What exactly is included in first fix electrical?

First fix electrical covers everything that is installed before the walls are plastered and the floors are laid. This includes running cables from the consumer unit position to each accessory position, installing back boxes (metal or dry-lining boxes) at the correct height for switches, sockets and fused spurs, fitting cable containment (trunking, conduit or cable tray) where required, installing ceiling roses or downlight housings, running cables for smoke and heat detectors, pulling cables for data and TV points, and installing temporary supplies for the build if needed. First fix does not include fitting the accessories themselves (faceplates, switches, sockets) — that is second fix. The cables are left coiled at each accessory position, ready for the plasterer to work around them and the electrician to return for second fix.

What are the BS 7671 safe zones for cable routes?

Under BS 7671:2018+A4:2026, a cable installed in a wall or partition must comply with Table 52.1 (Regulation 522.6.202). The footnote to Table 52.1 defines a prescribed zone as a zone within 150 mm from the top of the wall or partition, or within 150 mm of an angle formed by two adjoining walls or partitions. A prescribed zone can also be formed horizontally and vertically from any point, accessory or switchgear located on the wall, and wiring from any circuit can be installed in such a zone. Where the location of the accessory, point or switchgear can be determined from the reverse side, a zone formed on one side of a wall or partition of 100 mm thickness or less extends to the reverse side. There is no prescribed zone at the floor line. What the zone buys you depends on the rest of Table 52.1: in a wall without metallic parts, a cable less than 50 mm from the surface must be in a prescribed zone and have additional protection by a 30 mA RCD with the characteristics of Regulation 415.1.1, or instead comply with Regulation 522.6.204 (for example an earthed metallic covering or earthed conduit). At 50 mm or more in a wall without metallic parts, no additional impact protection is required. If the wall or partition contains metallic parts — a metal-stud partition, for instance — protection is required at any depth.

How deep should cable chases be in walls?

BS 7671 does not specify a maximum chase depth — chase depth limits are a structural matter and come from the Building Regulations Approved Document A (Structure) and the masonry design standards it refers to. Vertical chases are limited to a proportion of the wall thickness, and horizontal chases are limited more tightly again because they cut across the load path; check the current Approved Document A figures for the wall thickness you are working with rather than working from a rule of thumb. Chases should not be positioned back to back on opposite sides of a wall. For stud partition walls, cables are run through drilled holes in the timber studs or noggings and chase depths do not apply — but the cable must be kept clear of the screw line where plasterboard will be fixed, and grommets or bushes should be used where cables pass through metal studs to prevent abrasion. Whatever the chase depth, the electrical requirement is unchanged: the cable still has to satisfy Table 52.1 of BS 7671 for its depth below the finished surface.

Do I need to notify Building Control before starting first fix?

Under Part P of the Building Regulations (England and Wales), certain electrical work in dwellings must be notified to the local Building Control body before work starts. Notifiable work includes the installation of a new circuit, the installation of a new consumer unit, and any electrical work in a special location such as a bathroom, a room containing a shower, a swimming pool or a sauna. If you are registered with a competent person scheme (NICEIC, NAPIT, ELECSA or similar), you can self-certify the work and notify Building Control through the scheme. If you are not registered with a competent person scheme, you must notify Building Control before starting the work, and they will arrange inspection at appropriate stages. For a full rewire or new build, this typically means a Building Control inspection at first fix stage (before plastering) and at completion.

What cables should I use for first fix in a new build?

For domestic first fix in a new build, the standard cable is flat twin and earth (T+E) to BS 6004, or BS 7211 where a low smoke halogen-free cable is specified. The usual starting points are 1.0 mm² for lighting, 2.5 mm² for socket ring final circuits and smaller socket radials, 4.0 mm² for a cooker or immersion heater circuit, and 6.0 mm² or 10.0 mm² for a shower or a larger cooker. Treat those as starting points only — the size that actually goes in has to be confirmed against the circuit design current, the reference method for the route, grouping, ambient temperature, thermal insulation and volt drop, which is what the cable sizing calculator is for. For fire detection and fire alarm wiring, use a fire-resistant cable to BS 7629-1 (for example FP200 Gold or equivalent) selected to meet the standard or enhanced grade required by BS 5839-1. For data, Cat6 is the usual domestic choice. Cable colours follow BS 7671 Table 51: brown for line, blue for neutral, green-and-yellow for the protective conductor. Where a blue core is used as a switched line — the classic switch drop — it has to be identified as a line conductor at its terminations, so oversleeve it brown.

Do cables in insulated walls or loft spaces need to be derated?

Yes — this is one of the most commonly overlooked first fix issues in new builds. Regulation 523.9 says that for a single cable likely to be totally surrounded by thermally insulating material over a length of 0.5 m or more, the current-carrying capacity shall be taken, in the absence of more precise information, as 0.5 times the current-carrying capacity for that cable clipped direct to a surface and open (Reference Method C). For shorter lengths in insulation the derating factors in Section 2.6 of Appendix 4 apply: 0.88 at 50 mm, 0.78 at 100 mm, 0.63 at 200 mm, 0.51 at 400 mm and 0.5 at 500 mm or more. Those factors are appropriate to conductor sizes up to 10 mm² in insulation with a thermal conductivity greater than 0.04 W/m·K. In Part L-compliant new builds, external walls, loft spaces and ceiling voids are heavily insulated, so a large share of the cable runs in those areas are affected. The practical consequence at first fix is simple: a halved rating is a big reduction, and a cable chosen from a clipped-direct figure can be undersized before it is even installed. Size the cables against the actual route before ordering materials, not after.

How do I coordinate first fix electrical with the plumber?

Coordination with the plumber is critical to avoid clashes. Before first fix starts, agree the following: positions of boiler, cylinder and any mechanical ventilation units (these need electrical supplies and switching), routes for heating pipes (to avoid running cables directly above or below heating pipes, which affects cable current-carrying capacity), positions of bathroom and kitchen accessories (to ensure electrical back boxes do not clash with pipe runs in the wall), and the position of the consumer unit (not directly above a boiler or water cylinder, with adequate clearance for working on the board). On new build sites, the electrical and plumbing first fix often happen simultaneously, so daily coordination is essential. A clash discovered after plastering is expensive to fix — it means chasing out finished walls, which damages the plaster, wastes time and creates friction with the builder.

INSTALLATION GUIDE

First Fix Electrical: Getting the Hidden Infrastructure Right

First fix is the foundation of every electrical installation. Cable routing, back boxes, containment and coordination with other trades have to be right before the plaster goes on, because mistakes discovered afterwards are expensive to put right. This guide covers the BS 7671 rules that decide each of them.

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12 min readUpdated 2026-08-07Andrew 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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The short answer

What is first fix in electrical installation?

First fix is the electrical work done before the walls are plastered and the floors are laid: running cables, fitting back boxes, installing containment and drilling joists. Cables in a wall must satisfy Table 52.1 of BS 7671, and cables through joists must be at least 50 mm from the top or bottom edge. Second fix — accessories, the consumer unit and testing — follows once the plaster is dry.

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Key takeaways

01First fix is everything installed before the plaster goes on — cables, containment, back boxes and drops. Second fix is the accessories, the consumer unit and the testing.
02A cable in a wall or partition is governed by Table 52.1 (Regulation 522.6.202). At A4:2026 the requirements previously in Regulation 522.6.203 were relocated into that table, so depth from the surface and whether the wall contains metallic parts now decide what protection is needed.
03A prescribed zone is within 150 mm of the top of the wall, within 150 mm of an angle formed by two adjoining walls, or horizontally and vertically from any point, accessory or switchgear. There is no prescribed zone at the floor line.
04A cable passing through a joist must be at least 50 mm from the top or bottom of the joist, or comply with Regulation 522.6.204 (Regulation 522.6.201).
05Regulation 411.3.4 requires 30 mA RCD additional protection for AC final circuits supplying luminaires within domestic premises — every lighting circuit needs an RCD-protected way on the board schedule.
06Regulation 421.1.7 was redrafted at A4:2026: AFDDs are a requirement on socket-outlet final circuits up to 32 A in high rise residential buildings, HMOs, purpose-built student accommodation and care homes, and recommended in all other premises. Decide this before you order the consumer unit.
07Part P notification is required for new circuits in dwellings, new consumer units, and work in special locations such as bathrooms and rooms containing a shower.

01 · Installation Guide

What Is First Fix Electrical?

First fix electrical is the stage of an electrical installation that takes place before the walls are plastered and the floors are finished. It is the hidden infrastructure — the cables, containment, back boxes and mounting points that will be concealed behind the finished surfaces. Everything installed at first fix must be correct before it is covered up, because accessing it afterwards means damaging the finished building.

On a typical domestic new build or full rewire, first fix accounts for the larger share of the total installation time. It involves running all cables from the consumer unit position to every switch, socket, light and fixed appliance position in the property. It also includes installing containment (conduit, trunking or cable tray), fitting back boxes into walls, and pulling cables for smoke detectors, data points and any specialist systems.

The quality of first fix directly determines the quality of the finished installation. Cables routed outside BS 7671 safe zones risk damage from future fixings. Back boxes fitted at the wrong height or in the wrong position mean awkward accessory placements that the customer will notice. Containment that is too small for the number of cables makes pulling cables difficult and restricts heat dissipation.

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02 · Installation Guide

First Fix vs Second Fix: What Happens When

First and second fix are the same installation split by the plasterer. Anything that has to be buried goes in at first fix; anything that can be screwed on afterwards waits for second fix. Getting the split right is mostly a scheduling problem — you need two visits booked around the wet trades, not one.

Element	First fix (before plaster)	Second fix (after decoration)
Cables	Run from the board position to every outlet, left long and coiled at each box	Stripped, sleeved and terminated into the accessory
Back boxes	Chased into masonry or fixed to studs, set to the finished plaster line	Faceplate fixed to the box, grommets and gasket checked
Accessories	None fitted	Sockets, switches, spurs, ceiling roses, downlights, extract fans
Consumer unit	Position agreed and marked, circuit cables dressed in and labelled	Board fitted, circuits connected, RCD and AFDD ways allocated, schedule completed
Containment	Conduit, trunking, tray and capping installed and cables drawn in	Lids, covers and accessory boxes made off
Testing	Continuity and insulation resistance on the concealed work before it is covered	Full initial verification and the Electrical Installation Certificate
Position in the programme	After the structure is weathertight, before the plasterer	After plastering, decoration and floor coverings

Regulation 641.1 is the reason the testing splits across both visits: every installation shall, during erection and on completion before being put into service, be inspected and tested to verify, so far as is reasonably practicable, that the requirements of BS 7671 have been met. Once the plaster is on, the concealed work can no longer be inspected — so the inspection has to happen while it is still open.

03 · Installation Guide

Cable Routing and Safe Zones

Cable routing is the most critical aspect of first fix. Every cable must follow a route that minimises the risk of damage during and after construction, complies with BS 7671, and allows the cable to carry its design current without overheating.

What counts as a prescribed zone

Regulation 522.6.202 requires a cable installed in a wall or partition to comply with Table 52.1. The footnote to that table defines the prescribed zones:

Within 150 mm from the top of the wall or partition.
Within 150 mm of an angle formed by two adjoining walls or partitions.
Horizontally and vertically from any point, accessory or switchgear located on the wall. Wiring from any circuit can be installed in such a zone.

Where the location of the accessory, point or switchgear can be determined from the reverse side, a zone formed on one side of a wall or partition 100 mm thick or less extends to the reverse side.

There is no prescribed zone at the floor line. A run dropped to skirting level and taken horizontally gets nothing from the zone rules — plan routes accordingly.

Table 52.1 — what a cable in a wall actually needs

A4:2026 relocated the old Regulation 522.6.203 requirements into Table 52.1, so the protection now depends on two things: how deep the cable sits below the finished surface, and whether the wall or partition contains metallic parts.

Wall construction	Cable less than 50 mm deep	Cable 50 mm or more deep
Without metallic parts	Installed in a prescribed zone and given additional protection by an RCD with the characteristics of Regulation 415.1.1; or comply with Regulation 522.6.204	No additional impact protection required
With metallic parts	Installed in a prescribed zone and given additional protection by an RCD with the characteristics of Regulation 415.1.1; or installed in a prescribed zone and comply with Regulation 522.6.204	Given additional protection by an RCD with the characteristics of Regulation 415.1.1; or comply with Regulation 522.6.204

Regulation 415.1.1 is the 30 mA figure: an RCD with a rated residual operating current not exceeding 30 mA, recognised in AC systems as additional protection. The practical catch is the bottom row — a metal-stud partition contains metallic parts, so a cable in it needs protection at any depth, not just under 50 mm.

The Regulation 522.6.204 alternatives

Where Table 52.1 allows Regulation 522.6.204 instead of an RCD, the cable shall:

incorporate an earthed metallic covering complying with the requirements of BS 7671 for a protective conductor of the circuit concerned, the cable complying with BS 5467, BS 6724, BS 7846, BS 8436 or BS EN 60702-1; or
be installed in earthed conduit complying with BS EN 61386-21 and satisfying the requirements of BS 7671 for a protective conductor; or
be enclosed in earthed trunking or ducting complying with BS EN 50085-2-1 and satisfying the requirements of BS 7671 for a protective conductor; or
be provided with mechanical protection against damage sufficient to prevent penetration of the cable by nails, screws and the like; or
form part of a SELV or PELV circuit meeting the requirements of Regulation 414.4.

Cables through joists and battens

Regulation 522.6.201 covers the floors and ceilings. A cable installed under a floor or above a ceiling shall be run in a position where it is not liable to be damaged by contact with the floor or ceiling or their fixings. A cable passing through a joist within a floor or ceiling construction, or through a ceiling support such as under floorboards, shall be installed at least 50 mm measured vertically from the top, or bottom as appropriate, of the joist or batten — or comply with Regulation 522.6.204.

That 50 mm is the electrical rule. The structural rules for where you are allowed to drill a joist at all — position along the span, hole diameter relative to joist depth, spacing between holes, and the general preference for drilled holes over notches — come from the Building Regulations and the timber design guidance, not from BS 7671. On a new build, confirm them with the frame designer before you start boring holes.

Two A4:2026 changes that decide your board

Both of these are consumer unit decisions, and both have to be made at first fix — before the board position is fixed and the unit is ordered.

Regulation 411.3.4 — 30 mA RCD on domestic lighting

Within domestic (household) premises, additional protection by an RCD with a rated residual operating current not exceeding 30 mA shall be provided for AC final circuits supplying luminaires. This is a "shall", not a recommendation. At first fix it means every lighting circuit you run has to be assigned to an RCD-protected way on the board schedule.

Regulation 421.1.7 — AFDDs, required in four building types

A4:2026 redrafted this regulation, and it is no longer a flat recommendation. AFDDs conforming to BS EN 62606 shall be provided for single-phase AC final circuits supplying socket-outlets with a rated current not exceeding 32 A in high rise residential buildings (HRRBs), houses in multiple occupation (HMOs), purpose-built student accommodation, and care homes. For all other premises, AFDDs are recommended for the same circuits. Where used, AFDDs shall be placed at the origin of the circuit to be protected, which drives both the type of board and the number of ways you need. The note to the regulation assumes a high rise residential building is over 18 m in height or in excess of six storeys, whichever is met first.

In practice, planning cable routes before drilling and chasing saves significant time. Mark out accessory positions on the walls, plan the runs from each position back to the consumer unit, and identify any crossings or shared routes where containment will be needed.

04 · Installation Guide

Back Boxes and Mounting Points

Back boxes (also called pattress boxes) are installed at first fix to provide a mounting point for the accessories that will be fitted at second fix. Getting back box selection and positioning right at first fix avoids problems later.

Metal back boxes (masonry walls) — 25 mm or 35 mm deep for standard switches and sockets, 47 mm deep for dimmer switches and some smart switches that have deeper mechanisms. Use galvanised steel boxes with an earth terminal.
Dry-lining boxes (plasterboard walls) — cavity-fixing boxes that grip the plasterboard when tightened. Available in single, double and triple gang sizes. Check the box depth against the plasterboard-to-stud gap before you cut.
Standard heights — sockets at 450 mm and switches at 1200 mm from finished floor level, measured to the centre of the box. These are not BS 7671 requirements; they are the industry defaults and they sit inside the accessibility range that Building Regulations Approved Document M works to.
Cooker switch position — beside the cooker rather than above it, so nobody has to reach over a hot hob to isolate. Around 1350 mm from finished floor level is common practice, and within reach of the appliance it controls.

Allow sufficient cable at each back box position for the second fix electrician to work comfortably. Leave at least 200 mm of cable protruding from each box. That is enough length to strip, terminate and push back into the box without straining the connections.

05 · Installation Guide

Containment Systems: Conduit, Trunking and Cable Tray

Containment protects cables from mechanical damage, simplifies cable management, and provides a professional finish in exposed or surface-mounted installations. The choice depends on the installation environment, the number of cables, and whether the containment will be concealed or visible.

PVC conduit

Round PVC conduit (20 mm or 25 mm) is used for concealed runs in masonry walls and floors, with the cables drawn in after the conduit is fixed. Regulation 522.8.2 requires a conduit or ducting system buried in the structure to be completely erected between access points before any cable is drawn in — so it has to be finished, not half-finished, before you pull.

Steel conduit

Galvanised steel conduit provides mechanical protection and can serve as the circuit protective conductor — Regulation 543.2.1(f) recognises a metal conduit or metallic cable management system as a protective conductor, provided it satisfies the rest of Section 543 for continuity and cross-sectional area. That means every coupler, bush and box has to be made off properly, and the continuity has to be tested.

PVC trunking

Mini-trunking and dado trunking are used for surface-mounted cable management, commonly in commercial offices and retail premises, in sizes from 16x16 mm upwards. Use Elec-Mate's trunking fill calculator to check the cable count against the capacity of the section you have specified.

Cable tray and basket

Cable tray (perforated or ladder type) and cable basket are used in commercial and industrial installations for running large numbers of cables over long distances. Cables are laid on the tray rather than enclosed, which ventilates them and reduces the grouping penalty compared with the same cables bunched in an enclosure.

BS 7671 does not publish a numerical fill percentage for conduit or trunking. Capacity is worked out from the cable factor and conduit or trunking factor tables in the IET On-Site Guide, which take account of the run length and the number of bends. Elec-Mate's conduit fill calculator does that arithmetic for you. What BS 7671 does require is Regulation 522.8.1: the wiring system shall be selected and erected to avoid damage to the sheath or insulation of cables and their terminations during installation, use or maintenance, and lubricants that can have a detrimental effect on the cable or wiring system are not permitted.

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06 · Installation Guide

Coordination with Other Trades

First fix electrical rarely happens in isolation. On any building project — new build, extension or rewire — the electrician must coordinate with plumbers, plasterers, carpenters and the main contractor. Poor coordination is one of the most common causes of delay and rework.

Plumber — agree positions for the boiler supply, cylinder immersion, unvented cylinder controls, underfloor heating manifold and any mechanical ventilation. Avoid running cables directly above or below hot water pipes.
Plasterer — all first fix must be complete and signed off before plastering starts. Back boxes should finish flush with the plastered surface, neither recessed behind it nor proud of it. Agree the plaster thickness and set the boxes to suit.
Carpenter — coordinate stud positions for dry-lining boxes, agree joist drilling positions, and confirm the kitchen unit layout before you set worktop socket and switch heights. Cables through joists still have to meet the 50 mm rule in Regulation 522.6.201, so the holes have to suit both trades.
Main contractor — agree the programme, access arrangements and any temporary supplies needed for the build. First fix follows structural work and precedes plastering in the build sequence.

Use Elec-Mate's quoting app to produce a first fix specification and quote that details every accessory position, circuit allocation and containment requirement. Sharing it with the builder and the other trades at the start of the project prevents misunderstandings and keeps the programme on track.

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07 · Installation Guide

Part P Notification for First Fix Work

Part P of the Building Regulations (England and Wales) makes certain domestic electrical work notifiable. The work must either be carried out by a registered competent person, who can self-certify, or notified to Building Control before it starts.

First fix work that is notifiable under Part P includes:

Installation of a new circuit — any new circuit added to an existing or new consumer unit.
Consumer unit replacement or relocation, including the installation of a new consumer unit in a new build.
Any electrical work in a special location — bathrooms, rooms containing a shower, swimming pools, saunas and hot tub enclosures.
A full rewire or new build installation — the entire installation is notifiable.

If you are registered with NICEIC, NAPIT, ELECSA or another competent person scheme, you can self-certify. You complete the installation, carry out initial verification, issue the Electrical Installation Certificate, and notify Building Control through your scheme. The scheme issues a Building Regulations Compliance Certificate to the customer.

If you are not registered with a competent person scheme, you must notify Building Control before starting the work. They will inspect at first fix stage, before plastering, and again at completion. Building Control charges a fee for this inspection and the amount varies by local authority.

08 · Installation Guide

Common First Fix Mistakes to Avoid

First fix mistakes are expensive because they are hidden behind finished surfaces. By the time one is discovered it usually means opening up a wall or a ceiling. These are the ones that come back most often:

Cables outside a prescribed zone with nothing else in place — running diagonally across walls or at arbitrary heights, with no 30 mA RCD and no earthed metallic containment. Table 52.1 gives you options, but it does not give you none.
Treating a metal-stud partition like a timber one — a wall containing metallic parts needs protection at any depth. The 50 mm let-off only applies to walls without metallic parts.
Not leaving enough cable at back box positions — 50 to 100 mm makes second fix termination awkward and increases the risk of a poor connection. Leave at least 200 mm.
Wrong back box depth — a 25 mm box for a dimmer that needs 35 mm or 47 mm. The mechanism will not fit, and the box has to be replaced after plastering.
Forgetting the smoke detector interconnect — interlinked smoke and heat detectors are a Building Regulations requirement. The interconnect has to be run at first fix or you are surface-clipping it later.
Not photographing cable routes — photograph every run before plastering. It is a record for the next person and it can be attached to the EIC as supporting evidence.

09 · Installation Guide

First Fix Completion Checklist

Before signing off first fix and letting the plasterer in, work through this checklist to make sure nothing has been missed:

Cables run to every accessory position — sockets, switches, lights, spurs, cooker, shower, smoke detectors, data points, EV charger, outdoor lighting.
EV charger circuit sized and consumer unit capacity assessed. Regulation 722.311.201 allows load curtailment, including load reduction or disconnection, either automatically or manually, to be taken into account when determining maximum demand of the installation or part of it.
Every cable in a wall checked against Table 52.1 for its depth and the wall construction — prescribed zone, 30 mA RCD, or a Regulation 522.6.204 method.
Cables through joists at least 50 mm from the top or bottom, or protected to Regulation 522.6.204.
Every lighting circuit allocated to a 30 mA RCD-protected way on the board schedule (Regulation 411.3.4).
AFDD requirement settled for the premises type before the consumer unit is ordered (Regulation 421.1.7).
Back boxes at the correct height and depth, set to the plaster line, with at least 200 mm of cable protruding.
Containment installed where required and cables drawn in.
Cables labelled at both ends — at the accessory position and at the consumer unit position. This saves hours at second fix.
Continuity and insulation resistance tested on everything about to be covered, and the results recorded. Regulation 641.1 requires inspection and testing during erection as well as on completion.
Photographs taken of all concealed cable routes before plastering.
Consumer unit position marked and cables dressed ready for second fix.

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Frequently Asked Questions About First Fix Electrical

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First Fix Electrical: Getting the Hidden Infrastructure Right

What is first fix in electrical installation?

Key takeaways

What Is First Fix Electrical?

Get the BS 7671 A4:2026 Cheat Sheet — free

First Fix vs Second Fix: What Happens When

Cable Routing and Safe Zones

What counts as a prescribed zone

Table 52.1 — what a cable in a wall actually needs

The Regulation 522.6.204 alternatives

Cables through joists and battens

Two A4:2026 changes that decide your board

Regulation 411.3.4 — 30 mA RCD on domestic lighting

Regulation 421.1.7 — AFDDs, required in four building types

Back Boxes and Mounting Points

Containment Systems: Conduit, Trunking and Cable Tray

PVC conduit

Steel conduit

PVC trunking

Cable tray and basket

Try Elec-Mate free for 7 days

Coordination with Other Trades

Build the first fix specification once

Part P Notification for First Fix Work

Common First Fix Mistakes to Avoid

First Fix Completion Checklist

Design the full installation before you start drilling

Frequently Asked Questions About First Fix Electrical

What exactly is included in first fix electrical?

What are the BS 7671 safe zones for cable routes?

How deep should cable chases be in walls?

Do I need to notify Building Control before starting first fix?

What cables should I use for first fix in a new build?

Do cables in insulated walls or loft spaces need to be derated?

How do I coordinate first fix electrical with the plumber?

Continue reading

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Second Fix Electrical

AI Circuit Designer

Cable Sizing Calculator

Part P Building Regulations

New Build Electrical

House Rewire Guide

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Plan First Fix Jobs Properly