How do you test a ring main continuity?

The Ring Circuit Test sequence:

Within the distribution board, remove the Line, the Neutral and the Earth conductors from its terminals.
Measure between Line to Line to get the reading for “r1”
Measure between Neutral to Neutral to get the reading for “rn”
Measure between Earth and Earth to get the reading for “r2”

How do you test a ring main circuit?

To test a ring you must firstly measure the end to end resistance of L-L, N-N and E-E. You should then connect the incoming live with the outgoing neutral and measure the resistance at the furthest point in the circuit. Then also the reverse of the with the outgoing live to the incoming neutral.

How do you measure ZS on a ring circuit?

To find the zs of a ring circuit you need to cross connect at the origin of the ring, ie, connect the incoming phase to the outgoing cpc and vice-versa, then measure between phase & cpc at all of the sockets, the one with the highest reading gives the r1+r2 figure, just add this to your ze figure and you`re there!

What does a continuity test on a ring final circuit prove?

Typically electricians have reckoned that the resistance of the cpc when compared with that of the line and neutral conductors is always in the order of 1.67 times greater. For every ring final circuit a test is required to verify the continuity of each conductor, including the cpc (Regulation 612.2.

Which is better radial or ring circuit?

Ring circuit wiring offered a more efficient and lower cost system which would safely support a greater number of sockets. The lower costs aspect was related to fact that wires with a smaller diameter could be used, compared to radial wiring. Ring circuits provide low protection against overcurrents.

How many stages are there in a ring final continuity test?

Three Steps
Continuity of ring final circuits – Guidance Note 3 (Page 45) The test is undertaken in Three Steps and you must follow all the steps in the correct sequence. The readings taken should be the same if all conductors have the same CSA and are correctly wired.

How do I know if my ring is radial?

The only way to be (pretty) sure whether sockets are on a ring or radial circuit would be by looking inside the consumer unit (or ‘fuse box/board’). Fony, FYI, this is the problem if you just look at a socket.

What will a successful ZS test prove?

A Zs test is not to prove an earth connection exists, although it would do so, but to prove that the CPD would operate within the time required by BS7671. Smpling should be of circuits, not equipment of a circuit that is being tested.

What does a ZS test prove?

Zs represent earth fault loop impedance and consists of Ze and (R1+R2). These are measurements of the fault current from the supply transformer to the building. It covers the entire electrical cycle. If Zs are too high, not enough fault current can flow and the MCB may not trip at all.

How do you find the resistance of a CPC?

To calculate the resistance of the CPC you end up with an equation with (R2 + RN) / 4 = R1 where R1 is the line conductors resistance, R2 is the CPC resistance and RN is the resistance of the neutral wire.

Why is radial connection better than ring?

Why is a ring main better than a radial?

4.1. 2 Earth Continuity Cable If the earth continuity cable is disconnected at a point around the ring, there will still be earth continuity at each socket. To this extent the ring is safer than the radial circuit. Loss of an earth continuity conductor on a radial circuit may not be noticed until a shock is received.

When to use resistance testing for HCV treatment?

If Y93H is present, weight-based ribavirin should be added or another recommended regimen should be used. Resistance testing is most important in clinical practice when the results would modify treatment management by impacting the duration of therapy and/or inclusion of ribavirin, or result in selection of alternative therapy.

How is the resistance of a ring final Circuit determined?

One such judgement involves determining whether the end-to-end resistance of a circuit protective conductor (cpc) in a ring final circuit is reasonable when compared with the end-to-end resistances of the line and neutral conductors.

When do you need a ring final circuit test?

For every ring final circuit a test is required to verify the continuity of each conductor, including the cpc (Regulation 612.2.2 refers). Domestic ring final circuits are, more often than not, wired using flat win and earth cable having 2.5 mm 2

What kind of conductors are used in ring final circuits?