Risk Assessments · Mandatory · Pre-Construction

RAMS — Electrical Installation Works

This RAMS covers first and second fix electrical installation, temporary supplies, and testing and commissioning. It addresses risks of electrocution, arc flash, cable strikes, and work in live environments. All electrical work must comply with BS 7671 and be carried out by competent, qualified electricians with appropriate isolation procedures.

Last reviewed: 29 March 2026 — This guide reflects UK law as of this date. MHSWR 1999 / BS 7671 remains current with no amendments enacted as of 29 March 2026. Next scheduled review: 29 March 2027.

RAMS category	B9 Electrical Installation Works
Primary legislation	Electricity at Work Regulations 1989 (EAWR)
Technical standard	BS 7671:2018+A3:2024 (IET Wiring Regulations, 18th Edition)
Live working	Prohibited unless dead working is unreasonable in all the circumstances and suitable precautions are in place (EAWR Regulation 14)
Safe isolation	Mandatory before any electrical work on existing circuits — must follow a documented 8-step procedure using a proving unit
Competence standard	18th Edition qualification (City & Guilds 2382), NICEIC or NAPIT registration, ECS card
Enforcing authority	Health and Safety Executive (HSE)

1. What It Covers

A RAMS for Electrical Installation Works covers all aspects of installing, altering, maintaining, and testing electrical systems on construction sites. This includes first fix and second fix wiring, distribution board installation, temporary site supplies, lighting circuits, power circuits, fire alarm and emergency lighting installation, data and communications cabling where it interfaces with mains power, and the testing and commissioning of completed installations.

The legal framework is built on the Electricity at Work Regulations 1989 (EAWR), which impose absolute duties in relation to systems, work activities, and protective equipment. The technical standard is BS 7671:2018+A3:2024 — the IET Wiring Regulations, commonly known as the 18th Edition — which sets out the requirements for the design, selection, erection, inspection, and testing of electrical installations. Compliance with BS 7671 is not itself a statutory requirement, but departure from it must be justified, and in practice courts and the HSE treat compliance with BS 7671 as the benchmark for meeting the general duties under EAWR.

Contact with electricity is one of the highest-consequence hazards on any construction site. Even at 230V single phase — the standard domestic and commercial supply voltage — contact can cause cardiac arrest, severe burns, and death. The risk is amplified on construction sites by the presence of temporary supplies, incomplete installations, damaged cables, wet conditions, and metallic structures that can become live through fault conditions.

“No person shall be engaged in any work activity on or so near any live conductor (other than one suitably covered with insulating material so as to prevent danger) that danger may arise unless—(a) it is unreasonable in all the circumstances for it to be dead; and (b) it is reasonable in all the circumstances for him to be at work on or near it while it is live; and (c) suitable precautions (including where necessary the provision of suitable protective equipment) are taken to prevent injury.”— Electricity at Work Regulations 1989, Regulation 14

230V can kill — do not underestimate domestic voltage

The majority of fatal electrical contacts on UK construction sites involve 230V single-phase supplies — not high-voltage systems. A current of just 50 milliamps across the heart is sufficient to cause ventricular fibrillation. Wet conditions, metallic environments, and damaged insulation — all common on construction sites — significantly increase the risk. Every electrical task, regardless of voltage, must be treated with the same rigour.

2. Safe Isolation Procedure

Safe isolation is the single most critical procedure in electrical installation work. Before any work is carried out on an existing circuit or installation, that circuit must be confirmed dead using a documented, repeatable procedure. The 8-step safe isolation procedure is the industry-standard method. Every electrician must be trained in it, and every RAMS involving work on existing circuits must reference it explicitly.

Step	Action	Purpose
1	Identify the circuit to be worked on	Confirm the correct circuit using drawings, schedules, and labelling. Misidentification is a leading cause of electrical incidents.
2	Identify the point of isolation	Locate the correct isolating device (MCB, MCCB, isolator, fuse) for the specific circuit. Confirm it disconnects all live conductors.
3	Prove the voltage tester on a known live source	Confirm the test instrument is functioning correctly before relying on it. Use a proving unit or known live supply.
4	Isolate the circuit	Switch off and lock off the isolating device. Apply a lock with a unique key held by the person carrying out the work.
5	Test the circuit is dead	Use the proved voltage tester to confirm the circuit is dead at the point of work. Test between all conductors and between each conductor and earth.
6	Prove the voltage tester again on a known live source	Confirm the test instrument is still functioning correctly after the dead test. This eliminates the possibility that the instrument failed between steps 3 and 5.
7	Attach warning notices	Apply caution labels at the point of isolation and at the point of work. Labels must state the circuit is isolated and must not be re-energised.
8	Begin work	Work may now commence on the confirmed dead circuit. The lock and notices remain in place until work is complete and the circuit is ready for re-energisation.

The proving unit is non-negotiable

Steps 3 and 6 — proving the tester before and after the dead test — are what distinguish a safe isolation procedure from simply switching off and hoping. A voltage tester can fail without visible indication. If the tester is faulty at step 5, it will show dead when the circuit is actually live. Proving the tester on a known live source (ideally a proprietary proving unit) immediately before and after the dead test eliminates this risk. Skipping these steps has been a direct cause of fatal electrical contacts.

Lock-off is personal — one lock per person

Where multiple electricians are working on the same isolated circuit, each person must apply their own lock to the isolation point using a multi-lock hasp. No individual's lock may be removed by anyone other than that individual. The circuit must not be re-energised until every lock has been removed by its owner. This prevents the situation where one electrician re-energises a circuit while another is still working on it downstream.

3. Key Hazards

The following table identifies the principal hazards associated with electrical installation works on construction sites, who is at risk, the contributing risk factors, and the controls that must be addressed in the RAMS.

Hazard	Who at risk	Risk factors	Controls
Electric shock (contact with live conductors)	Electricians, other trades working near electrical installations, labourers	Failure to isolate before work; incorrect circuit identification; damaged insulation; exposed conductors in incomplete installations; wet conditions reducing body resistance	Safe isolation procedure (8-step) with lock-off; RCD protection on all construction site supplies (30mA for socket outlets); permit to work for work on or near live systems; insulated tools; rubber matting where required
Arc flash	Electricians working on or near distribution boards, switchgear, and high-current circuits	Short circuit caused by tool contact, loose connections, or contamination; working on or near live high-energy conductors; inadequate PPE	Dead working wherever possible; arc flash risk assessment for all work on distribution equipment; arc-rated PPE (face shield, gloves, flame-resistant clothing) where live working is justified; approach boundaries defined and enforced
Hidden cables (cable strikes)	All trades drilling, cutting, chasing, or fixing into walls, floors, and ceilings; electricians and general operatives	Cables buried in walls or floors without accurate records; no cable avoidance survey carried out; reliance on assumed cable routes rather than detection	Cable avoidance tool (CAT) scan before any penetrative work; review of as-built drawings and cable route records; visual inspection for surface-mounted trunking and conduit; permit to work for penetrative work in high-risk areas
Falls from height	Electricians installing lighting, containment, and distribution equipment at height; cable tray and basket installation at ceiling level	Working from ladders for extended periods; inadequate access equipment for the task; reaching beyond safe limits; unprotected edges on open floors	WAH hierarchy applied (avoid, prevent, minimise); MEWP or tower scaffold for extended overhead work; ladder use restricted to short-duration, light-duty tasks only; edge protection where working near open edges
Fire from electrical fault	All building occupants and construction site personnel; adjacent properties	Loose connections generating heat; overloaded circuits; incorrect cable sizing; damaged insulation; combustible materials stored near temporary electrical equipment	Installation designed and installed to BS 7671; inspection and testing before energisation; correct cable sizing calculations; thermographic survey of distribution boards before handover; fire extinguisher at point of work during testing and commissioning
Manual handling	Electricians handling cable drums, distribution boards, transformers, and containment systems	Heavy cable drums (up to several hundred kilograms); awkward lifting positions in confined or overhead spaces; repetitive carrying of materials to upper floors	Mechanical handling for heavy items (cable drum stands, trolleys, hoists); team lifts for intermediate loads; manual handling assessment for all tasks involving loads above 20 kg or repetitive lifting; delivery to point of use where possible

4. Competence

Electrical installation work is one of the most heavily regulated trade activities on a construction site. The combination of high-consequence hazards and complex technical standards means that competence requirements are stringent at both organisational and individual levels. The RAMS must specify the competence requirements for every person involved in the electrical works.

Requirement	Standard / Qualification	Notes
18th Edition qualification	City & Guilds 2382-22 (or equivalent)	Mandatory for anyone designing, installing, inspecting, or testing electrical installations to BS 7671. Must be current — the 18th Edition (with Amendment 3, 2024) is the current version. Earlier edition certificates are expired.
Approved contractor scheme	NICEIC Approved Contractor, NAPIT, ELECSA, or equivalent Part P scheme	Organisational registration that confirms the contractor operates under a regime of regular assessment. NICEIC is the most widely recognised in construction. Registration must be current and the scope must cover the type of work being carried out.
ECS card (Electrotechnical Certification Scheme)	JIB/ECS — various grades (Apprentice, Installation Electrician, Approved Electrician, Technician)	The ECS card is the construction industry standard for verifying individual electrician competence. It is the electrical equivalent of the CSCS card. The card grade must be appropriate to the work being carried out. Labourers assisting with electrical work must hold an ECS Labourer card.
Inspection and testing qualification	City & Guilds 2391-52 (or equivalent)	Required for any person carrying out initial verification or periodic inspection and testing. The 2391-52 covers both initial verification and condition reporting. The person signing off electrical test certificates must hold this qualification.
Safe isolation training	Included in NVQ Level 3 and 18th Edition; standalone refresher courses available	Every electrician must be trained and assessed in the 8-step safe isolation procedure. Training must be refreshed periodically. The RAMS must confirm that all operatives on site have current safe isolation competence.

NICEIC registration is organisational — not individual

NICEIC Approved Contractor status confirms that the contracting organisation has been assessed and that a nominated Qualified Supervisor oversees the work. It does not confirm the competence of every individual electrician on site. The principal contractor must still verify that each operative holds an appropriate ECS card and 18th Edition qualification. Relying on NICEIC registration alone — without checking individual credentials — leaves a gap in the competence chain.

5. Common Mistakes

Failing to carry out safe isolation before working on existing circuits

The most common and most dangerous mistake in electrical installation work. Every year, electricians are killed or seriously injured because they assumed a circuit was dead without carrying out the full 8-step safe isolation procedure. The RAMS must mandate safe isolation for all work on existing circuits, and the procedure must be followed without exception — including proving the tester before and after the dead test.

Omitting arc flash risk from the RAMS for distribution board work

Work on or near distribution boards, switchgear, and high-current circuits carries a significant arc flash risk. An arc flash can generate temperatures exceeding 19,000 degrees Celsius and cause fatal burns in a fraction of a second. The RAMS must include an arc flash risk assessment for all work on distribution equipment and specify arc-rated PPE where live or near-live working is unavoidable.

Not scanning for hidden cables before penetrative work

Cable strikes are a leading cause of electrical injury on construction sites. Drilling, chasing, or fixing into walls, floors, and ceilings without first scanning with a cable avoidance tool (CAT) is a foreseeable and avoidable risk. The RAMS must require CAT scanning before any penetrative work and must not rely solely on assumed cable routes or as-built drawings, which are frequently inaccurate.

Using operatives without current ECS cards or 18th Edition qualifications

Every electrician carrying out installation work on a construction site must hold a valid ECS card at the appropriate grade and a current 18th Edition qualification. Using unqualified or under-qualified operatives is a breach of the Electricity at Work Regulations and a failure of the competence requirements under CDM 2015. The RAMS must list the competence requirements and the principal contractor must verify them before allowing anyone to commence electrical work.

Relying on RCDs as the primary control rather than isolation and dead working

RCDs are an important secondary protection measure, but they are not a substitute for safe isolation and dead working. An RCD can fail, can be bypassed, and does not protect against all fault types. The RAMS must specify dead working as the primary control for all work on circuits, with RCD protection as an additional layer — not as the sole defence against electric shock.

6. Frequently Asked Questions

Is live working ever permitted on a construction site?▾

Only in extremely limited circumstances. The Electricity at Work Regulations 1989, Regulation 14, prohibit live working unless three conditions are all met: (1) it is unreasonable in all the circumstances for the circuit to be dead; (2) it is reasonable for the person to be working on or near it while live; and (3) suitable precautions are taken to prevent injury. In practice, live working on construction sites is rarely justifiable. Testing and fault-finding on live circuits may be necessary, but installation work should always be carried out dead. Any live working must be authorised under a formal permit to work.

What is the difference between an ECS card and a CSCS card?▾

The ECS (Electrotechnical Certification Scheme) card is the electrical industry equivalent of the CSCS card. It is administered by the JIB (Joint Industry Board) and covers all electrotechnical occupations. ECS cards are recognised as an affiliated scheme under the CSCS umbrella, so an ECS card is accepted on construction sites in place of a CSCS card. An electrician should hold an ECS card, not a generic CSCS card, because the ECS card verifies trade-specific qualifications and the 18th Edition certification that a general CSCS card does not.

Does the 18th Edition Amendment 3 (2024) change the RAMS requirements?▾

Amendment 3 to BS 7671:2018 was published in 2024 and introduces updates to several areas including energy efficiency, prosumer installations, and electric vehicle charging. While it does not fundamentally alter the risk assessment approach, the RAMS must reflect the current edition of BS 7671 in force at the time of the installation. Electricians must hold the current 18th Edition qualification that covers Amendment 3. RAMS referencing earlier amendments should be updated.

Who can sign off an Electrical Installation Certificate (EIC)?▾

An Electrical Installation Certificate must be signed by the designer, the installer, and the person carrying out the inspection and testing. The person carrying out the inspection and testing must hold a City & Guilds 2391-52 (or equivalent) qualification. The installing contractor should be registered with an approved scheme (NICEIC, NAPIT, ELECSA, or equivalent). Self-certification under Part P of the Building Regulations is only available to contractors registered with an approved scheme.

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