Rn continuity

[elesde]

IV JUST DONE MY PART P, HOWEVER IV BEEN GOIN OVER ALL MY NOTES ETC AND HAVE REALIZED THAT WHEN WE DO DEAD TESTS ON SAY A LIGHTING CIRCUIT WE TEST
R1+R2 FOR CONTINUITY AND POLARITY .
BUT WHY DONT WE TEST CONTINUITY OF RN? SURELY WE WANT TO MAKE SURE RN IS CONECTED SECURELY AND NOT DAMAGED, AND I KNOW WE DONT NEED TO RECORD THIS EITHER BUT SHOULD WE NOT TEST IT SAY WITH R1 +RN CONECTED? ???
GOT A SIMILUR QUESTION ASKED IN ..dead test>
THAT GOT ME THINKIN BOUT THIS

RN CONTINUITY..


ANYONE? AS IM PUZZELED AND PROB JUST OVERLOOKIN THE OBVIOUS AS USUAL

 

[ian.settle1]

IV JUST DONE MY PART P, HOWEVER IV BEEN GOIN OVER ALL MY NOTES ETC AND HAVE REALIZED THAT WHEN WE DO DEAD TESTS ON SAY A LIGHTING CIRCUIT WE TEST
R1+R2 FOR CONTINUITY AND POLARITY .
BUT WHY DONT WE TEST CONTINUITY OF RN? SURELY WE WANT TO MAKE SURE RN IS CONECTED SECURELY AND NOT DAMAGED, AND I KNOW WE DONT NEED TO RECORD THIS EITHER BUT SHOULD WE NOT TEST IT SAY WITH R1 +RN CONECTED? ???
GOT A SIMILUR QUESTION ASKED IN ..dead test>
THAT GOT ME THINKIN BOUT THIS

RN CONTINUITY..


ANYONE? AS IM PUZZELED AND PROB JUST OVERLOOKIN THE OBVIOUS AS USUAL

It's done on ring circuits but not as you say on radials.

 

[jreid67]

IV JUST DONE MY PART P, HOWEVER IV BEEN GOIN OVER ALL MY NOTES ETC AND HAVE REALIZED THAT WHEN WE DO DEAD TESTS ON SAY A LIGHTING CIRCUIT WE TEST
R1+R2 FOR CONTINUITY AND POLARITY .
BUT WHY DONT WE TEST CONTINUITY OF RN? SURELY WE WANT TO MAKE SURE RN IS CONECTED SECURELY AND NOT DAMAGED, AND I KNOW WE DONT NEED TO RECORD THIS EITHER BUT SHOULD WE NOT TEST IT SAY WITH R1 +RN CONECTED? ???
GOT A SIMILUR QUESTION ASKED IN ..dead test>
THAT GOT ME THINKIN BOUT THIS

RN CONTINUITY..


ANYONE? AS IM PUZZELED AND PROB JUST OVERLOOKIN THE OBVIOUS AS USUAL

Thats what i was thinking, someone could of wired the cpc through the switch (i know its not going to happen) and theres no way of proving it unless you test R1 and R2

 

[elesde]

on a light circuit,hmm,

r1 r2 test this checks continuity of live and cpc/earth.

this also this is checks polarity wen you test and flick switches etc>makes sure live is used not neutral in the switch.

if earth is somehow wired in to the switch as sugested im guessing this would show up in the insulation resistance test
(but not 100% sure)so thats another new question wev got.

then there is the Rn neutral continuity?, im now guessin this may show on insulation resistance too as ... er
or ... lost my train of thought now.. am goin to go back to my notes and books..

It's done on ring circuits but not as you say on radials.

exactly but i was just wondering why not? i mean if lets say there was a break in the neutral rn just enough to make an ark then would that melt the cable etc and maybe start a fire. and no one would know as we dont check RN continuity only r1 and r2.... its just got me thinkin...maybe rn continuity test should be added on test sheets etc?

 

[lockhes]

iv wondered this aswel

after doing my fault finding exam yesrtday and having a couple of neutral continuity faults im going to start doing them just to make sure

 

[rob1967]

I agree you should test Rn on a lighting circuit as recently I came across a situation I would never believe, someone had wired up a light fitting with the live going right throught the fitting to the switch ( connected to the common ) but with the neutral connected at the load side ( L1 ) so when the switch was on the live was connected direct to the neutral..............bad or what ????

 

[coldelsol]

Do the test anyway regardless of test sheet records .& remember this test will be at the furthest point and will help determine the length of cable or confirm continuity especially as some test may be on an old installation that dosent have a cpc present .And will be more apparent with live earth loop impedence test to confirm .

 

[platty1005]

When you wire a new circuit you are supposed to verify by Visual inspection that the connections are correct and the installation completely satisfies BS 7671. Testing is for SAFETY not function.
The first test is continuity of the CPC's and bonding conductors because earthing and bonding is for SAFETY
The second test is Insualtion Resistance to check for incorrect connection and damage to cables and accessories The insualtion Test is for SAFETY
The third test is Polarity to check single pole switches and protective devices are wired in the line Conductor this test is for SAFETY
The fourth test is for earth loop impedance to ensure the protective device will operate in the permitted time this test is for SAFETY

On Radial circuits there is no requirement to test continuity of Line or Neutral conductors the R1 + R2 test is a convenient way of testing the continuity of R2 the CPC.

ON Ring circuits r1 , rn and r2 are tested to ensure that each conductor Line, Neutral and CPC are indeed unbroken in other words wired in a ring this is step one of a three step test for SAFETY

If a circuit does not work correctly or it has any fault then continuity of individual conductors may be carried out as a means of fault finding but Rn is not required in a correct and safely wired circuit it just wastes time

 

[coldelsol]

When you wire a new circuit you are supposed to verify by Visual inspection that the connections are correct and the installation completely satisfies BS 7671. Testing is for SAFETY not function.
The first test is continuity of the CPC's and bonding conductors because earthing and bonding is for SAFETY
The second test is Insualtion Resistance to check for incorrect connection and damage to cables and accessories The insualtion Test is for SAFETY
The third test is Polarity to check single pole switches and protective devices are wired in the line Conductor this test is for SAFETY
The fourth test is for earth loop impedance to ensure the protective device will operate in the permitted time this test is for SAFETY

On Radial circuits there is no requirement to test continuity of Line or Neutral conductors the R1 + R2 test is a convenient way of testing the continuity of R2 the CPC.

ON Ring circuits r1 , rn and r2 are tested to ensure that each conductor Line, Neutral and CPC are indeed unbroken in other words wired in a ring this is step one of a three step test for SAFETY

If a circuit does not work correctly or it has any fault then continuity of individual conductors may be carried out as a means of fault finding but Rn is not required in a correct and safely wired circuit it just wastes time[/quote]

A nice very informative bla bla ,but on initial testing wouldn't it be better to confirm you have neutral continuity before switching on to find out if you have a fault wether a radial or ring circuit .WHAT IF A NEUTRAL CABLE WAS ADRIFT YOU'D BE BACK TRACKING FAULT FINDING LIVE .
a correct safely wired circuit would be one you can prove continuity through its entire length .dont forget a nuetral conductor is considered a phase conductor ,well it was in 2381 / 2391
The second test is Insualtion Resistance to check for incorrect connection and damage to cables and accessories The insualtion Test is for SAFETY (quote)
An insulation test will not prove you have a neutral present .

my main point is how long does it actually take to connect 2wires together and bell them out ?

sometimes regs dont add what you get on site !

 

[platty1005]

Hi Coldesol

I may have appeared a bit patronising but The IET and the IEE has had contributions from thousands of highly qualified and trained engineers over the last 120 years. The latest version of the wiring regs and guidance note 3 does not deem testing Rn for every circuit as necessary.

The reason for Inspection and testing is to ensure the installation is SAFE to be energised. Good workmanship carried out by competent installers using quality equipment should ensure it works correctly.
Imagine a new 3 phase Industrial lighting circuit with 27 luminaires at high level testing the continuity of the CPC at each fitting is required. If the test requirements then were extended to include R1 + Rn how much extra time would this cost.

 

[coldelsol]

Hi
I didn't find it Patronising so no offence taken .
even 27 light fittings high level would take only a few minutes more with respect i would take it that the test was done by two people with regards to hieght .be a bit of a pig if the platform was put away and found that a nuetral was out somewhere .

well each to there own ,its by my experience dont take everything for granted .

colin

 

[Monkey1984]

I've just finished my 2391 exams and with that we had to test R1/RN on all circuits including lighting, It takes a couple of minutes longer to do and I'll continue doing it purely as an extra test to identify any problems on existing circuits (Periodic as an example)

If I am rewiring any circuits I want to make sure its completely safe before signing it off. Its not that I don't feel capable but if there is a problem I don't want to have to go back to it.

Just my opinion but as mentioned there is no rule saying you HAVE to do this, its purely your choice.