CIS Scheme for Electricians: Complete Guide for Contractors and Subcontractors

The Construction Industry Scheme (CIS) is an HMRC tax administration system that applies to payments made by contractors to subcontractors for construction work. Electrical installation work is explicitly included within CIS's scope.

You are a contractor under CIS if:

• You pay subcontractors for construction or electrical work
• Your business spends more than £1 million per year on construction work in any three-year period (making you a "deemed contractor" even if construction isn't your main business)

You are a subcontractor under CIS if:

• You are paid by a contractor for electrical installation or related construction work
• You can be a sole trader, partnership, or limited company

Many electricians are both simultaneously — they receive payments from a main contractor (acting as a subcontractor) and also engage their own subcontractors (acting as a contractor). In this situation, you have obligations in both directions.

Domestic-only work: CIS applies to construction work carried out for a business, not to work carried out for a private individual in their own home. If you do purely domestic electrical work with no business clients, CIS is unlikely to apply — but the moment you take on a commercial or B2B contract, it may.

As a subcontractor:

Register with HMRC before you receive your first CIS payment. You can register online through the HMRC CIS registration service or by phone. You will need your UTR (Unique Taxpayer Reference) from your Self Assessment registration. Once registered, contractors can verify your status with HMRC and make deductions at the correct rate.

As a contractor:

You must register as a contractor with HMRC's CIS scheme before you make your first payment to a subcontractor. Registration is separate from your Self Assessment registration. Once registered, you will need to:

• Verify each new subcontractor with HMRC before paying them for the first time
• Make the correct CIS deductions from payments
• File monthly CIS returns
• Provide subcontractors with a payment and deduction statement

Verifying subcontractors: before paying a new subcontractor, you must verify them through HMRC's CIS online service or via the HMRC CIS telephone service. Verification tells you which deduction rate to apply. You cannot simply take a subcontractor's word for their registration status — failure to verify is your risk, not theirs.

HMRC specifies three deduction rates, and the correct rate depends on the subcontractor's registration status:

20% — Registered subcontractor

Applied when the subcontractor is registered with CIS and HMRC verification confirms this. The 20% deduction is taken from the labour element of the payment only — not from the cost of materials. If a subcontractor invoices you £500 labour + £200 materials, you deduct 20% of £500 (= £100) and pay £600.

30% — Unregistered subcontractor

Applied when verification confirms the subcontractor is not registered with CIS. The 30% rate is a higher deduction to incentivise registration. If someone claims to be registered but HMRC verification shows they are not, apply 30% — do not take the subcontractor's word over HMRC's response.

0% — Gross payment status

Subcontractors with gross payment status receive the full payment with no CIS deduction. HMRC grants gross payment status to businesses that meet turnover, compliance, and business criteria. As a contractor, you verify whether gross status applies during the verification step — HMRC's response will tell you.

Important: what deductions apply to

CIS deductions apply only to the labour element of an invoice. Materials supplied by the subcontractor (including fuel for plant, consumables directly incorporated into the work, and equipment hire) are deductible from the calculation. VAT is excluded entirely. If a subcontractor's invoice is not broken down between labour and materials, you should make reasonable enquiries — paying a lump-sum invoice without a labour/materials split puts you at risk.

As a contractor, you must file a CIS monthly return with HMRC by the 19th of each month, covering payments made to subcontractors in the previous tax month (which runs from the 6th to the 5th).

What to include in each return:

• Details of each subcontractor paid in the period
• The total amount paid (excluding VAT)
• The amount of any materials cost included in the payment
• The CIS deduction made

Filing the return: you can file online through HMRC's CIS online service or via compatible accounting software. Paper returns are no longer accepted for most contractors.

Nil returns: if you made no payments to subcontractors in a tax month, you must still file a nil return unless you have notified HMRC that you are an "inactive contractor" for a period. Missing a return — even a nil one — triggers an automatic penalty.

Penalty for late filing: HMRC charges automatic penalties for late CIS returns. The first return filed late incurs a £100 penalty. Further late returns in the same tax year incur escalating penalties — up to £3,000 for twelve consecutive late returns. Set up a calendar reminder for the 19th of every month to avoid this.

Payment of deductions: the CIS deductions you hold must be paid to HMRC by the 19th of the following month (22nd if paying electronically). These are not your money — they are tax withheld on behalf of your subcontractors.

Gross payment status (GPS) allows subcontractors to receive payments in full without CIS deductions. For electricians with significant subcontractor income, achieving GPS is worthwhile — it improves cash flow by avoiding the wait to reclaim deducted amounts through Self Assessment or corporation tax returns.

HMRC's eligibility criteria for gross payment status:

• Your business must have been operating for at least 12 months
• You must have a good tax compliance record (no significant late filing or payment history)
• You must meet a minimum net turnover threshold — for sole traders, currently £30,000 per year from construction work; for partnerships and companies the threshold differs

Applying for gross payment status: apply through the HMRC CIS online service. HMRC checks your compliance record and turnover before granting or refusing status. GPS is reviewed annually — if your compliance record deteriorates, HMRC can withdraw it.

If you lose GPS: HMRC will notify you and your contractors. Deductions revert to 20% until status is restored. Maintaining tax compliance (on-time filing and payment of all taxes, not just CIS) is the most important protection against losing GPS.

These are the errors that generate the most HMRC enquiries and penalties in the electrical contracting sector:

Paying subcontractors without verifying them

You must verify every new subcontractor with HMRC before paying them. Using the wrong deduction rate because you didn't verify — or because you took the subcontractor's claim at face value — makes you liable for any shortfall, plus interest and potential penalties.

Deducting CIS from materials

CIS deductions apply to labour only. Deducting 20% or 30% from the full invoice including materials overpays HMRC and underpays your subcontractor — which can create disputes and means you're remitting money you didn't need to.

Missing monthly return deadlines

The 19th of each month is a hard deadline. Automatic penalties start from the first missed return. Even if you made no payments that month, a nil return is required unless you've notified HMRC you're inactive.

Failing to give subcontractors payment statements

You must provide each subcontractor with a written payment and deduction statement by the 19th of the tax month following payment. Subcontractors need this to reclaim their CIS deductions through their own tax return. Failing to issue statements is a separate offence from late filing.

Treating employees as CIS subcontractors

Someone who works under your direction, uses your tools, and works exclusively for you is likely an employee under HMRC's employment status rules — not a self-employed subcontractor. Paying them under CIS when they should be on PAYE carries significant risk: backdated PAYE, National Insurance, interest, and penalties. If you're unsure, use HMRC's Check Employment Status for Tax (CEST) tool before deciding.