Question regarding dead polarity test. Please Help.

[nazoom]

Hi

I am bit unsure when carrying out dead polarity test on a one way switch and two way switch. Where do the test probes go and on what?

Do we make contact at the switch line and the cpc of a ceiling rose? or do we contact at the line and cpc at ceiling rose?

What happens in two way switch?

Many Thanks.

 

[JUD]

Connect probes to switch line and cpc at ceiling rose.

With the switch on you should get a reading and with the switch off it should be open circuit.

(Line an cpc connected at DB obviously)

 

[telectrix]

and if the reading doesn't go open circuit when the switch is operated, either the switch is wired incorrectly or you are switching neutral. (rare, but not unknown)

 

[SirKit Breaker]

Just to add to Jud's post, if you try to do it at the switch, you will not prove polarity, you will just prove the switch works. If for some strange reason you connected the switches in the neutral, you would get the same readings as if it were in the line, so as Jud states do it that way. If you are just venturing into the testing world, then get hold of Guidance Note 3, this explains in great detail, and with good illustrations all the testing procedures.

Cheers............Howard

 

[nazoom]

Many thanks to all.

 

[Farmelectrics]

Another way of doing it is link l e at board go to your last light fitting on circuit and test across l e this gives you your r1 r2 test and also proves polarity your switching arrangement could be done by function testing

 

[JUD]

Another way of doing it is link l e at board go to your last light fitting on circuit and test across l e this gives you your r1 r2 test and also proves polarity your switching arrangement could be done by function testing

This should also be done across switch line and earth. The switch drop should be included in your R1+R2. Operating the switch then proves polarity. Two birds with one stone and all that.

 

[nazoom]

Sorry what is the switch drop? Do you mean operating two way switch one at time?

 

[nazoom]

Sorry what is the switch drop? Do you mean closing light switch for 1 way and 2 way (switch one at time) at continuity and open the switch at polarity?

 

[JUD]

The switch drop is the wire/cable between the ceiling rose and the switch. It is part of the circuit and needs to be included in the R1+R2 test.

Connecting your probe to the switch line will include the conductors feeding and returning from the switch. Turning off the switch will break the line conductor, hence proving polarity.

 

[Farmelectrics]

If all your switches are in the on state the test will include your switch drops anyway

 

[JUD]

If all your switches are in the on state the test will include your switch drops anyway

Only if you connect your probe to the switch line at the ceiling rose. Connecting it directly to the loop doesn't include the switch drop.

 

[nazoom]

Thanks for clearing things to me.

 

[sedgy34]

Hi

I am bit unsure when carrying out dead polarity test on a one way switch and two way switch. Where do the test probes go and on what?

Do we make contact at the switch line and the cpc of a ceiling rose? or do we contact at the line and cpc at ceiling rose?

What happens in two way switch?

Many Thanks.

nazoom to your phone and call an electrician in

 

[Farmelectrics]

if your swiches are on then you can test at loop your swich wire becomes a continuation of your loop hence the light comes on just saves a bit of time with your testing you can do it the other way but why not put all switches on and do the test once