Residential
Blocks with many homes on one supply
Rising mains feed many flats from one incoming supply, so one fault reaches every home on it.
The problem
What happens when the neutral fails on the network side?
On a common type of supply known as PME, one conductor on the network side carries both the neutral and the protective earth. When it breaks, your building loses the reference everything else depends on.
The IET records that a break in that shared conductor can put up to 230 volts on metalwork connected to your earthing, and up to 400 volts across single-phase equipment designed for 230. Pipework and other metalwork bonded to that earth can become live, and whatever is plugged in is exposed to a voltage it was never built to take.
It is not hypothetical. In March 2023 a single network fault sent up to 415 volts into around 500 homes across 20 streets in one English town, damaging appliances and boilers.
The fault starts on the network operator's side of the meter, so the conductor is not yours to repair. The people, the equipment and the building on your side of it are still yours to look after, and the consequences land with you whether or not anyone has reported the fault yet.
The Wiring Regulations already require dedicated protection against this fault wherever people charge a car outdoors. The same fault can reach every other circuit in a building, where no equivalent requirement applies, and a five-yearly inspection shows the installation only on the day it is tested.
How it works
How do you see a fault that starts outside your building?
We keep a continuous watch on the supply where it enters your building and at each distribution board, so a lost neutral, a broken shared conductor or live metalwork is known the moment it happens rather than discovered through damage.
When the neutral is lost, when the shared neutral and earth conductor breaks, when metalwork that should never be live picks up voltage, or when the supply runs outside its normal range, the watch raises the alarm by text and email and on your building management system.
It can switch off the circuits you choose, automatically or remotely, and it can link to your fire alarm. Which circuits drop and which must stay on is a design decision for your building, not a default setting, and we make it with you before anything is fitted.
Detection is only half of it. Someone has to answer an alarm in the middle of the night, decide what is safe to leave running, tell the people in the building, and get the network operator out to repair a conductor you do not own. We own that whole chain as one accountable party, and we keep a record of each alert and what was done, so your safety file shows it.
It sits alongside your periodic inspection and your maintenance contract, never in place of either. The inspection tells you the installation is sound on the day. The watch tells you when the supply stops being sound on every other day.
What you get
What a continuous watch gives you
Risk
Live metalwork seen as it happens
Voltage on pipework and other bonded metalwork raises the alarm the moment it appears, instead of waiting to be reported by whoever finds it.
Risk
Chosen circuits switched off on a fault
When the supply goes out of range, the circuits you have chosen can be switched off automatically, so costly and sensitive equipment is not left running on a supply it was never built for.
Risk
One owner from alarm to repair
Alarm handling, isolation, the people in the building and the call to the network operator, handled by one accountable party rather than left between contractors.
Obligation
Safe between inspections
Your periodic inspection stays exactly as it is. The watch covers the days in between, which is where a supply-side fault arrives.
Obligation
A record you can show
Every alert, and what was done about it, kept on record for your safety file, your insurer and anyone who inspects you.
Cost
A chance to limit the damage
One network fault can damage appliances, boilers and plant across many properties. Knowing early, and switching off what matters, gives you the chance to limit what has to be repaired, replaced or compensated.
Evidence
What the evidence shows about the hazard
Every figure below describes the hazard and what it costs when it lands, from the IET, a network operator's own statement and the Home Office. They are not our results, and we do not present them as if they were.
230 VCan appear on earthed metalwork when the network's shared neutral and earth conductor breaks (IET, Wiring Matters, March 2021)
400 VCan reach single-phase equipment designed for 230 volts when the break is on a three-phase section (IET, same)
500 homesSupplied with up to 415 volts by a single network neutral fault in one English town, March 2023 (the network operator's own statement)
17%Of fires in non-domestic buildings in England started in electrical distribution, the largest identified source of ignition, year to March 2026 (Home Office)
Where it applies
Where the consequence is highest
Compliance
The compliance you carry
The UK environmental and safety duties that commonly reach electrical supply safety. Open any one for what it requires, the deadlines, what is at stake, and how to evidence control. Every entry is sourced.
PRS electricalObligationRiskElectrical safety standards in private rented homes (England Regulations 2020)
What you must doHave the electrical installation inspected and tested by a qualified person at least every five years, and act on what the inspection finds.
Applies toPrivate landlords letting homes in England.
When it bitesThroughout every tenancy, with the installation inspected and tested at least every five years.
DeadlinesIn force 1 June 2020; new tenancies from 1 July 2020; existing tenancies from 1 April 2021
What is at stakeA local authority may impose a financial penalty of up to GBP 30,000 per breach.
How to evidence itA current inspection report for each home and a record of any remedial work completed.
Legal basisElectrical Safety Standards in the Private Rented Sector (England) Regulations 2020 (SI 2020/312). Issued by Ministry of Housing, Communities and Local Government; enforced by local housing authorities.
Keep watch on the supply between inspections, so a fault that arrives after the test is known the day it happens.
Social rented electricalObligationRiskElectrical safety in social rented homes (England, SI 2025/1043)
What you must doInspect and test installations before a tenancy and at regular intervals, check provided electrical equipment at intervals of no more than five years, put unsafe equipment right within 28 days, and keep and supply the records.
Applies toRegistered providers of social housing in England.
When it bitesBefore each tenancy and at regular intervals throughout it.
DeadlinesIn force 1 November 2025; from 1 May 2026 for tenancies granted before 1 December 2025
What is at stakeNo penalty figure for the social rented extension was confirmed in our review; compliance is also assessed against the Regulator of Social Housing consumer standards.
How to evidence itInspection reports, equipment check records and remedial records held for each property.
Legal basisElectrical Safety Standards in the Private Rented Sector (England) (Amendment) (Extension to the Social Rented Sector) Regulations 2025 (SI 2025/1043). Issued by Ministry of Housing, Communities and Local Government.
Add a continuous watch on each block's supply to the inspection programme, with every event recorded against the building.
Awaab's LawObligationRiskAwaab's Law Phase 2: electrical hazards in social homes
What you must doInvestigate and make safe an emergency hazard within 24 hours. Investigate a significant hazard within 10 working days and complete safety work within 5 working days of the investigation concluding. It is a duty to act once aware, not a duty to monitor.
Applies toSocial landlords in England.
When it bitesFrom 30 November 2026, once the landlord is aware of a hazard presenting a significant risk of harm, including electrical hazards and fire and explosions.
DeadlinesIn force 30 November 2026
What is at stakeNo fine figure confirmed in our review; the duties are enforceable by tenants and sit alongside the regulator's consumer standards.
How to evidence itA record of when each hazard became known, the investigation, and the safety work, measured against the statutory timescales.
Legal basisHazards in Social Housing (Prescribed Requirements) (England) (Amendment) Regulations 2026. Issued by Ministry of Housing, Communities and Local Government.
An alarm makes you aware sooner, and we build the out-of-hours response so the hazard is being made safe as soon as the clock starts.
EAWRObligationRiskElectricity at Work Regulations 1989 (duty holders)
What you must doComply with the Regulations in so far as they relate to matters within your control; employees must co-operate. A network fault is outside your control, but its effects inside your building are not.
Applies toEvery employer and self-employed person, for electrical systems within their control, in any workplace from a school or care home to a hotel or office.
When it bitesContinuously, wherever people work with or near an electrical system you control.
DeadlinesOngoing (continuous duty)
What is at stakeEnforced by the HSE under health and safety law.
How to evidence itClear responsibility for each installation, current inspection and maintenance records, and a record of how supply faults are handled.
Legal basisElectricity at Work Regulations 1989 (SI 1989/635), regulation 3. Issued by Health and Safety Executive.
Know the moment the supply to a building you are responsible for turns unsafe, and have one party own the response.
BS 7671 722ObligationRiskPEN fault protection for outdoor EV charging (BS 7671 regulation 722.411.4.1)
What you must doProvide protection against the touch voltage an open PEN conductor can cause, by a device that disconnects the live and protective conductors, or by an earth electrode arrangement.
Applies toElectric vehicle charge points located outdoors, or likely to charge a vehicle outdoors, on a PME (TN-C-S) supply.
When it bitesOn installing a charge point in that situation.
DeadlinesRequired since Amendment 1 (2020) and retained since; Amendment 4 is reported to become the only current version on 15 October 2026
What is at stakeA British Standard rather than a statute; it is the reference used to show an installation meets the statutory duties.
How to evidence itThe installation certificate recording the protective measure used.
Legal basisBS 7671, the IET Wiring Regulations, regulation 722.411.4.1; product standard IET 01:2024 for open-PEN detection devices. Issued by IET and BSI.
The same fault the Wiring Regulations guard against at the car charger can reach every other circuit in the building. We watch the whole supply.
The honest part
What this is, and what it is not
Electrical safety is a field with good reason to distrust bold claims, so here is the position stated plainly.
This does not repair the network conductor. That belongs to the network operator, and we call them in. It does not replace your periodic inspection, and on its own it does not make any building compliant with anything. It does not promise that no fault will ever cause harm. What it does is watch the supply continuously, raise the alarm when the neutral is lost or metalwork goes live, switch off the circuits you have chosen, and put one accountable party in charge of what happens next. Where a building takes its supply at high voltage through its own transformer, the exposure is different, and we will tell you so at assessment rather than sell you something you do not need.
Assessment starts with how your building is supplied and where its boards are, and tells you plainly whether this fault can reach your building at all.
Questions answered
What is a broken neutral, or open PEN, fault?
On a common type of supply called PME, one conductor on the network side carries both the neutral and the protective earth. If it breaks, the IET records that up to 230 volts can appear on earthed metalwork and up to 400 volts can reach single-phase equipment. The fault is on the network operator's side of the meter, but its effects arrive inside your building.
Does our periodic electrical inspection cover this?
A periodic inspection shows the condition of your installation on the day it is tested. It does not test the network's conductor, and it cannot see a fault that develops after the engineer has left. A continuous watch covers the days in between, alongside the inspection, not instead of it.
Isn't this the network operator's problem?
The conductor is theirs, and so is the repair. The people and the equipment connected to it while the fault is live are yours to look after. We make sure you know the moment it happens, switch off what should not keep running, and get the network operator out to fix it.
Is this required by law?
Not for a building's general installation. The Wiring Regulations already require dedicated protection against this fault where cars are charged outdoors, which shows how the standards body regards the hazard. For everything else it is part of taking reasonable steps for the people in your building, and we will not tell you otherwise.
What happens when it detects a fault?
It raises the alarm by text and email and on your building management system, and it can switch off the circuits you have chosen, automatically or remotely. It can also link to your fire alarm. We design which loads drop and which stay on with you, before anything is installed, and we own the response from there.
Which buildings benefit most?
Buildings where many people share one supply, where the people inside may not be able to react to a fault, and where equipment or continuity matters: residential blocks, care and supported living, schools, hotels and public buildings. A site supplied at high voltage through its own transformer is a different case, and the assessment will say so.
Related
Where this connects
Housing & Residential BlocksElectrical safety for residents between inspections, across the housing stock.Social CareResidents who cannot always raise the alarm themselves.EducationSchools and trusts responsible for pupils every day the building is open.Broken Neutral ProtectionThe fault explained, and what protection for a whole building looks like.
Start with one building's supply
Tell us which building concerns you most. We will look at how it is supplied, where a network fault could reach, and what a continuous watch and response would look like there, before you commit to anything.
Speak to the Team
Tell us your challenge
Tell us the cost, the risk or the obligation you are facing. A senior member of our team will respond, in confidence, with how we would help.
Every enquiry is handled in strict confidence.