@@just_noXi No, but if you understand the switching then you test before any passive switches or indeed any switches as they themselves could be faulty.
Hi, I agree, with what you said! Similarly I do not trust indicators either, mate of mine thought he was in neutral on his motorcycle let his clutch out thinking it safe, you know the rest .. Turns out the 12+ permanently fed bulb grounded to the frame ground instead of through the neutral switch to frame ground! Always factor in the possibility of electronic failure, this underpinns what is said in the regulations about what is considered to be an isolator, nothing with a semiconductor qualifies as a switch that can be trusted! Electric=careful treatment.
I investigated a similar fault on a domestic ring main..(we suspect was as a result of a ground floor extension many years ago) it turns out the 1st floor and ground floor ring mains were crossed, thus is either breaker was turned on, 230VAC as present. There was obviously potential for current flow up to 64A (2 32A MCBs), or if either breaker was off (causing the ring to be broken) you ended up with 2 very large spurs off of 1 32A breaker!
I had a similar fault on a customers timer clock for their central heating where the relay contacts were welded together on the hot water call side. They had a plumber replace the timer and it worked for a while, then failed again, the plumber then changed the zone valve and the problem still existed. He said you need an electrician as there's a permanent live in the hot water switching, I came and checked the wiring, the relay had fused together in the new timer clock, I freed off the contacts and deduced the back emf from the old zone valve motor was causing the relay to arc and fuse together. Been OK ever since. You need to be careful with relays in circuits they can feedback live mains without you knowing. Always prove dead before touching any conductors. Great video JW.
Really interesting video, thx The diagram was brilliant btw. Very clear. I draw complex diagrams for my job and I know how hard it is to produce an informative yet simple to comprehend diagram.
Legend!!!!! Where were you this weekend! I’ve spent hours fault finding! Turned out a breaker intermittent fault! Just found another issue to make a video on!
+John Ward Point of note: This is a good example where RCBOs would detect this interconnect immediately, but shared-RCD would not!. Related nasty interconnects -- have you seen neutral-neutral shorts or neutral-cpc shorts, in combination with loose/disconnected neutrals, such that some particular CPC/neutral is actually getting overloaded/overheated, bearing in mind there is usually no overcurrent-detection in neutrals let-alone CPCs?
I remember doing a home job in a local club to fit an emergency exit light. When I switched off the breaker for the upstairs lighting I heard a roar from the downstairs bar.! Guess what? The tv went off! I reset the breaker and the tv went on! The wiring in the place was a real mess. I fitted the light and I did an emergency exit myself! I didn't want get involved in somebody else's botch job! Life's too short!!!
Hi John I'm glad I was listening, because you have just said what had occurred to me regards first power up and the way P.I.R.sensors behave, I was only considering that behaviour as I was imagining how bloody award it would prove to find such a fault unless you factor in a brief waiting period each time! Or better still remove everything and confirm the wiring first! Just knowing the switch on behaviour is definitely useful! Unless you know you would wear out a bald patch with the amount of scratching of the head! Interesting video, top work John.
This is why when you start to have many PIRs and many fittings it's much better to use contactors. This assuming that the interconnect was semi deliberate to get the ground floor lights on when the upstairs pir was triggered. Using low voltage switching (24v dc normally) and contactors for the lights you can wire it up in whatever combination you want without this sort of fault being possible
Two adjacent circuit breakers tied together? That would have been a lot more interesting with a split-phase system. Pretty amazing you found the problem though, I hope they'd paid you well.
Yep very nasty if you believed as you might that the wire you've removed is the load side and therefore safe and someone upstairs pops out for some milk..... Good to illustrate this type of scenario, safety depends upon it! Thank you John
Can we have more of these please, maybe include the decision tree of tests as you go along? My have to be filmed at the time, post event narration would be fine 👍
Very interesting JW, I wonder how many electricians proceeded before you on these faults. Excellent direction and graphics, very difficult to transcribe a circuit in to easily understood form (seconding another subscriber). Thanks for sharing.
I had two circuits joined by a two way circuit and guessing by it being fed from a Wylex board had been like it for years. Though I'm surprised it hadn't been picked up before. As two lights on two way were in series in one scenario so they were on but dimmer
Testing PIR sensors can be extra annoying as well, I don't know where they were placed or what type they were. But if it's in a spot where natural light can make it to them those things tend to be outfitted with a brightness sensor as well... not triggering above a certain detected light level.
@@markevans2294 In this case they would. The panel is only one single row, and the circuit breakers are directly side by side: mosel-elektro.de/user/images/artikel/big/1st.-hager-kdn363f-3-phasenschiene-10mm%B2-3polig-%2Bn-12te-gabel-10062.jpg
@@simonschertler3034 the fault would still happen on different phases as well, the PIR was bridging the circuits when they was been triggered, if this was a 3 phase system magic would of happens (assuming the 2 PIRs was in there own phase) get a nice bang (plus the bill)
Unlikely to have a three phase supply in a typical U.K domestic building, especially if the block of flats was previously a large house that had been converted (of which there are huge numbers in U.K. towns and cities).
Reguarding fault finding this circuit how would people go? My initial thinking was the relay in the PIR, however John mentioned testing the N as well, which through me abit in my method of thinking. Cheers
I understand the faulty PIR and the crossconnect between the two circuits but where was the DC voltage coming from? I had a somewhat similar problem years ago in a duplex we were renting. The hallway lights were connected to two different apartment services. Agree with the other posters never assume you have cut power - faults and miswires create all kinds of unusual situations.
Maybe there was only 1 sensor on original install. Additional sensors added after the fact. That scenario makes sense in a building with no lift (elevator). Also makes sense give that board looks like there were multiple visits. Modification obviously not well thought out.
I suspect the link between the two circuits was installed after the initial install because the owner wanted all the lights to turn on no matter which sensor was activated and got a dodgy electrician. It may have changed hands since.
John, Another difference in vocabulary from across the pond. You call the connection from two breakers to one circuit a fault. Here we call this a Dumb assed electricians mistake. Question, is it normal over there to run single circuit on breakers with common trip bars? We don't do that normally over here unless neutral is common. Love the shirt!
Did you separate the circuits or was that not in your remit? If it wasn't in your remit would you still have been paid for discovering it and fixing the problem? If you did separate the circuits, how did you go about finding the connection?
Faults were fixed, both circuits linked onto a single 10 amp circuit breaker. Wasn't practical to separate them, as the sensor locations meant that people going downstairs would be in the dark until they reached the lower floor.
Stair lighting being either fluorescent or LED can safely be powered from one circuit, which is probably how they were supposed to be wired, or the 2 circuit's shouldn't have been wired together in the first place.
Win-win-win situation! It took you a while to figure it out, so you charged more (unless you gave a fixed price beforehand). Your video allowed you to justify the higher charge to the custoimer. Look how complicated it was! And you had a video to upload here. Does it get any better than that?
This is why we always test for live before touching any circuit even if we believe it to be off.
Does this prevent you from triggering the second pir after you tested the wire?
@@just_noXi No, but if you understand the switching then you test before any passive switches or indeed any switches as they themselves could be faulty.
Hi, I agree, with what you said!
Similarly
I do not trust indicators either, mate of mine thought he was in neutral on his motorcycle let his clutch out thinking it safe, you know the rest ..
Turns out the 12+ permanently fed bulb grounded to the frame ground instead of through the neutral switch to frame ground!
Always factor in the possibility of electronic failure, this underpinns what is said in the regulations about what is considered to be an isolator, nothing with a semiconductor qualifies as a switch that can be trusted!
Electric=careful treatment.
I investigated a similar fault on a domestic ring main..(we suspect was as a result of a ground floor extension many years ago) it turns out the 1st floor and ground floor ring mains were crossed, thus is either breaker was turned on, 230VAC as present. There was obviously potential for current flow up to 64A (2 32A MCBs), or if either breaker was off (causing the ring to be broken) you ended up with 2 very large spurs off of 1 32A breaker!
I appreciated the video which brought the circuit to life. This is really useful information to open our minds to strange faults.
I had a similar fault on a customers timer clock for their central heating where the relay contacts were welded together on the hot water call side. They had a plumber replace the timer and it worked for a while, then failed again, the plumber then changed the zone valve and the problem still existed. He said you need an electrician as there's a permanent live in the hot water switching, I came and checked the wiring, the relay had fused together in the new timer clock, I freed off the contacts and deduced the back emf from the old zone valve motor was causing the relay to arc and fuse together. Been OK ever since. You need to be careful with relays in circuits they can feedback live mains without you knowing. Always prove dead before touching any conductors. Great video JW.
Really interesting video, thx
The diagram was brilliant btw. Very clear. I draw complex diagrams for my job and I know how hard it is to produce an informative yet simple to comprehend diagram.
Smashing, super, great as Jim Bowen said on the odd occasion.
Informative and interesting!
Legend!!!!! Where were you this weekend! I’ve spent hours fault finding! Turned out a breaker intermittent fault!
Just found another issue to make a video on!
Would be good to see where the link in installation was.
+John Ward
Point of note: This is a good example where RCBOs would detect this interconnect immediately, but shared-RCD would not!.
Related nasty interconnects -- have you seen neutral-neutral shorts or neutral-cpc shorts, in combination with loose/disconnected neutrals, such that some particular CPC/neutral is actually getting overloaded/overheated, bearing in mind there is usually no overcurrent-detection in neutrals let-alone CPCs?
I liked your videos because it have a good content
I remember doing a home job in a local club to fit an emergency exit light. When I switched off the breaker for the upstairs lighting I heard a roar from the downstairs bar.! Guess what? The tv went off! I reset the breaker and the tv went on! The wiring in the place was a real mess. I fitted the light and I did an emergency exit myself! I didn't want get involved in somebody else's botch job! Life's too short!!!
All clubs are the same. I've noticed.
Hi John I'm glad I was listening, because you have just said what had occurred to me regards first power up and the way P.I.R.sensors behave, I was only considering that behaviour as I was imagining how bloody award it would prove to find such a fault unless you factor in a brief waiting period each time! Or better still remove everything and confirm the wiring first!
Just knowing the switch on behaviour is definitely useful!
Unless you know you would wear out a bald patch with the amount of scratching of the head!
Interesting video, top work John.
Well spotted and explained john.keep up the superb work and videos.well done.
This is why when you start to have many PIRs and many fittings it's much better to use contactors.
This assuming that the interconnect was semi deliberate to get the ground floor lights on when the upstairs pir was triggered.
Using low voltage switching (24v dc normally) and contactors for the lights you can wire it up in whatever combination you want without this sort of fault being possible
maybe the interconnect added was so that any sensor would turn all the lights on, but the relay only melted closed later on.
would be more fun if these where on different phases
How long did it take you to find the linking wire between the two circuits in a block of flats? And how did you go about tracking it?
I bet that was a real bastard to find !
Two adjacent circuit breakers tied together? That would have been a lot more interesting with a split-phase system. Pretty amazing you found the problem though, I hope they'd paid you well.
Really interesting video John 👍
Another good one....Thanks
Nice explanation
Yep very nasty if you believed as you might that the wire you've removed is the load side and therefore safe and someone upstairs pops out for some milk.....
Good to illustrate this type of scenario, safety depends upon it!
Thank you John
John you still have your superman pyjamas on !
Can we have more of these please, maybe include the decision tree of tests as you go along?
My have to be filmed at the time, post event narration would be fine 👍
Very interesting JW, I wonder how many electricians proceeded before you on these faults.
Excellent direction and graphics, very difficult to transcribe a circuit in to easily understood form (seconding another subscriber).
Thanks for sharing.
I had two circuits joined by a two way circuit and guessing by it being fed from a Wylex board had been like it for years. Though I'm surprised it hadn't been picked up before. As two lights on two way were in series in one scenario so they were on but dimmer
These is back feed if you test at the board you can quickly fined out which circuit feeding the other one
Testing PIR sensors can be extra annoying as well, I don't know where they were placed or what type they were. But if it's in a spot where natural light can make it to them those things tend to be outfitted with a brightness sensor as well... not triggering above a certain detected light level.
with 3 phase system, that fault would been found really fast. "Circuit for testing fuses" :D
Assuming the circuits were on different phases...
@@markevans2294 In this case they would. The panel is only one single row, and the circuit breakers are directly side by side:
mosel-elektro.de/user/images/artikel/big/1st.-hager-kdn363f-3-phasenschiene-10mm%B2-3polig-%2Bn-12te-gabel-10062.jpg
Of course, in 3phase systems you such a foult only occur if the 2 MCBs are on the same phase and the same RCD.
@@simonschertler3034 the fault would still happen on different phases as well, the PIR was bridging the circuits when they was been triggered, if this was a 3 phase system magic would of happens (assuming the 2 PIRs was in there own phase)
get a nice bang (plus the bill)
Unlikely to have a three phase supply in a typical U.K domestic building, especially if the block of flats was previously a large house that had been converted (of which there are huge numbers in U.K. towns and cities).
Very interesting :)
Reguarding fault finding this circuit how would people go? My initial thinking was the relay in the PIR, however John mentioned testing the N as well, which through me abit in my method of thinking.
Cheers
I understand the faulty PIR and the crossconnect between the two circuits but where was the DC voltage coming from?
I had a somewhat similar problem years ago in a duplex we were renting. The hallway lights were connected to two different apartment services. Agree with the other posters never assume you have cut power - faults and miswires create all kinds of unusual situations.
DC voltage might have been related to the PIR internal power supply - possibly some sort of capacitor dropper arrangement feeding in to the system.
@@philjordan1749 I agree but if that is the root cause why only on one circuit? Could also be a result of the lights, assuming they are LED or CFL.
He addresses this in the video. There are emergency lights on the circuit, which have a battery to supply them
@@puckcat22679 What kind of power supply feeds back battery voltage to the mains?
Tom Schmidt,
It may be a high-impedance ... but still, somewhat poor design I suppose.
Maybe there was only 1 sensor on original install. Additional sensors added after the fact. That scenario makes sense in a building with no lift (elevator). Also makes sense give that board looks like there were multiple visits. Modification obviously not well thought out.
Original install with 8 sensors, 1 outside each of the 7 apartments and 1 at the main door.
Fully botched original install then!
@@jwflame somone doesn't know the meaning of functional testing then!
Super John
I suspect the link between the two circuits was installed after the initial install because the owner wanted all the lights to turn on no matter which sensor was activated and got a dodgy electrician. It may have changed hands since.
And that can be a long day on a ladder trying to find where the miswired connection between floors is.
John, Another difference in vocabulary from across the pond. You call the connection from two breakers to one circuit a fault. Here we call this a Dumb assed electricians mistake. Question, is it normal over there to run single circuit on breakers with common trip bars? We don't do that normally over here unless neutral is common. Love the shirt!
Super T shirt
i wonder if superman has a JW T-shirt lol
Did you separate the circuits or was that not in your remit? If it wasn't in your remit would you still have been paid for discovering it and fixing the problem? If you did separate the circuits, how did you go about finding the connection?
Faults were fixed, both circuits linked onto a single 10 amp circuit breaker. Wasn't practical to separate them, as the sensor locations meant that people going downstairs would be in the dark until they reached the lower floor.
@@jwflame That makes good sense.
HAHAHA Superman PJs
i wonder if superman wears a JW T-shirt lol
Stair lighting being either fluorescent or LED can safely be powered from one circuit, which is probably how they were supposed to be wired, or the 2 circuit's shouldn't have been wired together in the first place.
its not them two blacks in the far right of the DB is it? :D
keep calm. draw a picture.
Superjohn
Bloody link
nice t shirt .....
Win-win-win situation!
It took you a while to figure it out, so you charged more (unless you gave a fixed price beforehand).
Your video allowed you to justify the higher charge to the custoimer. Look how complicated it was!
And you had a video to upload here.
Does it get any better than that?