A row of current PAT labels on appliances can be reassuring, but it does not confirm that the circuits supplying them are safe. Fixed wire testing vs PAT is not a choice between two versions of the same service. They assess different parts of your electrical system, and a well-managed site will often need both.
For duty holders, facilities managers and business owners, understanding the difference helps prevent gaps in compliance planning. It also makes it easier to schedule inspections around your operations, manage remedial work promptly and show that electrical risks are being controlled sensibly.
Fixed wire testing vs PAT: the key difference
PAT, or Portable Appliance Testing, concerns movable electrical equipment and the leads, plugs and connections that supply it. This can include computers, monitors, kettles, extension leads, cleaning equipment, workshop tools and portable heaters. A trained engineer combines a visual inspection with appropriate electrical tests, then records the outcome and identifies any items that should be removed from use.
Fixed wire testing examines the permanent electrical installation within the building. This includes distribution boards, consumer units, fixed cabling, sockets, light fittings and protective devices. It is usually recorded through an Electrical Installation Condition Report, commonly known as an EICR.
In simple terms, PAT asks whether an appliance is safe to use. Fixed wire testing asks whether the electrical infrastructure supplying that appliance remains safe. A passing PAT result cannot identify a deteriorating circuit, damaged fixed cable or an issue inside a distribution board. Equally, a satisfactory EICR does not confirm that an extension lead or portable appliance has been maintained safely.
What fixed wire testing covers
During fixed wire testing, the engineer inspects and tests parts of the installation to identify deterioration, defects, damage and non-compliance that could create danger. Depending on the size and layout of the premises, testing may cover circuits serving sockets, lighting, emergency lighting supplies, plant, kitchens, workshops and specialist areas.
The report will normally record observations using a classification code. A C1 observation indicates danger present and calls for immediate action. A C2 observation identifies a potentially dangerous condition requiring urgent remedial work. FI means further investigation is needed without delay. A C3 observation is an improvement recommendation and does not, on its own, make the report unsatisfactory.
Testing can require circuits to be isolated, so preparation matters. A site-specific plan should identify critical equipment, areas that cannot lose power during working hours and suitable testing windows. In offices, schools, healthcare settings and occupied commercial properties, arranging work in phases or outside core hours can reduce disruption significantly.
Fixed wire testing is generally carried out in line with BS 7671 requirements. The EICR provides a clear record of the installation’s condition, any limitations to the inspection and the remedial work needed to restore or improve safety.
What PAT testing covers
PAT testing begins with checks that are often just as valuable as the electrical measurements. Engineers look for damaged plugs, loose wiring, cracked casings, unsafe repairs, overloaded adaptors and unsuitable leads. These visible defects can present an immediate risk and may be found before any test instrument is used.
The electrical tests selected depend on the appliance type and construction. They may include earth continuity, insulation resistance, polarity and functional checks. Not every item is tested in exactly the same way. For example, a double-insulated appliance does not require an earth continuity test, while sensitive electronic equipment may need an alternative test method.
A professional PAT programme should leave you with a usable asset record, not simply a collection of stickers. Records should identify the item, its location, test date, result and any action taken. This is particularly helpful where equipment moves between rooms, departments or sites.
PAT testing can usually be completed with limited interruption to normal activity. Good planning still matters, especially where staff need computers, specialist equipment or shared appliances at particular times. Agreeing the scope in advance avoids missed assets and unnecessary repeat visits.
Are both inspections a legal requirement?
UK law does not prescribe a universal annual PAT testing date or a single fixed wire testing interval for every business. The legal duty is to maintain electrical systems so far as reasonably practicable to prevent danger. This duty sits within the Electricity at Work Regulations 1989 and wider health and safety responsibilities.
The right inspection frequency should therefore be based on risk. Factors include the type of premises, the age and condition of the installation, how heavily equipment is used, whether appliances are moved frequently, the environment in which they operate and the competence of users.
A busy construction environment, commercial kitchen or workshop will usually require more frequent attention than a low-risk office with newer equipment. Likewise, a school may need a careful programme for shared and frequently handled equipment, while a healthcare setting may have critical services that demand detailed planning before fixed wire testing begins.
Industry guidance provides recommended maximum intervals for periodic inspection, but these are not automatic rules for every site. Your EICR may also recommend the date by which the next inspection should take place. If conditions change, such as after flood damage, major alterations, repeated circuit faults or a change in use, an earlier inspection may be appropriate.
Where businesses commonly leave a gap
The most common gap is treating PAT as the entire electrical compliance plan. PAT labels are visible and easy to understand, whereas the fixed installation is largely hidden behind walls, ceilings and distribution boards. Yet faults in the installation can affect every item connected to it.
Another issue is uncertainty over responsibility in rented premises. A lease may place responsibility for parts of the electrical installation on the landlord, tenant or managing agent. Do not assume that another party has arranged the EICR. Check the agreement, establish who controls the relevant areas and request current documentation where responsibility sits elsewhere.
Changes to a site can also create risk. Extra desks, additional heaters, new machinery and a growing reliance on extension leads may overload circuits or introduce equipment that has never been added to the PAT register. A review after moves, refurbishments or operational changes is a practical part of ongoing compliance.
How to plan fixed wire testing and PAT effectively
Start with a current picture of the site. Keep the latest EICR, records of completed remedial work and an up-to-date list of portable appliances together. This gives you a clearer view of outstanding actions and helps prevent duplicated effort.
Before fixed wire testing, discuss access requirements, circuit shutdowns, sensitive areas and any equipment that must remain operational. If testing has limitations because a circuit cannot be isolated, ensure these are recorded and addressed through a follow-up plan. An inspection report is only useful when its findings are understood and acted on.
For PAT, define what is included. Company-owned appliances are straightforward, but employee-owned chargers, hired equipment, landlord-supplied items and equipment brought in by contractors can complicate responsibility. Your risk assessment and site rules should make expectations clear.
Where possible, align PAT testing with other planned safety activity, but do not force both services into the same visit if that would disrupt the site or compromise the inspection. Fixed wire testing needs different access, time and preparation from portable appliance testing. The efficient approach is the one that suits the building and protects normal operations.
Choosing a competent testing provider
The quality of electrical testing depends on the competence of the person carrying it out and the clarity of the resulting records. Look for engineers with appropriate qualifications, relevant experience and an approach that accounts for the way your premises operate. For sites where staff, pupils, patients or visitors are present, DBS-cleared engineers can provide additional reassurance.
A reliable provider should explain the scope before work starts, identify likely disruption honestly and provide clear reports that distinguish urgent defects from recommendations. They should also be able to discuss practical next steps if faults are found, rather than leaving you with technical paperwork and no clear route forward.
Janus Safety Solutions plans work around each client’s site, with qualified engineers focused on practical compliance and minimal disruption. Where required, a pre-job discussion, survey and health and safety risk assessment can help ensure testing is properly organised from the outset.
The most useful question is not whether fixed wire testing or PAT is more important. It is whether your current arrangements address both the building’s electrical installation and the equipment people use every day. A current EICR, a risk-based PAT programme and prompt remedial action provide the evidence and reassurance a responsible duty holder needs.