Polarity: Testing at light switch

[PC Electrics]

Quite correct. The sentence should read:

Your IR test (at the board end) will prove there is no cross connection between any of the 3 conductors.

 

[Dambo]

4 quick questions guys (If 4 questions can be quick!):

1) Am I right in saying that when testing L-E, when the switch is on there should be continuity but when the switch is off there is no continuity?

2) Wouldn't a visual check simply uncover any potential problems?

3) On ES lampholders why is the live tested on the centre contact?

4) Is a low resistance ohmmeter or a voltage / continuity tester used to carry out the test?

 

[green-hornet]

1) There will always be at least one wire showing continity with the light off, it is important to include the whole circuit which is why the switches are always on.

2) Visual is just as important as testing, it could when doing live tests save your life potentially.

3) this is the correct polarity for this type of fitting

4) you need to record the highest result you find on the test certificate, so a simple continuity tester will not do and the digital type that do give a reading are not as accurate as a low resistance ohmmeter

 

[Risteard]

The line conductor must be connected in the centre-pin so that when you are screwing an Edison Screw lamp in, should your fingers touch the side of the fitting which hasn't been isolated they will come into contact with the neutral rather than line.

 

[Dambo]

1) There will always be at least one wire showing continity with the light off, it is important to include the whole circuit which is why the switches are always on.2) Visual is just as important as testing, it could when doing live tests save your life potentially.

3) this is the correct polarity for this type of fitting

4) you need to record the highest result you find on the test certificate, so a simple continuity tester will not do and the digital type that do give a reading are not as accurate as a low resistance ohmmeter

Regarding 1 - So the test simply involves putting one probe on L and one probe on E and if a voltage is present then the polarity is correct?

Regarding 4 - On the PIR is the polarity not just indicated with a tick?

 

[patspark]

hi damien if you have a copy of the on-site guide.

look on page 86 you will find the explanation and diagram

hope that helps

 

[green-hornet]

Regarding 1 - So the test simply involves putting one probe on L and one probe on E and if a voltage is present then the polarity is correct?Regarding 4 - On the PIR is the polarity not just indicated with a tick?

There will be no voltage present, this is a dead test, under no circumstances should you test continuity live.

A simple continuity test could be say a 6 volt battery and a torch lamp.

You connect one lead to live and one lead to earth if continuity is there then the lamp will light.

On a pir yes and also on the full electrical installation certificate.

Providing all tests are carried out polarity can be confirmed by doing R1+R2, visual at test points, and insulation tests which are all carried out with no supply.

 

[Dambo]

Thanks green hornet but to be honest i'm none the wiser. All I want to know is:

a) Is the polarity test at a lighting point carried out with a low resistance ohmmeter or a continuity tester?

B) Does the test simply involve, after having linked L and E at the CU, putting one probe on L and one on E at the lighting point to check for correct polarity?

 

[green-hornet]

You are confusing polarity with continuity.

The link you do at the cu only provides you with a continuity confirmation.

However by confirming this continuity which is the R1+R2 test it also provides you with the knowledge that polarity is correct. L=L N=N E=E.

If you do not get any continuity at the light switch then it would mean that one of the cables is not connected or polarity is wrong.

 

[kiwiNCFC]

Quite a good thread this is. Just been looking through back pages and this was quite a good read!

 

[spinlondon]

If you conduct the continuity test with a continuity tester, you will then have to conduct the R1+R2 test with a low ohm meter.

If you conduct the R1+R2 test with a low ohm meter, you will prove continuity at the same time.

 

[sparkytim]

Continuity tester IS normally a LOW OHM test meter.

 

[Lurch]

Continuity tester IS normally a LOW OHM test meter.

Except when it's not.

In the eyes of the definitions in the books etc... they're different. I have both in the tool bag, a simple go\no go continuity tester and a meter.

 

[VoltzElectrical]

Aye, I know that part, but what I can't understand is why between L and E???

you could theoretically achieve functional switching by switching the neutral instead of the line. The light would still go on and off, BUT, this is not permitted. by performing a polarity test you confirm that the switch breaks the line conductor. the test is a continuity test. to do a continuity test you must have CONTINUITY> by linking live and earth you close one end of a loop. when you put your probes on live and earth of that circuit at another point, that loop is closed through the tester, and voila! best to get a copy of the onsite guide. it has nice big colour pictures.

 

[ianmacd]

My Fluke voltage tester has a built in continuity tester but its not a low ohm test meter.

 

[VoltzElectrical]

my fluke voltage tester makes a lovely omelette and can hold a tune too. lol.

 

[ianmacd]

my fluke voltage tester makes a lovely omelette and can hold a tune too. lol.

You going for the award of most irrelevant post in a thread?

 

[VoltzElectrical]

lmbo that's what.

 

[SPECIAL LOCATION]

I'm still not getting it guys, sorry.I'm studying to be an electrician and doing a question now on polarity.

Slightly off topic but I am confused by:-

How come you got an NICEIC Domestic installer logo under your name..

If you are still not yet qualified?

:|

 

[Lurch]

Slightly off topic but I am confused by:-How come you got an NICEIC Domestic installer logo under your name..

If you are still not yet qualified?

:|

TBF, that post was in January, someone dug it up again the other day. Still worrying though.