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Ring Main at Consumer unit

Former Community Member
Former Community Member
My daughter has just had an electrical safety check done and I suspect that the electrician has been over zeleous..

Would anyone care to comment.


There is no grommet where the meter tails enter the consumer unit and the outer insulation stops just short of the knockout.

He has graded this C1.   Now my opinion is that that does not present an  an immediate threat to the safety of personell

It needs fixing but surely only a C2?


More intriguing.  He gives a C3 to the ring circuit because the two legs enter the consumer unit through separate knock outs.  I can't find that in the regs


And finally an old chestnut which has been discussed before.   A C3 because two radial "circuits" are served by a single breaker..  I have always argued that the definition of a circuit is that it is served by a single breaker.  Certainly if both radials were brought to a junction box outside the CU and then connected to the breaker by a single cable it would meet the definition of a radial..


Thanks for your attention

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  • Former Community Member
    0 Former Community Member
    davezawadi (David Stone):

    The primary insulation of the tails can be seen or touched, that is your observation. The sheath IS NOT INSULATION, it is mechanical protection. There is no reason to suspect the primary insulation allows contact with live parts, the correct code is C3, requires improvement. This idea of moving out is complete nonsense, as is C1 or C2. The installation does not meet the requirements of the regulations but is not DANGEROUS. If you think this is dangerous, you and I have wildly different visions of reality. I assume you spend all day hiding in bed, unless damaged you cannot get a shock from LV insulation! It is untidy, and needs some work.


    Just for information, if these were HV cables at say 33kV you could get a tingle if the shielding were not connected due to capacitive coupling of a small current through the small capacitance to your hand, but you need a very high voltage to make this large enough to feel. Because you might jump back and fall this should probably be a C2, but not with 230V.


    I do not know who the "you" refers to in this post, but if itis me you are are misrepresenting me.  I am completly in agreement with you.  In my opinion the lack of sheath is a C3.  There are two other places in the installation where,, at socket entries, where primary insulation is visible and these have been graded C3

    The fact that there is no grommet and the primary insulation is in contact with the edge of the knock-out is a seperate and more contentious issue.   I have done an experiment with a piece of tail cable and an old back box and found it almost impossible to damage the cable on the edge of a bare knock-out


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  • Former Community Member
    0 Former Community Member
    davezawadi (David Stone):

    The primary insulation of the tails can be seen or touched, that is your observation. The sheath IS NOT INSULATION, it is mechanical protection. There is no reason to suspect the primary insulation allows contact with live parts, the correct code is C3, requires improvement. This idea of moving out is complete nonsense, as is C1 or C2. The installation does not meet the requirements of the regulations but is not DANGEROUS. If you think this is dangerous, you and I have wildly different visions of reality. I assume you spend all day hiding in bed, unless damaged you cannot get a shock from LV insulation! It is untidy, and needs some work.


    Just for information, if these were HV cables at say 33kV you could get a tingle if the shielding were not connected due to capacitive coupling of a small current through the small capacitance to your hand, but you need a very high voltage to make this large enough to feel. Because you might jump back and fall this should probably be a C2, but not with 230V.


    I do not know who the "you" refers to in this post, but if itis me you are are misrepresenting me.  I am completly in agreement with you.  In my opinion the lack of sheath is a C3.  There are two other places in the installation where,, at socket entries, where primary insulation is visible and these have been graded C3

    The fact that there is no grommet and the primary insulation is in contact with the edge of the knock-out is a seperate and more contentious issue.   I have done an experiment with a piece of tail cable and an old back box and found it almost impossible to damage the cable on the edge of a bare knock-out


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