# How dangerous is your home electrical system? **URL:** \ **Category:** Factual Questions\ **Created:** [January 8, 2003, 8:37pm UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366 "2003-01-08T20:37:39Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Lissa](https://avatars.discourse-cdn.com/v4/letter/l/85f322/32.png) [@Lissa](https://boards.straightdope.com/u/Lissa)\ **Post date:** [January 9, 2003, 4:17am UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/21 "2003-01-09T04:17:20Z")
My mother was electrocuted about two years ago. While painting the outside of a house, her metal ladder touched a wire that carried all of the juice into the home. (The insulation on the wire was almost gone.) It threw her about ten feet, and burned a two-inch-deep grove into the ladder itself. Amazingly, after a short hospital stay, she was fine. But when it comes to dangerous electricity, there’s a risk in older homes that I was not aware of until I was negotiating to purchase one. Older homes sometimes still have what’s called “knob and tube” wiring. The inspection on our prospective home revealed that the house, built in the '20s, had this type of wiring. Curious, my husband made a few calls, and found out that it’s a huge fire risk. When we called our insurance company to inquire about coverage, they told us they would not insure the house unless the wiring was updated to code, which would mean tearing out walls to get rid of all of the old wiring, and replacing it with new. Sometimes homeowners are not even aware that they have it. Unscrupulous electricians will sometimes “jump” the wiring into a new box to enlarge the juice flow, and this is even riskier, since the old wires can’t handle the higher loads. ---
**Author:** ![Master\_Wang-Ka](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/master_wang-ka/32/3325_2.png) [@Master\_Wang-Ka](https://boards.straightdope.com/u/Master_Wang-Ka)\ **Post date:** [January 9, 2003, 4:32am UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/22 "2003-01-09T04:32:51Z")
I once lived in an apartment that was a converted warehouse. The landlords had reconditioned everything… but left the electrical system untouched. The place was still wired for 220 volts, instead of the 110 that most household appliances use. Each and every power socket in that place had enough juice to run your refrigerator, or your dryer, or your washing machine. This caused one of the light switches to explode in my hand one evening. Zapped the hell out of me, stunned me, and was otherwise an extremely unpleasant experience. Furthermore, we all got to experience it at LEAST twice, due to the fact that it was in the main bathroom, and all us Americans are conditioned to reach out with a hand and flip on the lights when entering a dark room. Took WAY too long to get that damn switch fixed. But, I point out, myself and my roommates are still alive… ---
**Author:** ![kniz](https://avatars.discourse-cdn.com/v4/letter/k/c37758/32.png) [@kniz](https://boards.straightdope.com/u/kniz)\ **Post date:** [January 9, 2003, 4:44am UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/23 "2003-01-09T04:44:30Z")
[ul]Is there an **OSHA** inspector around? :p[/ul] ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [January 9, 2003, 5:08am UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/24 "2003-01-09T05:08:23Z")
> [@](#): > > \*Originally posted by handy \* > \*\*I do wiring & I don’t mind the shock too much. I asked the elec comp guy when he came cause I was getting shocked taking a bath & he said he does mind getting shocked. So I guess its a matter of personal preference or being dumb as a kid where my brothers would dare me to put my finger in the socket & I would 🙂 \*\* Well, \*_handy_, it’s been nice knowing your. ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [January 9, 2003, 5:38am UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/25 "2003-01-09T05:38:55Z")
A couple of things here. From my Fluke Multimeter manual is a warning > [@](#): > > \*\*Use caution when working with above 30V ac rms, 42V ac peak, or 60V dc. Such voltages pose a shock hazzard. \*\* and from the [IEEE](http://www.es.oersted.dtu.dk/~kah/31650/Documents/ElectricalShock/Electrical-Shock-Standards.pdf) (page 5) I found the following > [@](#): > > \*\*The skin has a variable resiistance which is quite high for dry intact skin and low for moist or torn skin. using a value of 500 ohms and applying Ohm’s law a person across 120V might have a current as high as 240mA through his or her body when the contact points are any two limbs. > … > The threshold of perception for a finger tapping contact at 60 Hz is approx. 0.2mA. > … > A somewhat higher current than the threshold of perception is the let-go current level. (At this current level) the victim can be involuntarily held by his or her own muscles to the energized conductor he or she is grasping and cannot let go. Contact resistance may then decrese so that lethal current may then pass. > … > Half of the men could not let go at 16mA. > … > (Using the formula given in the article) a safe current limit is considered 500mA for shocks of less than 0.2 seconds in duration and 50mA for shocks of longer than 2 seconds. \*\* it is clear that a shock from 120V line voltage can kill if it lasts long enough. half the men could not let go at 16mA and the human body can conduct about 15 times that. (Personal story) I usually wire outlets live, and treat the system like the OP said as **enriched plutonium**. I needed to change out the outlet behind the stove one warm summer day. My wife, whom I love dearly, ragged on me to turn off the power. So to please her I plugged in a lamp and went out to the box. I flipped off the breaker and the lamp was off. Circuit is dead right? Anyway I pulled out the stove a couple of feet and started to rewire the socket. I was leaning back against the gas stove, sweating like a pig (hot summer day remember?) I undid the hot lead and grabbed it, no problem and attached it to the new socket. I then undid the neutral (white lead), grabbed it and got the shock of my life. I felt the current run up my left arm through my chest and out my sweaty back into the stove. I could not let go of the wire, but I did manage to move my feet, and pulled away from the wire. I found out later what happened. I had grabbed the neutral (return) wire, which is common to all the circuits in the house. Because I had only turned off the one breaker, my hot sweaty body made a good ground for the rest of the circuits, and I got juiced. My advice is turn off all the circuits **AND** treat the wires like they are made from **enriched plutonium** ---
**Author:** ![Uncommon\_Sense](https://avatars.discourse-cdn.com/v4/letter/u/f9ae1b/32.png) [@Uncommon\_Sense](https://boards.straightdope.com/u/Uncommon_Sense)\ **Post date:** [January 9, 2003, 5:50am UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/26 "2003-01-09T05:50:01Z")
Actual Electrician Here. Quickly; the term electrocute, electrocuted, electrocution all mean that someone has been killed by electricity. I almost pooped myself when Lissa said her mom had been electrocuted. See Santa`s reply. 120 volts is not to be taken lightly. The odds of death are low, but still too high to mess with. What causes death/damage to the body are three things. 1. amperage 2. the path through the body 3. the amount of time exposed If your not grounded or don`t complete the path to another voltage phase or the nuetral then your not going to be hurt. If these conditions are met you won`t even realise you are in contact with a live voltage source. Treat all wires as though their hot and turn off the circuit before you work on it. Freak things happen all the time with electricity and it would not take much for you to be hurt/killed by house wiring. ---
**Author:** ![Uncommon\_Sense](https://avatars.discourse-cdn.com/v4/letter/u/f9ae1b/32.png) [@Uncommon\_Sense](https://boards.straightdope.com/u/Uncommon_Sense)\ **Post date:** [January 9, 2003, 5:51am UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/27 "2003-01-09T05:51:36Z")
Hi Rick. It did NOT take me twelve minutes to type that. ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [January 9, 2003, 6:17am UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/28 "2003-01-09T06:17:20Z")
It took me forever to type mine as the docs I qouted from were in adobe and I’ll be dammed if I know how to C/P from them. 🙂 ---
**Author:** ![jk1245](https://avatars.discourse-cdn.com/v4/letter/j/49beb7/32.png) [@jk1245](https://boards.straightdope.com/u/jk1245)\ **Post date:** [January 9, 2003, 1:23pm UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/29 "2003-01-09T13:23:57Z")
Thanks for all the responses/stories. Just to clarify to those who are questioning my sanity. I do not use the “touch and swear” method to determine if a wire is hot. I was merely wondering if was likely to touch a live wire and live to tell about it. Also one more question to the more knowledgable electrical folk: How do you work on wires without being grounded? Doesn’t just standing on the ground ground you, or will your shoes insulate you (provided, of course, you don’t have copper soled shoes!)? Thanks again ---
**Author:** ![Uncommon\_Sense](https://avatars.discourse-cdn.com/v4/letter/u/f9ae1b/32.png) [@Uncommon\_Sense](https://boards.straightdope.com/u/Uncommon_Sense)\ **Post date:** [January 9, 2003, 1:39pm UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/30 "2003-01-09T13:39:26Z")
> [@](#): > > \*Originally posted by jk1245 \* > \*\*Thanks for all the responses/stories. > Also one more question to the more knowledgable electrical folk: How do you work on wires without being grounded? Doesn’t just standing on the ground ground you, or will your shoes insulate you (provided, of course, you don’t have copper soled shoes!)? > > Thanks again \*\* That is the tricky part. You can never guarantee that you are not grounded. Wearing rubber soled shoes helps. You could also stand on dry cardboard, plastic, or a rubber mat. If you do wear shoes, your feet should be dry and the soles should not be cracked or have any metal filings or nails in them. Be sure that you are not touching anything grounded with your other hand or any part of your body for that matter. FYI - What I do if I have any doubt, and I HAVE to work on a hot circuit, is quickly tap the exposed part of the wire with my finger. If I don`t get the TINGLE then I consider myself safe. I also wear good work boots that keep me from being grounded. ---
**Author:** ![NeedAHobby](https://avatars.discourse-cdn.com/v4/letter/n/3d9bf3/32.png) [@NeedAHobby](https://boards.straightdope.com/u/NeedAHobby)\ **Post date:** [January 9, 2003, 1:45pm UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/31 "2003-01-09T13:45:07Z")
A friend of mine told me a technique he uses when working with household circuits. First, he turns off the circuit. Then he takes a screwdriver and shorts out the wires (and through Rick’s story, I’d short them to ground too.) If huge sparks fly out, the circuit is still live; otherwise it’s much more likely to be safe. Why risk your life when you can risk a hand tool instead? ---
**Author:** ![drachillix](https://avatars.discourse-cdn.com/v4/letter/d/48db29/32.png) [@drachillix](https://boards.straightdope.com/u/drachillix)\ **Post date:** [January 9, 2003, 1:59pm UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/32 "2003-01-09T13:59:35Z")
> [@](#): > > \*Originally posted by Gary T \* > Yes. One fellow told me years ago that if he had to check a wire manually, he would brush it with the **backs** of his fingers. If the wire were hot, his hands would clench, pulling his fingers away from it. Since detailed searches in burning buildings are often by feel we were taught in fire academy to pat around under and behind furniture with the back of our hand/glove for that very reason. My big question is this. I know that sometimes it is not feasible to shut off power before working on something (like part of a main on/off in a breaker box) is there any way to reduce the likelyhood of getting cooked like heavily insulated boots or some kind of ground strap to make you a path of greater resistance. ---
**Author:** ![Popup](https://avatars.discourse-cdn.com/v4/letter/p/94ad74/32.png) [@Popup](https://boards.straightdope.com/u/Popup)\ **Post date:** [January 9, 2003, 2:10pm UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/33 "2003-01-09T14:10:42Z")
I have a very useful tool, but I’ll be damned if I know what to call it in English. Basically it measures the electrodynamic field around conductors to tell you if they’re hot or not. I don’t quite understand how it works (which is really bugging me), but it has this single wheel where you set the sensitivity, and then when you get close to a hot wire it starts beeping. A bit like a GM counter, but for EM-fields. Since an unfortunate accident when I touched 220V (hurt like hell, but I’m here to tell the tale) I always test wires with this tool before touching. A very handy tool for anyone fiddling with wiring. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [January 9, 2003, 2:30pm UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/34 "2003-01-09T14:30:31Z")
> [@](#): > > _Originally posted by whuckfistle_ > \*\*What causes death/damage to the body are three things. > > 1. amperage > 2. the path through the body > 3. the amount of time exposed\*\* I assume #1 refers to actual current _through the body_. Because the current _capability_ of the circuit, whether it be 15 Amps or 1500 Amps, doesn’t matter… ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [January 9, 2003, 2:32pm UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/35 "2003-01-09T14:32:35Z")
> [@](#): > > \*Originally posted by NeedAHobby \* > \*\*A friend of mine told me a technique he uses when working with household circuits. First, he turns off the circuit. Then he takes a screwdriver and shorts out the wires (and through Rick’s story, I’d short them to ground too.) If huge sparks fly out, the circuit is still live; otherwise it’s much more likely to be safe. Why risk your life when you can risk a hand tool instead? \*\* Sounds like a good way to start a fire. Why not just purchase a $2 neon bulb tester? ---
**Author:** ![Early\_Out](https://avatars.discourse-cdn.com/v4/letter/e/6f9a4e/32.png) [@Early\_Out](https://boards.straightdope.com/u/Early_Out)\ **Post date:** [January 9, 2003, 3:34pm UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/36 "2003-01-09T15:34:48Z")
> [@](#): > > \*Originally posted by handy \* > \*\*…as a kid … my brothers would dare me to put my finger in the socket & I would 🙂 \*\* This explains a lot! 😃 ---
**Author:** ![handy](https://avatars.discourse-cdn.com/v4/letter/h/b5a626/32.png) [@handy](https://boards.straightdope.com/u/handy)\ **Post date:** [January 9, 2003, 4:40pm UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/37 "2003-01-09T16:40:01Z")
"Wearing rubber soled shoes helps. You could also stand on dry cardboard, plastic, or a rubber mat. If you do wear shoes, your feet should be dry and the soles " Well, don’t forget gloves! They are the most important. People can take a Taser shot, which is what, 50,000 volts? Thats kinda small compared to 120V. Does it matter if its AC or DC? ---
**Author:** ![Mort\_Furd](https://avatars.discourse-cdn.com/v4/letter/m/8e8cbc/32.png) [@Mort\_Furd](https://boards.straightdope.com/u/Mort_Furd)\ **Post date:** [January 9, 2003, 5:07pm UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/38 "2003-01-09T17:07:46Z")
What matters is the amount of current. The tazer puts out high voltage, but damn near no current. As soon as you put a load on the terminals of the tazer, the voltage drops. A tazer has (or at least should have) a current limiter or regulator to keep the current below lethal levels. Also, a tazer jolt doesn’t normally pass through the heart. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [January 9, 2003, 5:11pm UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/39 "2003-01-09T17:11:28Z")
> [@](#): > > \*Originally posted by handy \* > \*\*People can take a Taser shot, which is what, 50,000 volts? Thats kinda small compared to 120V. Does it matter if its AC or DC? \*\* Good questions, but you’re opening a can of worms that will result in _endless_ discussions. Does it matter _where_ current enters & exits the body? Yes. Is there a difference between AC and DC? Yes. Does frequency matter? Yes. Does source impedance matter? Yes. Is there a difference between peak voltage vs. RMS? Yes. Does anyone agree on all of this stuff? No. ---
**Author:** ![Mort\_Furd](https://avatars.discourse-cdn.com/v4/letter/m/8e8cbc/32.png) [@Mort\_Furd](https://boards.straightdope.com/u/Mort_Furd)\ **Post date:** [January 9, 2003, 5:26pm UTC](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366/40 "2003-01-09T17:26:22Z")
Righto. Short and simple: Electricity can kill you. Do you really want to discover by personal experience under just exactly which circumstances? [Previous page](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366.md?page=1) [Next page](https://boards.straightdope.com/t/how-dangerous-is-your-home-electrical-system/147366.md?page=3)