# Changing An Electrical Outlet Without Turning The Power Off **URL:** \ **Category:** Factual Questions\ **Created:** [July 30, 2010, 3:12am UTC](https://boards.straightdope.com/t/changing-an-electrical-outlet-without-turning-the-power-off/548545 "2010-07-30T03:12:58Z")\ **Posts on this page:** 5\ **Page:** 7
**Author:** ![Balthisar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/balthisar/32/2825_2.png) [@Balthisar](https://boards.straightdope.com/u/Balthisar)\ **Post date:** [November 8, 2019, 12:33am UTC](https://boards.straightdope.com/t/changing-an-electrical-outlet-without-turning-the-power-off/548545/121 "2019-11-08T00:33:44Z")
> [@Patch](#): > > I used to work on a military base, and I was chatting with the base electricians one day about working with electricity, as they work with both high voltage (12kV and up) and house wiring (120V). I mentioned that I figured they’d have more accidents with guys moving from working on 120V stuff to 12kV stuff as there’s a lot more voltage, but they told me it’s the opposite. They see more accidents with the guys who go from 12kV to 120V as they are complacent (“I’ve handled 12,000 volt stuff! 120V is nothing.”) and get fried. The guys who move up to 12kV are scared of getting electrocuted, and so don’t shortcut safety. Industry, too, and this is so much the truth. No one (for the most part) dies in the substation. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 8, 2019, 12:58am UTC](https://boards.straightdope.com/t/changing-an-electrical-outlet-without-turning-the-power-off/548545/122 "2019-11-08T00:58:36Z")
Back when I was working as an electrician’s assistant, I learned that you should always have at least three points of safety: That is to say, three separate precautions, any one of which, if it works properly, should be enough to guarantee safety. So, for instance, you switch off the breaker, and use one hand at a time, and use insulated tools. Or if one of those isn’t practical, you add another one (rubber gloves, maybe). That way, if any one, or even two, points of safety fail, you’re still safe. ---
**Author:** ![BubbaDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bubbadog/32/333_2.png) [@BubbaDog](https://boards.straightdope.com/u/BubbaDog)\ **Post date:** [November 8, 2019, 6:51pm UTC](https://boards.straightdope.com/t/changing-an-electrical-outlet-without-turning-the-power-off/548545/123 "2019-11-08T18:51:53Z")
I grabbed an energized 345KV line with my bare hands! It’s true. I had the opportunity to visit an AB Chance lab. Wearing a Faraday suit I was to climb a 12 foot fiberglass ladder while holding a fiberglass stick which held a hook that ran along a cable to my Faraday suit. Once close enough to the line (it was 15 feet off the ground, inside a laboratory) I used the stick to connect my tail and energize my suit. Climbed up three more steps and grabbed the conductor with my right hand. Just for fun I gave it a kiss. I was the human equivalent to a bird sitting on a wire. The Faraday suit was for protection from the line’s EMF field. If I wasn’t wearing the suit I would have currents running through my body based on my feet being further away from the conductor than my hand. The Faraday suit was like an elastic jump suit. The legging section fit around my ankles. Since right below my ankles was uncovered I could feel corona discharge there. It felt like a 70 MPH wind was blowing against my feet. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [November 8, 2019, 7:43pm UTC](https://boards.straightdope.com/t/changing-an-electrical-outlet-without-turning-the-power-off/548545/124 "2019-11-08T19:43:59Z")
> [@Tim\_T-Bonham.net](#): > > An experienced electrician friend said that he considered 240V the most dangerous. Because 120V is low enough that you can generally let go, thus breaking the circuit. And 480V is strong enough to usually throw you across the room (breaking the circuit). But 240V often paralyses people, so they can’t let go of the live wire. So they get shocked longer, with more chance of injury/death. What also factors into it (and is probably a more significant factor than muscle paralysis) is how much current flows across the heart. At lower voltages, you don’t get enough current to reliably throw your heart into fibrillation. As the current increases, the heart is more reliably thrown into fibrillation, so the fatality rate rises. Your heart has kind of a weird design in that the fibrillation state is stable. In other words, if you can get your heart into fibrillation, it won’t get out of that state on its own. This is why you need a defibrillator. At higher voltages and currents though, a funny thing happens. Instead of the electricity just screwing up your heartbeat and throwing the heart into fibrillation, all of the heart muscles tend to just clamp. I should probably point out that in this state the heart is still not pumping blood, so if you don’t somehow get removed from the source of the current you’re still toast. But unlike the fibrillation state, once your heart comes out of this muscle clamp, it generally tends to go back into a normal rhythm all by itself. And then at even higher voltage and current levels, the electricity just cooks you to death. So it’s kinda weird that if you start at zero and increase the current, electricity generally gets more and more dangerous, but then the fatality rate decreases once you get to the point where your heart muscles clamp, and then the fatality rate increases again with the current once you get past that. > [@Patch](#): > > I used to work on a military base, and I was chatting with the base electricians one day about working with electricity, as they work with both high voltage (12kV and up) and house wiring (120V). I mentioned that I figured they’d have more accidents with guys moving from working on 120V stuff to 12kV stuff as there’s a lot more voltage, but they told me it’s the opposite. They see more accidents with the guys who go from 12kV to 120V as they are complacent (“I’ve handled 12,000 volt stuff! 120V is nothing.”) and get fried. The guys who move up to 12kV are scared of getting electrocuted, and so don’t shortcut safety. I design industrial controls for a living, and I’ll add a “me too” to this. I don’t think anything of climbing into an area or poking around in a cabinet as long as it’s all 240 volts or less. I don’t just blindly walk up and touch exposed contacts or anything quite that stupid, but I really don’t get as concerned as I probably should about safety until the voltage gets to 480 and above. > [@BubbaDog](#): > > I grabbed an energized 345KV line with my bare hands! Um… yeah. No thanks. I’ll stay way over here in the control room while you go ahead and do stuff like that. No, I don’t care if you’re offering me a Faraday suit. I don’t wanna. At those kinds of voltages you have to be careful about pointing at anything because your fingertip might draw an arc. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [November 8, 2019, 9:14pm UTC](https://boards.straightdope.com/t/changing-an-electrical-outlet-without-turning-the-power-off/548545/125 "2019-11-08T21:14:54Z")
So, where do we all stand on using those V-belt tensioning tools while the engine is running? Or adding a new plumbing line with the pressure on? [Previous page](https://boards.straightdope.com/t/changing-an-electrical-outlet-without-turning-the-power-off/548545.md?page=6)