Polarity

[ADS]

I've been reading an interesting discussion elsewhere - I won't say where.

Thought I'd bring it up here to see what the general thoughts were.

How do you test to confirm polarity on a radial socket circuit during initial verification - bearing in mind you have to tick the box on the test sheet?

 

[gram1980]

I do R1+R2 to confirm polarity at each point, then Zs at highest

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[Hardy Sparky (Mvc)]

I have a little unit that it made by kewtech which checks socket/loop/polarity/RCD. when I first got it didn't trust it so I backed it up with the test results and it works bang on, easy quick but no results

 

[Technician]

I would do short lead between line and CPC,

followed by short lead line and neutral.

You could include short lead neutral to cpc.

The first test gives (R1 + R2) calculated,

but you have proved polarity dead in the same

manner as the three steps in ring final testing.

Followed by live Zs at furthest point and the others

if need be.

That could be followed up live with a socket plug-in

but as a result it is invalid.

 

[ADS]

I do R1+R2 to confirm polarity at each point, then Zs at highest

This doesn't confirm polarity.

I have a little unit that it made by kewtech which checks socket/loop/polarity/RCD. when I first got it didn't trust it so I backed it up with the test results and it works bang on, easy quick but no results

I'm guessing this is for live testing - I'm talking about dead tests during initial verification.

I would do short lead between line and CPC,followed by short lead line and neutral.

You could include short lead neutral to cpc.

The first test gives (R1 + R2) calculated,

but you have proved polarity dead in the same

manner as the three steps in ring final testing.

Followed by live Zs at furthest point and the others

if need be.

That could be followed up live with a socket plug-in

but as a result it is invalid.

This, I agree with, but how many sparks actually do it?

 

[Chr!s]

The same way you carry it out on a Ring

 

[Hardy Sparky (Mvc)]

Time is always a test, I got these units because the lads will say have tested when it's not done and when you have been doing it for a long time every sparks knows what the test results should be,so this makes it easy for them to know it's safe. And yes it's live test only. I think you will find everyone is guilty of not doing every test every time!! But the Market is coming up with new,easy and quick ways of testing all the time !

 

[Chr!s]

Just join L -N then L-E then N-E, go around each socket, this will confirm polarity

 

[Revved Up Sparky]

I would do short lead between line and CPC,followed by short lead line and neutral.

You could include short lead neutral to cpc.

The first test gives (R1 + R2) calculated,

but you have proved polarity dead in the same

manner as the three steps in ring final testing.

Followed by live Zs at furthest point and the others

if need be.

That could be followed up live with a socket plug-in

but as a result it is invalid.

This could be done effectively and fairly quickly by having three x three pin plugs. One with a L-E link inside, one with a N-E link inside, and one with a L-N link inside.... with each plug clearly marked in permanent ink L-E, N-E, L-N. Have your mate stand at the DB with continuity tester across L-E then plug the L-E plug into all sockets, then your mate puts the tester across N-E and the process is repeated with the N-E linked plug etc. Obviously you need to make sure you remove the plug before you energise the circuit !. NIC probably frown upon this method though saying the linking out should be done in the DB with testing done on the sockets but this slightly unorthodox method would not require any disconnecting of cables/ loosening of terminal connections to insert link.

 

[ADS]

Whichever method you use, it remains confirmed that you have to test R1 + R2 and R1 + Rn to confirm polarity on a socket outlet, regardless of whether it's a ring or radial. Another way would be to use a wander lead on R2 and then on R1 or Rn.

I'm just wondering how many sparks actually do this.

The discussion arose from a news report of a plumber being electrocuted due to a 'Line' and 'CPC reversal on a socket outlet, making the washing machine live when plugged in. The R1 + R2 test alone wouldn't have shown this.

 

[Chr!s]

Whichever method you use, it remains confirmed that you have to test R1 + R2 and R1 + Rn to confirm polarity on a socket outlet, regardless of whether it's a ring or radial. Another way would be to use a wander lead on R2 and then on R1 or Rn.I'm just wondering how many sparks actually do this.

The discussion arose from a news report of a plumber being electrocuted due to a 'Line' and 'CPC reversal on a socket outlet, making the washing machine live when plugged in. The R1 + R2 test alone wouldn't have shown this.

Quite right, id like to think most electricians no how to test for polarity, testing wont come much easier

 

[Technician]

I am pretty much convinced that a lot of folk go in

and do favours.

I checked some circuits in my Mum's house and I

found one socket reverse polarity.

I came to the conclusion that the proximity of the

socket front to the Fridge freezer meant that the

person could not visually CHECK the terminations.

Tests were not done but this is how I found it.

I SAW that point wired up years before and it WAS

correct.