Polarity Test

[1337]

I know an R1+R2 test will indicate Polarity but ignoring that, how do you preform a Polarity test?
and how does it vary between testing on a radial, ring and lighting circuit?

While im posting a thread, another question... when doing an RCD test what Amps do you test at? 10A? 30A?

Thank you!

 

[Farmelectrics]

Well you don't ignore r1 r2 because that tells you straight if you have polarity I think you mean mili amps as well for your rcd test

 

[chrish_1977]

Polarity is a live test

 

[Plonker 3]

Polarity is a live test

Is it?

A R1&R2 test can be used for this too.

 

[Plonker 3]

I know an R1+R2 test will indicate Polarity but ignoring that, how do you preform a Polarity test?
and how does it vary between testing on a radial, ring and lighting circuit?

While im posting a thread, another question... when doing an RCD test what Amps do you test at? 10A? 30A?

Thank you!

Struugling with your homework are we?

 

[1337]

Sorry I rushed posting this thread
Nope, just revising.

 

[Plonker 3]

Ok. So what do you think the answers should be?

 

[1337]

For Polarity I think you can test by putting the live in the earth bar buts that's all I can remember at the moment. I suppose the Polarity question is kind is irrelevant now, assuming you will never get asked to prove Polarity at all after the R1+R2 test.

And the RCD test I can't remember if you need to test on 10 or 30 / I which cases you should test at 10 or 30

 

[Guest111]

You THINK you can test by putting the live in the earth bar! you need to read your OSG a bit more,as for the 10 or 30 bit that depends on the trip rating of the rcd if its 30 milliamp then you test at 30 milliamp if its 10 milliamp then you test at 10 milliamp.

 

[1337]

I remember watching a video showing something close...

Found it
Polarity - YouTube


I'am at college, never really done any testing and want to get a head start for when I need to learn them. I know I'm probably asking silly questions but I'm trying to learn!

 

[Farmelectrics]

no such thing as a silly question 1337 when you do your r1 r2 you have acheived polarity as well so just tick the box on test cert were it ses polarity when you energise sockets after dead testing them you can plug in a polarity tester aswell testing rcd you set the tester to the apropiate range ie 30ma then you do a series of tests at half its value then x1 its value followed by x5 its value hope this helps but as said a good read of gn3 will explain this

 

[Guest111]

I remember watching a video showing something close...

Found it
Polarity - YouTube

I'am at college, never really done any testing and want to get a head start for when I need to learn them. I know I'm probably asking silly questions but I'm trying to learn!

Nothing wrong with asking questions mate,sometimes it's better to have a hunt around like you have done first then come and ask questions when you have a bit better understanding of what you are trying to do.And yes regards polarity testing by linking out L and E at cu then doing a continuity test at each socket outlet that does prove the polarity is correct. a test adaptor is handy for this or if cash is tight then a bit of flex with a plug top on one end and strip block on the other will do. good luck with your learning.

 

[Jurasic Spark]

no such thing as a silly question 1337 when you do your r1 r2 you have acheived polarity as well so just tick the box on test cert were it ses polarity when you energise sockets after dead testing them you can plug in a polarity tester aswell testing rcd you set the tester to the apropiate range ie 30ma then you do a series of tests at half its value then x1 its value followed by x5 its value hope this helps but as said a good read of gn3 will explain this

So if this reveals a polarity issue isn't it a bit like shutting the stable door once the horse has bolted? You should prove polarity before energising the circuit.

 

[Jurasic Spark]

Nothing wrong with asking questions mate,sometimes it's better to have a hunt around like you have done first then come and ask questions when you have a bit better understanding of what you are trying to do.And yes regards polarity testing by linking out L and E at cu then doing a continuity test at each socket outlet that does prove the polarity is correct. a test adaptor is handy for this or if cash is tight then a bit of flex with a plug top on one end and strip block on the other will do. good luck with your learning.

How would this reveal a L and E reversal??

 

[Plonker 3]

How would this reveal a L and E reversal??

Simply turn the switch on and off. You have to use some common sense when testing.

If that way is incorrect how do you test for polarity?

 

[wiganspark]

i thought interconnecting r1/rn on your ring was the only way to prove polarity on sockets before the circuit is energised ?

 

[Jurasic Spark]

Simply turn the switch on and off. You have to use some common sense when testing.

If that way is incorrect how do you test for polarity?

Agreed but how would this reveal a L and E reversal

 

[Plonker 3]

Agreed but how would this reveal a L and E reversal

When you operate the switch your meter will either show a very high reading or a very low reading.

Visually check the device is correctly wired at the terminals.

So how do YOU test for polarity if you dont know the answer to your own question?

 

[Farmelectrics]

jurasic i said earler in my post that you would have proved polarity by doing r1 r2 once we carry out are r1 r2 test and it conforms to bs7671 that means after are ir test we can energise the circut i did say that in my post

 

[markc123]

I remember watching a video showing something close...

Found it
Polarity - YouTube


I'am at college, never really done any testing and want to get a head start for when I need to learn them. I know I'm probably asking silly questions but I'm trying to learn!

Hello buddy, if you don't already have it.....go on amazon and buy Guidance Notes 3....i know you'll probably be able to loan it from your college - but its best to have your own copy. Make GN3 your bedtime reading for the next couple of months and you'll have a very nice head start on the course. GN3 is the fountain of knowledge for testing.

Good luck.

 

[chrish_1977]

Polarity is a live test

Is it?

A R1&R2 test can be used for this too.

That's what they told me on my 2391

 

[Plonker 3]

That's what they told me on my 2391

It can actually be either a live or dead test.

 

[Farmelectrics]

r1 r2 honest it proves polarity lol

 

[Jurasic Spark]

It can actually be either a live or dead test.

There are 3 objectives which need to be confirmed whilst doing a dead polarity test. Once this is done the live polarity test is to ensure the correct polarity of the incomiong supply, done with an approved voltage tester before energising the supply.

 

[NrVolts]

i think i know what durassic spark is aiming at.i had the same thoughts at college.concider this R1 and R2 is a loop .you have you meter on the ends of that loop .ok now make a break in the earth ..oh look you get open circuit ,just like you would if you operated a switch .visual check connections and a live test would be best,but even that wouldnt find two swaps in polarity in one circuit.
his point is spotting reversed polarity.hope this edit worked as ide look a right numpty if not lol.

 

[Jurasic Spark]

When you operate the switch your meter will either show a very high reading or a very low reading. Would it make any difference to your readings if you swapped the leads over on your meter???

Visually check the device is correctly wired at the terminals. You can only visually see the terminals and not whats inbetween

So how do YOU test for polarity if you dont know the answer to your own question?

Think about it, its common sense.

 

[Plonker 3]

Well then if what is says in BS 7671, the OSG and GN 3 isnt good enoigh for you I suggest you wire all circiuts in singles in trunking pulling each core in individially. That is the only way you can 100% guarantee none of the things you point out actually occur.

 

[Jurasic Spark]

Well then if what is says in BS 7671, the OSG and GN 3 isnt good enoigh for you I suggest you wire all circiuts in singles in trunking pulling each core in individially. That is the only way you can 100% guarantee none of the things you point out actually occur.

No need to get sarcastic I'm only trying to stimulate thought, after all electrics is a thinking man's game and the most technical of all the trades. None of the books you mention are instruction manuals, you might need to apply what you refer to as "common sense"

 

[Plonker 3]

No you are correct. But we are talking about fixed wire testing here not appliance testing which doesn't fall under the remit of the OPs question.

So how do you check for polarity if all the obstacles you stated are in the way?

 

[Jurasic Spark]

A bit more thought with regard to RFC testing as the O.P did refer to this....

The end to end values from Step 1 of the recognised test sequence for a rfc containing 4 skts are:
L 0.5 ohms N 0.5 ohms CPC 0.83 ohms.
When cross connected at the board the following values are read at each skt using an adapter and not removing the socket front.

State whether they are acceptable and if not give possible reasons for the bad readings


Step 2
Socket 1 = 0.25 ohms
Socket 2 = 0.25 ohms
Socket 3 = Over Range
Socket 4 = 0.31 ohms

Step 3
Socket 1 = Over Range
Socket 2 = 0.34 ohms
Socket 3 = Over Range
Socket 4 = 0.42 ohms

 

[Plonker 3]

I have asked several times now without getting a actual answer, please answer this time rather than trying to avoid the question. How do you prove polarity if the methods mentioned in this thread are unacteptable.

If you are struggling with a exam question then by all means start a new thread where someone will help you.

 

[Jurasic Spark]

I have asked several times now without getting a actual answer, please answer this time rather than trying to avoid the question. How do you prove polarity if the methods mentioned in this thread are unacteptable.

If you are struggling with a exam question then by all means start a new thread where someone will help you.

You said that polarity could be proved by linking R1 and R2 at the DB and.........
"When you operate the switch your meter will either show a very high reading or a very low reading."
I asked you:
Would it make any difference to your readings if you swapped the leads over on your meter???
You didn't answer this so I'll tell you, of course it wouldn't make a difference to your reading if you swapped the leads of the meter over. And for exactly the same reason it wouldn't make a difference to your reading if the L and E were reversed at any point inbetween the DB and where you are carrying out the test.
So do you still think you have proved polarity?

​

 

[Plonker 3]

Seeing as you are not answering my question I think I shall just leave posting on it anymore.

 

[Jurasic Spark]

Seeing as you are not answering my question I think I shall just leave posting on it anymore.

Ok no problem. If you have ago at my RFC test question the answer will hopefully become apparent.

 

[trev]

i thought interconnecting r1/rn on your ring was the only way to prove polarity on sockets before the circuit is energised ?

Cross connectL and N at the CU then go round the RFC testing between them at each outlet, you should get a reading at each point. Then cross connect R1 and R2 at the CU and repeat, the highest reading being the one recorded.
1337, get your hands on a copy of GN3 and have a good read of it. When you're done read it again and again etc. When you come to the testing module you'll be several jumps ahead.

 

[Guest55]

Geez , were making a meal of this topic lol.
polarity checks are done both dead and live.
in addition to visual conformation , an earth loop tester will show L-E reversal and wont allow test , in answer to the earlier query.

 

[Guest55]

trust trev to butt in just before me lol.

 

[lauriehurman]

1337
If you really want to get a headstart (you've probably given up by now) ...

Don't say Live when you mean Line.
This is important (and not just for your exams). Understand that Neutral is live and can kill you.

Laurie

 

[NrVolts]

i did RFC test question and it does make you think

socket 1 reversed polarity L-N
socket 2 -ok
socket 3 Earth &Neutral reversed
socket 4 spur off the ring.
Anyone else have a go at this ? Dilb?