What is a prelims section in an electrical tender?

Preliminaries (prelims) cover the costs of running the contract that are not directly attributable to labour or materials. For an electrical contractor this includes site management, attendance at site meetings, temporary supplies and lighting, welfare facilities (if not provided by the main contractor), tools and plant, testing equipment, PPE, site signage, insurance, bonds, and warranty costs. On commercial projects prelims typically represent 8 to 15 per cent of contract value. Many electrical contractors underprice prelims and then find their overhead is not recovered.

What labour rate should I use in my electrical tender?

Your all-in labour rate must cover the electrician's base hourly rate, National Insurance contributions (13.8 per cent employer's NI), holiday pay (12.07 per cent of pay for workers on zero-hours or pro-rata for salaried), pension contributions (minimum 3 per cent employer under auto-enrolment), industry sick pay (if JIB-registered), travel time and allowances if applicable, and your overhead recovery rate. In 2026 a realistic all-in rate for a qualified electrician in London is £55 to £75 per hour, and £42 to £55 outside London. Do not use apprentice labour rates in your tender unless you have confirmed the programme allows for supervision.

How much should I mark up materials in an electrical tender?

A standard materials markup for electrical contractors is 15 to 25 per cent on trade price. This covers your purchasing costs, delivery, site storage and losses, handling, and the administrative cost of procurement. On specialist or long-lead items (switchgear, containment systems, distribution boards) consider a higher markup to account for procurement risk. Always check tender documents for "open book" or "schedule of rates" requirements — some public sector contracts require you to declare your markup percentage and may cap it.

What is the difference between NEC and JCT contracts for electricians?

NEC4 (particularly the Engineering and Construction Subcontract) uses a compensation event mechanism: any change to scope, delay caused by the main contractor, or event not at the subcontractor's risk is a compensation event that must be notified within eight weeks. Failing to notify in time can forfeit your entitlement. JCT uses loss and expense claims and extension of time (EOT) applications. JCT design and build contracts are common in housing and commercial fit-out. NEC3/NEC4 is dominant in infrastructure, rail, utilities, and public sector work. Whichever form you use, read the Z clauses (NEC) or amendments (JCT) carefully — these are where onerous bespoke terms are inserted.

What H&S documents do I need to include with my electrical tender?

A tender submission for commercial electrical work typically requires: a company health and safety policy, method statements for key activities (cable installation, containment, termination, testing), risk assessment index, evidence of CDM 2015 competence (CDM coordinator appointment if principal contractor, or pre-construction information acknowledgement as a contractor), CHAS or equivalent accreditation certificate, public and employers' liability insurance certificates, and relevant staff qualification records (C&G 2382, 2391, IPAF, PASMA, asbestos awareness). Large clients may also require ISO 45001 certification or Safe Contractor approval.

How do I price a programme for an electrical tender?

Your programme should be resource-loaded — meaning each activity has labour allocated to it so the reviewer can see how you will achieve the programme. Use a Gantt chart (Asta Powerproject, Microsoft Project, or even a well-presented Excel programme). Include programme float: if you quote a programme with zero float you are telling the client you have no contingency for delays. A realistic programme with 10 to 15 per cent float is more credible than an optimistic programme that will clearly slip. Show key interfaces with other trades (first and second fix, commissioning, handover) and any long-lead item delivery milestones.

What is an Employer's Requirements document?

The Employer's Requirements (ERs) are the client's technical specification for the project, usually produced by the M&E consultant or the client's design team. They define the system types required (lighting, power, containment, fire alarm, BMS integration), performance standards, commissioning requirements, O&M manual format, and often the preferred manufacturers. Always read the ERs alongside the contract conditions. Contradictions between the ERs and the contract drawings are common and must be clarified via tender queries before submission — pricing an ambiguity incorrectly after award can be very costly.

BUSINESS GUIDE

How to Write Electrical Tenders: Winning Commercial Work in the UK

A complete guide to pricing and writing winning tenders for commercial electrical contracts — prelims, labour rates, materials markup, programme, H&S documentation, NEC4 and JCT contracts, and the common mistakes that lose tenders before the price is even read.

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16 min readUpdated 2026-05-18Andrew 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

1A winning electrical tender is won on preliminaries, programme credibility, and health and safety documentation — not just on the lowest price.
2Always read the Employer's Requirements (ERs) and contract conditions in full before pricing. Onerous conditions and unlimited liability clauses can make a low-price tender financially catastrophic.
3Prelims typically account for 8 to 15 per cent of contract value on commercial electrical jobs. Under-pricing prelims is one of the most common reasons electrical contractors lose money on tender.
4NEC4 Engineering and Construction Subcontract (ECS) and JCT Design and Build are the two most common contract forms in commercial electrical work. Understanding compensation events (NEC) and loss and expense (JCT) is essential to recovering cost on site.
5The Housing Grants, Construction and Regeneration Act 1996 (as amended by the Local Democracy, Economic Development and Construction Act 2009) gives subcontractors statutory rights to interim payments and adjudication — know these rights before you sign any subcontract.

01 · Business Guide

Understanding Commercial Electrical Tenders

A commercial electrical tender is a formal submission in response to a request for tender (RFT) or invitation to tender (ITT) from a main contractor, developer, or client. It is different from a domestic quote in almost every respect: the documentation is more extensive, the pricing methodology is more structured, and the contract terms carry significantly more risk.

Single-stage tendering — the client issues full tender documents (drawings, specification, BoQ if applicable, contract conditions) and all tenderers price from the same information. Common on straightforward commercial fit-out and domestic housing projects.
Two-stage tendering — stage one is a competitive tender on preliminary costs and overhead and profit percentage; stage two involves the preferred contractor in the design development before final price agreement. More common on complex commercial, healthcare, and education projects.
Negotiated tender — the client approaches one contractor directly, usually based on an existing relationship or framework appointment. Requires the same documentation rigour but without direct price competition.

Before committing to a tender, assess your bid/no-bid criteria. Tendering costs real money — estimator time, drawing take-off, supplier enquiries. Only tender for work you can genuinely deliver and have a realistic chance of winning.

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02 · Business Guide

Reading and Pricing the Employer's Requirements

The Employer's Requirements (ERs) are the technical heart of any tender. They define what the client wants built, to what standard, and with what level of performance. Failing to read them in full before pricing is one of the most expensive mistakes an electrical contractor can make.

Technical specification — defines system types (small power, lighting, containment, fire detection, emergency lighting, BMS interface), materials standards, cable types and ratings, containment specification, and commissioning requirements. Price to the specification, not to a lesser standard.
Drawings and design information — check drawing issue status. Tender drawings marked "for information" or "preliminary" carry more design risk than "for construction" drawings. If the design is incomplete, price a design allowance and state your assumptions clearly.
O&M and commissioning — many ERs require full O&M manuals, as-installed drawings (CAD or Revit), commissioning witnessed by the client's engineer, and extended defects liability periods (12 to 24 months is common). These all have a cost — include them.
Tender queries — raise all ambiguities in writing before the tender submission deadline. Clarification questions and answers (Q&As) are usually issued to all tenderers and become part of the contract documents. Never make assumptions on ambiguous scope — query it.

03 · Business Guide

Pricing Preliminaries Correctly

Preliminaries (prelims) cover all contract costs that are not direct labour or materials. They are often the section that electrical contractors most consistently under-price, resulting in contracts that technically break even on measured work but lose money overall.

Site management — electrical site manager or working foreman cost for the duration of the project. Include their travel, accommodation if required, site vehicle, phone, and laptop.
Testing equipment — calibrated multifunction testers, loop impedance testers, insulation resistance testers. Include calibration costs (typically annual) and replacement batteries.
Site attendance and meetings — time for site progress meetings, subcontractor co-ordination meetings, design team meetings. On a 12-month project with weekly meetings, this is a significant cost.
Insurance and bonds — performance bonds (typically 10 per cent of contract value), parent company guarantees, and any additional insurance requirements specified in the contract.
Overhead and profit — your company overhead recovery (typically 10 to 15 per cent of turnover) plus your target profit margin (5 to 10 per cent on commercial subcontract work). State these as separate line items where the tender format allows.

04 · Business Guide

Building Accurate Labour Rates

Your all-in labour rate is the foundation of your tender pricing. An incorrect rate — even by a few pounds per hour — will result in a significant pricing error across a contract with thousands of man-hours.

Base hourly rate — either JIB rates (published annually) or your own employment contracts. The JIB 2026 rate for an Approved Electrician is £20.12 per hour. For self-employed labour-only subcontractors, agree the rate before the job, ensure CIS deductions are applied (20 per cent for registered, 30 per cent for unregistered), and issue a subcontract agreement.
Oncosts — add employers' NI (13.8 per cent above the secondary threshold), holiday pay (12.07 per cent for workers without fixed holiday entitlement), pension (minimum 3 per cent employer contribution), JIB contributions if applicable, and any enhanced sick pay.
Productivity allowance — experienced estimators apply a productivity factor to account for non-productive time (travel between floors, waiting for lifts, tool collection, safety briefings). A factor of 0.85 to 0.90 is typical for commercial site work.

Build a labour rate spreadsheet template and update it at least twice per year to reflect NI thresholds, JIB rate changes, and National Minimum Wage uplifts (effective April each year).

05 · Business Guide

Materials Markup and Procurement Risk

Materials pricing in a tender must account not just for the cost of materials, but for the risk of price increases between tender and delivery, procurement cost, and waste.

Standard markup — 15 to 25 per cent on trade price is the commercial norm for electrical materials. This covers delivery, storage, handling, waste, and procurement overhead. For high-value items (switchgear, distribution boards) consider a lower percentage markup in absolute terms but ensure the margin in pounds covers your risk.
Price fluctuation — on contracts longer than six months, include a price fluctuation clause in your tender or add a contingency for material price increases. Copper cable prices are particularly volatile and can move 15 to 20 per cent in a year. The NEC4 Option X1 price adjustment mechanism exists for this purpose.
Long-lead items — switchgear, specialist luminaires, and custom distribution boards can have lead times of 16 to 26 weeks. Order these immediately after award. In your tender, flag lead times as a programme risk and request an early order commitment within the contract conditions.

06 · Business Guide

Programme and Programme Float

Your construction programme is one of the most scrutinised documents in a tender submission. A credible, resource-loaded programme demonstrates competence and gives the client confidence that you understand how to deliver the works.

Resource loading — allocate labour to each activity so the reviewer can verify you have sufficient resource to achieve the programme. Show the number of electricians on site per phase.
Trade interfaces — show dependencies with other trades: when first-fix containment must be complete for plasterboard, when second-fix can begin after decorating, when power-on is needed for commissioning. Demonstrating awareness of trade interfaces impresses clients.
Float — include 10 to 15 per cent programme float to reflect real site conditions. Under NEC4, total float belongs to the project (not the contractor), but terminal float (at the end of your programme) is yours. Protect your terminal float carefully.
Long-lead milestones — mark the order date for switchgear and other long-lead items as a programme milestone. This creates a contractual record that delay in award or access will affect the programme.

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07 · Business Guide

Health and Safety Documentation

H&S documentation is a mandatory part of any commercial electrical tender. Under the Construction (Design and Management) Regulations 2015 (CDM 2015), every contractor on a notifiable project must demonstrate competence in health and safety management.

Company H&S policy — must be signed and dated within the last 12 months. State your health and safety objectives and arrangements. For companies of five or more employees this is a legal requirement under the Health and Safety at Work etc. Act 1974.
RAMS (Risk Assessment and Method Statement) — produce RAMS for each key electrical activity: cable installation and termination, working at height, work on or near live conductors, and use of power tools. The H&S audit guide covers RAMS in detail.
Accreditation — CHAS (Contractors Health and Safety Assessment Scheme) or Constructionline Gold are accepted as pre-qualification evidence by most main contractors. Renew these annually and include the current certificate in every tender.
Insurance evidence — public liability (minimum £5m, many clients require £10m), employers' liability (minimum £5m, legally required if you employ anyone), and professional indemnity if your scope includes design.

Use the Elec-Mate RAMS generator to produce professional RAMS documents that meet commercial tender requirements. Having well-structured RAMS ready to customise saves hours per tender.

08 · Business Guide

NEC4 and JCT Contracts: What Electricians Need to Know

Understanding the contract form is not optional — it governs how you get paid, how changes are valued, and what happens when things go wrong. The two most common forms in UK commercial electrical work are NEC4 and JCT.

NEC4 Engineering and Construction Subcontract (ECS) — used extensively in public sector, infrastructure, utilities, and healthcare. The compensation event mechanism requires you to notify any event that affects your scope or programme within eight weeks. Failure to notify extinguishes your entitlement. Early warnings are a positive obligation under NEC — use them.
JCT Design and Build 2016 — common in commercial fit-out, housing, and education. Changes are valued as variations. Loss and expense is recoverable for regular progress matters (access, late information, disruption). Extension of time applications must be made in writing as soon as delay is reasonably apparent.
Housing Grants, Construction and Regeneration Act 1996 — gives every construction contractor (including electrical subcontractors) the right to interim payments at intervals of not less than 28 days, the right to suspend for non-payment after giving seven days' notice, and the right to adjudicate any dispute. These rights cannot be contracted out of on construction contracts.

Always read the Z clauses in NEC4 contracts and the amendments schedule in JCT contracts. These are where main contractors insert conditions that modify standard terms — sometimes dramatically increasing your risk exposure. If in doubt, seek legal advice before signing.

09 · Business Guide

Common Mistakes That Lose Electrical Tenders

Most electrical tenders are not lost on price alone. They are lost on the quality of the submission, the credibility of the programme, the completeness of the H&S documentation, and sometimes on pricing errors that make the tender uncompetitive or financially unviable.

Not reading the full specification — pricing to drawings alone and missing specification requirements (cable ratings, containment type, commissioning obligations) results in scope gaps that cost money post-award.
Under-pricing prelims — forgetting to include site management, testing equipment, site meetings, insurance uplift, and overhead recovery in the prelims section is one of the most common and costly errors.
Not pricing design risk — on design and build contracts, if you are accepting design responsibility for any part of the electrical works, you need professional indemnity insurance and a design allowance in your price.
Submitting late — most tender systems are electronic and close at a precise time. A submission received one minute after the deadline is typically rejected automatically. Allow time for upload, checking, and confirmation.
Unqualified clarifications — stating "price excludes X" in your submission without formal tender query confirmation can lead to disputes. Raise exclusions formally during the tender period and get written responses.

10 · Business Guide

Tools to Help You Win Commercial Tenders

Winning commercial electrical tenders consistently requires a system — for pricing, for documentation, and for tracking what works. The right tools reduce the time cost of tendering and improve the quality of your submissions.

Quote and Tender Pricing

Use the Elec-Mate quoting app to build structured price submissions with materials and labour breakdown. Export to PDF for professional tender submissions. See also the quote writing guide for domestic and smaller commercial jobs.

RAMS and H&S Documentation

Generate professional Risk Assessments and Method Statements with the Elec-Mate RAMS generator. Build a library of activity-specific RAMS that you can customise for each tender — saving hours per submission and improving quality.

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Frequently Asked Questions About Electrical Tender Writing

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How to Write Electrical Tenders: Winning Commercial Work in the UK

Key Takeaways

Understanding Commercial Electrical Tenders

Get the BS 7671 A4:2026 Cheat Sheet — free

Reading and Pricing the Employer's Requirements

Pricing Preliminaries Correctly

Building Accurate Labour Rates

Materials Markup and Procurement Risk

Programme and Programme Float

Price the job in minutes, not evenings

Health and Safety Documentation

NEC4 and JCT Contracts: What Electricians Need to Know

Common Mistakes That Lose Electrical Tenders

Tools to Help You Win Commercial Tenders

Quote and Tender Pricing

RAMS and H&S Documentation

Win more commercial electrical tenders with Elec-Mate

Frequently Asked Questions About Electrical Tender Writing

What is a prelims section in an electrical tender?

What labour rate should I use in my electrical tender?

How much should I mark up materials in an electrical tender?

What is the difference between NEC and JCT contracts for electricians?

What H&S documents do I need to include with my electrical tender?

How do I price a programme for an electrical tender?

What is an Employer's Requirements document?

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