PAT Testing Explained: Who Needs It, How Often and What Is Actually Tested?

PAT testing is the familiar name for in-service inspection and testing of electrical equipment to determine whether it is safe for continued use. It can include visual inspection and electrical testing where appropriate.

ISIT means In-Service Inspection and Testing of Electrical Equipment. It is the modern professional terminology used in the IET Code of Practice.

The law requires electrical equipment that could cause injury to be maintained so it does not present danger, but it does not prescribe one universal PAT test or annual interval for every item. Some sectors have specific additional duties.

No. HSE explicitly says the law does not require annual testing of every appliance. Frequency should reflect equipment type, environment, use, damage risk and maintenance history.

There is no single correct interval for every item. A risk-based system considers movement, environment, construction, use, user behaviour, previous results, failures and manufacturer information.

No. Class I, Class II, electronic and other equipment can require different approaches. The competent person selects appropriate tests after identifying the equipment and its protective measures.

There is no universal England rule requiring every private landlord to PAT-test every supplied appliance every year. Equipment still needs to be safe, and licensing or local authority requirements can add duties.

Where a social landlord provides electrical equipment under the tenancy, the current regulations require it to be checked by a qualified person at least every five years and an ISIT equipment record obtained. The check may involve visual inspection, electrical testing or both as the qualified person considers necessary.

Requirements can depend on licence conditions, local authority rules, the property and equipment supplied. Not every HMO has an identical testing regime.

No general law requires every inspected/tested item to carry a PAT label. HSE says labels and records can be useful management tools, but they are not universally mandatory.

Yes. The label is not the inspection. Whether equipment is safe depends on its condition and appropriate assessment. A management system may still choose to use labels.

No. It records an assessment at a point in time and cannot override new damage or an inadequate inspection. The actual condition always matters.

Sometimes a label is being used to identify fixed equipment connected at that point. A sticker on the socket or FCU alone does not demonstrate that the connected equipment was properly inspected or tested; the equipment record should identify what was assessed.

Yes, the modern IET Code of Practice can include relevant fixed/permanently connected electrical equipment. That equipment assessment should still be distinguished from inspection of the fixed wiring installation.

Class I equipment relies on protective earthing as part of its protection against electric shock. Where appropriate, continuity of that protective path is therefore an important part of assessment.

Class II equipment uses double or reinforced insulation and does not rely on protective earth in the same way as Class I. The inspection/test approach is therefore different.

Class III equipment uses an extra-low-voltage arrangement where applicable. The associated supply/adapter and complete arrangement may still need to be considered.

For appropriate Class I equipment it is used to assess whether the protective conductor path is effective. It can reveal a broken or poor earth connection even though the appliance still operates.

It is one method used, where appropriate, to assess the condition of electrical insulation. The exact test method depends on the equipment; modern electronics may require alternative approaches.

Damage such as cracked cases, exposed cores, overheated plugs and poor cable entries can be unsafe even if an electrical test result appears acceptable.

HSE says new equipment should be supplied safe and does not normally require a formal PAT test simply because it is new. A visual check for obvious transit damage is sensible.

Yes. An internal short circuit or overcurrent fault can cause an MCB or the overcurrent element of an RCBO to operate.

Yes. Earth leakage/residual current from equipment can operate an RCD or RCBO. The exact cause still needs diagnosis.

The fault may be in the appliance, socket, fixed circuit or elsewhere. Tripping does not automatically mean the consumer unit is faulty.

No inspection can predict every future failure. PAT/ISIT assesses condition at the time using appropriate inspection and testing. Some functional faults may require specialist appliance diagnosis.

Unsafe equipment should not simply stay in service. Depending on the fault it may be removed, repaired, replaced and retested where appropriate.

Yes. AVAG provides a detailed inspection/testing report, commonly called a PAT certificate, recording the equipment assessed and results. The report is more meaningful than a sticker alone.

Labels can be provided where requested or useful as part of the customer’s equipment-management system. They are not a universal legal requirement.

A socket is part of the fixed installation, not the appliance. If a label is used near a socket or FCU to identify a connected fixed appliance, the record should make clear which equipment the inspection relates to. A sticker on the socket itself does not prove the equipment was assessed.

Depending on the agreed system, the report can include asset ID, equipment description and location, Class/type, visual result, electrical test results where applicable, PASS/FAIL, date, comments and a future review/inspection date where appropriate.

Yes. An RCBO provides both overcurrent and residual-current protection, so different kettle faults can cause it to operate for different reasons. The fault still needs to be diagnosed rather than assumed from the trip alone.

Competence depends on the level of work. Basic user checks or low-risk visual inspection may be carried out by a suitably trained person. Combined inspection and electrical testing requires greater knowledge, suitable equipment and the ability to interpret results.

Not in every case. HSE requires competence for the work being done rather than a blanket rule that every PAT activity must be performed by an electrician. More complex testing and fault diagnosis demand greater electrical knowledge.

PAT/ISIT assesses electrical equipment. An EICR assesses the condition of the fixed electrical installation. They can interface, but they answer different safety questions.

Yes. If evidence suggests the issue is not limited to equipment, AVAG can provide separate professional electrical fault finding for the fixed installation.