Do I need an electrician to wire a shed in the UK?

If the shed is being supplied from the house via a new circuit, the work is notifiable under Part P of the Building Regulations. This means it must either be carried out by an electrician registered with a competent person scheme (such as NICEIC, NAPIT, or ELECSA) or you must apply to your local Building Control before starting work. A registered electrician can self-certify the work and issue the necessary Electrical Installation Certificate (EIC). If you do the work yourself without notification, you risk a fine, difficulty selling the property, and an uninsured installation that may not meet safety standards.

What cable do I need to run electricity to a shed?

SWA (Steel Wire Armoured) cable is the standard choice for an underground run from the house to the shed. The most common size for a domestic shed is 2.5mm² or 4.0mm² SWA, depending on the load and cable length. For runs up to about 20 metres with a 20A circuit, 2.5mm² three-core SWA is usually adequate. For longer runs or higher loads (e.g. a workshop with power tools), 4.0mm² or 6.0mm² may be needed to keep voltage drop within limits. The SWA cable must be buried at a minimum depth of 500mm (or 450mm under a hard surface such as a patio) and protected with underground cable warning tape laid approximately 150mm above it.

Can I extend the PME (TN-C-S) earth to my shed?

You can, but it requires a documented risk assessment. BS 7671 Regulation 9.2 warns that extending a PME earth to an outbuilding can present a risk if the PEN conductor is lost — this could put a dangerous voltage on all exposed metalwork in the shed. For sheds with significant metalwork (metal-clad sheds, metal workbenches) or where livestock or people may be in prolonged contact with earthed metalwork, a TT earthing arrangement with a local earth rod at the shed is usually the safer option. The earth rod must be tested (target value below 200 ohms, ideally below 100 ohms) and the circuit must be RCD protected (30mA for socket outlets, 100mA or 300mA for the sub-main depending on design).

What IP rating do I need for accessories in a shed?

It depends on the shed construction. A well-insulated, lined shed with a solid door can use standard domestic accessories (IP20). An unlined timber shed, which is more prone to dust and moisture ingress, should have accessories rated IP44 minimum. The consumer unit in any shed should be at least IP44 if the environment is dusty, or IP65 if there is any risk of water ingress (for example, near the door in a shed without guttering). Metal-clad switches and sockets rated IP44 are widely available and a practical choice for most sheds.

How deep should the cable trench be for a shed?

The minimum burial depth for SWA cable in a domestic garden is 500mm (approximately 20 inches). If the cable passes under a hard surface such as a patio, driveway, or path, the minimum depth is 450mm. The cable should be laid on a 50mm bed of sand at the bottom of the trench, with another 50mm of sand over the top of the cable before backfilling. Yellow/black underground cable warning tape must be laid approximately 150mm above the cable. If the cable passes through a wall (house or shed), it must enter through a gland and be properly sealed to prevent water ingress.

How much does it cost to get electricity to a shed in the UK?

A basic shed electrical installation — SWA cable run up to 15 metres, small consumer unit, two double sockets and two light points — typically costs between £400 and £800 including materials, labour, and certification. A more comprehensive installation for a workshop shed — longer cable run, larger consumer unit, multiple socket circuits, dedicated power tool circuit, external security light — can cost £800 to £1,200. Costs increase significantly if the trench route is long, crosses hard landscaping that needs reinstating, or if the shed requires a TT earth rod installation. These prices include the EIC but exclude any remedial work needed at the house consumer unit (e.g. adding a spare way or upgrading to accommodate the new circuit).

Do I need a separate consumer unit in the shed?

Yes. BS 7671 requires that the shed has local isolation and its own overcurrent and RCD protection. A small consumer unit (4 to 6 way) or an enclosed isolator with RCBOs is the standard approach. The consumer unit provides local isolation so the shed circuits can be switched off independently, local RCD protection for personal safety, overcurrent protection for each final circuit in the shed, and a clear point of isolation for anyone working on the shed electrics. The sub-panel in the shed is fed from a dedicated way in the house consumer unit, protected by an MCB or RCBO sized for the SWA cable.

INSTALLATION GUIDE

Shed Electrical Installation: Complete Wiring Guide for UK Electricians

Everything you need to know about running electricity to a garden shed — SWA cable selection, sub-panel design, lighting and socket layout, earthing options (PME vs earth rod), IP ratings, Part P notification, and realistic 2026 pricing.

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14 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

1Shed electrical installations are notifiable under Part P of the Building Regulations because the work involves a new circuit in a special location (outside the main dwelling). You must either be registered with a competent person scheme (NICEIC, NAPIT, etc.) or apply to Building Control before starting work.
2SWA (Steel Wire Armoured) cable is the standard choice for the underground run from the house to the shed. It must be buried at a minimum depth of 500mm (or 450mm under a hard surface) with warning tape above.
3The shed requires its own sub-panel (consumer unit) with appropriate overcurrent and RCD protection. An RCBO board is the simplest approach for a small outbuilding.
4Earthing in the shed depends on the supply type: TN-C-S (PME) supplies require a risk assessment before extending to an outbuilding — an earth rod (TT arrangement) at the shed is often the safer option.
5IP ratings matter in sheds — accessories should be IP44 minimum for non-insulated sheds. Weatherproof enclosures (IP65+) are required for consumer units in damp or dusty locations.

01 · Installation Guide

Shed Electrical Installation: What You Need to Know

Running electricity to a garden shed is one of the most common domestic electrical jobs in the UK. Whether the customer wants a few lights and sockets for a hobby workshop, a home office, or a fully kitted-out man cave, the electrical principles are the same: get the cable from the house to the shed safely, install a local sub-panel with RCD protection, wire the final circuits, test, and certify.

This guide covers the complete process from planning through to certification, including cable selection, trench requirements, earthing options, IP ratings, and the Part P notification requirements. It is written for qualified electricians carrying out the work and for homeowners researching what is involved before getting quotes.

The work is notifiable under Part P of the Building Regulations because it involves a new circuit in a location outside the main dwelling. A registered electrician can self-certify and issue an Electrical Installation Certificate (EIC).

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02 · Installation Guide

Planning and Regulations

Before any physical work begins, the installation must be planned and the regulatory requirements understood. The key considerations are:

Part P notification — shed electrical installations are notifiable work. The electrician must be registered with a competent person scheme (NICEIC, NAPIT, ELECSA, etc.) to self-certify, or the homeowner must apply to Building Control before work starts.
Site survey — assess the cable route from house to shed. Identify any obstacles (patios, paths, tree roots, drainage runs) and measure the distance. Check the house consumer unit for spare ways and capacity.
Load assessment — determine what the customer wants in the shed (lights, sockets, heating, power tools, EV charger). This drives the cable size, circuit design, and consumer unit specification.
Earthing assessment — check the supply type (TN-C-S, TN-S, TT) and decide whether to extend the existing earth or install a local earth rod at the shed. This is a critical safety decision covered in detail below.

03 · Installation Guide

Supply Options: Sub-Main from the House

The shed is supplied from the house via a sub-main cable. This cable is protected at the house end by a dedicated MCB or RCBO in the house consumer unit (or a separate switch-fuse if there are no spare ways). At the shed end, it terminates in a local consumer unit or distribution board.

Small Shed (Lighting + Sockets)

For a basic installation — two or three light points and a couple of double socket outlets — a 20A or 32A circuit from the house is sufficient. Use 2.5mm² or 4.0mm² SWA cable depending on run length. A 4-way consumer unit in the shed with RCBOs is the simplest approach.

Workshop Shed (Power Tools)

For a workshop with power tools (table saw, welder, compressor), a larger sub-main is needed. A 40A or 50A circuit with 6.0mm² or 10.0mm² SWA cable provides headroom for high-demand equipment. A 6-way or 8-way consumer unit allows separate circuits for lighting, sockets, and dedicated appliances.

The sub-main cable must be sized for the maximum demand at the shed, accounting for voltage drop over the cable run. Use the cable sizing calculator to determine the correct cable size for the run length and load.

04 · Installation Guide

Cable Selection and Routing

SWA (Steel Wire Armoured) cable is the standard choice for the underground run from house to shed. The steel wire armouring provides mechanical protection and, in TN-S or TT installations, can serve as the circuit protective conductor (CPC). The key requirements are:

Burial depth — minimum 500mm in a garden, 450mm under a hard surface (patio, path). Lay the cable on a 50mm sand bed with 50mm of sand cover above.
Warning tape — yellow/black underground cable warning tape must be laid approximately 150mm above the cable to warn anyone digging in the future.
Wall entries — the cable must pass through the house wall and shed wall using SWA glands. Seal both entries to prevent water ingress. Use ducting through walls where possible.
Cable sizing — size for the load, accounting for voltage drop (max 5% from origin to furthest point, though 3% is the practical target for sub-mains). For a 20A circuit at 25m, 2.5mm² SWA is typically adequate. For 32A at 25m, use 4.0mm² minimum.

If an underground route is not practical (e.g. across a courtyard with existing hard landscaping), the SWA cable can be run overhead on a catenary wire at a minimum height of 3.5m (or 5.2m if vehicles pass underneath). However, underground is the preferred and more common approach for domestic sheds.

05 · Installation Guide

Sub-Panel Installation in the Shed

The shed must have its own consumer unit or distribution board providing local isolation, overcurrent protection, and RCD protection. The consumer unit must comply with current regulations regarding enclosure type:

Consumer Unit Enclosure

Amendment 4 to BS 7671 requires consumer units to be either non-combustible (metal) or mounted on a non-combustible surface. In an outbuilding, a documented risk assessment may support the use of a non-ferrous (plastic IP65) enclosure to reduce corrosion risk — particularly in damp environments. This risk assessment must be appended to the Electrical Installation Certificate. Without a documented risk assessment, use a metal consumer unit on a non-combustible backboard.

A typical small shed installation uses a 4-way or 6-way RCBO board. This provides individual RCD and overcurrent protection for each circuit without the complexity of split RCD boards. Wire the incoming SWA through an appropriate gland into the consumer unit, and distribute to the final circuits: lighting, sockets, and any dedicated appliance circuits.

06 · Installation Guide

Lighting and Socket Layout

The lighting and socket layout depends on the shed size and intended use. Common configurations are:

Lighting — LED battens or bulkhead fittings are practical for sheds. For a workshop, aim for 300 to 500 lux at bench height. A 6W to 10W LED batten per square metre of bench area is a reasonable rule of thumb. Include a switch at the door. For larger sheds, add an external PIR-controlled bulkhead for security.
Socket outlets — position sockets at bench height (approximately 1100mm) for workshop use, or at standard height (300mm to 450mm) for general use. A minimum of two double socket outlets is recommended even for small sheds. For workshops, four to six doubles positioned around the workspace avoids trailing extension leads.
Dedicated circuits — if the customer has specific high-power equipment (welder, table saw, compressor), provide dedicated radial circuits from the sub-panel rather than relying on socket outlets. This prevents nuisance tripping and provides correct overcurrent protection for the equipment.

All socket outlet circuits in the shed must be 30mA RCD protected. IP ratings for accessories should match the environment — IP20 for a dry, lined shed; IP44 minimum for an unlined or poorly sealed shed; IP65 for outdoor accessories.

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07 · Installation Guide

Earthing Arrangements: PME vs Earth Rod

The earthing arrangement for the shed is one of the most important design decisions. The options depend on the supply type at the house:

TN-C-S (PME) Supply

Most UK homes have a PME supply. Extending the PME earth to an outbuilding introduces a risk: if the PEN conductor is lost, the neutral-to-earth voltage can appear on all exposed metalwork in the shed. BS 7671 Regulation 9.2 requires a risk assessment. For sheds with significant metalwork (metal-clad sheds, metal workbenches, metal water pipes), installing a local earth rod at the shed (creating a TT arrangement for the outbuilding) is the safer choice. The earth rod must achieve an acceptable resistance (below 200 ohms) and the circuit must be RCD protected.

TN-S or TT Supply

If the house has a TN-S (earth provided by the DNO cable sheath) or TT (earth rod at the house) supply, the earth can be extended to the shed via the SWA armouring and a separate CPC within the cable. For TT supplies, an additional earth rod at the shed may improve the earth fault loop impedance and disconnection times, but is not always necessary if the main earth rod value is adequate.

Whatever the arrangement, the earthing must be tested during commissioning. Record the earth electrode resistance (if applicable) and the earth fault loop impedance at the furthest point of every circuit in the shed on the EIC schedule of test results.

08 · Installation Guide

Testing and Certification

The shed installation must be fully tested and an Electrical Installation Certificate (EIC) issued before the installation is energised. The scope of testing includes:

Continuity of protective conductors (ring final circuits and radials)
Continuity of ring final circuit conductors (if ring circuits are used)
Insulation resistance (500V DC, minimum 1 megohm between L-N, L-E, and N-E)
Polarity at all termination points
Earth electrode resistance (if a TT earth rod is installed at the shed)
Earth fault loop impedance (Zs) on every circuit
RCD operation (30mA, trip time within 300ms at rated current, 40ms at 5x)
Prospective fault current (PSCC) at the origin of the shed installation

The EIC must be issued for the new circuits and the sub-main. If a competent person scheme member carries out the work, the certificate is self-certified and notified to Building Control through the scheme. The homeowner should receive a copy for their records.

09 · Installation Guide

Tools and Materials Checklist

Based on practical work intelligence data, the following tools and materials are typically required for a shed electrical installation:

Tools Required

Insulated screwdriver set
Torque screwdriver (for consumer unit connections)
SWA cable cutters and strippers
SWA gland kit and gland wrench
Drill and masonry bits (wall entries)
Shovel or mini-digger (for trenching)
Cable drum cart
Multimeter and continuity tester
Insulation resistance tester (500V)
Earth fault loop impedance tester
RCD tester
Crimping tool and ferrule kit

Materials Required

SWA cable (2.5mm² to 10.0mm² depending on load)
Underground ducting and warning tape
Sand for cable bed (50mm above and below)
SWA glands (house end and shed end)
Consumer unit (IP44/IP65, non-combustible enclosure)
MCBs or RCBOs for each circuit
Non-combustible backboard (if metal CU required)
Twin and earth cable for final circuits (1.0mm², 1.5mm², 2.5mm²)
Switches, socket outlets (IP rated as needed)
LED light fittings (battens or bulkheads)
Earth rod and clamp (if TT arrangement)
Cable clips, trunking, and conduit as needed

10 · Installation Guide

Typical Costs (2026 UK Pricing)

Shed electrical installation costs vary depending on the cable run length, shed size, and specification. The following are realistic 2026 UK prices including materials, labour, and certification:

Basic shed (up to 15m run) — 2 light points, 2 double sockets, 4-way RCBO board: £400 to £700.
Standard shed (15m to 25m run) — 3 light points, 4 double sockets, external light, 6-way board: £700 to £1,000.
Workshop shed (25m+ run) — full lighting, 6+ double sockets, dedicated power circuit, heating, earth rod: £1,000 to £1,200+.
Add-ons — earth rod installation: £80 to £150. Trench through patio or hard landscaping: £150 to £400 for reinstatement. Consumer unit upgrade at house (if no spare ways): £300 to £500.

11 · Installation Guide

For Electricians: Quoting and Delivering Shed Installations

Shed electrical installations are bread-and-butter domestic work with good margins. A typical job takes half a day to a full day depending on the trench length and specification. The key to profitability is an accurate site survey, correct cable sizing on the first visit, and efficient on-site execution.

Cable Sizing on the Survey

Use the cable sizing calculator to determine the SWA size while you are on site. Measure the run, estimate the load, and get the cable size confirmed before you quote. No more guessing and over-ordering.

Professional Quoting

Price the job with Elec-Mate's quoting app. SWA cable, glands, consumer unit, accessories, labour, trench work, testing, and certification — all itemised with your margins. Send a professional PDF quote from the survey.

EIC on Your Phone

Complete the Electrical Installation Certificate on site after testing. AI board scanning, voice test entry, and instant PDF export. Send the certificate to the homeowner before you leave the job.

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Frequently Asked Questions About Shed Electrical Installation

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Shed Electrical Installation: Complete Wiring Guide for UK Electricians

Key Takeaways

Shed Electrical Installation: What You Need to Know

Get the BS 7671 A4:2026 Cheat Sheet — free

Planning and Regulations

Supply Options: Sub-Main from the House

Small Shed (Lighting + Sockets)

Workshop Shed (Power Tools)

Cable Selection and Routing

Sub-Panel Installation in the Shed

Consumer Unit Enclosure

Lighting and Socket Layout

Try Elec-Mate free for 7 days

Earthing Arrangements: PME vs Earth Rod

TN-C-S (PME) Supply

TN-S or TT Supply

Testing and Certification

Tools and Materials Checklist

Tools Required

Materials Required

Typical Costs (2026 UK Pricing)

For Electricians: Quoting and Delivering Shed Installations

Cable Sizing on the Survey

Professional Quoting

EIC on Your Phone

Quote, install, and certify shed electrics

Frequently Asked Questions About Shed Electrical Installation

Do I need an electrician to wire a shed in the UK?

What cable do I need to run electricity to a shed?

Can I extend the PME (TN-C-S) earth to my shed?

What IP rating do I need for accessories in a shed?

How deep should the cable trench be for a shed?

How much does it cost to get electricity to a shed in the UK?

Do I need a separate consumer unit in the shed?

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Fantastic app for electricians

Absolutely amazing

Trusted by electricians across the UK

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