A loft conversion electrical package typically costs £1,800 to £5,000. This guide covers required circuits, consumer unit upgrade considerations, cable routing by loft type, smoke alarm requirements, and Part P notification.
Free for 7 days · No charge until day 8 · Cancel anytime · Used by 1,000+ UK electricians
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.
1,000+
UK electricians
“Replaced three separate apps with Elec-Mate. Certs, quotes, and scheduling all in one place.”
Daniel Palmer — DP Electrical
A loft conversion is one of the most cost-effective ways to add floor area to a house. The electrical work is a substantial part of the project cost and must be planned carefully alongside the structural and building fabric works. Getting the electrical first fix right during the build phase avoids expensive remedial work once the plasterboard is up.
The electrical package for a loft conversion typically includes new circuits from the consumer unit (or from a new upgraded consumer unit), first-fix cable installation in the new stud walls and ceiling, second-fix installation of accessories, smoke alarm installation, testing and certification under BS 7671:2018+A4:2026, and Part P notification.
This guide covers typical costs, consumer unit requirements, the circuits needed, cable routing challenges by loft type, fire detection, and how to quote and certify loft conversion electrical work professionally.
Every key change in the 2026 amendment on one page. AFDDs, TN-C-S protection, new schedule columns, model forms. Pinned on your van dash.
Costs vary significantly by loft type, floor area, and whether a consumer unit upgrade is required. Typical ranges for a single-room loft conversion:
Elec-Mate's quoting app helps UK electricians price loft conversion electrical packages with itemised materials, consumer unit options…
Try it free for 7 days
The consumer unit is the first thing to assess on a loft conversion survey. The questions to answer are:
A new 18th edition split-load metal consumer unit with dual RCD protection (or individual RCBOs) costs £400 to £800 to supply and install (materials and labour). Quote it as a separate line item so the homeowner understands the value.
A typical single-bedroom loft conversion requires the following circuits as a minimum:
Dedicated lighting circuit for loft room and landing. 1.0mm or 1.5mm twin and earth. Consider LED downlights with dimmable driver for master bedroom lofts.
Ring final or 20A radial socket circuit. Minimum 4 double sockets in the main room. Additional USB combination sockets at bedside positions if used as a bedroom.
Dedicated circuit for electric underfloor heating mat or panel heater. Size for total load plus 20% margin. Smart thermostat with floor sensor recommended.
Extractor fan spur, shaver socket, bathroom lighting (IP44 minimum in Zone 2), and supplementary bonding if metallic waste and supply pipework is present.
The smoke alarm circuit (mains-powered, interlinked) is a critical addition that must be included in every loft conversion quote and EIC.
Professional quotes with the remedial estimator, then invoice from your phone the moment the work is done. From £6.99/mo.
Try the quoting tools freeThe type of loft conversion determines how cables are routed from the consumer unit to the new floor. This affects labour time significantly:
Use the voltage drop calculator to verify that the cable run from the consumer unit to the loft lighting and socket circuits does not exceed the 3% voltage drop limit for final circuits.
Fire safety is a critical element of loft conversion Building Regulations approval. The requirements are:
The smoke alarm circuit must be included in the EIC. Use a dedicated 6A or 10A MCB for the smoke alarm circuit, wired from the consumer unit on a 1.0mm or 1.5mm twin and earth cable. Do not wire smoke alarms as spurs from lighting circuits.
Loft conversions are high-value projects for electricians: the electrical package is typically one of the larger sub-contract elements, and builders value reliable, professional electrical contractors who can co-ordinate with the build programme. Key differentiators:
Provide the builder with a written first-fix programme — which circuits you will install in which sequence. Builders love sub-contractors who make their lives easier. Use the Elec-Mate quoting app to generate a materials list for the first-fix package.
Complete the EIC after testing and submit to your competent person scheme before leaving site. The homeowner and builder both need the Part P certificate to sign off the Building Regulations application — delays cost them money and damage your reputation.
Long vertical cable runs to the loft can have significant voltage drop. Use the cable sizing calculator on the survey to specify the correct cable size — upgrading from 2.5mm to 4mm on a long socket circuit run is a common requirement on loft conversions.
Join 1,000+ UK electricians using Elec-Mate for professional quoting, cable sizing, and on-site EIC certificates for loft conversion projects.
Try it free for 7 daysVerified reviews from the UK App Store.
Elec-Mate is my go to app for business and electrical work. It's feature rich without feeling cluttered. A true all in one app for quotes, certs, calculations, RAMS, EICRs, and more. I use it every day without fail, and it makes my workflow much smoother since I'm not jumping between apps anymore. The price-to-feature ratio is excellent. Any issues I've had, the developer responds within the hour and usually fixes them the same day. 100% recommend.
I've used the app and the web based version for a while now and it's well worth the investment. If you're an apprentice or experienced Spark give it a go, you won't be disappointed.
I've been using Elec-Mate for a while now, and honestly, it's one of the best apps I've ever downloaded. Every aspect of it feels thoughtfully designed, from the clean and intuitive interface to the powerful features that make everything so easy to manage. It's clear that a lot of care and attention went into building this app, and it shows in every detail.
Real feedback from real sparks
“Replaced three separate apps with Elec-Mate. Certs, quotes, and scheduling all in one place.”
Daniel Palmer
Sole Trader · DP Electrical
“I've won two contracts this month because I could turn quotes around same-day with the AI cost engineer.”
Nathan Perry
Electrician · NP Electrical Services
“The study centre got me through my AM2. Mock exams and flashcards are brilliant.”
Jake Pizey
3rd Year Apprentice · Apprentice
Elec-Mate gives UK electricians professional quoting, cable sizing, and on-site EIC certification for loft conversion projects. 7-day free trial, cancel anytime.
“Replaced three separate apps with Elec-Mate. Certs, quotes, and scheduling all in one place.”
Daniel Palmer, DP Electrical
From £6.99/mo after trial — less than a coffee a week
We use cookies to improve the app and measure what works. Cookie Policy