R1 + R2 doubled on the double

[spark-ticus]

Hoping someone can shed some light on why, when i tested R1+R2 on the double sockets on a ring in my garage, on 1 side of the socket i got a reading of 0.25 ohms (which was consistant with other sockets on the ring ) but on the other side i got 0.46 ohms ?? They are old socket faces (approx 6 years) checked all terminations which are fine, not sure why i would get this reading?? Any takers?

 

[tony mc]

Resistance of the socket if you remove it and place your probes on the CPC and Line you will get a more definate reading.

This tends to happen alot especially on old or unused sockets !

 

[spark-ticus]

Ah, ok cheers tony. Would you consider it a defect and change it?

 

[telectrix]

try shoving a plug in and out a few times. could also be resistance in the switch. flick it on and off a few times.

 

[spark-ticus]

Will try that, cheers telectrix

 

[Guest112]

had the same problem during my 2391 the examiner mentioned what tele and tony said about the resistance of the socket outlet especially old ones, but this does greatly affect the resistance and the 0.05 difference allowance goes out the window unless you remove each socket on the ring and test, but my boss works it out on 20min a circuit not too great when you get a board full of rings !!

 

[leonard]

had the same problem during my 2391 the examiner mentioned what tele and tony said about the resistance of the socket outlet especially old ones, but this does greatly affect the resistance and the 0.05 difference allowance goes out the window unless you remove each socket on the ring and test, but my boss works it out on 20min a circuit not too great when you get a board full of rings !!

When i was doing my 2391 i was told that the 0.05 allowance was only for the loop conductors when tested at the DB and not on the socket .

 

[jjnr78]

I would consider it a defect unless there were visible signs of corrosion. You should find that the Zs value is more of an indication if there's a problem with the socket outlet. If it produces an excessive resistance, then recommend a change.

 

[Guest112]

When i was doing my 2391 i was told that the 0.05 allowance was only for the loop conductors when tested at the DB and not on the socket .

the 0.05 allowance is for the end to end tests at the DB on all conductors of the ring unless its T&E where youd expect 1.67 times higher compared to line and neutral

and on step 2 and 3 the 0.05 still applies because you are testing the same length of circuit at each point, these readings are the readings for R1+R2 on the line and cpc figure of 8 test, the figure of 8 tests that the ring hasnt been installed wrong by being bridged etc

 

[leonard]

the 0.05 allowance is for the end to end tests at the DB on all conductors of the ring unless its T&E where youd expect 1.67 times higher compared to line and neutral

and on step 2 and 3 the 0.05 still applies because you are testing the same length of circuit at each point, these readings are the readings for R1+R2 on the line and cpc figure of 8 test, the figure of 8 tests that the ring hasnt been installed wrong by being bridged etc

I agree with you ,but that is in ideal world when every thing is new and properly connected ,in the real world the resistance measured on the socket outlet can be different because of mechanical part of the socket itself , specially the were and tear during the life of the socket.

 

[Guest112]

I agree with you ,but that is in ideal world when every thing is new and properly connected ,in the real world the resistance measured on the socket outlet can be different because of mechanical part of the socket itself , specially the were and tear during the life of the socket.

yeah definately aslong as the readings are about the same i think its acceptable i know a lot of sparks who dont even do the three step method and probably dont remember how they just end to end test them and R1+R2/4 and put down the expected reading rather than the measured one