Adapter and overcome – streamlining the process of ring final circuit measurement | Metrel

Adapter and overcome – streamlining the process of ring final circuit measurement | Metrel

Brendan Beaver, Manager of Metrel UK, looks at why the advent of adapters means that you can tailor the functionality of your test system around your requirement, without buying more than you need.

Adapters that extend the capabilities of MFTs seem to have confirmed themselves as the big idea of the 2020s. Just look at the plethora of EVSE adapters that have come out since we launched ours a few years ago. The adapters all mimic a vehicle at a charge point for functional testing as well as giving access to the supply system for electrical testing. Luckily, Metrel testers also had the capability of remote firmware updating so tests like the 6 mA dc breaker test could be introduced without having to replace the instrument.

Ring’s true

Continuing this trend, Metrel has introduced a ring continuity adapter (A2214) to streamline the process of ring final circuit measurement. It has been well received by customers who work alone as well as those who are under great time pressure.

Both the adapter and the mains plug BS1363 test lead are nulled, and the results are committed to the tester’s memory. Once done there is no need to repeat the nulling until something changes, like the croc clips or test lead are replaced, changing the resistance of the test system.

Testing is now quite a simple process. The adapter is connected to the tester which is in Rlow, RING mode. For the end to end continuity, the test parameter is set as r1, r2, rN and the test leads are clipped to the circuit in-comer and out-goer. The button is pressed and almost immediately all three results are displayed. The screen can then be saved for later reference.

Measurement of R1+R2 and R1+RN while the adapter performs the switching at the consumer unit.


The adapter is disconnected from the tester and left at the consumer unit where it will make all the connections required while you test around the ring. The calculated values of (r1+rN)/4 and (r1+r2)/4 are displayed while R1+R2 and R1+RN are measured and displayed for each outlet and the highest value retained. The adapter and tester communicate along the conductors to make the appropriate connections at the right time, often referred to as ‘the figure of eight’.

Not only does this process make it a one man job, it’s also much quicker. The free firmware update has been written for the MI 3100, MI 3125, as well as the touch-screen MI 3152 and MI 3155.

If you work with 3-phase supplies, Metrel has another adapter for you. By automating the testing the 3-phase active switch A1507 makes it faster and safer for you.

3-phase active switch and multifunction tester 3155 ready to save time improve safety when testing an industrial installation

You only need to make the connections between the switch and the installation under test once, and connect the active switch to either of the touch-screen testers. The tester controls the active switch, making and breaking connections as required, to run through a suite of measurements under your expert supervision from a safe distance. For example, the ten insulation tests required are initiated with the single press of the test button, each result being automatically committed to the tester memory for review, approval and certification.

View the Metrel A2214 Ring Continuity Adapter product data sheet here

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