CIS Deductions for Electricians: Pay Explained 2026

How CIS deductions work

When a contractor pays a subcontractor for construction work, the contractor must check the subcontractor's CIS status with HMRC and deduct tax from the labour element of the payment: 20% for a registered subcontractor, 30% where the subcontractor is unregistered or HMRC cannot verify them, and nothing where the subcontractor holds gross payment status. The contractor pays what it deducted straight to HMRC, and the subcontractor gets a payment and deduction statement as the paper trail.

Those deductions are advance payments toward the subcontractor's income tax and National Insurance — not a separate charge. Nothing is deducted from VAT charged on the invoice, from materials the subcontractor paid for, or from plant hire. At the end of the tax year the subcontractor files Self Assessment, HMRC sets the deductions against the actual liability, and any excess comes back as a repayment.

Registration is free and done with HMRC — no fee, no agent required, no reason to pay a middleman for it. The 30% rate is the expensive way to learn that: unregistered sparkies hand over nearly a third of every labour payment and wait until Self Assessment to get the overpayment back.

A sparkie invoice, worked through

Take a typical domestic job: a consumer unit replacement invoiced at £3,500 for labour and £900 for materials — the board, breakers, cable and sundries the sparkie bought. CIS applies to the labour element only. At the 20% registered rate the contractor deducts £700 (20% of £3,500) and pays it to HMRC. The sparkie receives £2,800 of the labour plus the full £900 for materials: £3,700 in the bank, with a £700 credit sitting with HMRC against the year-end tax bill.

• Invoice total: £4,400 (£3,500 labour + £900 materials)
• CIS deduction: 20% of £3,500 = £700 (materials untouched)
• Paid to the sparkie: £3,700
• Credit with HMRC: £700 toward income tax and National Insurance

Why sparkies so often end up owed a rebate

The 20% comes off every labour payment from the first pound — but income tax only starts after the £12,570 personal allowance, and allowable business expenses (van costs, tools, travel between jobs, insurance) come off before the liability is calculated. The deductions taken through the year therefore usually overshoot what is actually owed, and the Self Assessment reconciliation turns the excess into a repayment.

That is why the rebate is normal, not lucky. A sparkie invoicing £35,000 of labour in the year has £7,000 deducted at source; the actual income tax and National Insurance bill on that income, after the personal allowance and legitimate expenses, is typically thousands less. The difference comes back after the return is filed — which is also why filing on time matters: the repayment cannot arrive until the return does.

The expenses side is where electricians leave money behind. Materials are already protected from CIS, but the van, fuel, tools, test equipment calibration, workwear, phone and the home-office slice are legitimate costs that reduce the final bill. Keep receipts for all of it; the rebate is only as big as the records behind it.

Materials-heavy jobs and receipts

Electrical work is materials-heavy: consumer units, cable drums, downlights by the box, full rewires where materials run into the thousands. The CIS rule is clear — the contractor must not deduct from materials the subcontractor paid for — but it only works if the invoice separates labour from materials cleanly. One lump sum marked 'job price £8,000' invites the contractor to deduct 20% of the lot.

Invoice labour and materials as separate lines, every time, and keep the supplier receipts to back the materials figure. If the contractor buys the materials directly and you supply labour only, there is nothing to deduct from — but there is also no materials margin for you. And VAT: if you are VAT-registered, CIS is never deducted from the VAT element.

Disputes over the split are common on price work. The protection is paperwork: a written quote showing labour and materials separately, agreed before the job starts, leaves no room for the contractor to reinterpret it at payment time.

CIS vs umbrella for agency sparkies

Agency sparkies usually face a choice: CIS subcontractor or umbrella company. Under CIS you invoice the agency or contractor, take the 20% deduction, handle your own Self Assessment and keep the full rate minus the deduction. Under an umbrella, you become the umbrella's employee: PAYE tax and National Insurance each payday, payslips, a small margin fee skimmed off the top, and basic employment rights — but the headline rate is lower and the fee never stops.

Neither is wrong; they suit different priorities. CIS keeps more of the rate in your hands through the year and usually ends with a rebate, at the cost of admin and income that stops between assignments. Umbrella is simpler week to week and gives payslips a mortgage lender recognises, at the cost of the margin and a lower net rate. What matters is comparing the in-pocket annual figure, not the headline.

One warning: if an agency or umbrella tells you that you must use their preferred route and charges you for the privilege of being paid, walk away. Compliant umbrellas exist; the ones worth avoiding announce themselves.

When a limited company starts to make sense

The question every busy subcontractor eventually asks: at what point does the limited company beat CIS? The rough rule of thumb doing the rounds is consistent earnings around £45,000 a year and rising — below that, the accountant's fees and the admin usually eat the advantage; above it, the combination of corporation tax and dividend planning can leave more in your hands than the CIS route.

Treat that as a rule of thumb, not advice. The company brings real obligations: accounts, corporation tax, VAT registration once turnover passes the threshold, and the off-payroll working rules if your contracts start looking like disguised employment. The jump is worth an accountant's hour before it is worth anything else — a good one will tell you honestly whether your numbers clear the bar.

There is also a middle path many sparkies take: stay CIS while building the client base, and incorporate once the order book — not the ambition — says the income is stable. The company structure rewards consistency; CIS forgives volatility.

Cash-in-hand call-outs: declare it

Emergency call-outs are where cash-in-hand offers live: the Sunday-night fuse-board failure, the landlord with a tenant in the dark, the customer who suggests a discount for cash. The money is tempting and the work is real — but undeclared cash is undeclared income, and HMRC's data-matching has ended the era when it reliably went unnoticed.

Declare it through Self Assessment like any other income. The tax on a few hundred pounds of call-out money is a fraction of the penalty for hiding it, and clean books are what mortgage lenders, accountants and — if you ever incorporate — HMRC want to see. One penalty wipes out years of quiet extras.

Where the CIS figures come from

Deduction rates and the mechanics of the scheme are from GOV.UK: 20% for CIS-registered subcontractors, 30% where unregistered or unverifiable, 0% with gross payment status; no deduction on VAT, directly-paid materials or plant hire; registration free; overpaid deductions reclaimed via Self Assessment. Both GOV.UK pages were verified on 23 September 2026 and are listed in the sources.

The £19-an-hour ONS median is the employed anchor the comparisons are set against. The £3,500/£900 invoice is a typical domestic consumer-unit job used to show the arithmetic, not ONS data. The ~£45,000 limited-company threshold is a rough rule of thumb from industry practice, not tax advice — an accountant should confirm any decision.

Reviewed and updated

CIS rates and rules were last checked against GOV.UK on 23 September 2026. HMRC revises scheme guidance periodically — if a contractor tells you the deduction rate has changed, check the GOV.UK subcontractor page before believing them.