How do I find main contractors to subcontract electrical work to?

The most effective routes to finding main contractors are: trade bodies (the ECA and NICEIC both have contractor directories and networking events); regional construction associations (e.g. Constructing Excellence regional clubs); attending supply chain events organised by major contractors (Willmott Dixon, Wates, Kier, and others regularly hold supply chain days); Constructionline and Approved Contractors registers (main contractors search these directly); direct marketing (researching active projects on the Planning Portal and approaching the main contractor before they go to tender); and referrals from existing contacts. Cold approaches to main contractors' procurement teams are far less effective than networking or coming through a recognised framework.

What is CHAS and do I need it?

CHAS (Contractors Health and Safety Assessment Scheme) is a pre-qualification accreditation that assesses your health and safety management against a standard set of criteria. It is one of the most widely recognised schemes in UK construction and is accepted by the vast majority of main contractors as evidence of H&S competence. Without CHAS or an equivalent (Safe Contractor, Constructionline Health and Safety), most national main contractors will not place you on their supply chain register. CHAS accreditation costs from around £300 per year for a sole trader and requires submission of your health and safety policy, risk assessments, employer's liability insurance, and other documentation.

What is the Construction Industry Scheme (CIS) and how does it affect me?

The Construction Industry Scheme (CIS) requires main contractors (and other contractors who pay subcontractors for construction work) to deduct tax at source from payments to subcontractors and pay it directly to HMRC. If you are a registered CIS subcontractor, the deduction rate is 20 per cent of labour (materials are exempt from deduction). If you are unregistered, the rate is 30 per cent. You reclaim the deducted tax through your tax return or as a credit against PAYE if you have employees. Register as a CIS subcontractor through HMRC before you invoice any main contractor — deductions at 30 per cent significantly affect your cashflow.

What payment rights do I have as an electrical subcontractor?

The Housing Grants, Construction and Regeneration Act 1996 (as amended by the Local Democracy, Economic Development and Construction Act 2009) gives you: the right to interim payments at intervals of not less than 28 days; the right to receive a payment notice within five days of the payment due date, or to issue your own payment notice (a default payment notice) if the payer fails to issue one; the right to receive a pay less notice at least seven days before the final date for payment if the payer intends to pay less than the notified amount; the right to suspend work if payment is not made by the final date, after giving seven days' written notice; and the right to refer any payment dispute to adjudication (a statutory right that cannot be contracted out of).

What is the difference between direct subcontracting and labour-only subcontracting?

In a direct subcontract, you supply both materials and labour. You take responsibility for procurement, material costs, and delivery risk. Your margin is higher because you earn on both materials and labour, but your commercial exposure is greater. In a labour-only subcontract, the main contractor supplies all materials; you supply only labour. This reduces your financial risk (no material procurement, no price exposure) but your margin is lower because you only earn on your labour. Labour-only subcontractors are paid a lower rate per hour than direct subcontractors because the main contractor carries the material cost. Both forms are common in electrical subcontracting.

What should my subcontract agreement include?

A subcontract agreement should include: the scope of works; the contract sum and payment schedule; the contract conditions (usually the main contract back-to-back, or a standard form such as the ECA Domestic Subcontract); retention terms (typically 3 to 5 per cent, released in two halves at practical completion and end of defects liability period); the programme and access dates; variations procedure; notification requirements (particularly important under NEC contracts); insurance requirements; CDM duties; and dispute resolution (adjudication under the Construction Act). Never sign a subcontract that contains pay-when-paid clauses (prohibited under the Construction Act except in contractor insolvency), unlimited liability clauses, or time-bar clauses that are tighter than the statutory minimums without taking legal advice.

How do I price competitively for subcontract electrical work?

Pricing for subcontract work requires a different approach to domestic quoting. You need to account for: your all-in labour rate (base rate plus all oncosts); materials at net cost plus your markup; preliminary costs specific to your scope (site attendance, testing equipment, management time for site meetings); a programme float to reflect real site conditions; and a risk allowance for scope ambiguity. Check the main contract conditions before pricing — particularly liquidated damages (LDs) clauses, which flow down to subcontracts and can significantly increase your risk. Submit tender queries in writing before the deadline on anything unclear.

BUSINESS GUIDE

Electrical Subcontracting Guide UK: How to Find Work and Protect Your Payment

How to find main contractors, get CHAS and Constructionline, price winning subcontract bids, protect your payment rights under the Construction Act 1996, handle CIS deductions, and navigate direct vs labour-only subcontracting.

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15 min readUpdated 2026-06-10Andrew Moore, Founder of Elec-Mate

Written and reviewed by Andrew Moore, founder of Elec-Mate, against BS 7671:2018+A4:2026, IET Guidance Note 3 and the IET On-Site Guide.

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Key Takeaways

1The Housing Grants, Construction and Regeneration Act 1996 (as amended) gives every electrical subcontractor the right to interim payments at intervals of not less than 28 days, the right to suspend work for non-payment after seven days' notice, and the right to refer any payment dispute to adjudication.
2CIS (Construction Industry Scheme) deductions apply to most electrical subcontracting work. Registered subcontractors have 20 per cent deducted at source; unregistered subcontractors have 30 per cent deducted. Register with HMRC before starting subcontract work.
3CHAS accreditation and Constructionline registration are the most widely accepted pre-qualification credentials in the UK construction sector. Without at least CHAS, most national main contractors will not add you to their supply chain.
4Labour-only subcontracting (you supply labour; the main contractor supplies materials) carries lower risk but lower margin. Direct subcontracting (you supply materials and labour) carries higher margin but more commercial risk.
5Never start subcontract work without a signed subcontract agreement or at minimum a written order. Verbal agreements are very difficult to enforce and leave your payment rights unprotected.
6The electrical subcontractor who carries out the installation is responsible for signing the relevant sections of the Electrical Installation Certificate (EIC). Under BS 7671 Regulation 644.5, the signatory accepts responsibility for verifying compliance. The main contractor does not sign on your behalf — and cannot.

01 · Business Guide

What Is Electrical Subcontracting?

Electrical subcontracting means carrying out electrical work for a main contractor or specialist contractor rather than directly for a building owner. The main contractor holds the primary contract with the client and subcontracts specialist trades — including electrical — to specialist firms.

Advantages of subcontracting — regular volume of work from established clients; less time spent on marketing and quoting; access to larger projects than you could win directly; simplified administration (the main contractor manages the client relationship); opportunities to build long-term supply chain relationships.
Disadvantages — lower margin than direct-to-client work; payment can be slower (main contractor payment terms are typically 30 to 45 days); exposure to main contractor insolvency; less control over programme and site conditions; complex contract conditions with significant liability clauses.
Who uses subcontractors? — national and regional main contractors (Wates, Willmott Dixon, Vistry, Galliford Try, Morgan Sindall and others), M&E management contractors, specialist M&E contractors who subcontract installation to smaller firms, housing developers, and facilities management companies.

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02 · Business Guide

Finding Main Contractors Who Need Electrical Subcontractors

Getting on main contractor supply chains requires a proactive approach. Main contractors do not typically advertise for subcontractors in the way clients advertise for contractors — you need to make yourself known before the work exists.

Constructionline and Achilles — the leading supply chain databases used by main contractors to find and vet subcontractors. Registration gives you visibility to hundreds of main contractors searching for electrical subcontractors in your region. Constructionline Silver is the minimum acceptable level for most national contractors.
Supply chain days — major contractors regularly hold regional supply chain events where subcontractors can meet procurement teams. Sign up for notifications from contractors who are active in your area. The Electrical Contractors' Association (ECA) often promotes these events to members.
Planning Portal research — identify projects with planning permission in your area and research who the main contractor is likely to be. Approach their procurement team before tendering begins. Early engagement significantly improves your chances of being invited to tender.
Trade bodies and networking — ECA regional groups, NICEIC contractor events, and local construction industry groups are all routes to meeting main contractor procurement staff. In-person relationships remain one of the most effective ways to get on tender lists.

03 · Business Guide

CHAS, Constructionline, and Pre-Qualification

Pre-qualification credentials are the gatekeepers to main contractor supply chains. Without the right accreditations, you will not be invited to tender regardless of your technical ability. These are the most important ones to obtain.

CHAS — Contractors Health and Safety Assessment Scheme. Accepted by over 50,000 buyers in UK construction. Annual fee from approximately £300 for sole traders. Required: H&S policy, risk assessments, employer's liability insurance, public liability insurance, method statements for key activities.
Constructionline — a supply chain management and pre-qualification database. Silver level adds financial assessment and quality management to the CHAS health and safety requirements. Gold level adds an onsite audit. Most national contractors require Constructionline Silver as a minimum.
Safe Contractor — an alternative H&S accreditation to CHAS, operated by Alcumus. Widely accepted by facilities management contractors, housing associations, and retail sector clients. Some clients specify Safe Contractor rather than CHAS — check client requirements before applying.
ISO 9001 — quality management system certification. Required by some public sector frameworks and larger private sector clients. More expensive and time-consuming to obtain but opens significant additional procurement opportunities. Often required above a certain contract value threshold.

The H&S audit guide covers the documentation you need to assemble for CHAS and Constructionline accreditation, including RAMS templates and CDM 2015 compliance.

04 · Business Guide

Pricing to Win Subcontract Electrical Work

Subcontract pricing requires the same discipline as direct tendering but with additional consideration of the main contract conditions that flow down to your subcontract.

Read the main contract conditions — liquidated damages (LDs) clauses in the main contract typically flow down to subcontracts. If the main contractor faces LDs of £5,000 per day for late completion, they may seek to pass these to you if delay is in your section. Price this risk explicitly.
Retention — most subcontracts include retention (typically 3 to 5 per cent) held until practical completion (half released) and end of defects liability period (balance released). Price retention costs into your tender — you are effectively financing the retention amount.
Programme risk — subcontractors often bear programme risk from delays caused by other trades or the main contractor's programme management. Include a programme risk allowance and use the notification provisions in the contract (compensation events under NEC, extension of time under JCT) to protect your position when delays occur.

For detailed guidance on building your tender price, see the electrical tender writing guide, which covers prelims, labour rates, materials markup, and programme pricing in detail.

05 · Business Guide

Direct Subcontracting vs Labour-Only Subcontracting

The distinction between direct and labour-only subcontracting affects your pricing, your CIS obligations, your VAT position, and your commercial risk exposure.

Direct subcontracting — you supply materials and labour. You earn margin on both. You manage procurement, carry material price risk, and are responsible for delivery. VAT applies to the full contract value (materials and labour). CIS deductions apply to the labour element only (verified by the gross amount less the cost of materials, as evidenced by invoices).
Labour-only subcontracting — you supply labour only; the main contractor supplies materials. Lower margin but lower risk. CIS deductions apply to the whole payment (since there are no materials to deduct). Domestic reverse charge VAT applies if both you and the main contractor are VAT-registered and the main contractor is not the end client — this is a common compliance issue that electrical subcontractors get wrong.
Domestic reverse charge VAT — since March 2021, the domestic reverse charge applies to most subcontract electrical work between VAT-registered businesses in the construction sector. If the reverse charge applies, you do not charge VAT on your invoice — the main contractor self-accounts for the VAT. Get advice from an accountant familiar with construction VAT before issuing your first subcontract invoice.

06 · Business Guide

CIS Tax Deductions — What Electrical Subcontractors Must Know

The Construction Industry Scheme (CIS) is administered by HMRC and applies to almost all payments from contractors to subcontractors for construction work, including electrical installation. Non-compliance with CIS carries significant penalties.

Register before you start — register as a CIS subcontractor with HMRC before receiving your first subcontract payment. A registered subcontractor has 20 per cent deducted; an unregistered subcontractor has 30 per cent deducted. The deduction is a prepayment of tax — it does not mean you pay tax twice.
Gross payment status — once you meet HMRC's criteria (turnover threshold, tax compliance record), you can apply for gross payment status, meaning no CIS deduction is made from your payments. You then pay your tax directly through self-assessment. This significantly improves cashflow.
Monthly statements — main contractors must provide a monthly CIS deduction statement showing the gross amount paid, the deduction made, and the net amount paid. Keep these statements — you need them to reclaim deductions through your tax return.

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07 · Business Guide

Protecting Your Payment — Construction Act 1996

The Housing Grants, Construction and Regeneration Act 1996 (as amended by the Local Democracy, Economic Development and Construction Act 2009) gives electrical subcontractors powerful statutory rights that cannot be contracted out of. Know these rights — they are your most important financial protection.

Right to interim payments — you are entitled to interim payments at intervals of not less than 28 days throughout the contract. The main contractor must issue a payment notice within five days of the payment due date specifying the amount they propose to pay.
Default payment notice — if the main contractor fails to issue a payment notice, you can issue your own (a "payee's payment notice" or "default payment notice") for the amount you consider due. This becomes the notified sum and must be paid by the final date for payment.
Pay less notice — a main contractor who intends to pay less than the notified sum must issue a pay less notice at least seven days before the final date for payment. Without a valid pay less notice, the full notified sum is due.
Suspension — if the main contractor fails to pay by the final date for payment, you have the right to suspend work after giving seven days' written notice. Suspension is a powerful remedy — use it as a last resort but know that you have the right.
Adjudication — any dispute under a construction contract can be referred to adjudication at any time. An adjudicator's decision is binding and enforceable immediately (it can be enforced through the courts within weeks). This is the fastest and most cost-effective way to resolve payment disputes.

Pay-when-paid clauses (where the main contractor only pays you when the client pays them) are prohibited under the Construction Act, except in the event of the client's insolvency. If a main contractor tries to include such a clause in your subcontract, it is unenforceable.

08 · Business Guide

Subcontract Agreements — What to Look Out For

Never start work without a signed subcontract or at minimum a written order. The subcontract governs your rights and obligations — signing one that contains onerous clauses can make financially sound projects into loss-making ones.

Unlimited liability clauses — some main contractor subcontracts attempt to make you liable for all consequential losses arising from your default. For an electrical subcontractor, this could mean liability for the main contractor's liquidated damages, loss of profit, and client claims. Resist or cap your liability.
Short notification time bars — some contracts require you to notify compensation events or variations within a very short period (14 days or less) on pain of losing your entitlement. Read these provisions carefully and set up a system to notify in time.
Design responsibility — some subcontracts include design obligations (design of containment systems, cable sizing, circuit protection). If you accept design responsibility, you need professional indemnity insurance. If you did not quote a design fee, raise this before signing.
Retention release conditions — check what triggers retention release. Some contracts tie retention to the main contract practical completion and defects certificate rather than your section. This can mean waiting years for your retention.

The ECA (Electrical Contractors' Association) publishes a standard domestic subcontract form and provides members with contract advice. Membership is worth considering if you intend to build a significant subcontracting business.

09 · Business Guide

BS 7671 Certification When Subcontracting

One of the most common misunderstandings in electrical subcontracting is who is responsible for BS 7671 certification. The answer is clear: the electrical subcontractor who carries out the installation signs the Electrical Installation Certificate (EIC) — not the main contractor.

Who signs the EIC — BS 7671 Regulation 644.5 requires that an EIC be signed or otherwise authenticated by the skilled person(s) responsible for each stage: design, construction, and inspection & testing. By signing, the signatory accepts responsibility for verifying that BS 7671 has been met for that stage. The multiple-signature EIC (the model form in Appendix 6) exists precisely to allow different persons to sign separately for design, construction, and inspection & testing where these are carried out by separate parties.
The main contractor cannot sign for your work — a main contractor (or M&E management contractor) is not the person who carried out the electrical installation and cannot lawfully authenticate the EIC for your scope. If a main contractor asks you to hand over unsigned paperwork for them to complete, refuse: they do not have the technical responsibility or the competence authority for your installation.
Scope your certificate to your scope of works — Regulation 644.3 requires the certificate to include details of the extent of the work covered. On a subcontract where you are responsible for specific circuits or areas only, your EIC covers your scope. The main contractor (or a separate contractor) will produce a separate certificate covering their scope. Do not sign for work you have not designed, constructed, or tested.
Schedule of Inspection and test results — every EIC must be accompanied by a Schedule of Inspection and a Schedule of Circuit Details and Test Results (Regulation 644.3), both based on the model forms in Appendix 6 of BS 7671. As the subcontractor, you must provide these to the main contractor as part of your package — they are not optional and form part of the handover documentation required by the client.

Generate compliant EICs, Schedules of Inspection, and test result schedules directly in Elec-Mate. See also the EIC guide for a full walkthrough of what each section requires.

10 · Business Guide

Tools for Electrical Subcontractors

Running a successful electrical subcontracting business requires good administration: programme tracking, payment applications, variation records, and H&S documentation. The right tools make this manageable without a dedicated office team.

Payment Applications and Invoicing

Track your subcontract payment applications and invoices with Elec-Mate. Set reminders for payment due dates, record pay less notices received, and track outstanding retentions. See also the tender writing guide for pricing your next subcontract bid.

RAMS for Subcontract Tenders

Generate professional RAMS documents for every activity in your subcontract scope using the Elec-Mate RAMS generator. Build a library of pre-approved RAMS that you can customise for each tender — the most time-efficient approach for contractors tendering regularly.

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Frequently Asked Questions About Electrical Subcontracting

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Electrical Subcontracting Guide UK: How to Find Work and Protect Your Payment

Key Takeaways

What Is Electrical Subcontracting?

Get the BS 7671 A4:2026 Cheat Sheet — free

Finding Main Contractors Who Need Electrical Subcontractors

CHAS, Constructionline, and Pre-Qualification

Pricing to Win Subcontract Electrical Work

Direct Subcontracting vs Labour-Only Subcontracting

CIS Tax Deductions — What Electrical Subcontractors Must Know

Price the job in minutes, not evenings

Protecting Your Payment — Construction Act 1996

Subcontract Agreements — What to Look Out For

BS 7671 Certification When Subcontracting

Tools for Electrical Subcontractors

Payment Applications and Invoicing

RAMS for Subcontract Tenders

Run your electrical subcontracting business with Elec-Mate

Frequently Asked Questions About Electrical Subcontracting

How do I find main contractors to subcontract electrical work to?

What is CHAS and do I need it?

What is the Construction Industry Scheme (CIS) and how does it affect me?

What payment rights do I have as an electrical subcontractor?

What is the difference between direct subcontracting and labour-only subcontracting?

What should my subcontract agreement include?

How do I price competitively for subcontract electrical work?

Continue reading

Tender Writing Guide

Quote Writing Guide

Contract Templates

Framework Contracts

H&S Audit Guide

What electricians say

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Manage Your Subcontracting Business with Elec-Mate