MikeR
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| posted on 11/8/10 at 10:20 PM |
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OT - fountains in bedrooms are a bad idea
Oooops - discovered that the depth stop on my circular saw needs to be done up really tight today.
Found this out after very carefully setting the depth and cutting a floor board with water pipes underneath. Holding a running circular saw as a 1
foot fountain appears is an interesting (hopefully not to be repeated) experience. Finding out 20 minutes later that the next pipe was a gas pipe
that the gas fitter hadn't removed when he moved the boiler was a little scary.
Spent the rest of the evening mopping up and sorting out the pipes. Due to having a dripping light fitting i removed the light in the kitchen (after
turning the electrics off). Spaced out the wires and turned on the lights again so the g/f could see. Forgot i'd turned the electrics on so the
misses could see and .....
well .........
turns out if you electrocute yourself whilst putting a light back, and your insulated from ground, and your girlfriend is grounded, and she's
holding a metal fitting, that she's handing to you .........
She doesn't find it funny that she got electrocuted 
She also doesn't find it funny that you're laughing your head off saying things like "wowsers, that was a shock, haven't done
that since i was about ten"
Note to self - always check the electrics are off before tampering 
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omega0684
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| posted on 11/8/10 at 10:27 PM |
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PMSL 
I love Pinto's, even if i did get mine from P&O!
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slingshot2000
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| posted on 11/8/10 at 10:37 PM |
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Wowser! SApeaking as a qualified electrician, you have both had an extremely lucky escape. A good friend of mine tried to change a light bulb in her
kitchen. She could not remember if light switch was on or off and she got a shock that made her grip the light fitting harder and harder as the fuse
didnt blow. She eventually shook herself free of the metal step ladder she was standing on and fell some distance to the floor. Some time later she
was found laid on the concrete kitchen floor by her teenage daughter. She had been unable to get o her feet as she had a very bad compound fractures
to both her tibia and fibia. It was so bad that the first surgeon that saw her considered amputating her leg below the knee. It was only looked at
again because one of the nurses pointed out that she was infact a theatre nurse at the same hospital.
Please, please, please make sure you switch off at the main switch before working on live circuits. And remember, pulling out a fuse or switching off
a circuit breaker only stops the live/phase and we do have AC power in the UK !
Glad you are both ok and can you see the funny side of this.
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MikeR
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| posted on 11/8/10 at 10:46 PM |
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I'm normally very good with switching things off. I deliberately have a cooker switch with a power socket so i can power down the whole house
apart from one isolated socket.
Unfortunately i've only been living with someone a few months and aren't used to having to take them into account (and have some power
on). With the kitchen being dark i forgot the lights had power. One thing that does surprise me now looking back was that the RCD didn't trip
(new CU installed 2 weeks ago so only had RCD's for a couple of weeks!)
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Simon
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| posted on 11/8/10 at 11:04 PM |
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Hmmm. PC mouse has been playing around recently so went and bought another tonight. Took over an hour for the software to load (2nd time after an
error message during loading). Haven't been able to get new mouse/keyboard working but old mouse now works fine. (£30 wasted).
Missus killed the shower this evening, so just ordered another (for £280).
Lightswitch in living room knackered (dimmer, no knob) using a screwdriver in hole, got shock. so need some of them.
And I spent about £95 on diesel before all this started.
And the (Anglian Windows) front door has no adjustment on hinges (and was last adjusted by them when they fitted it), and it's dropped. More to
the point they want £104 for a callout. Anglian Windows won't be invited to work on this house again. to55ers
At least the oil leak on toy car only turned out to be loose pump cover screws!
Cheap night!
ATB
Simon
[Edited on 11/8/10 by Simon]
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norfolkluego
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| posted on 11/8/10 at 11:20 PM |
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quote:
Originally posted by slingshot2000
Please, please, please make sure you switch off at the main switch before working on live circuits. And remember, pulling out a fuse or switching off
a circuit breaker only stops the live/phase and we do have AC power in the UK !
Glad you are both ok and can you see the funny side of this.
Seriously, can you explain what that means (to a non electrician), I thought if the fuse/mcb was cut, the circuit was dead, are you saying you always
have to switch off completely at the consumer unit to work safely
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slingshot2000
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| posted on 12/8/10 at 01:16 AM |
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Seriously, YES!
In the Uk we use "alternating current" to transmit power; IE- it goes 240volt positive to 240volt negative ! You fuse is on the live side
of the circuit, while it is live! Switch this off and the "neutral" is sat there; waiting to alternate !
Most electrical 'faults' in the UK are neutral/earth faults, and thay are connected together(same voltage) back at the power-station, but
at your house(240volts) can and will kill you.
Switch it off!
I use a voltage detector that can sense upto 600volts to mkae sure a circuit is dead, before I work on said circuit, I then make sure the circuit
tester is still working - using a battery powered 'verifying -unit' !
NEVER WORK LIVE !
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jabs
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| posted on 12/8/10 at 07:45 AM |
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quote:
Originally posted by slingshot2000
In the Uk we use "alternating current" to transmit power; IE- it goes 240volt positive to 240volt negative
Think you mean 120v positive to 120v negative else we would have 480v supply
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Grimsdale
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| posted on 12/8/10 at 08:28 AM |
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actually it goes up to about 350V each way, the 240v is a root mean squared value.
http://en.wikipedia.org/wiki/Root_mean_square
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Macbeast
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| posted on 12/8/10 at 08:28 AM |
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" Electrocuted " means killed by electricity - from American electric chair, electricity + executed.
Are you having a joint funeral ?
I'm addicted to brake fluid, but I can stop anytime.
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MikeR
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| posted on 12/8/10 at 08:43 AM |
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if i mess up again probably
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peteday_uk@btinternet.com
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| posted on 12/8/10 at 09:58 AM |
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Thank you.......I have just read out your post to the whole sales team, who haven't stopped laughing, nothing like some one elses misfortune to
brighten up the day. (Sorry....I know it could have been much more serious and prob not a laughing matter.)
Anyway I'll see you at the next meet, i'll def buy you a drink for such an entertaining story!!! Hopfully I'll have some build
updates too.
Pete.
[Edited on 12/8/10 by peteday_uk@btinternet.com]
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David Jenkins
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| posted on 12/8/10 at 11:28 AM |
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quote:
Originally posted by Grimsdale
actually it goes up to about 350V each way, the 240v is a root mean squared value.
http://en.wikipedia.org/wiki/Root_mean_square
Peak-to-peak voltage across the sine wave is around 650v in Europe (according to that wiki article). I believe that it was done like that because
240v RMS has roughly the same heating power as 240v DC.
Story made me laugh, though I shouldn't when it's someone else's misfortune! That's the sort of situation where you rush of to
the stopcock and THEN find that it's seized up totally...
[Edited on 12/8/10 by David Jenkins]
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Ninehigh
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| posted on 12/8/10 at 01:41 PM |
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quote:
Originally posted by slingshot2000
Seriously, YES!
In the Uk we use "alternating current" to transmit power; IE- it goes 240volt positive to 240volt negative ! You fuse is on the live side
of the circuit, while it is live! Switch this off and the "neutral" is sat there; waiting to alternate!
I was under the impression that the neutral and earth went to earth and not back to the power station...
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David Jenkins
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| posted on 12/8/10 at 01:58 PM |
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Neutral is earthed at the local sub-station, IIRC.
This means that it can have a significant voltage induced from the live wire if the sub-station is far away.
The end result is:
Live - obviously, loads of volts
Neutral - floating somewhere between earth and live.
Earth - should be local earth - but may not be if you're busy chasing a fault in the wiring.
[Edited on 12/8/10 by David Jenkins]
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MikeR
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| posted on 12/8/10 at 02:45 PM |
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i guess ive got another bit of uck with the substation being about 200 meters away.
As for the stop cock, i always have it an eigth of a turn off full on so there is less chance of it seizing on. Boiler people had it only just on. I
hit fully closed within a turn,mild panic thinking ive turned it the wrong way, turned the tap the other way, all the way to fully on, more anxiety,
turned the tap off - finally.
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Liam
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| posted on 12/8/10 at 07:46 PM |
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quote:
Originally posted by slingshot2000
Seriously, YES!
In the Uk we use "alternating current" to transmit power; IE- it goes 240volt positive to 240volt negative ! You fuse is on the live side
of the circuit, while it is live! Switch this off and the "neutral" is sat there; waiting to alternate !
Most electrical 'faults' in the UK are neutral/earth faults, and thay are connected together(same voltage) back at the power-station, but
at your house(240volts) can and will kill you.
Switch it off!
I use a voltage detector that can sense upto 600volts to mkae sure a circuit is dead, before I work on said circuit, I then make sure the circuit
tester is still working - using a battery powered 'verifying -unit' !
NEVER WORK LIVE !
That's excellent advice, although it sounds, correct me if I'm wrong, that you have a common misunderstanding of alternating current.
Sounds as if you're suggesting the live and neutral wires are alternately at 230V with respect to earth, i.e. they are essentially identical and
neutral is just as dangerous to touch as live?
That's not true - neutral is connected to earth (at the substation transformer, or even in the property if it's TN-C-S) so it will always
be at or very close to 0V with respect to earth under normal conditions. Live alternates between +325V and -325V with respect to earth (230Vrms).
The reason it's still excellent advice to switch off the entire installation, or at the very least thoroughly check for dead with a proper
voltage tester (NOT a neon screwdriver), is because unless you know every inch of your installation you can never be sure switching off a single MCB
will totally kill the wiring you intend to work on, or some fault doesn't exist that could make neutrals become live. Particularly relevant to
working on lighting circuits, a borrowed neutral can result in a situation where you switch off one lighting circuit MCB, verify the light
you're going to work on is dead by operating the switch or testing, but as soon as you cut a cable (or otherwise break the neutral -
disconnecting a junction box for example), some or all of the neutral cable for that circuit becomes live! So if working on lighting be sure to switch
off all lighting circuits in case you have a borrowed neutral. Switching off the whole installation is safest of all.
Dave - any induced voltage on a neutral will dissipate straight away since it's connected to earth. The reason you might measure voltage with
respect to earth on a neutral a long way from a substation is simply because under normal conditions the neutral carries current and earth does not.
Therefore there is voltage drop IxR along the neutral cable, and so if neutral is at 0V with respect to earth where they are connected at the
substation, it must be at something above 0V with respect to earth the futher away from the substation you go. Barring fault conditions, the cables
are sized such that neutral voltage at a point of use is tiny - certainly not dangerous. If you ever can measure 'significant' voltage
with respect to earth you could have a dangerous fault that may not necessarily be in your instalation, eg a high resistance neutral somewhere, or
even a completely disconnected (and hence floating) earth!
Mike - you're lucky to be alive to be honest! Glad you are. You should be pretty concerned the RCD didn't trip because it's most
likely faulty and wont trip next time either. I'm assuming you're 100% sure that ighting circuit is on an RCD in the first place - most
likely should be if your CU was replaced that recently. There's a chance that your GF was insulated from earth sufficiently (possible depending
on footware, floor, covering, house consruction etc etc) that only a very low fault current flowed - too low to operate the RCD. Pretty unlikely as it
sounds like you both got a good belt. I'd be on the phone to the sparky telling him what happenned and demanding he test/replace that RCD (and i
dont mean press the test button). I assume they were tested when the CU swap was done?
[Edited on 12/8/10 by Liam]
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JoelP
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| posted on 12/8/10 at 07:55 PM |
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good post there liam, i was going to mention similar about the neutral thing but didnt want to get into a row over it.
Beware! Bourettes is binfectious.
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Liam
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| posted on 12/8/10 at 08:20 PM |
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quote:
Originally posted by JoelP
good post there liam, i was going to mention similar about the neutral thing but didnt want to get into a row over it.
Lol thanks! I dont want to get into any rows - just dispel myths and misunderstandings . Maybe lately I'm suffering a little from
'someone-is-wrong-on-the-internet-raaaaaa' syndrome?
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MikeR
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| posted on 13/8/10 at 10:25 AM |
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Liam - thanks for the post .........
I got a good tingle / zap in my hand and I moved it instantly going wowsers. G/f got a funny sensation and achy / tingly foot.
You've got me worried about the RCD as the whole lot was changed, it was tested (well one socket a room was & he got the count of sockets
wrong!)
Problem i've now got is i'm really not happy with the work the gas company did (they subcontracted the spark). I've had them back
twice to fix faults and i'm still fixing things (like floor boards). The spark wasn't impressive either.
Is there a simple way to safely DIY test an RCD? (should they just pull out like old style fuses as well?)
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David Jenkins
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| posted on 13/8/10 at 11:05 AM |
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quote:
Originally posted by Liam
quote:
Originally posted by JoelP
good post there liam, i was going to mention similar about the neutral thing but didnt want to get into a row over it.
Lol thanks! I dont want to get into any rows - just dispel myths and misunderstandings . Maybe lately I'm suffering a little from
'someone-is-wrong-on-the-internet-raaaaaa' syndrome?
Don't worry folks - I'm not going to get precious about it!
The main point I was trying to make was that the neutral is earthed at the sub-station, not locally to the house. Also that it is wiser to treat
neutral as carefully as the live connection - just in case of a wiring error you don't know about (yet!).
As for testing the RCD - they usually have a test button on the front, so that's a good place to start.
One query - you were connected to the lights when you got your shock, weren't you? I'm sure I've read somewhere that lighting
circuits don't usually go through an RCD... one for the electrical experts to confirm/deny!
[Edited on 13/8/10 by David Jenkins]
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Liam
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| posted on 13/8/10 at 11:31 AM |
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I have been stupid enough to trip an RCD before and it was more like being hit than tingled, so it is possible the fault current was just too low to
operate the RCD. The only way to be sure is to test it properly though. You should have an EIC and on it should be a page of test results, and on that
should be tripping times in ms for the RCDs.
Are you sure your lighting circuit is on an RCD? As David says they traditionally wouldn't be, but the latest regs concerning protecting cables
concealed in walls (i.e. your switch drops, for example) effectively impose RCD requirements on all circuits in a domestic install. So it's most
likely all your circuits were (or should have been) put on two or more RCDs during the CU swap. Photo of CU would help.
The RCDs are DIN rail mounted and wont just pull out, not that that would aid you in testing one anyway. The test button only tests the internal
mechanism of the RCD itself - that it isn't stuck for example. It does not confirm that a circuit connected to the RCD will operate it in the
event of a fault. You can't really test one fully without a proper RCD tester. I mean you could always deliberately wire up a neutral/earth
fault then turn the circuit on - that will trip the RCD without much drama, but I dont recommend that at all. And even if you did that and verified
the RCD tripped, you wouldn't know if it tripped within the required time and at the required current level. A proper tester can do various
tests and will time how long the RCD takes to trip and also measure at what current it tripped. As above, you should have at least the trip times @
1xrated current on your EIC if they've been tested.
I'd still phone the company and tell them you recieved a shock that didn't trip an RCD and that you would like it testing/sorting.
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JoelP
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| posted on 13/8/10 at 06:34 PM |
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a n-e fault wont always trip the rcd anyway, because if there is no current being drawn elsewhere in the house then the neutral and earth conductors
will be at the same potential.
You would need a proper test device.
Do you have two rcds in your new board? Would have to be less than a year old really to have the lights on the RCD.
Beware! Bourettes is binfectious.
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MikeR
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| posted on 13/8/10 at 08:49 PM |
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The board was brand new 2 weeks ago. Its got two separated RCCB's (i think thats the term) rated at 80 amps. One covers the 3 RCD's that
do central heating, oven, downstairs lights, the other covers the 3 RCD's that do ring main, upstairs lights and shower.
It hasn't got any lights on it (that i can see - so they're not lit normally).
[Edited on 13/8/10 by MikeR]
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JoelP
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| posted on 13/8/10 at 09:06 PM |
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my bad grammar, i meant the lighting circuit on the rcd, which you seem to have.
I cant see how you got a shock tbh, unless you were insulated from earth (whats your step ladder made of?) and were yourself part of a l-n circuit, in
which case the RCD would not trip, as no current would be lost to earth.
Do you have certificates from the spark who swapped the board?
Beware! Bourettes is binfectious.
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