> Then again, electrical work can be life threatening, so the potential damage is rather high.
As a DIYer, I was shocked to find what the previously hired professional electrician left for me: a secondary panel for the whole structure that controls exactly one outlet. The sub panel was apparently not fed from the main panel, but rather from a panel in a different building, so simply switching the main breaker of the breaker panel to off did not turn off that one specific outlet, you know the one I was trying to replace. Why that one outlet (GCFI in the bathroom) required it’s own sub panel was not clear at all but my left hand was numb for a few hours. Thankfully it didn’t go further than that (maybe a few copies of me in the multiverse died but not this one).
The GFCI didn’t go off so I don’t think I touched the ground wire. I wasn’t myself grounded but I grabbed the outlet as I pulled by grasping the sides and my hand completed the circuit between the live and neutral wires. I am generally really careful about this kind of stuff but this was a complete surprise with the wiring of the place.
Honestly it didn’t actually do much beyond just small muscle twitches in my hand. I only realized what happened after I let go of it and my hand still felt a little funny. Definitely do not recommend but at least it was a 240V outlet or anything like that.
Wouldn't plugging in a small appliance (electrical toothbrush, phone charger, alarm clock, etc) be enough to tell you if a socket is live? Why have an extra device unless you need to do actual tests (ie, check what the voltage/current draw is)? Plug in something with a power indicator before shutting off the power, and check it before you start working.
The metal inside the socket that completes the circuit with the male pins can age and get bent, losing contact unless the plug is at just the right angle or the pins are bent in the right direction. It's unreliable and unsafe. If its your house and you're intimately familiar with the state of the sockets, it's slightly less unreliable and unsafe.
The EM coming off AC mains makes a non contact detector hard to fool and it's such a simple device that even cheap knockoffs are reliable.
Yup. They know having an electrician do all the work minimizes the risk of you needing to get payed out, so they want it so.
But the insurance doesn't care about your additional cost, since it's your cost, not theirs.
They don't go "cost of professional < additional risk * potential damages", they go "additional risk * potential damages > 0".
Then again, electrical work can be life threatening, so the potential damage is rather high.