S
sambotc
Carried out a consumer unit change yesterday, haven't done much of this before, mainly testing new circuits i've installed.
So the actual consumer unit change went ok, i'm going to show this job to my assessor for CPS so wanted to make sure everything was tip top. I upgraded the meter tails to 25mm, main earth to 16mm, main bonding to 10mm etc.
First mistake I made was to do the testing after installing the board!
How do most people carry out continuity testing on lighting circuits? Most of the light fitting weren't pendants so I seemed to take ages messing about with different light fittings taking them apart etc to get to the terminals, really frustrating when the wiring was shoddy, cables coming out of connector blocks etc the loop terminal was often stuffed into the ceiling void etc
Is it acceptable to test continuity R1 & R2 etc from the switch itself or will the reading of the switch wires cause inaccurate readings?
On to the ring final, which is 1 circuit for the whole house and no R1 or Rn continuity :thumbs_down: started to split the ring and found that the wiring in the kitchen had been bodged, ring had been extended connector blocks everywhere, knew it was going to be problems. Figured out what was the original wiring and reconnected in the same configuration and all was good. Thought i'd run all the tests as is so left the 3 new sockets disconnected.
Went on to IR L-N , fail. Split the ring in the same place as I had just reconfigured and tracked it down to one side of the kitchen. Took me ages to find the culprit which was a hidden socket under the kitchen sink which had burnt out. New socket front ideal.
So went back to look at the wiring I had disconnected, after some tests I found out the numpty who wired the kitchen up had got his wires crossed (literally) and a switched fused spur that was supposed to switch a built in freezer (that I had turned off to carry out testing) was switching the ring main in half!
So, rewired the offending sockets/switched fused spur and retested continuity, all was good. Re-test IR, L-E fail ..... FFS!
Cutting a very long story short, dismantled kitchen and built in freezer and fridge, to find that the freezer had been hard wired into fused spur with no means of isolation. Disconnected freezer and all was good. Re wired freezer into fridge fused spur so that both can be isolated fron the same switched fused spur above worktop level. Is this acceptable?
Retested IR L-E only to find the fault had disappeared even though there was no obvious reason for it to fail other than an internal fault?
Any ideas?
IR was coming back a 0.09M ohms, and I was surprised the RCD didn't trip on the new board????
By this time the customer was obviously well cheesed at the previous electrician, I had started yesterday morning and by the time I had figured out what was going on each time etc (bearing in mind I am still sort of fumbling my way through these tests a bit, trying to guess where the wiring goes some sockets with 4 cables in the back which disappear behind tiles)
Anyway it all finally tested good, one thing I noticed was how much the IR test changes when fixing the socket fronts back, approx 5-10M ohms less every time, is this normal I just put it down to the cables all being jammed together? Started around 300M ohms and I tested after screwing back each fascia and noticed this approx drop each time.
So, as you can tell, my first EICR really put the mind to test, but kind of glad it happened in someone's house I knew and also so close to home! Good experience, but are they often like this or was I just unlucky? I know I probably spent a lot more time on identifying the faults compared to someone with more experience in this kind of thing.
How often do you come across things like this and how would you handle the situation, would you just record it on the certificate or are you obliged to find a fault when IR is that low?? Not that I would want to walk away, but in another instance the customer may not want their kitchen dismantled or pay the extra time to find the fault?
Thanks in advance, sorry for the long post, been a long job!
So the actual consumer unit change went ok, i'm going to show this job to my assessor for CPS so wanted to make sure everything was tip top. I upgraded the meter tails to 25mm, main earth to 16mm, main bonding to 10mm etc.
First mistake I made was to do the testing after installing the board!
How do most people carry out continuity testing on lighting circuits? Most of the light fitting weren't pendants so I seemed to take ages messing about with different light fittings taking them apart etc to get to the terminals, really frustrating when the wiring was shoddy, cables coming out of connector blocks etc the loop terminal was often stuffed into the ceiling void etc
Is it acceptable to test continuity R1 & R2 etc from the switch itself or will the reading of the switch wires cause inaccurate readings?
On to the ring final, which is 1 circuit for the whole house and no R1 or Rn continuity :thumbs_down: started to split the ring and found that the wiring in the kitchen had been bodged, ring had been extended connector blocks everywhere, knew it was going to be problems. Figured out what was the original wiring and reconnected in the same configuration and all was good. Thought i'd run all the tests as is so left the 3 new sockets disconnected.
Went on to IR L-N , fail. Split the ring in the same place as I had just reconfigured and tracked it down to one side of the kitchen. Took me ages to find the culprit which was a hidden socket under the kitchen sink which had burnt out. New socket front ideal.
So went back to look at the wiring I had disconnected, after some tests I found out the numpty who wired the kitchen up had got his wires crossed (literally) and a switched fused spur that was supposed to switch a built in freezer (that I had turned off to carry out testing) was switching the ring main in half!
So, rewired the offending sockets/switched fused spur and retested continuity, all was good. Re-test IR, L-E fail ..... FFS!
Cutting a very long story short, dismantled kitchen and built in freezer and fridge, to find that the freezer had been hard wired into fused spur with no means of isolation. Disconnected freezer and all was good. Re wired freezer into fridge fused spur so that both can be isolated fron the same switched fused spur above worktop level. Is this acceptable?
Retested IR L-E only to find the fault had disappeared even though there was no obvious reason for it to fail other than an internal fault?
Any ideas?
IR was coming back a 0.09M ohms, and I was surprised the RCD didn't trip on the new board????
By this time the customer was obviously well cheesed at the previous electrician, I had started yesterday morning and by the time I had figured out what was going on each time etc (bearing in mind I am still sort of fumbling my way through these tests a bit, trying to guess where the wiring goes some sockets with 4 cables in the back which disappear behind tiles)
Anyway it all finally tested good, one thing I noticed was how much the IR test changes when fixing the socket fronts back, approx 5-10M ohms less every time, is this normal I just put it down to the cables all being jammed together? Started around 300M ohms and I tested after screwing back each fascia and noticed this approx drop each time.
So, as you can tell, my first EICR really put the mind to test, but kind of glad it happened in someone's house I knew and also so close to home! Good experience, but are they often like this or was I just unlucky? I know I probably spent a lot more time on identifying the faults compared to someone with more experience in this kind of thing.
How often do you come across things like this and how would you handle the situation, would you just record it on the certificate or are you obliged to find a fault when IR is that low?? Not that I would want to walk away, but in another instance the customer may not want their kitchen dismantled or pay the extra time to find the fault?
Thanks in advance, sorry for the long post, been a long job!
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