Loft Conversion Rewiring
North London
Building a dormer, Mansard, or hip-to-gable loft conversion? We slot in alongside your builder — first-fix before plasterboard, second-fix after, with full Building Control sign-off. New lighting and ring circuits, en-suite shower supply where needed, hard-wired interconnected smoke and heat alarms, and tidy certification handed to your loft conversion specialist on completion.
NICEIC Registered Electrician · Coordinated With Your Builder · Building Control Sign-Off Included · 5-Star Rated on Google
Six Circuits a Loft Conversion Needs
A loft conversion is rarely a tap-into-the-existing-ring job. Each new room and en-suite needs its own correctly-sized supply, plus the alarm and ventilation circuits Building Control insists on. Here’s exactly what we install on a typical North London loft — sized to current 18th edition wiring regs.
Dedicated lighting circuit
6A · 1.5mm² — New lighting circuit fed direct from the consumer unit, RCD-protected, sized for ceiling pendants, downlights and any en-suite extractor. The existing top-floor lighting circuit is already loaded for the rooms below — extending it up would breach Reg 314.1.
Ring final socket circuit
32A · 2.5mm² — A dedicated ring final serving the whole new floor — bedrooms, dressing area, study desk. Never an extension of the downstairs ring (Reg 314.1). RCBO-protected at the board so a fault upstairs doesn’t kill the rest of the house.
En-suite shower supply
40–45A · 10mm² — If the loft has an en-suite electric shower, a 10mm² supply runs direct from the consumer unit to a ceiling-pull isolator, then to the shower. This is usually the load that drives the consumer unit upgrade decision — we check capacity at the survey.
Smoke + heat alarm interconnect
Grade D1 · mains + battery — New bedrooms mean Building Control will fail without grade D1 mains-wired interconnected smoke and heat alarms on every storey, with battery backup. Hard-wired together so one trigger sounds the lot. Non-negotiable on every loft conversion.
Smart heating zone control
230V + low-voltage control — Most loft conversions get their own heating zone — either a TRV-controlled rad loop or a fully zoned thermostat back to the boiler/manifold. We run the low-voltage control cable from the loft stat to the airing cupboard plus a power supply for any actuator.
Velux ventilation + automation
3A FCU · 1.5mm² — Powered Velux roof windows need a fused supply plus control wiring for the rain sensor and motor. Not optional on hip-to-gable conversions where openable area is mandated for fire egress. Wired during first-fix, connected to controls during second-fix.
Why Choose Rudi Electrics for Loft Conversion Rewiring North London?
Your concerns answered — here’s how we slot into a live loft build, work with your builder, and get the wiring signed off so Building Control passes first time.
“Will you coordinate with my loft conversion specialist?”
Yes — we work directly to the builder’s programme. First-fix happens after the steels are in and the floor is down but before plasterboard, so we can run cables through joists, drop into stud walls, and set back-boxes. Second-fix happens once the plasterers and decorators are clear: sockets, switches, downlights, en-suite extractor, smoke and heat alarms. We brief your loft specialist on day-one timings and stay flexible around their schedule.
“Will my consumer unit handle the new circuits?”
Most loft conversions need three or four new circuits — lighting, sockets, smoke alarm interconnect, and often an en-suite shower supply. We check your existing board capacity at the survey. If you have spare RCBO ways we use them; if not, we quote a consumer unit upgrade alongside the loft rewire (typically £800–£1,200 added). The shower load is the usual decider.
“What about smoke and heat alarm interconnection?”
Building Control will not pass a loft conversion without grade D1 mains-wired interconnected smoke and heat alarms across every storey, with battery backup. That means a new alarm in the loft (heat in any kitchen, smoke on the landing), a smoke alarm on every other floor, and all of them hard-wired together so one trigger sounds the lot. We install, test, and certify them as part of the loft package — never an afterthought.
“Do you do first-fix before the plasterboard goes up?”
Yes — first-fix has to happen before plasterboard, and we’ll arrange that around the builder’s carpentry and insulation work. Cables get run through pre-drilled joists at the safe zone, dropped into stud walls, and back-boxes set flush ready for the plasterer. We agree socket and switch positions with you on a marked-up plan before any cable goes in — cheaper to move a pencil mark than a chased cable.
“How do you handle the supply from downstairs?”
We never extend the existing top-floor ring up into the loft — Reg 314.1 of BS 7671 requires circuits to be sized for their load, and an existing ring is already loaded for the floor below. The new loft circuits get fed by fresh runs back to the consumer unit, routed through cupboards, airing-cupboard voids or the staircase wall — whichever the builder has left accessible. Cable routes are agreed before first-fix so nothing surprises the carpenter.
“Will you do the Building Control sign-off?”
Yes. As an NICEIC-Registered electrician we self-certify every circuit under Part P, lodge the notification with your local Building Control through NICEIC’s portal, and hand you the Electrical Installation Certificate plus minor works certificates for the alarm wiring. Your loft specialist gets a copy for the BC inspector — one less item on their snag list, no separate inspection to organise.
What Our Customers Say About Us
Real reviews from homeowners across North London. Live Google reviews below — for all 388+ reviews across Google, Checkatrade and MyBuilder, see our testimonials page →
Book Your Free Loft Rewire Survey
Tell us about your loft conversion and we’ll arrange a free no-obligation survey — fixed price quote agreed with your builder before any work begins.
NICEIC Registered
Every loft rewire by an NICEIC Registered electrician — fully BS 7671 18th Edition compliant, supplied with the applicable certification and Building Regulations documentation.
Fixed Price Quote
Free site survey, fixed price quote — no hourly billing, no surprise extras. You see the full scope before any work begins.
Coordinated With Your Builder
First-fix before plasterboard, second-fix after — we work to your loft specialist’s programme. Most conversions wired in 2–3 visits across the build.
From £1,500
Small dormer first/second fix from £1,500. Typical 2-bed + en-suite £2,500–£3,500. Always honest, always fixed.
How We Complete Your Loft Rewire
Coordinated with your builder from steels-in to BC sign-off. Most loft conversions wired across 2–3 site visits during the build programme.
Site Survey With Your Builder
We meet you and your loft specialist on site, walk the planned layout, agree socket and switch positions on a marked-up plan, and check the existing consumer unit for spare ways. Free, no obligation, takes 30–45 minutes.
Fixed Price Quote
You receive a detailed fixed-price quote covering all materials, labour, alarms, testing and certification. Builder gets a copy so the timings align with their programme. No hidden costs — the price quoted is the price paid.
First-Fix Wiring
Once the steels are in, the floor is down and the stud walls are up — but before plasterboard — we run all cables through joists at the safe zone, drop into stud walls, set back-boxes flush, and run the supply from your existing board.
Second-Fix & Accessories
After plasterers and decorators are clear, we fit sockets, switches, downlights, en-suite extractor, Velux controls and any heating zone thermostat. We connect circuits at the consumer unit, label everything, and energise the new floor.
Smoke & Heat Alarm Interconnect
Grade D1 mains-wired interconnected alarms installed on every storey — smoke alarms on landings, heat alarm in any kitchen, smoke in the loft itself — all hard-wired together so a single trigger sounds the lot. Battery backup tested.
Test, Certify & BC Notification
Full electrical testing — insulation resistance, earth fault loop impedance, RCD trip times. Electrical Installation Certificate issued, alarm wiring certificate issued, Building Control notified through NICEIC. Your builder gets a copy for the BC inspector.
Loft Conversion Rewiring Pricing
Quick reference for North London loft rewires. Fixed quotes given after a free site survey with your builder.
- ✓ New lighting & sockets ring
- ✓ Mains-wired interconnected smoke alarms
- ✓ First-fix & second-fix to builder’s programme
- ✓ Full testing & applicable electrical certification
- ★ Dedicated lighting + sockets ring
- ★ En-suite shower supply (10mm²)
- ★ Heat alarm + smoke alarm interconnect
- ★ Coordination with loft specialist
- ★ Building Control notification & certification
- ✓ Multiple lighting zones & sockets
- ✓ Velux automation + ventilation supply
- ✓ Heating zone control wiring
- ✓ Consumer unit upgrade if required
- ✓ Full testing & applicable electrical certification
Professional Loft Conversion Rewiring North London — Across Every Conversion Type
From dormer extensions on Victorian terraces in Stoke Newington to hip-to-gable conversions on 1930s semis in Southgate — every loft type has its own wiring quirks, and we know what your builder will need from us.
Swipe to explore all property types
Victorian Dormer Terraces
📍 Crouch End, Hornsey, Stoke Newington, Highbury
Tight rear-dormer footprint, limited cable routes from the old top-floor ring, party walls limiting drilling. Existing consumer unit often a 1990s split-load — spare RCBO ways scarce.
Fresh circuit runs via the original chimney void or stairwell stud wall back to the board. Loft gets its own lighting + sockets ring, never an extension of the floor below. Consumer unit upgrade quoted upfront if needed.
Edwardian Mansard Conversions
📍 Stamford Hill, Stoke Newington, Highbury, Islington
Two new floors of headroom on flat-fronted Edwardian terraces. Steel-frame Mansard means cable routing has to dodge structural ties. En-suite is almost always part of the brief — 10mm² shower supply needed.
Two new circuits per floor — lighting and sockets — plus a dedicated 40A/45A shower supply direct from the board. Mansard ceilings get downlights on a separate dimmer zone. Velux openings wired for rain sensor automation.
1930s Hip-to-Gable Semis
📍 Southgate, Cockfosters, Arnos Grove, Bounds Green
Hip-to-gable adds significant headroom but Building Control mandates openable Velux for fire egress — needs powered automation. 1930s consumer unit usually undersized for added load. Plaster-and-lath landing makes cable drops awkward.
Velux rain-sensor and emergency-open wired from a fused supply with control cable to the wall switch. Consumer unit upgraded to 18-way RCBO board. Cables routed through new stud-wall voids the builder leaves accessible during first-fix.
Modern Conversion-Suite Builds
📍 Muswell Hill, Highgate, Crouch End, Hampstead
Master suite + en-suite + dressing room + landing study — multiple lighting zones, smart-thermostat heating zone, Velux automation, and TV/data points. Existing consumer unit rarely cuts it.
Multi-zone lighting design — bedroom, en-suite, dressing all on separate dimmers. Heating zone wired back to the boiler manifold. Data and TV runs alongside power during first-fix. Consumer unit upgraded for the new load.
Mid-build on a loft conversion in North London?
Loft Conversion Rewiring FAQs for North London Homeowners
Clear answers to the most common questions homeowners ask about loft conversion electrical work, builder coordination, alarm interconnection, and Building Control sign-off across North London.
For official guidance, visit Electrical Safety First or read the Building Regulations guidance. For full-house projects, see House Rewiring North London or Kitchen Rewiring North London.
Does my loft conversion need a separate lighting circuit?
Not automatically. The existing circuit load, protective device, cable route and proposed loft lighting must be assessed. A new circuit is installed where the design or condition of the existing circuit requires it.
Can’t I just extend the upstairs ring main into the loft?
It depends on the existing circuit, its test results, load, route and the proposed socket demand. The survey determines whether a suitable existing circuit can be extended or whether a new radial or ring-final circuit is required.
What about the en-suite shower — what supply does it need?
An electric shower needs a dedicated circuit designed from the appliance rating, cable route, installation method, protective device, voltage drop and disconnection requirements. The survey checks the existing supply and consumer unit before the cable size and isolation arrangement are specified.
Do I need new smoke and heat alarms for the whole house?
A loft conversion normally requires the dwelling’s fire-detection and warning arrangements to be reviewed as part of Building Regulations approval. The alarm grade, category, locations, interconnection and backup supply should follow the approved design and the requirements agreed with Building Control.
When do you arrive on site — before or after the plasterers?
Both. First-fix happens after the steels, joists, floor, and stud walls are in but before plasterboard — we run all cables, drop into stud walls, and set back-boxes. Second-fix happens after plasterers and decorators are clear — we fit sockets, switches, downlights, alarms, and connect at the board. Most loft jobs need 2–3 visits across the builder’s programme.
Will you coordinate directly with my loft conversion specialist?
Yes — we work to the builder’s programme and brief them on what we need. Same coordination pattern we use on house extension rewiring. Cable runs are agreed in advance so the carpenter doesn’t plate over a route we still need. Socket positions are marked on a plan with you before first-fix. The builder gets a copy of the certificate at the end so the Building Control inspector has it on the day. We’re used to working alongside loft specialists across North London.
Do you handle the Building Control notification?
Yes. For notifiable work within the scope of our NICEIC registration, we arrange the applicable Building Regulations notification through the competent-person scheme. You receive an Electrical Installation Certificate plus minor works certificates for the alarm wiring. Your loft specialist gets a copy for the BC inspector — one less item on their snag list.
Will my Velux roof window need wiring?
Only electrically operated roof windows or accessories need a power supply. The exact supply and controls follow the selected manufacturer’s specification; any escape-window requirement is determined by the approved building design, not by whether the conversion is hip-to-gable.
How much does loft conversion electrical work cost?
A small dormer with first-fix and second-fix — one bedroom, no en-suite — starts from £1,500. A typical 2-bedroom loft with en-suite and open landing runs £2,500–£3,500. Large multi-room Mansard or hip-to-gable conversions with a consumer unit upgrade are £4,500+. Final price is fixed after a free site survey with you and your builder. See our House Rewire Cost Guide for full-house pricing.
Do I need a heating zone thermostat in the loft?
Most loft conversions add a separate heating zone — either a TRV-controlled rad circuit or a fully zoned thermostat back to the boiler/manifold. This needs low-voltage control wiring from the loft thermostat to the airing cupboard, plus a 230V supply for any actuator. We coordinate with your plumber on cable routes during first-fix so it’s all in before plasterboard.
Mid-build on a Loft Conversion in North London?
Honest, fixed-price quotes after a free site survey with you and your builder. NICEIC-Registered, fully certified, Building Control notified. Covering all 8 boroughs across North London.
