IR Testing???

[mljc71]

Hi All- New to this - loving the challenges!

EICR'd my house and found one of my ring finals had an IR problem- just getting to grips with testing and trying to gain experience- college was good, however, felt like it was more of learning to pass exams!

My ring final has an issue- if i test with breaker open-(off) L(load side of breaker) to E (earth bar) = good reading, N(neutral bar) to E= good reading- but L to N a bad reading. so if a possible dead short between L-N why doesn't breaker trip?

However, if i do a IR L and N to E i get a good result!

Sorry for my inexperience but can anyone help me?

 

[sjm]

Neon indicator or appliance left attached.

 

[Jay Sparks]

What is the result between L/N? You say a dead short, so is the reading 0.00Mohms? Sounds like you may have something still connected like a spur that you may have missed.

Jay

 

[nominal voltage]

Make sure you have disconnected all appliances, especially freezers and fridges. A low Ir reading doesn't mean you have a short.because you are dealing in Mega ohms.

 

[mljc71]

nope checked that- has spots in bedroom connected somewhere, but left that part of circuit open,
why a good IR reading with the L-N to E:?
thanks for the reply

lol lots of diy bodges (not mine)! even got an off peak socket! spur'ed off eco10 lol

 

[Skyba]

Sounds like a load still connected, neon in a spur or something, could you have a spur in the loft for something if you've got some DIY stuff there.

 

[jon small]

definitely sounds like something still plugged in, did you do end to ends on ring final as had similar when i moved in - one side of ring and immersion heater feed transposed so low ir reading ( imm and ring on 32a mcb and 16a mcb nearly got zapped changing imm stat so did pir and found lots of horrors - funny had just been passed by council contractor)

 

[Skyba]

Also the reason you'll have a good reading between both live conductors to earth is because there's obviously no fault to earth hence why it seems like an appliance plugged in because otherwise your ring would trip.

 

[mljc71]

ty for replys only 2nd post i think!- will investigate further in loft- also for experience going to take all sockets off and connector block them- do a bell test to check continuity then do IR test- end to end- then cutting circuit into 2 and so on.

 

[mljc71]

why L+N to E a good reading? hheellppp want to learn

many thanks all

 

[sparks1973]

nope checked that- has spots in bedroom connected somewhere, but left that part of circuit open,
why a good IR reading with the L-N to E:?
thanks for the reply

lol lots of diy bodges (not mine)! even got an off peak socket! spur'ed off eco10 lol

caus your not testing through a load....

 

[jon small]

check for TV aerial amplifier or shower pump when your in the loft have come across this several times recently

 

[Skyba]

Because if there was a fault to earth you would have a reading between l+E and or N+E but because there isn't a fault present you will get a good reading, because you're getting a reading between N+L this either means there is a fault but more likely you're getting the reading from a load and the connection between L+N is across the load

 

[bigbaddave]

If your getting a good reading when connecting L&N and testing to Earth then i wouldn't be losing any sleep over it, However as mentioned above the readings defiantly insinuate that something is still plugged in to warrant poor readings. If your L&N to earth is over 1.0 meg then as long as your record how its been tested on the test sheet then that's sufficient.

 

[Octopus]

With an IR that low the only conclusion is something is still connected. You have to be very observant doing this job properly or you'll be going round in circles....

 

[sparks1973]

always set the meter to 250V DC first as well....then if there are any connected loads....you won`t fry em..lol...

 

[HandySparks]

If you test L to N on low ohms range, what reading do you get? You don't seem to understanding that "0.00Mohms" is not necessarily a "short"; it could be anything up to 10kohms.

 

[AIM]

Found one last week. Extension lighting spurred of through 5 Amp fuse from RFC. Spur behind double bed headboard upstairs.

ALWAYS do 250V test first to find loads not found on visual examination, customer memory/knowledge failure.

I've often found readings in the range of 0.04Mohms for mobile phone/door bell transformers etc... and 0.24-0.26Mohms for neon switches.

 

[PKBristol]

why L+N to E a good reading? hheellppp want to learn

many thanks all

You say L to E was good, and you say N to E was good, well L and N (connected together) to E is just doing the same test's, you're just doing both at the same time. When you connect L and N together they become one.

Paul.

 

[mljc71]

thanks all - found the load in loft- but also e happy with the result i had l+n to e - good to have a bit of reassurance - cheers
also lol on a funny note - or not- what can be done about a neighbours alarm going off-any veiws on the law if i rip out main fuse lmao ! providing no battery back up - ffs lol - spose just call enviromental is best option !!