no resistance end to end on L & N

[Ross1]

Hi, Im doing a end to end continuity on the house ring but am getting 0.00ohms on L -L & N -N but getting 0,42 ohms on E - E.

Ive done a point to point check right around the ring, all seems good but when I tested again I`m getting same results.

thanks

 

[malcolmsanford]

Is there 2 RFC and have you got the right ends ?

 

[Marvo]

Try using an analogue tester instead of a digital one, it will be less sensitive to induced surface voltages etc..

 

[robd]

split the ring in half and test continuity from the board to the point where you've split in half, if you've got continuity on one end but not the other work your way back round until you find the break in the circuit. What I mean by this is take a socket off the wall at a point you think is halfway, don't screw anything back on the wall until you've sussed it or else you'll spend your time doing the okey cokey with them. Think about it logically and all will become clear If for example someone's screwed through a cable it's unlikely they would've gone through the live and neutral conductor without hitting the earth, assuming it's wired in twin and earth

 

[robd]

and make sure you aren't using the wrong cable to try and get a reading off, have a good root round in the consumer unit and check you're not testing an end of the ring with another circuit

 

[gnselectricals]

Have you nulled your leads properly as you would usually see +2000 ohms not 0.00 if open circuit
Regards gram


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[telectrix]

i would say that the 0.42 is sensible. it's the 0.00 that you should be concerned about.

 

[robd]

sorry mis-read, 0.0 obv not open circuit so ignore me teach me to try and get technical on a Sunday! 0.0 might be right if you've got a rfc covering a very small area, failing that check your leads!

 

[Marvo]

i would say that the 0.42 is sensible. it's the 0.00 that you should be concerned about.

Yep, it was the 0.00 I was worried about, might be the high input resistance of a digital tester picking up RF or induced voltages.

 

[telectrix]

could try measuring with board isolated so all other circuits can't affect the reading with induced volts etc.

 

[Harry Worth]

Is it a Doll's house?
Or - On a ring final. 2.5mm2 Neutral and Live. 1.5mm2 on the CPC. The resistance of CPC end to end should be 1.67x higher than N & L end to end readings. In your case with .42 Ohms then the end to end readings should be circa .25 ±0.05 Ohms. Readings should be within 0.05 Ohm so 0.2 - 0.3 Ohm. (Still learning so please kick me where appropriate)

 

[Richard Burns]

I have a circuit in my house where the "ring" goes out to the shed but it is joined together in a connector block before it leaves the house, I have not tested it but this may well give similar results to the OP. e.g. has someone crossed the ring or joined it at the first socket out.

 

[telectrix]

I have a circuit in my house where the "ring" goes out to the shed but it is joined together in a connector block before it leaves the house, I have not tested it but this may well give similar results to the OP. e.g. has someone crossed the ring or joined it at the first socket out.

so why ain't you fixed it then. ???

 

[Richard Burns]

It is still cables in parallel CC is OK and in the words of so many customers it works! (sorry!)
Effectively unless there is a problem in the floor above the CU the connection into the CB is just a bit far away and one could consider it as a piece of 5mm going to start a ring 3m away and I am too lazy to take the floorboards up.

 

[telectrix]

fair enough. i have inherited a couple of unfused spurs on the rfc with 3 or 4 outlets on each. rather than spend hard earned on fitting FCUs, i've downrated the MCBs to 16A