Hi all. I have read from a book that to check the polarity is right , between live and common and live and earth you must have a reading of 230 volts and between common and earth a reading of 15V.If you connect the live and common the other way round ie: common in place of live and live in place of common you have a reading of 115 volts therefore wrong polarity.Why do you have a reading of 115volts? Should you not have a reading of 230V anyway? Please try to make this point as clear as possible. Thank you.
polarity
- Thread starter dotto
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Hi dotto,
breifly had a read of your post and its kinda confused me.
polarity is normally carried out using a bell/buzzer to check that single pole control and protective devices(circuit breakers) are connected in the phase conductor only.
i.e checking that bayonet edison screw lampholders have the outer contacts connected to neutral.
hope this helps
RMS
breifly had a read of your post and its kinda confused me.
polarity is normally carried out using a bell/buzzer to check that single pole control and protective devices(circuit breakers) are connected in the phase conductor only.
i.e checking that bayonet edison screw lampholders have the outer contacts connected to neutral.
hope this helps
RMS
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Polarity can also be checked by default using a meter to carry out an EFLI test.
Huh !!!!!
What book was that may I ask ?
Your reference to common I presume should be Neutral. Polarity tests are as previously said. Live to Earth and Live to Neutral are identical therefore Earth and Neutral are at the same potential. If you get voltages other than 230V I would suggest you are picking up backfeeds. Turn the power off and test for polarity properly before you turn it back on. In this case from what youve said I would recommend a full test anyway.
What book was that may I ask ?
Your reference to common I presume should be Neutral. Polarity tests are as previously said. Live to Earth and Live to Neutral are identical therefore Earth and Neutral are at the same potential. If you get voltages other than 230V I would suggest you are picking up backfeeds. Turn the power off and test for polarity properly before you turn it back on. In this case from what youve said I would recommend a full test anyway.
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Thank u 4 answering. If you connected it up the other way round ie: neutral in place of live and live in place of neutral would you have a reading of 230V or 115V? If 115V, can you explain it to me in simple words why? Thanks againJob_n_knock said:
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If you connected what up the wrong way round??
230 is 230 is 230 whether L-N, or N-L or indeed L-E or E-L.....
The thing about polarity is that you do not want switching devices in the neutral.
Why?
Because then you could think you have isolated the device, but in effect it will still be "live".
Can you explain it to me in simple words why you think voltage is halved when polarity is reversed?
230 is 230 is 230 whether L-N, or N-L or indeed L-E or E-L.....
The thing about polarity is that you do not want switching devices in the neutral.
Why?
Because then you could think you have isolated the device, but in effect it will still be "live".
Can you explain it to me in simple words why you think voltage is halved when polarity is reversed?
Yep
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