If you've ever done any household electrical work in the US - like installing a new power outlet - you'll be familiar with wirenuts, those orange (usually) conical gizmos that are used to join two wires together. I'll cut straight to my question: why!? I've never come across something which not only works so badly, but has such potential to burn a house down.
The theory is simple enough - twist together two wires, then screw the wirenut onto the wires. Sharp edges engage with wires, holding them together, providing an insulated over, and ensuring a decent electrical connection. If only that was the reality.
Today I had to fix the pool light in my swimming pool, which just stopped working after being installed only a few months ago. When I opened up one of the electrical boxes, I found that the installer had used wirenuts that were way too small. The wires had come untwisted. Result, no light. Annoying, but not too serious - although for someone who couldn't fix it themselves, it would have involved a callout and a cost of $150 or more.
The former owner of my house made various minor changes to the electrical wiring, installing extra sockets, switches and the like. Of course he used wirenuts for all of them. He hadn't tightened them properly, resulting in poor contact, and eventually lots of heat which (with the greatest good luck) did not cause anything more serious - though I did find scorch marks. I've got rid of all his handiwork now, of course.
If you've only ever dealt with electricity in the US, I can hear you thinking, so what other way could you do it? In Europe, wirenuts are unknown. Instead, terminal strips are used - plastic strips holding little brass blocks with two screws in. You put a wire in each end of one place, and tighten the screw down making a reliable and permanent contact. They don't take up any more space, and they don't set fire to your house. Yet in the US they are completely unavailable - even major trade suppliers like Digikey don't have them.
I'm sure our former owner could have found a way to abuse these in an incendiary fashion. But still I don't understand why wirenuts have such a hold.