r1 + r2 testing

[rapier]

Hi guys,
I was testing a new house yesterday that we have wired at work, i came to test the lighting circuit in the lounge and sun room, the lounge tested out ok but then in the sun room i tested to line and earth without the switch in the on position and got a reading.
So i then did a bit of fault finding and it was a run between 2 wall lights , i tested from one side of the it was 0.44 ohms then tested then other end and got a reading of 0.55 ohms.
Is there a limit of reading you can have with an interconnection? or is the cable knackered now and need to install a new link or do away with the 2 wall lights on the other side of the room?
Any tips would be great
Cheers

 

[Deleted member 9648]

Not sure what you are asking...the R1+R2 reading will be higher at the far end of the link cable..those readings sound about right....Is this with the switch in the off position?....if so presumably the wall lights are connected to the feed rather than the switch line....or more likely the switch is simply the wrong way up.

 

[rapier]

Sorry wirepuller, i have 4 1mm cables in position for wall lights in a sun room and i was testing the r1 + r2 for this lighting circuit and i tested at the end of the wall lights with the switch in the off positions, so i should get no reading if no interconnection but i had a reading and like you say i thought the feed and light wire were mixed up, but they weren't as i tested this out.
I then started at the first wall light to the switch no reading all good no connection then wall light 1 to 2 still good then from 2 to 3 there is an interconncetion between line and earth and this is where the problem lies and there the 2 readings i have stated in my first post, so i then did the same test to wall light 3 to 4 and no interconncetion so that cable is good as well.
I hope that sheds a bit more light.

 

[rapier]

Can anyone help? Or does it make no sense?
cheers

 

[PC Electrics]

Can anyone help? Or does it make no sense?
cheers

Sorry, makes no sense to me. Simply can't get to grips with what you're on about.

BTW: r1 and r2 are applicable to ring circuits only.

 

[cyberpunk]

sorry got to correct the previous post. r1 + r2 can be done on any domestic circuit not just the ring. iv'e been reading some of the posts on here.....looks like there are many sparks who don't know what they are talking about

 

[Sintra]

Have to disagree r1 & r2 along with rn can only be done on a ring final circuit. If you can explain how these are carried out on a radial circuit i would be very interested.

 

[cyberpunk]

2. Circuit Loop Test (dead test) ​

Reason for the test: Circuit loop testing ensures that ANY circuit wired in the installation are actually containing cables that conduct one end of the cable to the other, without a huge resistance in its path. Result recorded as R1+ R2​

 

[cyberpunk]

two sparks who don't know about r1 + r2 testing. unbelievable

 

[PC Electrics]

sorry got to correct the previous post. r1 + r2 can be done on any domestic circuit not just the ring. iv'e been reading some of the posts on here.....looks like there are many sparks who don't know what they are talking about

Really?
I suggest you get out your OSG and read up. In particular page 78, see the note and page 81 from the top

If you look at the chief examiners report for the 2391, you will see that there is considerable criticism of candidates failing to understand and use proper terminology. It's a major contributor to the 50+% failure rate.

 

[PC Electrics]

two sparks who don't know about r1 + r2 testing. unbelievable

Well, I'm perfectly au fait with r1 and r2 testing. Been doing it today on two RFCs.

 

[Sintra]

two sparks who don't know about r1 + r2 testing. unbelievable

I think it is you that doesn't understand have a look at guidance note 3.

 

[rapier]

So how do you test your contunity of a lighting circuit then? What i do is join cpc and line at board and then getting my readings at each outlet this way and putting it in (r1+r2) or if using flying lead put that in r2.

 

[cyberpunk]

deleted

 

[Ponty Massive]

Guy's R1 + R2 or r1 + r2 !!!!!!

 

[SimpleSimon]

So how would you word 'test method 1' when testing for CPC? Without the book in front of me I thought it was worded r1 + r2. Which uses a temp link between live and earth at the board. And testing using a low resistance ohmeter to get a continuity result.

 

[cyberpunk]

this is from a guy on here who knows what he is talking about i suggest you go back to college or do some revision

If you are R1+R2 testing on a radial circuit then you simply isolate all power at the DB i.e main switch off, place a link between Line and Earth of the circuit you want to test, then go to the end of that circuit and measure the continuity between Line and Earth.

For a ring main again isolate, joint Line 1 to Earth 2, Line 2 to Earth one and measure at each socket on that ring circuit, the highest reading you get being recorded as the R1+R2 for that ring circuit.

 

[Sintra]

Not being funny guys but it is down to the terminology again r1 and R1, two entirely different meanings.

 

[SimpleSimon]

Oh hang on. Are we getting our capital letters confused? Is that the reason? R1+R2 or r1+r2

 

[rapier]

Yeah its all down to capital letters thought it would be straight forward sorry guys as i mentioned it was a lighting circuit so thought you would know yes (R1 + R2) temp link in board or join together in a connector my personal prefrence.

 

[rapier]

So looking at my post now does it make sense ???

 

[morph]

osg only uses r1 +r2 and then R1 + R2 on the ring test to stop confussion
all circuits with a line conductor and cpc can and should be tested for the R1 and R2 value ,

 

[Ponty Massive]

other way around

 

[SimpleSimon]

Seems like alot of noise over very little.

 

[lloyd1980]

R 1 + R 2 = line and CPC on any cct

r 1 , r 2 , r n = end to end continuity on ring final ccts

its all in 7671/ guidance note 3 or the OSG

when you look at this section on testing does anyone else feel we are underpaid for the amount of knowledge we have
sparks are by far the best trade - HOORAH

 

[lloyd1980]

Seems like alot of noise over very little.

couldnt agree more

(handbags )

 

[rapier]

Dont worry yourselves ive sorted the problem thanks for all the help , it appered to be a faulty length of wire, managed to rip it out and put a new piece in without to much damage as i pulled it in the capping it was just getting around the corners.
The cable seemed to have a bulge in it when i pulled it out, so spliced it and the line seemed to have a a little blemish in it which was touching the cpc with no obvious sign of penertration damage, so must of been faulty cable.

 

[Deleted member 9648]

Not some of that imported junk was it?....quality cable almost never has problems like that....impact damage from a hammer etc can cause the cpc to penetrate a core with no obvious damage to the sheath.

 

[rapier]

I dont think so wirepuller the cable had the basec approved mark on it, so it may have been from tool damage or crap cable?

 

[ezzzekiel]

Seems like alot of noise over very little.

got to disagree on that one Si, incorrect terminolgy may not seem that important but in my opinion the guys are right, if you start mixing things up then where does the confusion end?

does a main bond become a main earth or an ohm an amp

the replys were not directed at the op asking the question but to the incorrect answers he was given, if he is learning then its best to learn the correct way from the start.

 

[SimpleSimon]

I get what your saying but it wasn't until Sinatra's post #15 that it was mentioned the two different terminologys. If the OP is learning it was all a bit cryptic until then, even I had to double check.

 

[telectrix]

two sparks who don't know about r1 + r2 testing. unbelievable

there's no such test as r1+r2. only R1+R2. see PC's post.

 

[Deleted member 9648]

I get what your saying but it wasn't until Sinatra's post #15 that it was mentioned the two different terminologys. If the OP is learning it was all a bit cryptic until then, even I had to double check.

I think Cyberpunks rather derogatory posts resulted in no one wanting to make it easy for him.....but yes,I agree...it's easy to get the two terminologies mixed up.