Your worst Electrical DIY Disasters!

[eveares]

Thought I would share this with you; a friend of mine called me over to his house after he kept getting big and painful electrical shocks of his kitchen sink.

His house is an old house with no RCD's.

It turned out; he had being doing some minor electrical work and his GF had replaced the light switch for him after she asked to help out. It turned out he did not check the switch after she had wired it; and below is what I found.

The switch!

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• eveares
• 27 Dec 2013
• 1

Who on earth would anyone wire the earth wire to L1!

Whats the worst electrical disasters and mistakes have you run into or found?[/b]

 

[plugwash]

It turned out; he had being doing some minor electrical work and his GF had replaced the light switch for him after she asked to help out. It turned out he did not check the switch after she had wired it; and below is what I found.

I hope you didn't stop investigating there. Unless it's a TT install* then even without a RCD connecting live to earth should blow a fuse or trip a MCB.

* If it IS a TT install then RCD protection needs to be added as a matter of urgency.

 

[eveares]

Yes it's a TT system with the earth not connected to neutral and no PE wire back to the substation.

Earth (via Earth rod) is also only supplied by a 4mm wire!

 

[rjm2k]

Maybe she thought the green and yellow looked prettier than the black

 

[bernardgreen]

his GF had replaced the light switch for him after she asked to help out.

Maybe she was trying to tell him something.

But seriously that place needs checking out. That error should have operated the over current device.

As to shocks from the sink. A shock that is severe enough to be painfull requires two points of contact with the body and these must be at different potentials. The sink was one, what was the other ? Maybe the sink was at ground ( earth ) and the other point of contact was live and thus the faulty item.

 

[eveares]

His house is an electrical nightmare; previous owner had done a lot of electrical work himself.

Earth was likely at a very high impedance and likely thus did not overload the fuse wire in the fuse cartridge. Earth loop impedance varies through out his house.

 

[Adam_151]

It is imperative that RCD protection is provided to all circuits ASAP.

a 100mA time delay RCD in the tails should be appropiate, and when other electrical upgrades are done, will discriminate with 30mA rcds fitted downstream (as long as they break the neutral, which a lot of single module RCBOs do not)

 

[i_am_fubar]

My worst find was this one. Continuity wise, fine, but pictures speak louder than words:

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• i_am_fubar
• 30 Apr 2013
• 3

or:

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• i_am_fubar
• 30 Apr 2013
• 2

 

[fidom]

My electrics were a disaster but not DIY, standard Hungarian practice in the '60s. There are lots of small round conduit junction boxes mounted high up on the wall. The wires are just twisted together and wrapped with cloth insulting tape. In several cases the last few inches of insulation was well charred and falling off, as the joints had overheated. There is no consumer unit, just a circuit breaker, which is before the meter. I have put right the most dangerous bits but it needs a total rewire. I would have done this already but I would like to do it all UK style with sockets at skirting board height and that is against the regs here. The German type sockets are horrible things to work with and it is difficult to get the wires secure in them as they have bits of thin tin to clamp the wires rather than solid blocks of brass.

 

[ekmdgrf]

Where to start?

* Found out that the B10 MCB marked "downstairs lights" didn't turn the downstairs lights off. Neither did any of the others. Eventually got them to go out by turning it off in conjunction with the B6 "Extractor fans" MCB. (You can see where this is going...) Removed a blanking plate in the bathroom to reveal a choc block joining the lighting and fan line conductors together...

* B32 > 2.5mm T&E > 13A FCU > underfloor heating

* B32 > 2.5mm T&E > timer > 1mm T&E + 3C&E (wired in parallel) > 13A FCU > immersion heater

* B6 > 4mm T&E > 4x 60W GU10 lamps (Is this what's called a "high power lighting circuit"?)

The real icing on the cake was the upstairs (come downstairs) socket circuit which has a couple of a runs of 2.5mm T&E from a B32 with a few sockets on (one of them with the neutral conductor broken) and also a run of 1mm T&E to a junction box. From that JB came:

- 2.5mm T&E > double socket (there was a d/c flex running behind the plaster and handing out behind a shelf)
- 2.5mm T&E > double socket > single socket > FCU for alarm (why the alarm company connected to this I have no idea)
- 3core flex > 4 way, daisy chained to another 4 way, with a 4 way plugged into that for good measure (located downstairs)
- 2core flex to another room with another 4 way (no CPC)

On a positive note, the JB was "accessible for inspection".

 

[ChrisG29]

I wanted to extend a two way light, guess what the electrician had used for the common between the light switches ?

10 points if you said the earth conductor, (twin core & earth!!!).

In France, both live and neutral are switched / isolated at the consumer unit. So, trying to trace a cable using a neon, the consumer unit showed the circuit was live but the other end appeared dead.

After a lot of head scratching, I found a junction box in a cupboard. The junction box had a choc block linking to a spur, guess what ?

Another ten points if you guessed live and neutral had been swapped around in the junction box. (Until fairly recently there was no convention as to which pin on a socket was live and which was neutral, I think its still true for two pin sockets)

France again, replacing a bedroom wall light, needed to drill some holes for the new fitting, so just took out the lighting circuit fuse, bedroom light went off, so ok.

Started to remove the old fitting and got a belt, (ok my fault for not checking).

50 points if you can guess why !

The wall lights had been wired directly from the input to the fuse box i.e. were not fused at all. (I was a bit lucky there).

Chris G

 

[eveares]

I have just repaired my driveway lights as they got damaged when we had diggers in last year during an extension.

Guess what i found, the previous person who had wired them up had used black as neutral and grey as CPC/Earth!!! - of which were the neutral wires was also not sleeved.

Also armor of swa was not bonded/earthed as well!

lastly the wire going to the photo cell was 3 core flex where the earth wire had been used as the switched live!!!

 

[plugwash]

Guess what i found, the previous person who had wired them up had used black as neutral and grey as CPC/Earth!!! - of which were the neutral wires was also not sleeved.

I have to admit there is some wiring between a couple of sheds at my parents house which I did that fits that description. For some reason the NICIEC picked the opposite convention even though it's the one that would be less obvious to most newcomers.

 

[feynman]

Speaking of which: who is the genius who keeps changing the wire colours?

Red and black. Nice and simple. Intuitive. Everyone understands. Red is dangerous. Yellow and blue for the other phases if applicable.

Brown and blue. Hmmm, using a phase colour for neutral, not the best idea in the world. And how did earth become yellow and green? Another phase colour used in a non phase role. What was wrong with plain green? To many people, brown is the colour of earth, but here we use it as phase.

Now what have we got ? brown, black and grey?? WTF?

 

[bernardgreen]

What was wrong with plain green?

The important bit is that the CPC is bi-coloured and therefore can be seen as such by a peron who is colour blind. In theory a person would not put any bi-colour anyway where other than into earth terminals.

I tend to agree with your post.