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Socket Outlet Continuity

Former Community Member
Former Community Member
Hi,

This is my 1st post so please be kind to me........ ?

Whilst carrying out Ring Main Continuity either r1-rn and/or r1-r2 I have been getting differing results at various sockets by way of the plug top tester. The ring tests out fine when using probes on the back of the sockets. For example the healthy r1-rn was 0.4. At some sockets using the plug top test a double socket would give me 0.6 onside and 1.10 on the other - but all OK testing from the terminals at the rear.

I understand that this is probably down to lack of use - is there any limit to the losses through the socket.

They all tested out OK doing Zs. 

Am I being over cautious?

Many thanks
  • I would agree that measuring the continuity through the sockets will offen give varying results, in my case as much as 0.2 Ohms between two oulets on the same accessory. I always put it down to manufacuring tolerances getting progressively worse the cheaper the accessory. It appears that the lack of quality products is spreading......

    The other problem is that most if not all socket outlets are protected by RCDs. These device do not like being zapped with 25A pulses but prefer a 15mA current that is electronically adjusted. Where there is any form of pattener acculmanated between the socket and plug there will be a slight change in resistance.

    IMO on initial installation connect socket outlets and take measurements before attaching the plates to the backing boxes; for reports take samples or, if time and ecconomics allow, disconnect the plates before taking measurements

    Legh
  • You may find if you take the plug out and wipe it and put it back a few times the reading changes too, as there are microscopic layers of what we technical people call 'grot' (*)on the contacts, that build up over time, especially with older sockets. Decent sockets with stronger springs fare a bit better as there is a wiping/scraping action as the plug goes in.


    There is no need to be alarmed, the  test meter is only using small currents and voltages, if a real fault came on, then the thin layers of oxide that form would be blown away, and the current would rise to be enough to trip the breaker.

    The 'stabbing' action of probes on the back will get through correctly, and those are the readings to be trusted.

    Mike.

    * other more descriptive words are available, especially for sockets in chip shops and similar places.
  • " other more descriptive words are available, especially for sockets in chip shops and similar places."


    ?
  • Former Community Member
    0 Former Community Member
    Cheers guys - makes sense. I was questioning the quality of the outlets.


  • A few years back (prior 2000) our cllege tutor was telling us that they had a "test board type" set up in the engineering block for training apprennticesand when doing the ring and radial testing bit they noticed that the readings obtained had variance on the plug in testers but pretty good continuity on conductor testing, those sockets had been in place for a few years and he deliberatley kept them in place as a working example for them to "discover"
  • Dirty switch contacts if the socket-outlets are switched - in the case of "test boards" it's related to lack of use of the socket-outlets for drawing any real current, and in general when something "meaty" is plugged in the contacts should clean themselves.


    When this is the problem, you see a change in the resistance reading when you operate the switches a few times.
  • Former Community Member
    0 Former Community Member
    Thank you