Electric Shock but Mains Off?

[cervezaman]

Hi All, currently in our very modest 20 year old place in Spain. I decided to change the light fitting in the lounge. I put the RCD breaker down and also the main breaker. Thought all was good! Nearly knocked off the ladder from a shock from one of three wires!! It’s a simple single switched light fitting. I’ve managed to fit it now with the help of some pliers to help locate the wires in the terminal block. But, what could have caused this? Off is off no?!

[Spare tyre]

My first test would be to turn the light on and see what happens when the circuit is off via the breaker

[miniman]

Look on the bright side - the neighbours appear to be paying for your electricity.

[MDMA .]

miniman said:

Look on the bright side - the neighbours appear to be paying for your electricity.

AKA, grow on the go

[Jasey_]

This should be in everyone's toolkit !!

Non-contact AC Voltage detector

https://smile.amazon.co.uk/Electric-Non-Contact-In...

[paul.deitch]

Happened to friends of ours in north Italy. They always had large elec bills even though they went there about once a month.
Complained but shoulders were shrugged.
Had to do some electrical work and lo and behold the electrician got a mighty shock after "turning off" the elec.
The neighbours had cunningly swopped the meter connections but of course no-one knew about it....
Went on for about 10 years
Still they could afford it.

[kev1974]

Jasey_ said:

This should be in everyone's toolkit !!

Non-contact AC Voltage detector

https://smile.amazon.co.uk/Electric-Non-Contact-In...

This, utterly nuts not to check with one of those before touching the wires, electricians do make mistakes!

Remember to test it against a known live each time you get it out.

[Caddyshack]

Could it be an earth leak from another circuit?

[dhutch]

Jasey_ said:

This should be in everyone's toolkit !
Non-contact AC Voltage detector

Or one of these. You own sonic screwdriver.....
You can get one for £2 but the Wiha is a nicely made one.

https://uk.rs-online.com/web/p/mains-test-screwdri...


Daniel

[Jasey_]

dhutch said:

Jasey_ said:

This should be in everyone's toolkit !
Non-contact AC Voltage detector

Or one of these. You own sonic screwdriver.....
You can get one for £2 but the Wiha is a nicely made one.

https://uk.rs-online.com/web/p/mains-test-screwdri...


Daniel

Yeah - I had one of those - then it blew up in my hand one day I was using it.

much prefer the ones that start making a noise 5 inches from the power source

[Simpo Two]

cervezaman said:

Hi All, currently in our very modest 20 year old place in Spain. I decided to change the light fitting in the lounge. I put the RCD breaker down and also the main breaker. Thought all was good! Nearly knocked off the ladder from a shock from one of three wires!! It’s a simple single switched light fitting. I’ve managed to fit it now with the help of some pliers to help locate the wires in the terminal block. But, what could have caused this? Off is off no?!

'Hot working' eh!

I always have the appliance/light on to start with and make sure it goes off when I throw the breaker. Would that precaution have saved you or was it more subtle than that?

[dhutch]

Jasey_ said:

Yeah - I had one of those - then it blew up in my hand one day I was using it.

Really?

I dont like using the really cheap ones, but ive never heard of that,

[Jasey_]

dhutch said:

Jasey_ said:

Yeah - I had one of those - then it blew up in my hand one day I was using it.

Really?

I dont like using the really cheap ones, but ive never heard of that,

Yep !

Took me another 10 years before I went anywhere near electrics as I just about shat myself.

Came across the non contact ones which gave me the confidence to tackle electrics again !

[monoloco]

Did pretty much the same myself a few years back -effectively put myself in series with a 60W light bulb. Still gave me enough of a kick that my arm shot back and the screwdriver I had in my hand ended up embedded in the wall on the opposite side of the room like a circus knife thrower. Turned out one of the previous occupants of the place was either an utter bodge artist or a thief (or both!) and had hooked up one of the lighting circuits in a way that bypassed the electric meter -and the fuse box unit so it wasn't even fused. 'kin crazy.

Result is I would NEVER touch any electrics without using a mains tester as recommended above. They're cheap as chips and could just save your life.

(PS the embarrassing bit is I'm a full member of the IET which makes me a Chartered Electrical Engineer so I really should have know better!)

[dhutch]

monoloco said:

D....Turned out one of the previous occupants of the place was either an utter bodge artist or a thief (or both!) and had hooked up one of the lighting circuits in a way that bypassed the electric meter -and the fuse box unit so it wasn't even fused. 'kin crazy.

Nice! One of the neighbours has a spark put in a elec car charge socket, fully legit get up. Managed to get get it in before the meter! Its an old house, and I bet its a right mess of multiple CU's and henley blocks, but still, getting it between the meter and the cut-out is slightly impressive!

[dhutch]

cervezaman said:

Hi All, currently in our very modest 20 year old place in Spain. I decided to change the light fitting in the lounge. I put the RCD breaker down and also the main breaker. Thought all was good! Nearly knocked off the ladder from a shock from one of three wires!! It’s a simple single switched light fitting. I’ve managed to fit it now with the help of some pliers to help locate the wires in the terminal block. But, what could have caused this? Off is off no?!

Getting back to the OP.

The short answer is that some power must be coming from somewhere other than circuites isolated by the RCD and or Main Switch.

- Some board have two RCDS, or some pre-RCD circuits. If usually downstream from the main switch. Continental board designs do vary too.
- You might have more than one consumer unit, although its not overly common it can happen in extended or older properties.
- It might be coming in on the earth wire if there is some mad broken earth in the building/local area. Or neutral if single pole rcd/isolator?

If you turn the rcd and or mains switch off with the light on, does it go out?

Do you have anything, such as a neon screwdriver, which you could use to test which wire is live?

Tame sparky time?


Daniel

[TwistingMyMelon]

Jasey_ said:

This should be in everyone's toolkit !!

Non-contact AC Voltage detector

https://smile.amazon.co.uk/Electric-Non-Contact-In...

Bought that exact model and was using it at the weekend when doing my outside light!!

You never know how anything is wired and always worth checking with one of those as you go as well, as my misses has turned the power back on once , thinking that it had tripped, not realizing I was fitting a light upstairs!

[crispian22]

Have you got solar panels?;-)

[cervezaman]

Simpo Two said:

cervezaman said:

Hi All, currently in our very modest 20 year old place in Spain. I decided to change the light fitting in the lounge. I put the RCD breaker down and also the main breaker. Thought all was good! Nearly knocked off the ladder from a shock from one of three wires!! It’s a simple single switched light fitting. I’ve managed to fit it now with the help of some pliers to help locate the wires in the terminal block. But, what could have caused this? Off is off no?!

'Hot working' eh!

I always have the appliance/light on to start with and make sure it goes off when I throw the breaker. Would that precaution have saved you or was it more subtle than that?

I don’t think it would have helped, but good idea! Basically I have a small led light fitting which I installed a couple of years back. It stopped working a couple of months ago and I realized I’d bought a spare at the time as they were pretty cheap. It should have been a simple swap over job 😂

[cervezaman]

crispian22 said:

Have you got solar panels?;-)

Sadly no space for solar panels!!!! Lower your expectations!!