A Timely reminder

[skipper]

I often read through the posts, but seldom write anything as there are so many contributors who are way, way cleverer than me. Reading this forum should be compulsory for all apprentice sparks!

However, I had an experience on Friday that I thought worth sharing.

I'm working on a block of 8 holiday apartments that are being refurbed, putting up lights and re-installing hard wired convector heaters in bedrooms.
Every apartment has, so far, had both bedroom heaters on a ring final with a 32A MCB. The entire CU is RCD protected.

So, I go into apartment 7, flick the MCB off, remove the unfused hard outlet from the double bedroom wall, verify that it's dead and replace it with a fused outlet and wire the new convector heater in.

Off to the single bedroom, pull the hard outlet which still has the old heater attached. I switch it on, no red light. Of course not, the breaker is off. I reach for my terminal screwdriver to undo the live. Damn, left it in the other bedroom. Reach into my pocket for my trusty old testing driver.....which promptly glows as soon as I touch the screw!

Somebody had swapped the hard outlet with a single socket outlet when the bedroom furniture had been moved around. The LED in the convector heater had failed, hence no warning light, but the outlet was live. Had I used my VDE driver to undo the terminals, my next step would have been to straighten the conductors between finger and thumb! OUCH!!!
One way of testing the RCD, I suppose.

We all try to work safely. Yes, I SHOULD have switched the main switch off, but when others are at work and need the lights on it's not realistic.
Doing repetitive work to a timescale, with other tradesmen present, can lead to a lapse in concentration.
I've learned from my near miss, and verify properly EVERY time. Hope everyone else does as well.

 

[lee sandland]

I often read through the posts, but seldom write anything as there are so many contributors who are way, way cleverer than me. Reading this forum should be compulsory for all apprentice sparks!

However, I had an experience on Friday that I thought worth sharing.

I'm working on a block of 8 holiday apartments that are being refurbed, putting up lights and re-installing hard wired convector heaters in bedrooms.
Every apartment has, so far, had both bedroom heaters on a ring final with a 32A MCB. The entire CU is RCD protected.

So, I go into apartment 7, flick the MCB off, remove the unfused hard outlet from the double bedroom wall, verify that it's dead and replace it with a fused outlet and wire the new convector heater in.

Off to the single bedroom, pull the hard outlet which still has the old heater attached. I switch it on, no red light. Of course not, the breaker is off. I reach for my terminal screwdriver to undo the live. Damn, left it in the other bedroom. Reach into my pocket for my trusty old testing driver.....which promptly glows as soon as I touch the screw!

Somebody had swapped the hard outlet with a single socket outlet when the bedroom furniture had been moved around. The LED in the convector heater had failed, hence no warning light, but the outlet was live. Had I used my VDE driver to undo the terminals, my next step would have been to straighten the conductors between finger and thumb! OUCH!!!
One way of testing the RCD, I suppose.

We all try to work safely. Yes, I SHOULD have switched the main switch off, but when others are at work and need the lights on it's not realistic.
Doing repetitive work to a timescale, with other tradesmen present, can lead to a lapse in concentration.
I've learned from my near miss, and verify properly EVERY time. Hope everyone else does as well.

good post thanks

 

[Phil]

at least you missed out on the belt mate

 

[UNG]

I find voltstick is a useful piece of kit to verify if the circuit is dead, if it glows then it's out with the test lamps

 

[Des 56]

I find voltstick is a useful piece of kit to verify if the circuit is dead, if it glows then it's out with the test lamps

Sorry ung but I would only do the opposite,verifying something may be live

Those things are handy, but not for sticking fingers in after they tell you alls ok
They indicate only, and are dangerous tools to rely on
Just my opinion of course

 

[Phil]

i have learnt the hard way when i first started out when i worked with "mr i am the best spark ever" left the supply on telling me it was dead, so the fluke t5 is out every time even if i am sure it`s not live, i trust no one except the fluke.

 

[Jason Smith]

ok mate great bit of learning thats priceless. So you reached out for lets say, the L&N . I would of, as always cut disconnect the earth last. You grab both, either up your insulated fiberglass ladder or sat/crouched/laying stood on a wooden floor. The circuit thinks your the heater. and trys to supply you with some juice, how much I will let you calculate with the human body giving a resistance of about 1000 ohms. Lethal current for humans is about 0.23 amps. This is possibly the one type of shock that no device, rcd or otherwise will protect you from mate. When i did this one it only flowed through my hand, and lucky the cable was clipped so I could pull off.

thought that sounded wrong, 10-20 ma. cant get let go.
30-40, chest paralysis.- if no kiss of life, good night, possibly anyway.
70-90 - good night. MILLI AMPS.

MUST NOT EVEN TRUST YOURSELF. ONLY TRUST FLUKE. was in kitchen, had even removed all lighting conductors from my own installed RCBoS. Was tired, and had been removing switch drops for a re wire. Last one and quick flick in there with mr Fluke as all the others suddenly woke me up. This ****** was live. Strraight live to switch bogged off the mains. Procedure saved me. ALWAYS ALWAYS in there with Fluke.
Havent done this one but my Mentor even had the the main 100 amp in his pocket, he ran straightinto the lighting circuit that had been stolen from next door. And no he didnt get a belt because he was in there with the fluke. I suppose thats why I am so suspicious and carefull. I hope any shock I get is a little one.

 

[UNG]

Those things are handy, but not for sticking fingers in after they tell you alls ok
They indicate only, and are dangerous tools to rely on
Just my opinion of course

All test equipment only provides an indication whether is a volt stick, test lamp or a meter

Relying on any test equipment without proving it on a proving unit or live supply can be just as dangerous as relying on a volt stick without proving it

Jumping to conclusions can be dangerous in a lot of situations, if the neutral and earth were lost or disconnected a test lamp or meter would not necessarly detect that live was still present

 

[Fred West]

Hello Friends.
I find your close shaves and sometimes painful experiences with electric circuits most interesting.I am no superman by any stretch of the imagination,but I have had more electric shocks than I can count.First one I do remember was from a large black cable sticking up from a bomb site.if you wanted to be in the gang you had to touch it!
55 years ago the British Army did their best to train me as an electrician.Those day were mostly spent devising different ways of give your fellow sparks an unexpected belt.Perhaps sand at 100 degrees saved a few life's.It all come to a bit of a head when the C.O.rushed out to a Landrover where the door handle was running at 240 volts.Happy times!
By the way this is really good forum with people on it that really know their stuff.It certainly keeps my feeble brain ticking over.

Thank you

 

[Tester Steve]

I find voltstick is a useful piece of kit to verify if the circuit is dead, if it glows then it's out with the test lamps

I like 'em too!! Just so quick to run it across a cable or piece of equipment. Yes, they are wrong sometimes, but if it even glows a little, out with the tester. We all have our own ways and one belt is one too many, so lets stay safe, whatever method we use!!

Steve.

 

[DurhamSparky]

another Royal Navy story of mine!!!

i got a 440v from a 3 phase motor when reconnecting a water outlet behind it!!

some idiot fused up the panel that was disconnected above it! scary thing was the chimp who did it was a Petty Officer of the Royal Navy and you would think he had bit more brains about him... NOPE!!

on standing up straight my hand touched the yellow phase cable (double bagged in plastic) and as a result touched the blue cable and had a nice big blue flash with me in the middle!! i cant remember much apart from it hurt like hell and having all my hair standing up on arms and stuff and shaking very badly! luckily got no burns as the fuses did there job when the Arc happened!


VERY LUCKY!!!



steve

 

[Des 56]

All test equipment only provides an indication whether is a volt stick, test lamp or a meter

Relying on any test equipment without proving it on a proving unit or live supply can be just as dangerous as relying on a volt stick without proving it

Jumping to conclusions can be dangerous in a lot of situations, if the neutral and earth were lost or disconnected a test lamp or meter would not necessarly detect that live was still present

Fair comment

 

[mattb42]

I use my fluke volt stick all the time, it's always in my pocket but I always try and prove it on something live first.

 

[Jason Smith]

would just like to know that, amongst our less experienced collagues, that if you are not earthed, .i.e up a fiberglass set of steps or on a wooden floor,as nine times out of ten we would be, then there is NOTHING that will save you if you get hold of live an Neutral at the same time.

would like lee and skiipper to acknowledge that fact, as I think you are new to the industry.

 

[robsparky1975]

i normally use the fluke voltstick and/or tester but always check on known supply before and after making circuit dead,there are and have been cowboys doing wiring so we should expect at some point that things may not be as you would expect,i did recently have a reminder of safe working practise when isolating a lighting circuit,just me working in there doing a switch and instead of removing from cb flicked off,someone walked in and reset my own fault lesson learnt(i slapped myself round the chops for being such a wally)will deffo not do that again our safety and others no1 priority and not time/shedules i will not be rushed when its ready its ready leave us pros to it,i was not happy with myself so have learnt valuable lesson,if anyone has done 2391 or looking to do it this thread is most important.