How to check if a fuse feeds a ring final or 2 radial circuit

[kingeri]

Great news that you've made the right decision mate!

 

[247 handyman]

Yeah like I said I was just trying to help. I had to talk my brother in law out of just changing the fuse without getting it tested.

 

[kingeri]

Yeah like I said I was just trying to help. I had to talk my brother in law out of just changing the fuse without getting it tested.

That was very wise. You seem like a chap with lots of common sense!

 

[Pat H]

For clarity most multimeters don't offer a low enough continuity reading. To know the arrangement of the wiring we need to measure to fractions of an ohm reliably. Based on the readings we can then calculate the location of each point in the circuit based on the resistance. Most general millimetres just don't offer a low enough or consistent enough reading.

Sorry I can't offer more help and as you say there is a lot of information on google and you tube. Some very helpful people post detailed information on testing and procedures on the understanding the viewers are adults and able to judge what they are capable of or not but that its better they know than to not tell.
That doesn't seem to be the "style" of this forum where qualified experienced people can get help otherwise you will be referred to an electrician.

 

[HandySparks]

I was thinking about this recently. I don't think that the cross-connection method is particularly reliable for checking the configuration of a ring circuit where you have, for example a very short spur with more than one socket, where the additional resistance produced is minimal.

I came up with the following as a method that doesn't rely on detecting small changes in resistance:

Identify all the sockets and other accessories on the circuit.
Disconnect both ends of the line at the board and connect a resistance meter or a continuity tester across the ends.
At each accessory, disconnect the line and check that continuity at the board is lost. Then re-connect.
If breaking the connection at every accessory also breaks the ring, as indicated at the board, then you have a single, complete ring with no spurs and no cross connection.
Repeat for neutral and cpc if thought necessary (depending on wiring method).

Obviously measure ring continuity, IR, Zs, etc. as usual.

Thoughts?

 

[Des 56]

I was thinking about this recently. I don't think that the cross-connection method is particularly reliable for checking the configuration of a ring circuit where you have, for example a very short spur with more than one socket, where the additional resistance produced is minimal.

Obviously measure ring continuity, IR, Zs, etc. as usual.

Thoughts?

A couple of thoughts of mine Handysparks

Good thinking and I seem to agree with the outcome that ring continuity would be assured,but it also seems to entail major disruption at every socket, having to disconnect then test remotely at the dist board for each item and do so 3 times per socket,it would seem to be one very time consuming exercise

The main weakness I see is that the test is also a test of polarity and although the tester is likely to reconnect the items correctly,bad things do sometimes occur and this test would mean it is then down to a plug in jobbie or reliance on not getting it wrong ever

 

[Midwest]

Well you obviou

Just trying to show the OP the complexity, of a RFC test and the need for the correct equipment, a multimeter is no good for this test, not something for what is a DIYer or in this case a Handy man, who in all honesty shouldn't be fluffing around with something he has very limited knowledge, these videos are very informative for trainees etc, absolutely not to be used by non sparkies

Pete never linked up your post with OP's response, so no offence meant.

 

[Pete999]

Well you obviou

Pete never linked up your post with OP's response, so no offence meant.

None taken Mate

 

[Midwest]

Coolio

 

[Darkwood]

Another point I didn't see raised is if he in fact managed to get test results there is the issue of knowing how to interpret them, understanding what they mean and when action needs to be taken, a high ohms reading end to end may be dealt with differently by a professional as oppose to a DIYer, just because it shows a closed loop doesn't mean its safe to energise.

 

[kingeri]

Another point I didn't see raised is if he in fact managed to get test results there is the issue of knowing how to interpret them, understanding what they mean and when action needs to be taken, a high ohms reading end to end may be dealt with differently by a professional as oppose to a DIYer, just because it shows a closed loop doesn't mean its safe to energise.

I touched on it near the beginning:

To verify if it is a ring, you need to access every socket outlet on the circuit in turn (you will likely have to unscrew them all), after making temporary connections in the CU. You also need to know how to interpret the results obtained from your 'multi meter'.

 

[Darkwood]

So you did @kinger, my apologies... I just skimmed the answers and missed your note on the matter

 

[The Ghost]

I think I might be more concerned as to why suddenly are there fuses going so regularly, what is going on with the sockets if they did not do this before. You might find a temporary answer if you knew what they are plugging in when the fuse goes and encourage them not to. What do you think? At least until it can be investigated more thoroughly. Might be faulty equipment or overload from too many things on at the same time.

 

[HandySparks]

A couple of thoughts of mine Handysparks

Good thinking and I seem to agree with the outcome that ring continuity would be assured,but it also seems to entail major disruption at every socket, having to disconnect then test remotely at the dist board for each item and do so 3 times per socket,it would seem to be one very time consuming exercise

The main weakness I see is that the test is also a test of polarity and although the tester is likely to reconnect the items correctly,bad things do sometimes occur and this test would mean it is then down to a plug in jobbie or reliance on not getting it wrong ever

True. Certainly more disruptive that the conventional 'figure of eight' test.
I was really trying to think of a guaranteed way of proving a ring, as I often find that contact resistance makes for uncertain readings.

 

[mydigitalhome]

Nice to see Kris Kitcher again well known for his books and lecturing at Uni. in YouTube video