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Most electrical faults start small. A socket that feels warm, a light that flickers occasionally, a circuit breaker that trips once and then behaves itself. The temptation is to ignore them, particularly when they are intermittent. But some electrical faults carry a genuine risk of fire or electric shock, and the ones that are most dangerous are not always the most obvious.

Here are the electrical faults that should always be taken seriously, what typically causes them, and when to act.

Faulty Polarity

Faulty polarity — sometimes called reverse polarity or incorrect polarity — occurs when the live and neutral conductors in a circuit are connected the wrong way round. It is one of the more serious faults an EICR can identify, and the reason the original blog post on this site specifically called it out.

The danger is this: in a correctly wired circuit, the fuse or circuit breaker sits in the live conductor. When a fault occurs, the protective device operates, and the circuit is made safe. With reversed polarity, the fuse or circuit breaker is in the neutral conductor instead. The circuit may appear to work normally — lights come on, sockets function — but if a fault develops, the protective device may not operate correctly. Metallic parts of an appliance or fitting can remain live even when a switch is in the off position.

Faulty polarity is not always apparent without testing. It is identified as part of the testing sequence during an EICR and classified as a C2 observation—potentially dangerous and requiring remedial work.

Overloaded Circuits

Every circuit in your property is designed to carry a maximum current. When more current is drawn than the circuit is rated for — typically because too many high-powered appliances are connected — the wiring heats up. Modern circuit breakers are designed to trip before this heat reaches a dangerous level, but if the protective device is oversized for the circuit, or if it has been bypassed or tampered with, the wiring can overheat without triggering the protection.

Signs of an overloaded circuit include circuit breakers that trip repeatedly, sockets or plugs that feel warm to the touch, and discolouration or scorch marks around socket outlets. Extension leads daisy-chained together, or adaptors with multiple high-current appliances plugged in, are a common cause in domestic properties.

Deteriorated or Damaged Wiring

Electrical wiring has a finite lifespan. The insulation surrounding conductors can become brittle and crack over time, particularly in older properties with rubber-insulated or lead-sheathed wiring. Physical damage — from rodents, nails through cables, or mechanical wear where wiring passes through tight spaces — can expose live conductors.

Deteriorated wiring is not always visible. It may be hidden within walls, under floors, or in roof spaces. An EICR will identify deteriorated wiring through insulation resistance testing, which measures the integrity of the insulation across each circuit.

Loose or Corroded Connections

Electrical connections that have worked loose — at sockets, switches, junction boxes, or within the consumer unit — create resistance at the joint. Resistance generates heat. Over time, a loose connection can generate enough heat to char the surrounding materials and, in the worst cases, start a fire. Scorch marks around a socket or a burning smell near the consumer unit are warning signs that should never be ignored.

Connections can work loose over time due to vibration, thermal cycling (the repeated heating and cooling of conductors under load), or simply poor workmanship at the time of installation.

Absence of RCD Protection

A Residual Current Device (RCD) monitors the flow of electricity through a circuit and cuts the power within 40 milliseconds if it detects a leakage current — the kind that occurs when electricity passes through a person. Without RCD protection, a contact with a live conductor in a fault situation is far more likely to be fatal.

Current regulations require RCD protection for most circuits in a domestic property, but many older installations predate this requirement. If your consumer unit does not have RCD protection, this will be identified during an EICR and is likely to be recorded as a C2 observation.

What to Do If You Suspect a Dangerous Fault

If you notice any of the following, contact a qualified electrician promptly — do not wait:

• Scorch marks or discolouration around sockets, switches, or the consumer unit
• A burning smell from any electrical fitting or the fuse board
• Sparking from a socket or switch
• A circuit breaker that trips repeatedly without an obvious cause
• Sockets, plugs, or cables that feel warm when not under heavy load
• Flickering lights that persist even after the bulb has been replaced

For suspected gas leaks or situations where you believe there is an immediate risk, turn off the electricity at the main switch and contact your electricity network operator.

For non-emergency fault investigation and repair, ATO Solutions carries out electrical fault finding for domestic and commercial properties across South West London.

If you have ever had electrical work carried out in a bathroom or wet room, you may have heard your electrician refer to it as a ‘special location’. It is a term used in the wiring regulations — BS 7671, and it has specific implications for how electrical installations in those areas must be designed and protected. Here is what it means and why it matters.

The Definition of a Special Location

In electrical terms, a special location is any area where the presence of water significantly increases the risk of electric shock. The most common example is a bathroom or shower room, but the definition also covers:

• Shower cubicles and wet rooms
• Swimming pools and their surrounding areas
• Saunas and steam rooms
• Hot tub installations
• Garden and outdoor water features

The reason these areas are treated differently is straightforward. Water lowers the body’s electrical resistance, which means that a level of voltage that would cause little harm in a dry environment can become dangerous — or even lethal — when the person is wet or in contact with water. This is why the regulations require additional protective measures in these spaces.

The Zone System

Bathrooms and shower rooms are divided into zones under the wiring regulations, based on their proximity to water sources. Each zone has different requirements for the type of electrical equipment that can be installed within it.

Zone 0 is inside the bath or shower tray itself — the area in direct contact with water. Only specially designed, very low-voltage equipment rated to at least IPX7 (waterproof) can be installed here, such as certain submersible lighting fixtures.

Zone 1 covers the area directly above the bath or shower tray, up to a height of 2.25 metres from the floor. Equipment in this zone must be rated to at least IPX4 (splash-proof). Fixed showers, certain shower pumps, and SELV (Safety Extra Low Voltage) lighting can be installed here.

Zone 2 extends 600mm beyond the perimeter of zone 1, and again up to 2.25 metres from the floor. The same IPX4 minimum rating applies. This zone is where shaver sockets — which must be a specific transformer-isolated type — are typically permitted.

Outside the zones, standard electrical fittings can be used, but RCD protection is still required throughout the room.

RCD Protection Is Mandatory

Regardless of zones, all circuits supplying electrical equipment in a bathroom or wet room must be protected by a Residual Current Device (RCD). An RCD monitors the flow of electricity through a circuit and cuts the power within milliseconds if it detects a fault — fast enough to prevent a fatal electric shock in most circumstances.

Modern consumer units typically have RCD protection built in, but older installations may not. If your home has an older fuse board, an EICR inspection will identify whether your bathroom circuits are properly protected.

What This Means in Practice

For homeowners and landlords, the practical implication is that any electrical work in a bathroom or wet room must be carried out by a qualified electrician who understands the zone requirements and the relevant regulations. This includes installing or moving light fittings, adding shaver sockets, installing extractor fans, or running circuits for heated towel rails and underfloor heating.

This type of work is notifiable under Part P of the Building Regulations, which means it must either be carried out by a registered competent person — such as a NICEIC-registered electrician — or submitted to the local authority for inspection. A registered electrician will self-certify the work and issue the relevant certificate on completion.

Need Electrical Work in Your Bathroom?

ATO Solutions carries out electrical installation and inspection work in bathrooms, wet rooms, and other special locations across South West London. All work is carried out to BS 7671 by NICEIC-accredited engineers and fully certificated on completion.

Talk to Us About Bathroom Electrical Work

Call us for advice or to arrange a visit — no obligation.

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In 2005, the government introduced Part P of the Building Regulations, which brought domestic electrical installation work under the same regulatory framework as other building work, such as extensions and structural alterations. The rules have been updated since, but the core principle remains the same: certain types of electrical work in the home must meet a legal standard, and there must be a documented record that it has done so.

Here is what you need to know as a homeowner, landlord, or tenant commissioning electrical work.

What Is Notifiable Electrical Work?

Not all electrical work is notifiable. Replacing a like-for-like fitting — swapping a socket faceplate, changing a light fitting, or replacing a faulty switch — generally does not require notification. However, the following types of work are notifiable under Part P:

• Installing a new circuit in a property
• Replacing a consumer unit (fuse board)
• Any electrical work in a kitchen or bathroom
• Any electrical work in a garden or outbuilding
• Installing an electric vehicle charging point
• Adding a circuit for a new shower or cooker
• Electrical work associated with a loft conversion or extension

The underlying principle is that these are the types of work where a fault or substandard installation is most likely to pose a risk of fire or electric shock — either because of the environment (kitchens and bathrooms involve water and high-current appliances) or because the scale of the work is significant enough that errors in design or execution could have serious consequences.

Two Ways to Comply

There are two ways to ensure notifiable electrical work is legally compliant:

Option 1: Use a registered competent person. Electricians registered with a scheme such as NICEIC are authorised to self-certify their own work. This means they carry out the installation, test it, and issue the relevant certificate — an Electrical Installation Certificate (EIC) or a Minor Electrical Installation Works Certificate (MEIWC) — without requiring a separate inspection by the local authority. This is the most straightforward route for most homeowners.

Option 2: Notify the local authority. If you use an unregistered electrician, the work must be submitted to the local authority building control department before it begins. An inspector will then need to verify the completed work. This process involves a fee and can cause delays, particularly if the work needs to be redone to meet the required standard.

Why It Matters

The certificate issued on completion of notifiable electrical work is a legal document. It confirms that the installation has been carried out to the required standard and tested accordingly. Without it:

• You may face difficulties when selling your property — solicitors routinely request evidence of certification for any electrical work carried out since 2005
• Your home insurance may be affected if a claim arises from an uncertificated installation
• As a landlord, uncertificated work in a rental property can complicate your compliance position
• You have no independent verification that the work is safe

It is also worth noting that certificates cannot be retrospectively issued by a different electrician for work they did not carry out. If work was done without certification, the options are limited — typically either a full inspection and re-test, or redoing the work.

How to Check If an Electrician Is Registered

NICEIC maintains a public register of approved contractors at niceic.com. You can search by postcode to find registered electricians in your area, and verify that a contractor who claims to be registered actually is. Always ask to see the certificate on completion of notifiable work — a reputable electrician will provide it as a matter of course.

ATO Solutions — NICEIC Registered

ATO Solutions is registered with NICEIC. All notifiable electrical work we carry out is self-certified and fully documented. We issue the relevant certificate by email on completion of every job, to the property owner, landlord, or tenant as appropriate.

Need Electrical Work Carried Out?

Call us to discuss your project — we handle all certification as part of the job.

0800 050 2424