I have just been working on our electrics and, among other things, removed some sockets from a ring circuit as they were on a stud wall which will soon be removed.
While I was about it I checked the end-to-end continuity of the live and neutral conductors, they were OK but measured slightly different, one was about 0.6 ohms, the other about 0.8 ohms. Should I be worried and start checking for loose terminal screws or similar or is this difference within the variability one might expect?
The readings should be within 0.05 ohms of each on a T&E circuit.
"each other"
What are you using to do the test?
Of course on such low values, connections even in the tester itself can put them way out. Brian
A pretty good multimeter which consistently reads 0.0 ohms when the leads are shorted together. I have also used another (less good) multimeter and got pretty similar results.
So I should look for an issue somewhere. The meter has good enough discrimination I think so that I can split the ring in the middle somewhere and try measuring the two halves and do a 'binary chop' until I find the problem.
Correct, it is even difficult to get a decent contact with the probes for such low values of resistance. The meter needs to have good firm connections and support at least two digits after the decimal point to produce a worthwhie result.
I would say there is an issue.
I would just say check the tightness of all the socket terminals and not bother with divide and conquer on this one as there may be more than one at fault. How many sockets/fused spurs are there?
And remember to check the CU terminals.
Probably around 20 or so, maybe a few more than that.
Well they've been on and off several times for the measurements! :-)
With that number I would just check them all.
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