Frequently Asked Questions

Do I need planning permission for solar panels in London?

In most cases, no. Installing solar panels on a residential property in London is classified as Permitted Development under the Town and Country Planning (General Permitted Development) (England) Order 2015. This means you can proceed without submitting a formal planning application to your local authority, provided the panels do not protrude more than 200mm beyond the roof plane and are not installed on the principal or side elevation facing a highway.

However, there are important exceptions you must check before commissioning any work:

• Listed buildings - Permitted Development rights do not apply. You must apply for both Listed Building Consent and, in most cases, full planning permission. This affects a significant number of properties in boroughs such as Westminster, Kensington and Chelsea, and Islington.
• Conservation areas - If your property sits within a designated conservation area - common in neighbourhoods like Richmond, Hampstead, or Dulwich - Permitted Development rights for solar on principal elevations are restricted. Rear and slope installations are typically still permissible, but a pre-application enquiry with your local planning authority is always worthwhile.
• Article 4 Directions - Some London boroughs have issued Article 4 Directions that withdraw specific Permitted Development rights in defined areas. Your planning portal will confirm whether your postcode is affected.

Beyond planning, any grid-connected solar installation requires a G98 or G99 notification to UK Power Networks (UKPN), the Distribution Network Operator for most of London. Systems up to 3.68 kWp per phase can be registered under the simpler G98 notification after installation; larger or three-phase systems require prior G99 approval. electricalworks handles this entire DNO application process as a standard part of every solar installation we carry out - you will never be left to navigate it alone.

How long does a full house rewire take, and do I need to move out?

The honest answer is that timescales depend on the size and layout of the property, but as a practical guide:

• Two-bedroom flat or maisonette - typically 3 to 5 working days
• Three to four-bedroom terraced or semi-detached house - typically 5 to 8 working days
• Four to five-bedroom detached house or period conversion - typically 8 to 12 working days

London's period housing stock - particularly Victorian and Edwardian terraces with lath-and-plaster walls and suspended timber floors - can add time compared to modern new-builds, because careful first-fix routing and reinstatement work takes longer in properties where chasing and lifting must be managed sensitively.

On the question of whether you need to move out: we strongly recommend it for a full rewire. The first-fix phase involves lifting floorboards on every level, channelling walls for new cable routes, and generating significant quantities of plaster dust - even with dust sheets, HEPA vacuum extraction, and door-sealing protocols in place. Living in a property during full first-fix works is uncomfortable and impractical.

That said, staged rewires are possible and may suit your circumstances. We can agree a room-by-room sequence that keeps a defined portion of the property habitable while works progress through other areas. This approach extends the overall programme but avoids the need to vacate entirely. We discuss this in detail during the initial survey and build the programme around your situation.

What is an EICR, and how often do I legally need one?

An Electrical Installation Condition Report (EICR) is a formal inspection and test of a property's fixed electrical installation - wiring, consumer unit, earthing arrangements, bonding, and all circuits - carried out by a qualified electrician against the requirements of BS 7671 (the IET Wiring Regulations). The report assigns condition codes to any observations found:

• C1 - Danger present. The installation poses an immediate risk. Remedial action must be taken before the property is occupied or the supply reconnected.
• C2 - Potentially dangerous. The installation is not immediately dangerous but could become so. Remedial works are required urgently.
• C3 - Improvement recommended. The installation does not meet current standards but is not unsafe. Remedial work is advisable but not mandatory.
• FI - Further investigation required. The inspector cannot determine the condition of part of the installation without additional investigation.

An installation receives an unsatisfactory overall result if any C1 or C2 observations are raised. A satisfactory result can be achieved even with C3 observations.

The legal requirements by property type are as follows:

• Private rented residential properties - Under The Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020, landlords are legally required to have the fixed electrical installation inspected and tested at intervals of no more than 5 years, or at every change of tenancy if that occurs sooner. A copy of the EICR must be provided to each existing tenant within 28 days of the inspection and to any new tenant before they occupy the property.
• Houses in Multiple Occupation (HMOs) - The 5-year EICR requirement has applied since 2007 and is enforced via HMO licensing conditions.
• Owner-occupied residential properties - There is no legal mandate, but the IET recommendation is an EICR every 10 years, or on purchase of a property where the age and condition of the installation are unknown.
• Commercial premises - Typically every 5 years, or more frequently depending on the nature of the occupancy and equipment in use.

Where our NICEIC team raises C1 or C2 observations on your EICR, we provide a detailed remedial works schedule with itemised costings. All remedial work is completed under a separate Minor Works Certificate or, where scope warrants it, a full Electrical Installation Certificate.

Can you install an EV charger if I have an old fuse board?

Yes - but safely and legally, the condition of your existing consumer unit is the first thing we assess before any EV charger installation proceeds.

A 7 kW single-phase home EV charger draws up to 32A continuously. Current BS 7671 (18th Edition, Amendment 2) regulations require that any new circuit of this kind is protected by a correctly rated overcurrent device and, critically, by a Type A RCD or RCBO at minimum - and a Type B RCD if the charger manufacturer specifies one for their particular device.

Older consumer units - particularly those with rewireable fuses, or those fitted with the original 17th Edition MCBs - are typically not compatible with the protective devices required. In these cases, upgrading the consumer unit is a prerequisite of the installation, not an optional extra. The specific issues we look for are:

• Insufficient spare ways in the consumer unit to accommodate a dedicated 32A circuit
• Absence of surge protection devices (SPDs), now required under Amendment 2 for new installations in most dwelling types
• Inadequate earthing arrangements - particularly relevant in pre-1966 London properties still on a PME (Protective Multiple Earthing) TN-C-S supply, where additional earthing measures are required for EV charger circuits by BS 7671 Regulation 722.411.4.1
• Maximum demand - we check whether your incoming supply head and main fuse can accommodate the additional load without tripping or requiring a DNO supply upgrade

Where a consumer unit replacement is required, we upgrade to a fully enclosed metal consumer unit compliant with BS EN 61439-3, which also satisfies fire-rated enclosure requirements. The overall programme - consumer unit replacement, new dedicated EV circuit, and charger commissioning - typically takes one full day for a standard residential installation.

Will my solar panels and battery work during a power cut?

This is one of the most common questions we receive, and the answer depends entirely on what type of system you have installed - or are planning to install.

Standard grid-tied solar systems without battery storage shut down automatically the moment the grid supply fails. This is not a malfunction - it is a deliberate safety feature required by the G98 and G99 standards. The reason is to protect UK Power Networks engineers working on the distribution network during a fault. If grid-tied inverters continued to export electricity during an outage, they would energise cables that engineers assume are dead, creating a serious risk of electrocution. Your panels stop producing the moment UKPN cuts the supply at the street.

Grid-tied systems with standard battery storage - including entry-level battery products - behave the same way unless the battery specifically includes a backup or islanding mode. Not all batteries offer this functionality, and it is worth checking specifications carefully before purchase.

Systems with premium backup functionality - specifically the Tesla Powerwall 3, which we install as standard for clients seeking backup capability - operate differently. The Powerwall 3 includes a built-in backup gateway that detects a grid failure within milliseconds and automatically disconnects your home from the grid, forming its own isolated microgrid. Your solar panels continue to charge the battery and power your home entirely independently of UKPN's network for as long as the battery has capacity and the panels are generating.

The practical implications of a Powerwall 3 backup installation for a London household are significant. A 13.5 kWh battery supplying an average home drawing 8-10 kWh per day - reduced further during a daytime outage when solar is actively generating - can sustain essential circuits for 24 to 48 hours or more without any grid supply. We configure which circuits are backed up during commissioning, typically prioritising lighting, sockets, refrigeration, and broadband.

If backup power during grid outages is a priority for you - whether due to remote working requirements, medical equipment, or simply peace of mind in an older part of London's distribution network - book a call with our engineering team to discuss a Powerwall 3 specification tailored to your property.