Mild electrical shock felt through solder  - Page 1
Forum section: electronics / projects

author: MatCat
author_rank: Frequent Contributor
timestamp: January 10, 2015, 08:11:45 pm
content: I bought some 62/36/2 silver bearing solder from rat shack mainly because it was the thinnest gauge they had at 0.022", and I noticed that when I touch the solder I can feel mildly an electrical shock! It's not enough to really hurt but enough that after a second you react by wanting to really let go of the solder. I do not notice this when using any other solder, or holding pliers or other various metal objects while soldering, and no there is no power to the circuit being soldered. The iron itself is a radio shack digital, pictured below. I must say I like how this solder flows, makes damn good solder joints (pic attached below of what I was working on when I discovered the shock!) , but I don't like getting electrocuted.

author: bookaboo
author_rank: Frequent Contributor
timestamp: January 10, 2015, 08:15:29 pm
content: I had a similar experience with a weller iron. Turned out the mains lead was faulty (was probably not the original). Check is your tip correctly earthed all the way back. May or may not be your experience, I'd find the cause of the problem before going any further.

author: MatCat
author_rank: Frequent Contributor
timestamp: January 10, 2015, 08:19:34 pm
content: I also must point out I do not know for sure how well grounded the earth ground plugs in my place are either, I haven't really ever checked it, I think I will just to see...

author: tonyarkles
author_rank: Regular Contributor
timestamp: January 10, 2015, 09:36:30 pm
content: Quote from: MatCat on January 10, 2015, 08:19:34 pmThe ground pin on a standard 3-pin (north american) power plug is primarily there for safety reasons. From the outlet, there's "hot", "neutral", and "ground". Neutral and Ground should be connected together at some point (at the panel? I'm not an electrician), and should be at roughly the same potential at the outlet.The most common cause of problems like this is that the neutral and hot get wired backwards; either in the iron itself, or in the wall outlet. An easy way to check would be to unplug the iron and measure the resistance to both the hot and neutral pins on the power connector; if the tip is low resistance to the hot, then something is wired wrong in your iron. If not, it's possible that the outlet is wired backwards.

author: c4757p
author_rank: Super Contributor
timestamp: January 10, 2015, 09:39:56 pm
content: If when unplugged, the tip has low resistance toeitherpower pin - not just hot - you have ahugeproblem.More likely the source of the energy is capacitive.

author: ConKbot
author_rank: Super Contributor
timestamp: January 11, 2015, 06:10:27 am
content: Quote from: tonyarkles on January 10, 2015, 09:36:30 pmNeutral an Earth are connected at the main distribution panel, and only at the main panel. (well, inside the house, I think they are tied at the pole transformer also) Sub panels have an isolated neutral bar. (Sub panels in a detached building, i.e. workshop or shed or garage may vary depending on when they are done, I'm not sure what is currently code for that. )And +1 to it sounding like a bad ground somewhere and feeling leakage though EMI suppression caps. Hopefully the appliance cord, and not a wiring fault in the house.

author: devanno
author_rank: Regular Contributor
timestamp: January 11, 2015, 07:32:12 am
content: Clearly, it's not the solder that's the problem.I just wanted to say that I use this formulation of solder frequently and it does flow beautifully... makes beautiful joints.

author: Psi
author_rank: Super Contributor
timestamp: January 11, 2015, 08:02:56 am
content: Most likely your soldering iron tip is floating because of a bad earth.Try using a DMM set to AC volts and hold one terminal in your hand while touching the other to the iron tip.Most likely you will see ~60-100 VAC there which proves a bad earth. (~2V AC would be normal for general leakage)However, if you only started getting this feeling with this "new solder" that you bought (and not the old stuff you had) then there maybe another explanation.Do you get this 'shock' when holding the solder and not even touching the iron at all?Some people get an allergy to some types of metal being in contact with there skin. It's quite common with earrings.The body just decides it really doesn't like that metal and the person gets a strange sensation at the point of contact with it. (It can be described as a shock type feeling).It usually starts quite mild but the more exposure you have the worse it gets to the point were you just cant touch the stuff without feeling very ill.So if the DMM shows no earth issue then it could be a metal allergy (or flux allergy). That specific solder may contain traces of something you're allergic too. Try a different brand maybe.

author: LabSpokane
author_rank: Super Contributor
timestamp: January 11, 2015, 08:15:27 am
content: Get an AC outlet tester and check that outlet and the rest as well. Disconnected grounds and swapped line and neutral wires are extremely common with DIY electrical work.

author: SL4P
author_rank: Super Contributor
timestamp: January 11, 2015, 11:28:23 am
content: Quote from: ConKbot on January 11, 2015, 06:10:27 amNot trying top be facile or pretentious... but -Hopefullywon't pay the undertaker's bill. Check your earthing soon. Properly.

author: Monkeh
author_rank: Super Contributor
timestamp: January 11, 2015, 11:43:05 am
content: Quote from: tonyarkles on January 10, 2015, 09:36:30 pmNo, that is not a common cause of this, because nothing (excluding utterly ancient stuff, and some utter cheap crap) has one of the live conductors wired to an exposed conductive part. Swapping the two live conductors should never cause such things.

author: electr_peter
author_rank: Unknown
timestamp: January 11, 2015, 11:58:02 am
content: Most likely reason - no earth in the house completely or some break in earth line in appliance.With no earth everything is floating at 20-50% of mains voltage. Shock is perceived because you complete circuit. Shock is not that dangerous because of low capacitance coupling .However, it is small probability of some internal wiring fault + no earth. In this case it is much more dangerous.

author: MatCat
author_rank: Frequent Contributor
timestamp: January 11, 2015, 04:47:16 pm
content: I am fairly sure it's bad grounding in the building, because I have been shocked by the exposed metal of USB connectors, but it's so mild I always thought it was just me, but now I am fairly positive of it because I can get the same buzz from touching the BNC connector on my scope too. Remember it's very very mild, anyway the scope test of holding a probe and measuring the soldering iron tip reads 54V steady, and that goes for anything I touch connected to 'earth ground'.

author: jlmoon
author_rank: Unknown
timestamp: January 11, 2015, 04:58:26 pm
content: Quote from: MatCat on January 11, 2015, 04:47:16 pmI would suggest your ground at your service entrance is not really a true ground (floating at neutral potential) but more like a neutral which probably has some return current due to load imbalance created by loading one side of the 240 V input more heavily than the other. You need to verify that ground all the way back to the power pole that supplies power to your building. Look for a ground rod and the required bonding at your meter base too.

author: MatCat
author_rank: Frequent Contributor
timestamp: January 11, 2015, 05:10:31 pm
content: Quote from: jlmoon on January 11, 2015, 04:58:26 pmI am US so 110V here... I need to talk to my landlord, I live in a small complex in a studio with only 2 outlets in my room and the breaker box is in a locked room I have no access to, and I highly doubt he will do much about it.

author: devanno
author_rank: Regular Contributor
timestamp: January 11, 2015, 06:21:42 pm
content: If you have a bad or floating ground in your building, it's a building code violation. If your landlord isn't interested in doing something about it, you may remind him of this. If an improper ground is the case, the situation could get people killed.

author: MatCat
author_rank: Frequent Contributor
timestamp: January 11, 2015, 07:40:27 pm
content: Quote from: devanno on January 11, 2015, 06:21:42 pmI have talked to my landlord and confirmed there are no earth ground wiring behind the walls, the building was built in the 1940s before it was wired as such. I am not so sure about that, I do believe there are allowences for older buildings like this, but at either rate we discussed it and he plans on doing something about it soon, but not sure what.

author: c4757p
author_rank: Super Contributor
timestamp: January 11, 2015, 07:52:33 pm
content: Quote from: MatCat on January 11, 2015, 07:40:27 pmAn outlet without ground is one thing, but a grounded outlet with ground floating isseriouslydodgy and misleading, and your landlord is equally dodgy if "something" isn't "install proper grounding posthaste" and equally misleading if he didn't warn you when you moved in that the grounding on the outlets wasfake.

author: SeanB
author_rank: Super Contributor
timestamp: January 11, 2015, 08:08:08 pm
content: There is also a lot of fake grounded outlets in the USA which connects ground and neutral at the socket, as they originally were wired with a 2 wire no earth cable. Not a good idea, especially if the neutral is disconnected somewhere in the wall all the appliances float to line voltage and the available current is the regular operating current of the combined load.

author: devanno
author_rank: Regular Contributor
timestamp: January 11, 2015, 09:21:38 pm
content: Quote from: MatCat on January 11, 2015, 07:40:27 pmWell, at least he's looking at doing -something-. In many areas, the power must be run in EMT (Electro-metalic-tubing... most people just call it "conduit") the metal tubing and infrastructure is used as the "ground" in the system and separate ground wires are not run. Just an FYI. I live in Cook County, IL (not in Chicago, thank you ;-) ) ... and we've had very stringent electrical codes for decades... but using the building thinwall (EMT) as the ground is legit, at least in residential installations. Your local hardware store likely has outlet "testers" that are simply a device that plugs in and tells you if you have a ground fault or cross wired outlets, etc. About the size of a molded 3 - prong plug. Every kit should have one, especially if you're off doing 'field' work. They're only a couple of $.

author: MatCat
author_rank: Frequent Contributor
timestamp: January 12, 2015, 12:10:56 am
content: Well I went to the store and picked up an extension coord and a heavy duty screw it together yourself plug and made a ground only plug, I plugged it into my primary power strip and grounded the ground to a water pipe, now I measure 0.12v instead of 54v from the ground, and I do not seem to be getting shocked.

author: nanofrog
author_rank: Super Contributor
timestamp: January 12, 2015, 12:35:03 am
content: IIRC, grounded outlets weren't required until 1958 in the US's NEC for residential construction (grounded to the metal box, not a 3 prong plug).If it's feasible, you could see if there's access to a ground rod (or install one), run a dedicated ground between the box and ground rod, and replace the existing outlet with a GFCI. Done this a few times in older construction when there wasn't a separate ground present.Given the situation, this tends to be an economical solution to retrofitting older wiring, so may be a viable solution for your landlord (electrician will likely discuss this option).