What is a continuity test?

Glossary · Testing, inspection and certificates

How a continuity test works

Electricity needs a complete path. A continuity test checks that the conductors in a circuit give that path, with nothing broken or badly connected along the way. NICEIC describes it as a check that all wires are properly connected, with no unintended breaks or unnecessarily high resistance at joints and terminations.^{[1]NICEIC, Electrical Installation Condition Reports (EICRs)}

It is one of the circuit tests in an EICR. The others are insulation resistance, polarity, earth fault loop impedance and RCD testing, and NICEIC lists continuity first.^{[1]NICEIC, Electrical Installation Condition Reports (EICRs)} Our page on what an EICR tests shows where it fits.

A loose or corroded joint can have high resistance. That matters because the earth conductor must carry fault current if something goes wrong. If it is broken or high in resistance, protection that relies on it may not work as intended. Electrical Safety First lists a lack of earthing or bonding among the things periodic inspection looks for.^{[3]Electrical Safety First, Periodic Inspection and Testing}

What gets tested

The IET’s list of the minimum tests for a typical home with an RCBO on each circuit includes continuity of the protective conductor and continuity of the live conductors for ring final circuits.^{[2]Institution of Engineering and Technology (IET), Minimizing unnecessary live testing for initial verification (Wiring Matters, May 2025)} The IET says R1 plus R2 is determined by dead testing, and that this reduces the need to reach live terminals. It can also help verify polarity.^{[2]Institution of Engineering and Technology (IET), Minimizing unnecessary live testing for initial verification (Wiring Matters, May 2025)}

R1 plus R2 has a second use. The IET says adding it to the measured external earth fault loop impedance, Ze, gives the circuit’s earth fault loop impedance. Downstream of an RCD, the IET also says continuity of the protective conductors can be enough to confirm protection.^{[2]Institution of Engineering and Technology (IET), Minimizing unnecessary live testing for initial verification (Wiring Matters, May 2025)}

Example

Karen’s house in Kirkstall has a ring circuit feeding the downstairs sockets. During her EICR the electrician tests the continuity of the ring’s live conductors and of its protective conductor. In a ring, a break in the loop does not always stop the sockets working, because the circuit can still be fed from one end. That is why the continuity test is done rather than relying on the sockets working. The electrician records the readings on the schedule of test results and notes any observation on the report.

What people get wrong

Many people think that if every socket works, the wiring must be fine. A continuity test proves something different: that every conductor is complete and well connected. A socket can work while its earth connection is poor or its ring is broken at one point.

The second mistake is thinking this is a test an owner could do with a cheap meter. It needs specialist instruments and a competent person, and NICEIC says an EICR should never be a DIY job.^{[1]NICEIC, Electrical Installation Condition Reports (EICRs)}

The bottom line

A continuity test checks that your circuit conductors are complete and well connected, especially the earth conductor and the live conductors on a ring circuit. It is done with the circuit isolated and feeds into other tests such as earth fault loop impedance. Ask your electrician which circuits were covered when you read your EICR. Our EICR testing page explains how we report.