I stumbled across this one and given the grotty state of our electrics thanks to The Bodger I am acutely aware that the fault exhibited here could bite me.
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Interesting YouTube electrical fault video
- Thread starter RogerS
- Start date
I stumbled across this one and given the grotty state of our electrics thanks to The Bodger I am acutely aware that the fault exhibited here could bite me.
Windows
Old Oak
That was fascinating. Knowing nothing about electrics & boilers, I could conceptualise how the internals of the boiler might still be unexpectedly live if it were wired to receive power from two sources when only one is expected, but I don’t understand how the boiler ends up with live current on the pins of the plug. Presumably there was incorrect internal wiring on the boiler in addition to the mistaken attempt to get a permanent live from the wrong circuit?
jimhanna
Seedling
I found something similar with outside lights.
There was a light on the side of the house with a switch inside the door.
This was on the downstairs lighting circuit in the house.
At some point a couple of additional lights were added on the separate garage and
a cable run across from the house so that one switch brought on all the outside lights.
At a later date a movement sensor was added on the garage to bring on the outside lights.
Of course the sensor needed a permanent live so this was wired into the garage power, a separate circuit from the house electrics.
Result the outside lights were connected via two circuits at the consumer unit but only when it was dark and somebody had went out to the garage and triggered the sensor.
Working on the downstairs lights one night I went out to the garage for tools, switching on the outside lights as I went. Came back in, pulled the circuit breaker for the downstairs lights and fortunately discovered that the circuit was still live when I checked it before touching anything.
The switch for the outside lights being on meant the sensor was powering the whole downstairs lights circuit.
If I had waited a few minutes before starting work the sensor would have turned off and it would have been a perfect trap just waiting for some movement outside to make the whole thing live again.
There was a light on the side of the house with a switch inside the door.
This was on the downstairs lighting circuit in the house.
At some point a couple of additional lights were added on the separate garage and
a cable run across from the house so that one switch brought on all the outside lights.
At a later date a movement sensor was added on the garage to bring on the outside lights.
Of course the sensor needed a permanent live so this was wired into the garage power, a separate circuit from the house electrics.
Result the outside lights were connected via two circuits at the consumer unit but only when it was dark and somebody had went out to the garage and triggered the sensor.
Working on the downstairs lights one night I went out to the garage for tools, switching on the outside lights as I went. Came back in, pulled the circuit breaker for the downstairs lights and fortunately discovered that the circuit was still live when I checked it before touching anything.
The switch for the outside lights being on meant the sensor was powering the whole downstairs lights circuit.
If I had waited a few minutes before starting work the sensor would have turned off and it would have been a perfect trap just waiting for some movement outside to make the whole thing live again.
That's really terrifying to have live plug pins like that, it could have very easily killed someone 
Truly appalling that it was done by a "professional", if I was the home owner I'd be kicking up hell about it to the boiler installer.
Truly appalling that it was done by a "professional", if I was the home owner I'd be kicking up hell about it to the boiler installer.
Guineafowl21
Sapling
It didn't look like a direct live - voltage was down from 230V and dropped as appliances were plugged in, suggesting a high impedance source.
Switched live from thermostat probably activates a relay in the boiler. So the errant voltage source, at least on the neutral plug pin, was probably via the relay coil. The live might have got it via interference suppression circuitry.
Although it was indirect, you can still receive a nasty jolt from just a few mA.
Spectric
New Shoots
Twenty years experience and he did not prove dead once isolated, procedure is prove live then prove dead to confirm your isolation is responsible for the circuit being dead. He might have become complacent, an issue that also happens in woodworking with machinery. He also does not mention if he sought medical advice, following an electric shock it is always good to get checked out to ensure nothing has been damaged especially if it is between hands. That is the first boiler I have seen that is connected via a 13 amp plug, normal practice is to use a switched FCU and the person who installed that boiler is not electrically competant. New boilers need the permeant live for the pump overrun, so what else is also not correct ?
The other thing people get caught out by is getting a shock from a disconnected neutral, it catches a few out.
The other thing people get caught out by is getting a shock from a disconnected neutral, it catches a few out.
AJB Temple
Sequoia
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Yes. Interesting lessons for us all here. This guy does a lot of youtube technical (ish) vids and I was surprised he had not proved dead across all combinations. Very odd to connect a boiler with a 13amp plug though. I'm paranoid about electrical circuits after getting a big belt one day 27 years ago when our housekeeper turned back on a circuit at the CU I was working on in a bathroom. Not on purpose: she either had misunderstood me (she came from the Philippines) or simply forgot. Two lessons from that: I bought isolator locks and still use them and bought a proper Megger circuit tester.
DAMHIKT
AJB Temple
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When I finally got round to getting proper training (as opposed to my early DIY ventures decades ago) I was taught not only to prove live and prove dead, but also to prove that the test instrument has not failed for some reason mid test (such as battery failure or lead unplugged or damaged). This is to avoid false or misleading 'proofs'. I check that religiously as well nowadays. I use a Megger test meter the same as in the video, a battery pack proving unit delivering reliable live, and a two pole voltage tester Megger TPT420 which is a useful bit of kit to have in the electrical tool bag as it continues to detect voltage even if the batteries have failed (which you can easily tell by touching the two probe tips together).
Spectric
New Shoots
Yes an important point and why only a decent tester should be used, not one of those kids toys of the screwdriver type that glows ! The Fluke tester with proving unit is a good tool.
HappyHacker
Sapling
I was told by a gas Safe plumber that connecting a boiler via a plug instead of a fused connection unit was mandated by gas Safe for a few years. Mainly as I understand so that the removal of the plug proved isolation of Live and Neutral. A Gas Safe engineer to ld me to change my double pole switched fuse outlet to a plug as a SFCU was no longer allowed, I told him to go away. Speaking to another Gas Safe plumber more recently he said that plugs were not now recommended.
While I would always check all three connection for live I must say I could not guarantee that I always do it absolutely every time. I must also admit to creating a few wire strippers from wire cutters over the years by cutting into cables I KNOW to be dead. Fortunately good non contact voltage testers, I have at least three, have stopped me from doing this. Same rules apply - test the tester before and after.
Excellent advice above to prove dead and then test the tester against a known live/test box to ensure it is still working. Fluke replaced one of my testers under a recall as they had a few develop a fault in the cable with use.
While I would always check all three connection for live I must say I could not guarantee that I always do it absolutely every time. I must also admit to creating a few wire strippers from wire cutters over the years by cutting into cables I KNOW to be dead. Fortunately good non contact voltage testers, I have at least three, have stopped me from doing this. Same rules apply - test the tester before and after.
Excellent advice above to prove dead and then test the tester against a known live/test box to ensure it is still working. Fluke replaced one of my testers under a recall as they had a few develop a fault in the cable with use.
Windows
Old Oak
OK, so I have an outlet that I want to move from one side of a wall to the other. I think I need to disconnect the socket, pull the wire through the wall, then reconnect the socket on the other side. What test equipment (brands, makes, models) do I need to do this safely? I was thinking of turning off the power to the entire house when I do this because why not?
AJB Temple
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Internet advice on this stuff is unwise Windows: I might be tempted to suggest if you have to ask you don't know enough. The reference to "pull the wire through the wall" is a signal. In the UK you most likely have a ring and you most definitely don't want to convert a ring into a split ring with potentially undersized wires. it is much cheaper and much safer to get a qualified and building regs certified sparks to do it rather than buy test gear.
Be wary of turning off the power to do work if you are relying on the CU master switch. If you don't have an isolation switch between meter and CU, then you need to make sure you understand your risks. DIY electrics = fire risk often = insurers avoiding liability.
Be wary of turning off the power to do work if you are relying on the CU master switch. If you don't have an isolation switch between meter and CU, then you need to make sure you understand your risks. DIY electrics = fire risk often = insurers avoiding liability.
spb
Nordic Pine
The honest answer to "why not?" is because the equipment you need to do it properly costs more than an electrician does for a job like this.
The absolute minimum you'd need to do things properly and safely would be a safe isolation kit to reliably prove that the circuit's dead before working on it, and then a multifunction tester to test everything once you're done. Add in a copy of the regulations and the time to read and understand them, and it's really not worth it for an occasional one-off job. My fairly basic electrical toolkit was over a grand and I'd struggle to say it's definitely paid for itself over five years or so. The moment you get into major work that needs a completion certificate, DIYing it means paying building control fees so you don't save nearly as much as you'd think, and small jobs that don't need it don't generally cost that much in the first place.
Windows
Old Oak
I get what you’re saying.
Just to be clear, I wouldn’t be converting or adding anything. Not even changing the length of existing wires. Literally just disconnecting the sockets and reconnecting using exactly the same wire. (After taking photos showing the existing connections so I could reattach wires to terminals in exactly the same way). The sockets and the socket end of the wiring would be moving about 10” through space from one side of a wall to the other (from one room to another - the new room being a pantry area that currently has no sockets). Everything else would be untouched.
Based on an existing hole in the wall, it looks like the socket was originally on the side of the wall I want it on now and it had been moved to the other side of the wall.
If I were willing to make a larger hole in the wall, I would pass the socket through the hole without disconnecting the wiring first. I might investigate this option further, but I don’t think it will be practical.
In a normal world, I would pay an electrician for this and the 10 other jobs I’ve attempted to schedule. They fail to give quotes, or don’t turn up, or have no availability. I really don’t want to be doing electrical work (I am highly risk averse), but at some point, you’ve just got to get on with things.
Hope that clarifies what I‘m considering.
Cabinetman
Old Oak
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Re your last main sentence and not being able to tie an electrician down to a quote, I have found it relatively easy to get them to do work on an hourly rate, they prefer it this way I think, the work gets done, it was going to take that long to do the job anyway and it saves them the time to quote and write it up, in out bosh and paid. For smaller jobs it can also work if you can be flexible as to when they come, end of a day after finishing early on another job for example.
Windows
Old Oak
Thanks for the links. £700 of equipment is more than I’d be willing to spend right now. I could definitely get a pro to do what I need for less than that, if I could get a pro to do anything at all.
£200 is probably my equipment budget for my very limited uses. I see socket testers at £20-£60, no contact testers at £20-£30, and multimeters at £20-£150. Are tools in these categories at this price range useful at all? Someone mentioned Fluke earlier and I see Fluke products in this price range. Bearing in mind that my intended use is pretty much reassurance that I’m not going to be electrocuted while wiring in a light or changing out an existing socket (and perhaps exercising my curiosity about the correctness/safety of existing electrical work or new work done by someone else), are these tools appropriate for that purpose? I’m not trying to do electrician work, but I am looking for tools that will help reassure me that the power is off when I think it is. Maybe the safe isolation kit linked at £160 is the answer.
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Windows
Old Oak
This is a good point. We’ve let the electricians set the tone as to how they want to proceed whether with quotes or hourly (we’ve talked to both kinds of people and we’d be happy with either) and we’ve both expressed flexibility and tried to encourage some date setting on different occasions to see which would work. Sadly it hasn’t helped. And this isn’t a problem unique to electricians.
We wondered if we were having more difficulties because we’re newcomers, but talking to friends and neighbours everyone gets ghosted by tradies all the time, only for them to get in touch again 6 months later and ask if you still want the work doing. It’s ridiculous.
I did get lucky once where I only got ghosted for 3 weeks and then the guy got back in touch, I said work still needed doing, and he was at the house and finished the job within 30 mins so flexibility is definitely helpful. I should add that he didn’t actually say he was going to show up at all. I was just about to have a bath and I hear a truck pulling up outside and he’s already on the roof before I make it outside to see what’s what. He’s lucky he didn’t turn up 5 minutes later. He’d have got an eyeful through the skylight.
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spb
Nordic Pine
They're useful, and I have all of those in addition to the expensive MFT, but they're not really sufficient on their own. The short version is that they can tell you something is wrong, but not that it's definitely right. There are plenty of faults that the cheaper equipment just can't detect, and if you're going to do the tests that the regulations require, you need something that's designed for that purpose.
Pragmatically, of course, the whole "only do DIY if you can fully meet all the regulations and test it accordingly" line isn't always going to be followed. A socket tester like this one, with an earth loop impedance test function, will do most of what's needed for a simple socket faceplate swap, but there are plenty of dangerous faults that it can't detect and which are entirely plausible to introduce even on a simple job. If you're going to do DIY socket swaps and don't have the budget for the proper kit, that's the thing to get, just recognise that it can't remove all the risks.
Phil Pascoe
Old Oak
A problem with getting a fixed price for a job is that the tradesman will price to allow for all eventualities, especially in an old property.
A mutual friend was to do some work for my cousin and asked if he wanted a fixed price or an hourly rate. My cousin asked for a fixed price, which he was given and which he accepted. My friend did the job in half the time he'd allowed, he hit no snags, and my cousin objected to the bill. My friend said I asked you which way you wanted it and you didn't trust me enough to work at an hourly rate (they were friends, remember) so I had to allow for all the snags that were quite likely to crop up. I was fortunate, I hit no problems, but that's the way it works, you accepted the price, you had the option so hard luck.
A mutual friend was to do some work for my cousin and asked if he wanted a fixed price or an hourly rate. My cousin asked for a fixed price, which he was given and which he accepted. My friend did the job in half the time he'd allowed, he hit no snags, and my cousin objected to the bill. My friend said I asked you which way you wanted it and you didn't trust me enough to work at an hourly rate (they were friends, remember) so I had to allow for all the snags that were quite likely to crop up. I was fortunate, I hit no problems, but that's the way it works, you accepted the price, you had the option so hard luck.
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Windows
Old Oak
I feel good for the trade if they’ve quoted fixed and made good money on the deal. Bad form of the customer to complain. Practically speaking, I’ve never seen a quote that was actually a fixed price. If there’s a single large piece of kit, like a boiler, that price might be explicit, but everything else is always written as cost plus, estimated cost, or per hour. When y’all get work done with quotes, do you actually end up with fixed price?
spb
Nordic Pine
I'd say a majority of the jobs I've had done were fixed price, with it changing only where we changed the scope of work (by mutual agreement) part way through.
Sometimes it has been caveated though - e.g. when I had the consumer unit replaced, it was an EICR on day 1 and the actual change on day 2. The quote said what the fixed price would be if nothing came up on the EICR that couldn't be immediately rectified, and if anything did then I'd be asked about it before proceeding.
That said, I've never yet had to get a job done that was more than a few days' work. That's going to change before too long, so I suppose I'll find out how things happen differently on bigger projects.
Sometimes it has been caveated though - e.g. when I had the consumer unit replaced, it was an EICR on day 1 and the actual change on day 2. The quote said what the fixed price would be if nothing came up on the EICR that couldn't be immediately rectified, and if anything did then I'd be asked about it before proceeding.
That said, I've never yet had to get a job done that was more than a few days' work. That's going to change before too long, so I suppose I'll find out how things happen differently on bigger projects.
Guineafowl21
Sapling
It looks like you’re in that limbo, job too small for an electrician, maybe too big for you. A serious lack of tradies up here means there’s little point in contacting one. They won’t turn up. So I often ‘go it alone’, but I do have decent test gear.
I wouldn’t say your job is too far different from replacing a socket like-for-like, just on the other side of the wall.
For proving dead, get something like this:
For the proving dead function, there are no batteries to go flat, no settings to get wrong - it’s designed not to give a false negative.
Re: the proving box you’re supposed to use with it - every electrician I’ve seen work has simply tested while live, then switched off, then tested dead.
Check all combinations both times, L-E, L-N, E-N, unlike that Artisan plonker ^^.
Switching off at the main CU isolator should be fine - just be sure there are no other CUs about, or solar, etc. Make sure no-one can switch it on while you’re working. Electricians have lockout tags, but again, I’ve yet to see one used.
Spectric
New Shoots
When I first started we did not have all the test gear that is available now, certainly not multifunction testers that could perform automated test and record the data, in fact our mega tester had a windup handle and the three phase rotation meter was in a nice wooden oak box ! What we had back then to prove dead was a small tester that used a very low wattage bulb with a probe and a fly lead, first thing in the morning we checked it worked and that was it till the next day. In domestic the only radial was the kitchen cooker socket and we still fitted ring mains, only industrial was all done as radials and you did not have MCB's let alone RCB's.
1968. BBC OB vehicles were all fitted with RCBs on the mains outlets that fed monitors in the commentators gallery, for example.
Spectric
New Shoots
Important people with money, your average joe just got on with using fusewire from Woolworths, infact many people kept that on top of the board ready.
Sorry not sure what point you’re making. I was responding to your statement that “only industrial was all done as radials and you did not have MCB's let alone RCB's.”. The BBC certainly come under that category and used RCBs.