Well done Dave. Your usual jovial attitude hides your real care and attention sometimes, however all the usually pit falls that we see daily on social media were soundly indicated and ticked off. Having started on my electrical journey in ‘83 I have seen a good bit and in the recent months the level of hideous mistakes posted on Social Media is incredible. Now working in electrical compliance I would have normal picked up something but your spot on with this one! 👍 and a great watch too! Thanks for the content.
Best safe isolation video out there. Dunno why I even watched it really as a spark myself, but the cardinal rule of never trusting anybody else's word for it is something I'll probably actually take away from this video, not something I've gave much thought to before. But working with competent persons, whom I trust, it can seem like a waste of time, until it isn't. But love your sense of humour, reminds me of my college lecturer.
was putting a ring into a shed for my father and had removed the 30A fusecarrier from the old Bill switch splitter and put it on a shelf. Came back a day later and noticed the lights came on in the shed, Dad had found the fusecarrier I'd hidden, put it back in the switch, screwed the cover back on (the sort that presses a lever to allow the power to come on) and switched the power all on. No sockets in place, just the cut ends of the cable in metal boxes. Thank goodness I always double check this sort of thing. Cheers, Dad.
I've made a few mistakes in the past and had a few wallops. The worst was when I isolated the wrong circuit and ended up getting two of my digits caught between line and the cpc. Let me tell you - it is far more painful than just touching the line and completing the circuit through the ground. There was a direct copper path throughout the circuit with only a few centimeters of juicy flesh completing the path. I was in intense agony for a fraction of a second and as luck would have it there was a relatively modern split load board at the source. One of the RCDs tripped and saved me but even so, I was doubled over in pain and my hand ached for days aterwards. Lets just say i've been alot more diligent with safe isolation procedures ever since. Also as a final check AFTER a safe isolation proceedure - i will brush the back of my hand very QUICKLY and BRIEFLY across all the isolated live conductors just to put my mind at ease.
I don't know about that, but looking back, it was certainly a spiffing haircut back at the start of the sunny season compared to the unkempt mop I'm currently sporting!
I was assisting an electrician once at work, i was holding the test meter for him as he was up a short set of steps. He was testing between the phases and the meter blew up. He did nothing wrong and didnt expect it to happen. As you state in the video after the meter went bang the three phase supply was still live. No one was hurt, except the meter was toast!
Yikes! When I was a kid, I blew up my Tandy multimeter by sticking the probes into a socket outlet to measure the voltage, then (stupidly) switching it to the current setting. This is one of the reasons safe isolation requires a dedicated voltage tester rather than a multimeter which could be switched to the wrong setting. I would hope such is fused and protected to prevent anything exploding when you have it in your hands!
I’m currently training at college to become a electrician on level 2 doing health and safety at the moment as well as safe isolation...so these types of video are really helpful thankyou
would be interesting to measure current through the tester while its across 240v, im guessing it would be very small it dont take much to ignite a couple of neons, there will be some high value series resistors in there setting the voltage where each neon strikes, be interesting to see how it compares to the TIS (current wise) would give you some idea of what kind of shock (if any) you would get should you have contact to phase through the tester as you said in the vid by connecting leads in wrong order (live first) then touching the neg lead....... nice vid David thanks
Well let’s see I got my first good shock at around age 6 or seven when I grabbed a twist tie folded it into a U and plugged it in. Hence begins my electrical career. As far as rules in the United States for working live. It appears you have much different rules in your country. Yes we have rules but we do not follow them as such as it seems you are explaining. The amount of live work here in the United States is usual let’s just say. While I try to work everything off. We do not have rules for certain kinds of testers to be used while we are even doing checking or testing. We don’t even have those Megger fancy toys you guys have to check your basic circuits. No such thing like that here used regularly. Love your talks David thank you
Haha! There's a child curiosity abut what happens when you shove things into a socket outlet! Things are considered by some to be overprotective here, with health & safety being overzealous at times, but it's to get around blame culture; the rules are there stating how you're supposed to behave as employers and employees, and if someone chooses not to follow them, then it should be clearer where the liability rests I guess.
good video. you can never check to much as not discovering the incorrect wiring is the greatest danger. Now I need to watch electroBOOM do his shocking videos.
If you don't have a proving unit, is it safe to use a live socket where the face plate has been unscrewed and the socket terminals are exposed? Or should you put the probes into the holes where a plug would enter the socket? I understand the probe tips should be 4mm or less when doing this (i.e. keep the covers on). I am a home DIY'er and I am not ready to die, but I really want to change the face plates of my sockets. Thank you!
Worked on a semi detached house in the 80s the upstairs wouldn't turn off downstairs did . I found out the house was once one household . it has two consumer units one for upstairs in one property and another on the ground floor now in different property the doorways between the property had been blocked up and became they became two separate properties again the electrical supply was left as was so each neighbors didn't have control over the other floors power supply . one neighbor knew and took full advantage of the others free electric . until the day he went out and a few blown fuses and new pair of Plyer needed and the supply was terminated . the neighbor was a little bit annoyed that ground floor electric stopped working when he returned home . I did offer to reconnect on his side but he was a little angry . I've also had a loft lights wired into next doors supply another very Angy neighbor left in the dark and a supply hooked up to a lamppost in the street yes it still happens Always always test its off before removing anything we didn't have RCD's or fancy test meters back then .
Thanks Stevan. Either your voltage indicator will work and show the expected voltage when you put it onto the proving unit, or it won't. If it doesn't, then you need to check whether the issue is with the proving unit or the voltage indicator. The indicator can be verified using a known good source or supply, or the PU can be checked with a second voltage indicator if you have one.
As a electrician I've never had a serious shock, as a factory worker I got stunned with crt tv tube, my old boss got stuck on a dc circuit and left him with a cooked hand massive egg lump for life in his palm.
If the incoming neutral to the property fails then none of the tests will show a voltage but the live wire would still be live? Under these circumstances it would seem that the only way to indicate this would be by measuring the voltage from live to some earthed object such as a buried incoming metallic pipe or by using a neon mains tester type screwdriver?
Love the video, however as a 50 yr old sparky working in Thailand your procedure in unsafe. Use of voltage wand or neon screw driver is also require in these following truely terrible wiring faults. 1. Working on a hotel swimming pool pump panel, after following this exact procedure I got a shock! Someone had retro fitted the pump room light on a different CB on a different consumer unit and connected the neutral to one of the pump neutrals. So back feed phase comes from CB, through light switch, through lamp, to common neutral of the pump control panel, going through items such as warning lamps and contactor coils. 2. Working on a 3 bedroom villa with converted substructure, single phase consumer unit, switched off all CBs and main breaker. The main supply cable had been tapped into before it reached the comsumer unit to the feed the extra rooms developed post main build. The KWH was in the street so not stealing electric. Whilst removing electric tape from a junction box full twisted taped joints I got a shock. Lessons learned 1. Carry neon srewdriver. 2. Carry voltage wand Use them more often than all other tools combined.
Thanks Adrian. Neon screwdrivers and non-contact voltage detectors are not recognised as having a part in safe isolation in this part of the world, although any electrician over here would likely be armed with a non-contact detector as I am with my Fluke VoltAlert (neon screwdrivers tend to be frowned upon). A non-contact detector can provide an indication that something is live, albeit in a somewhat hit-and-miss way, but it cannot be relied upon to prove something is not. The sort of scenarios you describe such as a cross connected neutral and a source of supply which differs from where you assume it comes from would still require the steps and equipment seen here, and if you're not familiar with the installation, then some investigation beforehand to figure out as best as possible where that circuit is powered from and whether it is loaded with any surprises. Cross connected neutrals are rare at this end, although some houses have such on their wiring from the 1960's and 1970's, so if we're not sure and are just in to do a simple lighting job, we usually isolate all lighting circuits to ensure the neutral won't float high when disconnected. I have come across cross connected circuits that remain live when the fuse/breaker is pulled, but the procedure identified them as still live afterwards so further steps were taken to ensure full isolation before work started.
@@dsesuk we're just going through safe isolation at college and we're taught to test the consumer unit with voltage pen before anything else and then test on known supply.
@@greggdaniels6129 So what do they ask you to do with the non-contact at the CU? Unless it's isolated externally, there will be power going into the main switch and nothing coming out if it's switched off, but you'd test that with a voltage tester. I can't see how waving a non-contact at it helps, but I'd be interested to know what their reason and technique is!
In theory with a modern high impedance tester the resistance in the multimeter should keep the possible current flow very very low, I understand your reluctance to test it tho. It's more of an issue with low impedance settings/adapters or analogue meters. I got a definite tingle when I fucked up while using the low impedance mode of my meter.
Great video thanks David. I thought the TIS 845 Voltage tester has its own built in proving test function, do you use this or don't you trust it? Thanks.
Hi Chris. The 845 does indeed have an in-built test function. It does a lamp test, I don't know what other elements of its circuitry it tests. At least by placing it across a proving unit or known good supply then you know you're testing the its ability to correctly measure and display a voltage. When I'm using the 845 or any other voltage indicator, I tend to use a known good source to verify operation, although the proving unit is always available to me in my Fluke case!
@@dsesuk Yes it makes sense that using a proving unit or known good supply is a more reliable method of checking a tester works. Thanks for your explanation.
Still the cheap screwdriver will get a situation where live is connected and neutral and earth no, or worse a situation where live, neutral and earth are live at the same potential. This method will not verify that, because it assumes to have at least a neutral or an earth at 0v. That method works assuming that you have a up to code installation, where the earth is connected, where polarity of L and N is respected, but in reality, you find installation where the earth doesn't work (if present at all), L and N have the same cable colors, switches interrupt only the neutral, or worse 3-way switching done in the insane way where the light turns off either with N-N or L-L at the socket, neutral that becomes live when the circuit is turned off because someone took the phase from a circuit and the neutral from another (this is common), and all that sort of stuff.
Safe isolation missed a test between supply neutral and busbar side live. Diagonally across isolator. If a faulty double pole isolator has not disconnected live side (just neutral) then tests shown would pass but a current path would be available from live to earth such as busbar & metalwork. You get rid of melty plastic fuseboxes & replace with ah yes sparky time metal ones⚡❗
Hi david I have a question not related to this video it is on tt supplies dose the main earth need to be 16mm I also know the ZE reading needs to be under 200 but is that the same for the zs of all individual circuits as well so if I test the ring zs or cooker zs or shower will they also need to be lower than 200 any advice would be appreciated thanks
Hi Greg. On a TT you want to keep the impedance as low as possible, so when we're putting in a spike we often use 16mm to get from the spike to the MET just to ensure that link in the chain has a low resistance. The final circuits should test out as they would normally, so an R1+R2 should be well within specification for the CSA of the cable used, the type of overcurrent protective device and the length of the circuit. Although the Zs of the circuit will be well over that prescribed by the regs once the R1+R2 has been added to the high Ze, the individual circuits should still be designed and installed as though the Ze is low (i.e. it isn't right to say, "sod it, the Ze will blow the Zs out of the water anyway, so we can let the R1+R2 slip here"). If you see what I mean...
Hi. I’ve got my am2 this year so wondering do I have to lock off main switch because I could accidentally lock off wrong circuit and someone could turn on main switch if I step away from board. Would I have to prove the circuit also with proving unit if not
No, locking off the main switch wouldn't be practical in many applications, especially commercial. If you're following safe isolation correctly, then you'll have identified the correct circuit so that the wrong one isn't locked off. The proving unit is just to check your voltage tester is operative, not the circuit.
Hi David, another great video. Could you please inform me, and perhaps others, what are the risks of using your TIS (or similar device) as both the proving unit and the testing instrument. For example, could you first test the TIS is working by connecting together the two leads and getting a beep (the continuity test); then, second, go on to test the actual circuit, to see if it is dead or energised; and then third, use the same TIS instrument to reprove it is working by touching the leads together and getting a beep (testing continuity again)? I understand that you are only testing for continuity in the first and third tests, but you are also testing whether the instrument is working. I'm recently an ex-student, and I do not wish to become a ex-being, if using an instrument as described may lead to a frying. Any thoughts?
Hi Keith. Proving the continuity function of the instrument wouldn''t suffice I don't think. The internal components which form such a dead-test are not necessarily the same as those employed on a live voltage measurement, or at least they're not reacting to a like stimulus. The continuity function doesn't use the LED or LCD indicators which provide the feedback to the operator of the voltage reading, so a fault with the circuitry that controls those elements may result in an incorrect display that the continuity function wouldn't pick up. The 845 has a self-test feature which, I understand, health checks its circuitry and performs a lamp test to prove the LED and LCD displays are operational. Most voltage testers don't do this though, and a continuity test on other testers would only perhaps prove the batteries are good, but not much more.
@@dsesuk Thank you David for such a comprehensive reply. I'd better get a proving unit, though I must say, that many people whom might call themselves electricians don't appear to have a proving unit in their toolbox. The last such an electrician of 40 years experience proved that the cables going into the consumer unit in a university were dead by testing the other side of the main switch (the consumer side). That switch was locked off. He, pulled the lock off off because everything was dead, or at least he believed it to be. I then tested the incoming side which proved he has just energised the whole installation. From that moment he resented that I had saved his life, or mine, or others. Still, a lesson to me, knobheads are certainly out there and you cannot be too careful.
@@SqwarkParrotSpittingFeathers I'm afraid knobheads are aplenty out there Keith! But you're right, most sparkies I know have no proving unit and rely on testing on a known live source which is all very well until you're called to a job where there is apparently no power and you can't be sure what's good and what's not!
@@dsesuk in an emergency you could always use your MFT / IR tester to produce 250V as a proving unit. Bit crap but no reason why it wouldn't work. I'm really not a fan of voltage indicators though. I work on solar systems, and their voltages are in the 800-1000V range. Voltage indicators only go up to 690 so would be dangerous to use. If you're proving, testing, proving again then you can use a multimeter as if you have got it set wrong then it will fail the first proving. GS38 is ok with that, though not the first choice.
Been told by the NICEIC how to correctly carry out safe isolation procedure. Turn main switch off.remove fuse box cover .do NOT remove bus bar cover. Test top of main switch. Tester is working . Test top of 1st rcd ,L-N then L-E then N-E Then do the same on the 2nd rcd. The back to the top of the main switch to prove tester working .
i know this is not relevant, but cant help noticing the board next to you, its a wylex enclosure with schneider breakers, rcds and an mk main switch, and there is a central heating clock with tails in and out, how is that connected.
Merely for illustrative purposes using what was to hand (those tails pass through the clock without connection - it's pretending to be a meter). Not exactly splashing out on the production costs at this end!
The internal resistance of the Martindale and the input impedance of the Fluke form a voltage divider, hence a lower measured voltage than full mains voltage.
@@Lenny-kt2th The resistance of the martindale shouldn't affect the open circuit voltage on the nuteral which should be full mains weather it be an electric fire element or a high resistance such as a neon indicator on open circuit you will get full mains. DMM's are about 10Meg ohms not noticable in an o/c situation. Be worth a re visit with a DMM!
@@drivewasher the Martindale has a pretty low input impedance in order to harvest power to light itself up, about 200kohm. Most MFTs have input impedances of 3.5Mohm, where your average multimeter will be 10Mohm. There are exceptions with multimeters that have low impedance settings or my clamp meter (RS Pro 156, made by Appa and also branded Seaward and Megger) is also only 3.5Mohm.
I copped an eye popping 63A @240V it threw me into a brick wall about 5' behind me & F*** did it hurt & David I also stuck my finger in a light socket as a kid,in the 80's aside from that I have had 2 decent whollops,bringing my total to 3 decent ones & one BIG MOFO &yes I am an electrician 😁😁😁
I also copped the finger-in-light-socket as a kid thing. I had two lampholders each with their flexes twisted together, so to see which was plugged in I stuck my finger in one of them. Seemed like a good idea at the time!
How could you keep a straight face when coming out of the line about “lying in your own piss and shit and smelling of crispy bacon”? I was almost lying in a pool of my own piss and shit as it made me laugh so hard. Great videos by the way. Very informative.
you all prolly dont give a shit but does any of you know of a way to log back into an instagram account? I somehow lost my login password. I would appreciate any assistance you can give me
@Connor Lorenzo i really appreciate your reply. I got to the site through google and Im trying it out now. Looks like it's gonna take quite some time so I will get back to you later when my account password hopefully is recovered.
I one time had to cut in to a SWA an join it to a other SWA the power had to stay on I was sitting on a wood pallet going the Job. Then other job I was adding to a ring main some fool put power back on - So I then took a plug socket pulled the live pin out put in a neutral pin and wired L N E to each other an I had that plugged in to a socket in the room am working in so if a fool puts the power on the line am working on will be safe.
Also I had a loud buzzer box I did use plugged in so if I step away from part of the job an some one again did power up I would know. One time I pulled the fuses feeding a buzz bar on a job I can not say much about. Well what did happen I had the fuses in my tool box I hsd one foot on it I was cutting the end off the buzz bar an 30 meters down the other side round out of my view some one took a geny took the power lead with big crocks on an did re power it. As he needed power the other side. burning my hand an bottom of foot I think that day some one was holding on to me from the heavens. What I should of done was link it all out next to were I was working. But having the fuses in my box an yes the Fuse box was locked. He no longer had a job to come back to I was going to clamp him up and power on. I was locked in a store room until I did calm down. I do miss the work an re training to get back in
I too did stick my finger in a bayonet lamp holder in the 80s, I think it helped I was lying on a bed at the time and it just hurt my finger quite a lot 🙃😂
This is true, wiring should not be tied together as they need the air around them to dissipate the heat. As I've pointed out in other videos though (notably the one I did on the TIS859), this setup is not supposed to represent an ideal installation, it's for training and demonstration purposes and has a number of issues you wouldn't want to see in the field.
(2:40) - No, I disagree that it was just "luck" that didn't send you on to St Peter or whomever it may be these days standing gatekeeper to the promised land... No! I also stuck my finger into a lampholder socket way back in 1975. Foolish? Yes. Stupid? Also yes. Life threatening? Hardly. Sticking one's fingers into lamp sockets was a great sport back in the day. There is no way that this reckless activity could shorten one's lifespan by any amount. Although, if unlucky you could experience a nasty burn. Thing is, the path of the electrical current will always go by the shortest route. So if one sticks a finger in an empty electric lamp socket, the worst one could expect is a burnt finger. That's it. The mortal risk comes when the flow of electrons crosses the chest. Worst case (ideal for the Grim Reaper), scenario is getting shocked from one arm to the other. The next worst case is being shocked through arm via hand down through the feet. These are the two worst case scenarios and, as Davy says, is a real lottery. Don't even go there. For all the other types of shocks, the main danger would or might be falling off one's ladder. Ooops! >
400v motor with fault zated me while doing my apprenticeship stung like hell never been hit since but have had my pliers blown up because customer turn the power on so he could have a cupper remember your lock of kits
Yeah, well spotted. It was more a case of putting together something with what was to hand, after all it's only for illustrative purposes! I'll replace it if I ever get hold of a decommissioned meter I can use, but I'm too tight to buy one new - they cost about the same as a bottle of Jack Daniels!
I've been electrocuted a few time and luckily never suffered any ill effects 💭💭💭💭💭💭💭💭💭💭💭💭💭💭💭 Now where was I? Oh yeah, I've been electrocuted a few time and luckily never suffered any ill effects 💭💭💭💭💭💭💭💭💭💭💭💭💭💭💭 Although some people say, 🎵🎵 The hills are alive with the sound of music 🎵🎵 💭💭💭 Where was I? Oh yeah, I have a habit of repeating myself and 🎵🎵 These are a few of my favourite things 🎵🎵 bursting into song, but I don't think so 🤣🤣🤣🤣
Electrocution is basically electric execution. I guess you must be writing from beyond the grave. If it were just a shock, you would most probaly have recovered, r.i.p
@@generaldisarray Many people use electrocution vs shock interchangeably. But the difference between an electrocution and an injury from an electrical shock is literally a matter of life and death. ... An electrocution means that a person has died as a result of an electricity. You won't hear any member of a legal team or the HSE use the form of electrocuted if a death hasn't occurred. If it's an injury the term elctric shock is used. I honestly don't need a dictionary. I'd be an idiot to tell another person that I've been electrocuted. Especially If I'm making any form of communication.
Either it's giving out its stated voltage when you apply the voltage tester, or it isn't, in which case you need to determine whether it's the proving unit or voltage tester at fault. You can put the voltage tester across a known good supply to check that, and if it works then it may be time to replace the battery in the proving unit.
(0:30) - Sorry David. And you have to read all these comments in the correct order. (Most recent last). That's it! It's a quiff! A quiff! That's what it is! Don't like it. Sorry? No, not really. >
@@rokinben Ah, I see. It was shown when testing the socket around the 19 minute mark and the the sequence was described toward the end, but you're right in that it wasn't shown at the board at around the fifteen minute mark. Looks like I got distracted by babbling on about my voltage indicator on the day!
