Short answer: on an office-to-residential conversion the certificate you need first is not an EICR — it is an Electrical Installation Certificate (EIC) for each new flat, plus Building Control sign-off under Part P, because creating a dwelling is a material change of use and the flat is a new installation. An EICR comes into it in two places: for the parts of the old office installation you are keeping — the intake, the risers, the landlord’s distribution — which nobody can certify as new work, and then every 5 years once the flats are let. The job that catches developers out is not the testing. It is the supply: an office runs on one big three-phase intake, and six flats need six metered supplies. F & A Electrical prices conversions per flat and per board, and will walk the building with you before you commit. Call 07407 627542.
Do you need an EICR for an office-to-residential conversion?
Yes, but probably not the one you were quoted for. Developers ring us asking for “an EICR on the conversion” and what they actually need is a mix of three documents. Getting this wrong is expensive, because Building Control will not sign off a dwelling on a condition report, and a warranty provider or a buyer’s solicitor will spot it.
| What you are dealing with | Correct document | Who issues it | When |
|---|---|---|---|
| New wiring inside each converted flat — board, final circuits, accessories | Electrical Installation Certificate (EIC), BS 7671 model form, plus Part P notification | The contractor who did the work, registered with a competent person scheme | On completion of each flat, before handover |
| Existing office installation you are keeping — intake, sub-mains, riser distribution, sometimes car park and external lighting | EICR, scope and limitations written down | An independent test — you cannot certify work you did not do | Before design freeze, so you know what you are inheriting |
| An alteration or addition to a circuit that already exists and is staying | Minor Electrical Installation Works Certificate | The contractor | Per alteration |
| The flats once they are let on assured shorthold tenancies | EICR every 5 years, satisfactory | Independent, for the landlord | From the first tenancy |
| Common parts and the landlord’s supply — stair lighting, door entry, risers, lift | EICR, typically 5-yearly | For the freeholder or management company | Before the first leaseholder moves in, then on cycle |
The distinction between the two main forms trips up more people than anything else on a conversion. Our guide to EIC vs EICR sets out exactly which one applies to which piece of work, and why an installer’s certificate is not interchangeable with a condition report.
Class MA gets you planning — it does not get you Building Regulations
Most office-to-resi schemes in London go through Class MA permitted development rather than a full planning application. Since March 2024 the right is broader: the old 1,500 sqm floorspace cap has gone, and so has the requirement for three months’ continuous vacancy. You still need prior approval from the borough on a list of matters — natural light, noise, contamination, flooding, transport, fire safety on taller buildings — and the right does not apply on the ground floor in a conservation area, or to a listed building.
Two things matter for the electrics. First, Article 4 directions. Islington, Hackney, Camden and Tower Hamlets have all used them to remove or narrow commercial-to-residential permitted development across parts of their boroughs, so check the borough’s Article 4 map before you assume Class MA is available — we have seen schemes designed and half-ordered on the assumption it was.
Second, and more to the point here: prior approval is a planning consent, not a building safety one. Converting an office into flats is a material change of use, which brings the whole installation into scope of the Building Regulations — Part P for electrical safety, along with Part B for fire, Part E for sound and Part L for energy. Every new circuit in every flat is notifiable work. That is either notified through a competent person scheme such as NICEIC, or it goes through the borough’s building control on a building notice with inspections, which is slower and costs more.
The supply is the real problem: one three-phase intake, six flats
This is the part that decides your programme, and it is worth understanding before you exchange. A 1960s or 1970s office building of the sort that fills Station Road in New Barnet, the side streets off Tottenham Hale, or the City fringe around Old Street, will typically have a single three-phase supply sized for the building as an office — lifts, comms room, air conditioning, floor plates of dado trunking. It is one MPAN, one meter, one landlord.
Six self-contained flats you intend to sell or let separately need six separate single-phase supplies, each with its own cut-out, meter and MPAN, plus a landlord’s supply for the common parts. That is a service alteration by UK Power Networks: a new metering position, usually a purpose-built meter cupboard or room on the ground floor, service cables run up to each flat, and the old office intake reconfigured or replaced. It is chargeable work with a quotation process and a connection agreement, and the lead times run to months rather than weeks. Get the application in at design stage, not when the plasterers are finishing.
The alternative — keeping the single supply and sub-metering the flats from a landlord’s board — comes up on almost every scheme, usually to save the UKPN bill. It can be done, but know what you are signing up for: resale of electricity is capped by the maximum resale price rules, so you cannot recover more than you were charged; the landlord carries the whole supply and its standing charges; arrears become a landlord problem rather than a supplier problem; and flats on a sub-meter are harder to sell and to mortgage. On a build-to-rent block held long term it can make sense. On anything you intend to sell leasehold, it usually does not. See splitting a landlord’s board and supply.
How much of the old office installation can you actually keep?
Less than the drawings suggest. An office installation is designed around a completely different set of assumptions from a dwelling, and the honest answer on most conversions is that the containment is worth keeping and the wiring is not.
| What you find in the office | Keep or replace | Why |
|---|---|---|
| Steel conduit, trunking and tray in the risers and ceiling voids | Usually keep | Perfectly good containment, and it saves the worst of the first-fix labour — provided you pull new cable rather than reusing the conduit as the earth path |
| Radial power circuits off dado or perimeter trunking | Replace | Designed for desk loads on a cleaning contract, not kitchens, showers and washing machines. No RCD protection, and the circuit arrangement does not map onto a flat |
| Three-phase distribution boards, often BS 88 fused or early MCB | Replace at flat level | Each flat needs its own single-phase consumer unit with RCBO or dual-RCD protection and SPD consideration. Landlord’s board may be reusable if the EICR is satisfactory |
| Lighting circuits on 16A with no RCD, fed from a central switch panel | Replace | Dwelling lighting is domestic-rated, separately protected, and has to work when the occupier is asleep, not when a caretaker flips a panel |
| MICC (pyro) to emergency lighting and alarm | Case by case | Often sound, but the terminations are the weak point and few of them have been touched in thirty years |
| Main earthing and bonding at the old intake | Almost always redo | New meter position means new main earthing conductor and new main protective bonding to water and gas at the new entry points. This is the single most common C1 we issue on a half-finished conversion |
| The riser or intake cupboard itself | Keep, but its status changes | It stops being a cleaner’s cupboard and becomes a common part: fire-rated, accessible, labelled, nothing stored in it, and everything inside it becomes the freeholder’s responsibility for good |
That last row is worth dwelling on. On conversion after conversion, the riser gets used as storage during the build and nobody re-checks the fire-stopping where the new sub-mains penetrate the floors. On a building with a stay-put fire strategy that matters a great deal more than the code alone suggests.
Conversion electrical costs — London 2026
These are our own labour-only prices, inc VAT, for North and North East London. Our standard rate is £90 per hour plus VAT and the minimum charge for any visit is £108 inc VAT. Boards, devices, cable and accessories are supplied at cost and itemised; we do not mark them up. Anything at drawing stage is quoted after a walk-round, which is free.
| Item | Labour only, inc VAT | Notes |
|---|---|---|
| Pre-purchase or design-stage EICR on the existing office installation | from £280 | Tells you what you are inheriting before you commit. Scope and limitations written into the report |
| EICR on retained landlord’s supply, intake and risers after conversion | from £280 | Small block, 4–8 flats. Larger or three-phase with several sub-boards, £15 per circuit |
| Common parts only — stair lighting, door entry, riser | from £180 | 4–12 circuits, 2–3 hours |
| New consumer unit per flat, with EIC and Part P notification | from £550 per board | Board and devices at cost — see fuse board replacement |
| Sub-main from the landlord’s board or meter position to a flat | from £480 | Depends on the run, the containment and whether the riser is already open |
| Full first and second fix to a converted flat | Quoted per flat from drawings | Priced per circuit and per point. Our rewire cost guide gives the comparable domestic figures |
| Circuit identification, schedules and labelling per board | from £180 | Needed for handover; the old office boards never have a usable schedule |
| Emergency lighting — 3-hour discharge test and BS 5266 certificate | from £180 | Half a day plus a return visit to confirm recharge |
| EICR per flat once let, for the landlord’s 5-yearly duty | from £180 | Standard domestic pricing — see EICR cost London 2026 |
| PAT testing on landlord-supplied appliances in the flats | £5 per item, £108 minimum | See PAT testing |
| Out-of-hours working — before 8 am, after 6 pm, Saturday | +25% | Useful when the ground floor is still trading |
If the building keeps a commercial ground floor under the new flats — a very common Class MA outcome on a high street — you have three separate installations to certify and three parties who might pay. EICR for a shop with flats above covers how we split that, and commercial EICR cost has the per-circuit breakdown for the retained commercial part.
What the electrical certificates do not cover
An EIC or an EICR covers the fixed electrical installation and nothing else. On a conversion, these sit outside it and each needs its own paperwork — missing them is what holds up handover:
- Emergency lighting on the common escape route — designed to BS 5266, commissioned, and then an annual 3-hour discharge test with its own certificate. Not on the EICR.
- Fire detection and alarm. What you need is set by the building’s fire strategy, not by the electrician. Many small conversions with a stay-put strategy have no common alarm at all; others need a BS 5839-1 system in the common parts. Inside each flat you need BS 5839-6 mains-powered interlinked detection. See fire alarm installation.
- Smoke and carbon monoxide alarms under the 2015 regulations as amended — at least one smoke alarm per storey of each flat, and a CO alarm in any room with a fixed combustion appliance.
- Fire-stopping where sub-mains, data and containment pass through compartment floors and walls. An electrical contractor should record the penetrations they make; somebody has to own the survey.
- Lifts, door entry and gates — separate commissioning and maintenance regimes.
When does the 5-year EICR clock actually start?
On the first tenancy. Once a converted flat is let on an assured shorthold tenancy it is a specified tenancy under the Electrical Safety Standards in the Private Rented Sector (England) Regulations, and the landlord’s duties are the same as for any other let in London: a satisfactory EICR at intervals of no more than 5 years, a copy to the tenant within 28 days, a copy to a new tenant before they move in, a copy to the council within 7 days if asked, and any C1 or C2 remedied within 28 days or sooner if the report says so.
A new installation with a fresh EIC will not need its first EICR for five years, but the EIC does not substitute for it — hold both. If the conversion creates a licensable HMO rather than self-contained flats, the borough’s licence conditions sit on top and Haringey, Hackney and Enfield routinely ask at renewal: HMO EICR covers what they want to see. For the general landlord duties, landlord EICR London is the place to start, and the communal side is set out in EICR for leasehold flats and communal areas.
What goes wrong on these conversions in North London
We test a steady run of these across Barnet, Haringey, Enfield and the City fringe, and the same five findings come round again and again.
No main earthing at the new intake. The meters get moved to a new ground-floor cupboard, the sub-mains get run, and the main earthing conductor and bonding stay where the old office intake was. That is a C1, and on a part-finished job it is live.
Sub-mains sized for the drawing, not the diversity. Office three-phase capacity looks generous until it is divided by six flats each with a shower, a hob and possibly a car outside. Size for what the flats will draw, and decide on EV provision while the riser is open — retrofitting it into a finished common part costs several times more.
Communal lighting fed off one flat’s board. The classic on small conversions: the stair light is teed off whichever circuit was nearest. The leaseholder pays for the block’s lighting and can isolate it, and it makes the common parts untestable as a separate installation. It needs its own landlord’s supply.
No paperwork for the flat that was finished first. On phased conversions the first flat is often done by whoever was on site, with no EIC and no Part P notification. Building Control will ask, and so will the buyer’s solicitor — certifying as you go is far cheaper than reconstructing it later.
Damp meter cupboards. New ground-floor meter rooms in old commercial buildings are frequently below the old slab level and take water. Corroded main earthing in a wet cupboard is the most common serious finding we issue on converted blocks in the Pymmes Brook and Lea Valley corridors.
Frequently asked
Can I use the existing office EICR to satisfy the landlord regulations?
No. An EICR on the office installation reports on an installation that no longer exists in that form once you have converted it. Each flat is a new installation and needs its own certificate, and the 5-year landlord cycle starts from the first tenancy of that flat.
Do I need Building Control if I am using Class MA?
Yes. Prior approval under Class MA is a planning matter. The conversion is a material change of use, so the Building Regulations apply in full and electrical work is notifiable under Part P — either through a competent person scheme or through the borough on a building notice.
How long does UKPN take to split one supply into several?
Longer than anyone plans for. It is a quotation, a connection agreement and then scheduled works, and it needs a metering position designed into the ground floor. Treat it as a months-long item on the programme and apply at design stage — it is the single most common cause of a finished conversion sitting empty.
What if the report on the retained parts comes back unsatisfactory?
Useful at design stage, expensive at handover — which is why we push for the survey early. C1 means danger present and we make it safe on the visit; C2 has to be fixed. We itemise the remedials so you can price them into the scheme, and you are not obliged to use us. See after an unsatisfactory EICR and C1, C2 and C3 explained.
Can you certify work another contractor started?
Not as an EIC — nobody can certify installation work they did not carry out and cannot verify. What we can do is test what is there, issue an EICR with the limitations recorded, and then certify our own work from that point. Expect some opening up.
Who holds the certificates afterwards — the developer or the management company?
The flat EICs go with each flat and into the sale pack. The common-parts EICR, the emergency lighting certificate and the fire alarm commissioning belong to the freeholder or management company and need handing over formally. Build the pack as you go; reconstructing it two years later is how leaseholders end up paying twice.
Talk to us before the drawings are frozen
Tell us how many units the scheme creates, whether the ground floor stays commercial, and what the existing intake is, and we will walk the building and tell you what is keepable, what the supply work looks like and what the certificate pack needs to contain. The walk-round is free and it is worth doing before you order boards. Call or text 07407 627542.
F & A Electrical is an NICEIC Approved Contractor, Part P registered and works to BS 7671 18th Edition. Based in Tottenham N15, covering Haringey, Hackney, Islington, Enfield, Waltham Forest, Camden, Barnet, Newham and Tower Hamlets. Rated 9.32/10 from 242 reviews on Checkatrade.
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