Low R1+R2

[Bazultra]

I am currently testing a ring circuit with an r1 of 1.12 an rn of 1.12 and an r2 of 1.80
I have carried out my figure 8 test only to find that i have varying readings at the sockets between 0.40 and 0.80. How is it that I could be getting a low reading such as 0.40 with no parallel paths. I have made double sure I have carried out the figure 8 test correctly. Could this indicate a ring in a ring?

 

[dave274]

what would you like it to be? did you zero your test equipment?

 

[Johnuk]

oh boy

 

[telectrix]

from you r1 and r2 readings, you would expect R1+R2 at each outlet to be about 0.75ohms.

 

[Richard Burns]

Have you tried retesting the end to end values and making sure you have a good connection to the cable ends, a variation of 0.16 / 0.32 Ω could by caused by contact resistance or loose lead connections.
I assume the values you are measuring are for the r1 / rn figure 8?
Alternatively you could still have the ends the wrong way round and it is just a long run to the first socket.
What results do you get if you swap the connections round the other way?

 

[telectrix]

deleted due to incriminating myself for being stupid.

 

[Silly Sausage]

don't mention connections the wrong way. i've just been to a fault where N and E were swapped over twice on the same circuit.

You've given the game away!!!! :banghead::smilielol5:

 

[Edd]

You can get a low reading when doing a fig 8 test if you have a boiler circuit that has crossbonding, even with the load disconnected leaving the earths connected will give a lower reading as you aproch the spur. Look for something like that. Even a forgotton washing machine plunged in will cause this.

 

[PEG]

You can get a low reading when doing a fig 8 test if you have a boiler circuit that has crossbonding, even with the load disconnected leaving the earths connected will give a lower reading as you aproch the spur. Look for something like that. Even a forgotton washing machine plunged in will cause this.

It is surprising how many "testers" forget that disconnecting items from a RFC,may include what you have discussed,and leaving conductors,other than the line,still connected,can affect results. If only every RFC was as drawn in a text book...just posted about one i went to, a mixture of upstairs and downstairs radials,joined at one MCB,with at least two interconnections,and spurs going everywhere...extractors,boosters,garden lighting and a whole recently fitted kitchen...marvelous irate: