Another question for the electricians....

[Pale Rider]

Purely out of interest, is this the sort of stuff that it's now against regulations for a non-qualified person to touch?

The regs work for me, because wiring a 13 amp plug is about the limit of my knowledge.

 

[slowmotion]

Purely out of interest, is this the sort of stuff that it's now against regulations for a non-qualified person to touch?

The regs work for me, because wiring a 13 amp plug is about the limit of my knowledge.

I believe you are officially allowed to modify "existing circuits" but not install new ones. Part P must be the most widely ignored section of The Building Regulations anyway. Having recently discovered the "workmanship" of previous professional electricians in my own house, I can quite understand why.

 

[Pale Rider]

I believe you are officially allowed to modify "existing circuits" but not install new ones. Part P must be the most widely ignored section of The Building Regulations anyway. Having recently discovered the "workmanship" of previous professional electricians in my own house, I can quite understand why.

I've been wary of dodgy home electrics following a nasty experience as a child.

We lived in an old farmhouse in which mains electricity, and mains water for that matter, was a relatively recent addition.

One day I turned on a tap in a downstairs sink which was live.

For some reason, I was unable to let go of it, I recall leaning back with my feet under the sink, but still unable to release my grip on the tap.

Fortunately, my brother heard my screams and had the presence of mind to loop a hand towel around my neck and yank me free.

The fault was traced to a nail in a loose floorboard upstairs which had worked its way between a live cable and a water pipe, connecting the two.

 

[slowmotion]

Some years ago, we rather recklessly went away for a holiday, leaving "the professionals" to do their stuff. We got home late on a Friday night and I immediately smelled that distinctive whiff of arcing electrics and scorched plastic. It didn't take long to locate the source in a small room at the back of the house. It didn't have any lighting, but in the corner there was a faint orange glow that came from beneath the face of a double socket. The "professional" hadn't quite got round to tightening up the terminals and the socket was nearly entirely burnt through. A day later and we would probably have lost the house in a fire blamed on an electrical fault.

Yeah, Part P.

 

[swansonj]

I've been wary of dodgy home electrics following a nasty experience as a child.

We lived in an old farmhouse in which mains electricity, and mains water for that matter, was a relatively recent addition.

One day I turned on a tap in a downstairs sink which was live.

For some reason, I was unable to let go of it, I recall leaning back with my feet under the sink, but still unable to release my grip on the tap.

Fortunately, my brother heard my screams and had the presence of mind to loop a hand towel around my neck and yank me free.

The fault was traced to a nail in a loose floorboard upstairs which had worked its way between a live cable and a water pipe, connecting the two.

It's called the "let go" threshold, where the current through the nerves causes the muscles to contract and ensures that you can't let go. The threshold (generalisation, it depends on the person and the current path) is around 10mA at 50 Hz and the limits for safe levels of contact current are accordingly usually set at around 1 mA. 30 mA would be getting into fibrillation territory. That's far too low to blow a fuse but is the sort of issue a Residual Current Device (RCD) is intended to provide protection for.

When touching a wire, and even if you have tested that it is dead with a meter or tester, personally I was taught always touch it first with the back of my hand, so that if it's live, and the current causes muscle contraction, that contraction pulls the hand away from the wire rather than clamping it on.

 

[swansonj]

Some newer appliances will simply refuse to work though....

That's interesting - hadn't heard that before - does that mean they go to the trouble of building in a sensor and circuit just to detect polarity?

 

[Levo-Lon]

B&Q sell the screws..as will most places that sell wall sockets..

 

[Levo-Lon]

Some years ago, we rather recklessly went away for a holiday, leaving "the professionals" to do their stuff. We got home late on a Friday night and I immediately smelled that distinctive whiff of arcing electrics and scorched plastic. It didn't take long to locate the source in a small room at the back of the house. It didn't have any lighting, but in the corner there was a faint orange glow that came from beneath the face of a double socket. The "professional" hadn't quite got round to tightening up the terminals and the socket was nearly entirely burnt through. A day later and we would probably have lost the house in a fire blamed on an electrical fault.

Yeah, Part P.

My wife lost her Aunt in this exact same way..poor woman couldnt get out of bed..so that was that.
newly refurbed arms houses...fire started in the front room socket.

 

[gbb]

I had exactly the same once years ago but it was a fridge wired up via a short extension lead of uncertain origin. I happened to undo the extension lid to find the brown and blue were reversed....the fridge worked perfectly well either way.
I asked an electrician at the time (1980s) he said it wasn't a problem and explained why but I cant remember now...

 

[Tim Hall]

Like everyone else says, yes, the brown and blue look like they're in the wrong holes. The reason they're brown and blue not red and black isn't down to "new" colour coding, it's because they're the cores of a flex (which would normally have a plug on it) and are connected to a fused connection unit.

 

[jonny jeez]

[QUOTE 4307493, member: 45"]Yellowish top left? That's the brown, going into N load.[/QUOTE]
nah, its gold and blue

 

[swansonj]

Like everyone else says, yes, the brown and blue look like they're in the wrong holes. The reason they're brown and blue not red and black isn't down to "new" colour coding, it's because they're the cores of a flex (which would normally have a plug on it) and are connected to a fused connection unit.

Err... Surely brown and blue are the "new" colours, applied first to flex in the 1970s and now (2000s) to fixed wiring as well? Pre 1970s flex was red and black too.

 

[lazybloke]

The fridge will probably work fine but there are safety issues if the conductors are reversed. Too complicated to explain right now.

Think about the switch and the fuse in a typical appliance. It sits in the live supply cable, so it can isolate the appliance from the main voltage.

If the wires are transposed, everything may still appear to work correctly, but the mains voltage is now ALWAYS present in the device, because the switch or fuse now only breaks the current in the 'return' wire.

There are other safety mechanisms such as RCDs and double-pole switches, but not all wiring installations benefit from those. Basic wiring has to be correct for safety reasons.

 

[Tanis8472]

Why on earth would anyone wire an appliance into the back of a socket. Just madness to me. No fuse or cutout

 

[Tanis8472]

Which means that there is a problem in the circuit or appliance