How do you test a ring final 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.
What does a continuity test on a ring final circuit prove?
The purpose of this test is to ensure that the cables form a complete ring without interconnections between the wires, and the polarity is correct on all outlets.
How many stages are there in a ring final continuity test?
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.
What is a final ring circuit?
A ring main, or final circuit, is exactly what it says on the tin. It is a ring of cables, usually 2.5mm carrying twin and earth wires, circling your home, carrying the mains electricity to sockets on the way. It gets the power from the consumer unit and delivers it to the sockets.
What is continuity of ring final circuit conductors?
Continuity of Ring Final Circuit Conductors The objective of this dead test is to ensure that all ring circuit conductors are continuous throughout the ring, with no breaks and no interconnections and also that all connections are electrically and mechanically sound.
What is ring final circuit?
A ring circuit is also known as a ring final circuit. It is sometimes incorrectly referred to as a ring main or ring mains (which are outdated terms) or simply a ring. It is a wiring technique that permits the use of wire with a diameter that is smaller than that of a radial circuit with the same total current.
What is a final circuit?
Final circuit. A circuit connected directly to current-using equipment, or to a socket-outlet or socket outlets or other outlet points for the connection of such equipment.
What is the difference between a ring main and a ring final circuit?
A ‘Ring’ is a ring that is stuck on your finger or somewhere else; a ‘ring main’ is a distributed electrical supply that is fed along two separate cables in either a parallel path or in a diverged path to various points to join to provide further points of supply; ‘a ring circuit’ is a distributed supply circuit …
How many sockets can you have on a ring final circuit?
There is no limit to the number of sockets you can have on a ring main but there is a limit to the number of spurs you can have from those sockets or from the wiring between them. If you would like to know how to add a spur to an existing ring main, see our project on adding an extra socket.
What is a good insulation resistance reading?
Insulation resistance should be approximately one megohm for each 1,000 volts of operating voltage, with a minimum value of one megohm. For example, a motor rated at 2,400 volts should have a minimum insulation resistance of 2.4 megohms.
How do you measure the continuity of a ring final circuit?
This measurement would be (r1+rn) or (1 + rn)/4. The next diagram from Megger shows how you can check the continuity of ring final circuits with no spur.
What is the purpose of a ring circuit test?
The purpose of this test is to ensure that the cables form a complete ring without interconnections between the wires, and the polarity is correct on all outlets. The best way to do a ring circuit test is with the help of a Resistance Tester or with the Low Reading Ohm meter function of an Installation Tester such as the Megger 1553.
What is the continuity of ring final CCT?
The Continuity of Ring Final Cct. Conductors test is a pre-requesite to the integrity of any subsequent tests. Among other things, a partial test doesn’t provide a sound legal basis on which to legitimately proceed to the next test stage. (ie live testing)
How to test for low ohm in a ring circuit?
Step 1. Within the distribution board, remove the Line, the Neutral and the Earth conductors from its terminals. Since this is a ring circuit there will be two of each in the same terminal. Step 2. Select the low reading ohm meter function and null the tester.