What kind of Dangerous lighting wiring have you seen (or done)? I have seen probably the worst wiring in an old antique store. When we were walking around in there, they had old fluorescent lights that half were out, half were missing tubes (some broken with bare contacts hanging in front of you), and some buzzing like crazy. This shop had a very low ceiling, and had old lighting all over. (Sadly half of it has burnt down due to AN ELECTRICAL FIRE!) Anyway, this place had lamp cord running some lights/objects instead of romex, along with spliced lamp cords, and multiple scotch taped wires.

It had old ungrounded outlets that were cloth wires hanging down, with adapters and little extention cords, running all around the place. The fuse panels had no covers, and you can almost walk right into them. Going outside the shop into a fountain yard, they had about 20 small brown/white/and green indoor cords, running through the air, going down into a metal pipe, onto the wet ground through the FOUNTAINS, running old power strips, and a whole bunch of homemade/indoor outlets, with cloth wires. Oh, and where did that all plug into inside the shop?? It went through a window into and ungrounded outlet, that fed off of ANOTHER cord, that ran SOMEWHERE into an junction box.
All I can say is that the wiring in that place was HORRIBLE! (don't know the shop name). They also ran outdoor floodlights with spliced cords too. The ONLY real wires I saw were coming into the main service line and going to the fuse panel, to the occasional GOOD outlet. And, it was Knob and Tube. Thank goodness this place did not have high powered appliances. Now, let me here some of your stories:)

When I lived in California, a local thrift store burnt down due to bad wiring.

Recently i helped repair an apartment for my parent's friends. They were moving to a new one, and i was given the task to disassemble most of the electrical stuff they installed 20 years ago

A lot of stuff there was downright scary :

Electrical panel with bad model breakers that are known to fail in the way that they still work as switches, but won't trip on overcurrent

There is RCD in the panel. It looks ok from the front, but the handle is stuck and i cannot switch it off, and it does not react to pressing test. When i disassembled the panel i found out that all of the back is melted completely due to arcing - its just the welded remains of the RCD that are still there connecting the apartment. And part of it shattered when i tried to move it. The scary part ? The damage is totally hidden when staring at the front of the breaker with the panel assembled

Inside, the entire apartment is wired with 1.5mm^2 Cu. This did not prevent them from splicing 5KW instant water heater, washing machine.... Into the existing wiring, and upgrading the breaker from 16 to 25A to stop it from tripping

The building is old, with just 1 receptacle provided per room - total of 6 receptacles for the entire apartment !. So they added more of them. The wiring was either spliced into existing receptacles or connection boxes, one spliced into a light fixture (without lightbulb and the switch left on forever), or in just 1 case connected to the socket with a 6A rated unearthed soviet plug

They wired the additions with the "2 attached single-isolated conductors" white cables (typical old soviet cables), of 0.75mm^2. This did not prevent them from loading those at 10A or more

In 1 of the rooms 2-wire phone cable was used for that purpose instead of the soviet 2-wire mains cable

And 2 conductors mean no earth either. So no any protection against electrical shock in any of the "upgraded" circuits

The cables were attached to the walls using nails driven between the 2 conductors. Like knob and tube but no knob and 2 conductors together on the same anchor, with their isolation allready a bit damaged

Splices done with twisting and some weird cloth electrical tape (probably very old type of electrical tape). Many of the connections show signs of overheating. Some of the electrical tape deteriorated and fell off exposing the connections. Some was so badly wrapped tht it did not completely cover the connection in the 1st place

All that going on and under carpets, under beds, behind sofa etc

Of those wires, some are stranded Cu and some stranded Al, all just twisted together

Some of the added receptacles are vintage soviet ones, unearthed, open back etc

One of the sockets was modern, but instaslled into a hole in furniture (with the back pushed against a wall carpet) instead of a proper box

In the kitchen, a 4-way splitter used as a socket. It is installed through a wood board with holes for the 2 pins (earth one broken off), wires of the added wiring wrapped on its plug pins, and the 4 receptacles used for kitchen appliances including microwave and electrical kettle

Portable light fixtures (clip lamps etc) and a radio spliced directly into the wiring without any plugs

2 Wireless phones (wall transformers) connected by wrapping the wires around the plug pins and taping with electrical tape

Simple cotton thread (wrapped in a thick layer) as substitute for electrical tape in one of the connections

Lightbulb in the staircase, hanged above the entrance door, connected tot he same wiring (vintage candle bulb btw). The cable to the lamp is going through the steel door frame, in a way that the steel door is slammed directly on the thin wires every time it is closed

Washing machine receptacle added in the bathroom, in a location where it can be splashed from the shower. The receptacle is dry location only and open back (old style), and even then its plastic cover was partially broken (the TOP of it missing)

The socket getting its feed through the wall from a receptacle in a nearby room, with the wires being pressed (to the point of isolation damage) by the clips that hold the source receptacle in the wall. The wires are spliced in the bathroom wall with 3 aluminum wires all 3 of the same color, with the splice being hidden in the wall (in a place where moisture from the shower can get in). And this was the only added receptacle with earth in the entire apartment, though i am unsure whether they connected earth and neutral properly or reversed them (either way it would work if the RCD is damaged)

Chandelier in the living room with vertical base-down lamps. One of the lamps was never installed and debris accumulated over the years was enough to completely fill the E27 socket (i wonder wheter it ever arced or smoldered through under the surface at some point)

Light fixture in the toilet with wires isolation completely deteriorated and falled off - it did not short just because of the wires being spaced from each other



That was a setup that was just calling for electrocutions and electrical fires, but it actually worked perfectly from the day it was installed to the day that i ripped it apart

I took few pics of it (not much), and even better - i got to keep A LOT of the components, that includes several vintage light fixtures (of which 1 NOS) and 3 vintage lightbulbs, all the added wiring, and some other electrical gear. They left the apartment with all the dangerous upgrades removed by me, a terminal block replacing the burned RCD and a written notice for the new owners to install a new RCD immediately

sounds like it would be best to set a fire and leave than to do all this and have one start at a random time.worst i have found in my new shop was wires to a subpanel wedged in the switch jaws in a big disconnect switch.and a few buzzing,stinking preheat ballasts.they had been left with stuck starters and dead lamps for years.several tubes were black 6 inches from the end!how anyone could ignore the buzz and smell is beyond me!

When exploring some of the less used areas at my last work whilst bored on my break during nights, I discovered loads of firewalls that had cables and cable trays punched through them and then the gap filled in with expanding builders foam...

You're lucky they used foam at all! I've seen a number of huge holes where conduit was passed through without any firestopping or any attempt to patch the hole.

When exploring some of the less used areas at my last work whilst bored on my break during nights, I discovered loads of firewalls that had cables and cable trays punched through them and then the gap filled in with expanding builders foam...

Was it regular PU foam, or the thermal expansion fire stopping type? As far as I know, the latest is mandatory at least around plastic piping passing the fire section divider

In most 4x18W troffers the louver does not go all the way to the top - so the side of the ballasts / PFC capacitor is exposed

2 of those were installed in archive room in a big office (lots of paper files on shelfes, some dust, anybody getting in once in a few days at most). Since nobody cares about the lights in there, they let all teh lamps get to EOL and starters stuck (except 1 lamp out of

The ballasts in there (oddly 4x individual 18W allasts in each fixture and not 2x36W series) are Eltam Mini N which were known to overheat even in normal use. From the overheating in there with the stuck starters, all the plastic parts of the ballast were either melted or fallen apart, isolation of almost all wires in the fixture (including ones resting on the sharp edges of thre louvers and above empty space) brittle and cracked

So easily a fault that would emit a spark (or as quite common with those allasts, a shower of melted copper beads from the arced-over winding), that would fall on the paper and start a fire

In most 4x18W troffers the louver does not go all the way to the top - so the side of the ballasts / PFC capacitor is exposed

2 of those were installed in archive room in a big office (lots of paper files on shelfes, some dust, anybody getting in once in a few days at most). Since nobody cares about the lights in there, they let all teh lamps get to EOL and starters stuck (except 1 lamp out of

The ballasts in there (oddly 4x individual 18W allasts in each fixture and not 2x36W series) are Eltam Mini N which were known to overheat even in normal use. From the overheating in there with the stuck starters, all the plastic parts of the ballast were either melted or fallen apart, isolation of almost all wires in the fixture (including ones resting on the sharp edges of thre louvers and above empty space) brittle and cracked

So easily a fault that would emit a spark (or as quite common with those allasts, a shower of melted copper beads from the arced-over winding), that would fall on the paper and start a fire

Ash: It seems that the Eltam Mini N, didn't passed the Standards Institution of Israel, before it was marketed. As if it was so, the institution would prevent Eltam from selling this ballast.
If a ballast overheats on normal use, it shouldn't pass the institution tests and should be considered dangerous to use and illegal for marketing.

This ballast had been tested by our institution and found to be ok. It was made between about 1983 and 1997, that is 14 years

The ballast is rated for the temperatures it is usually getting to (Tw130) so it does not overheat above its rating. But it does not actually withstand those temperatures - the plastic terminal is deteriorating and falling apart etc. And it has very little design margin for the case of stuck starters - It would easily just melt the plastic covers on the ends of the winding away, and then when the coil is exposed and its isolation cracked or something, flash over and emit some sparks or a shower of melted copper bits

Our institution does not do stress tests properly (or at all ?) and this is not the only case - the plugs and sockets are also rated 16A  but they overheat above 10A in real world conditions. The water tank thermostats are made of low quality material so that in case of failure, the TCO itself would disintegrate and fail from the temperature yet it won't trip. Meltlights dont hold the size of lamp specified with them .... It looks like if they take a new, not worn product and test it once in good lab conditions to approve it