and will estimate the cost if you have none.

Take Dan, a self-employed electrician. A builder pays him for a rewire: £1,800 of labour and £600 of cable and fittings he bought. Dan is registered, so the builder deducts 20% of £1,800, which is £360, and pays him £2,040. Unregistered, the deduction would be 30%, or £540. Dan's £360 goes on his Self Assessment tax return as CIS deductions and counts towards his tax bill.

Once your work is steady, you can apply for gross payment status, so contractors pay you in full. As a sole trader you need at least £30,000 of turnover in the last 12 months, ignoring VAT and materials, a record of paying tax and National Insurance on time, construction work in the UK and a business run through a bank account. HMRC reviews it every year. See the gross payment status guide.

Making Tax Digital

If your qualifying income on your 2024-25 return was over £50,000, you should already have started Making Tax Digital for Income Tax (MTD) on 6 April 2026. Otherwise, if it was over £30,000 on your 2025-26 return, MTD starts for you on 6 April 2027. Qualifying income is your total turnover, before expenses, from all your self-employment and property, not just electrical work. In our reading that means your CIS pay before deductions and your homeowner work, plus any other sole trade and any rent. Wages and a partner's share of partnership profit do not count. Use the free MTD check, and the trades section for more on CIS.