mike12345 posted:

I need to buy a multimeter. There are a couple chinese ones on Ebay, selling for 2-3 bucks. Is that safe to buy? I don't want crap exploding in my hands or catching fire.

babyeatingpsychopath posted:

They'll be no worse than the $5 ones from Harbor Freight. Those will do voltage up to 120V without killing you. I wouldn't trust them to do current at all, and their leads are crappy enough that resistance measurements are probably only accurate to within 100ohm or so. The leads are seriously crappy and fall apart pretty quickly, so be mindful of that.

mike12345 posted:

I need to buy a multimeter. There are a couple chinese ones on Ebay, selling for 2-3 bucks. Is that safe to buy? I don't want crap exploding in my hands or catching fire.

L0cke17 posted:

So I live in an apartment, been here for like two weeks. Last night, when I was going to bed, I noticed that the screws on the light switches in the bathroom and closet were electrified, and had a rather significant shock when I went to turn them off. I put my finger near them, and from ~1/8th of an inch away I could feel my hair standing on end, didnt want to get any closer to that, because it was a decent jolt when I accidentally touched it the first time. I don't know my way around house wiring too much, but I turned off the breaker (which also powers 1/3 of my apartment ) and went to file a maintenance request. Quick googling had a lot of people trying to claim that it was just static on me (which seems like total horseshit to me) and some people saying it was either a loose ground wire, no ground wire, or a huge fire hazard because ground is shorted to something. I've been not impressed with the maintenance staff so far here, so if they dont deal with it (or even if they do) should I call a real electrician to come look at it? How much is that gonna cost me, and what should I do to make sure my apartment doesnt burn down in the next year due to something like this?

I also pulled the faceplates off and took a look after the breaker was off, and it looks like there are 2 wires plugged into the switch, and what may be a ground wire connected to the switch box (but it was hard to tell under all the paint and late at night), but the whole thing was spray-painted over at some point so colors are lost to me. Also the screws from the switch to the box are covered in paint, so if that wire is the ground, then the switch doesnt have any electrical connection to it, which may be the problem? I do own a nice multimeter, and design robots for a living, so I imagine if I had a guide or set of suggestions on what to look for I could maybe diagnose this myself, but I also know I dont really know enough to want to mess with it without some serious reading or expert help. So what should I do?

L0cke17 posted:

So I live in an apartment, been here for like two weeks. Last night, when I was going to bed, I noticed that the screws on the light switches in the bathroom and closet were electrified, and had a rather significant shock when I went to turn them off. I put my finger near them, and from ~1/8th of an inch away I could feel my hair standing on end, didnt want to get any closer to that, because it was a decent jolt when I accidentally touched it the first time. I don't know my way around house wiring too much, but I turned off the breaker (which also powers 1/3 of my apartment ) and went to file a maintenance request. Quick googling had a lot of people trying to claim that it was just static on me (which seems like total horseshit to me) and some people saying it was either a loose ground wire, no ground wire, or a huge fire hazard because ground is shorted to something. I've been not impressed with the maintenance staff so far here, so if they dont deal with it (or even if they do) should I call a real electrician to come look at it? How much is that gonna cost me, and what should I do to make sure my apartment doesnt burn down in the next year due to something like this?

I also pulled the faceplates off and took a look after the breaker was off, and it looks like there are 2 wires plugged into the switch, and what may be a ground wire connected to the switch box (but it was hard to tell under all the paint and late at night), but the whole thing was spray-painted over at some point so colors are lost to me. Also the screws from the switch to the box are covered in paint, so if that wire is the ground, then the switch doesnt have any electrical connection to it, which may be the problem? I do own a nice multimeter, and design robots for a living, so I imagine if I had a guide or set of suggestions on what to look for I could maybe diagnose this myself, but I also know I dont really know enough to want to mess with it without some serious reading or expert help. So what should I do?

kid sinister posted:

That sounds like a combination of what you looked up, a short to the box with either no ground or a faulty ground. We need more info. Are the boxes steel or plastic? Does your place have 3 prong outlets? If so, use your multimeter, set it to AC volts, stick one probe in the narrower slot and the other in the round hole. Now if they're properly grounded, the meter should read around 120V.

Do you have an extension cord long enough to reach an outlet on another circuit?

L0cke17 posted:

I did go home at lunch to check their progress, and the maintenance people have clearly been there, they said it was fixed, and the circuit was turned back on, and it was not acting the same as it was before. I don't know exactly what they did, but it no longer felt like it was electrified when I put my hand near it, and when I touched it after that nothing happened, so maybe its fixed?

I do have 3 prong outlets, and I can borrow an extension cord from work that would be long enough to grab another circuit.

The box may be metal? but its hard to tell under all the paint. I'll turn off the breaker again when I get home and scratch at a small area of the paint to see if its metal or plastic.

However, it doesnt look like they even removed the faceplate on either of the switches, so I worry what that means. They did at least open and mess with the fusebox it looks like, so maybe it wasnt grounded properly in there and they fixed that?

Option 3 is that it actually WAS an electrostatic discharge on my part. I had been shuffling around my standing desk, which is over carpet, for like 3 hours and the screw may have been the first thing I touched that was grounded, and after leaving for work and clipping into the ESD mat for working on electronics I no longer have that charge, so the maintenance people may have shown up and found nothing, and I found nothing after I got back from work. I still want to try and test every other alternative I can before I get too comfortable and believe that Im safe.

mike12345 posted:

I need to buy a multimeter. There are a couple chinese ones on Ebay, selling for 2-3 bucks. Is that safe to buy? I don't want crap exploding in my hands or catching fire.

kid sinister posted:

If it ain't broke, don't fix it. My guess is that the ground wasn't hooked up properly at that box and that the hot was touching either the switch frame or the steel box. If that was the case, then they may have needed to fix the ground farther up the branch (like at the panel) so that a short to ground in the future will actually trip the breaker instead of shocking somebody like what happened with you.

The difference between static shock and mains shock is the amps and voltage. Now amps is what hurts you, but volts is what makes electricity jump gaps. Static shocks have really high volts, high enough to jump a gap, but low amps so it's only a tickle. Mains voltage is really low, (compared to a static shock anyway) but with higher amps, enough to be dangerous. So the easiest way to tell the difference is this: when you were shocked, did you get shocked when you touched it or when you almost touched it?

L0cke17 posted:

Im not certain. It may have been almost touching, but I jerked away so fast I don't recall exactly. I was reaching from around the door-frame to turn it off, so I wasnt looking at it when I felt it either. Is there an easy way to tell with a multimeter if the screw is hot? Just for my sanity at this point.

Zero VGS posted:

Yeah you'll be fine. It's not like there are multimeters that aren't Chinese.

kid sinister posted:

That has to be the worst diagram I've ever seen. How about some labels on the devices?

Mode 7 Samurai posted:

Bad Munki posted:

Here, I re-drew your diagram, hopefully this is clearer:

Mode 7 Samurai posted:

Yes it has 2 black wires, 2 white wires, and 2 copper wires.

Mode 7 Samurai posted:

Thanks chief, real loving helpful.

gently caress ya'll, sorry I am not a goddamn electrician good at making wiring diagrams. I will just have my dad come over and help me instead of hearing you babies loving cry about my lack of artistic skills.

magic mountain posted:

C'mon dude, that was a great joke, how can you not laugh at that post.

Bad Munki posted:

Serious business only around here, thank you very much.

TooMuchAbstraction posted:

You can buy multipack 1-foot-long extension cords. They come in handy surprisingly frequently. Not just for stuff like your vacuum cleaner; you can also use them to get full use out of the ports on a power strip, for example.

there wolf posted:

Stupid question, but we have this vacuum that gets some pretty hard use and the plug starts getting torn off the cord every three months or so. Replacing the thing is a costly hassle, so the idea has been floated that we just attach an extension cord to it, and when that plug starts getting torn up then we just replace the cord. Any reason why this wouldn't work/cause fire and electrical deaths?

there wolf posted:

Stupid question, but we have this vacuum that gets some pretty hard use and the plug starts getting torn off the cord every three months or so. Replacing the thing is a costly hassle, so the idea has been floated that we just attach an extension cord to it, and when that plug starts getting torn up then we just replace the cord. Any reason why this wouldn't work/cause fire and electrical deaths?

there wolf posted:

It's the work vacuum. I only have so much control over it's use and repair, and I don't want to get shocked again. Temporary solution is pretty much my only solution right now.

GWBBQ posted:

Your coworkers are idiots and instead of walking over to the wall and unplugging it, they grab the cord and whip it around until the plug flies out of the wall.

there wolf posted:

Nope. A nice as it would be, there really isn't some large, obviously stupid action creating the problem. It's just a lot of small things that result in more stress on the chord than it can handle right now.

some texas redneck posted:

So I'm moved into my new apartment (well, new to me). I'm sure the place will eventually burn down on its own, since it has an early 80s FPE Stab Lok panel . But that's not why I'm here.

There's a recessed can light above the bar. Seems like a standard 6 inch can. Problem is, it turns off on its own after a few minutes. It'll cycle back on and off several times for a minute, then goes off for 5 minutes or so. It's doing this with incandescent, CFL, and LED bulbs installed, regardless of wattage (with one of the LEDs it would start flickering rapidly instead of going off completely). When it goes off for 5+ minutes, there's an audible "click".

I'm assuming this is a bad thermal safety, but I can't see one inside the can - the socket just has 2 wires leading out of the can. How much of a pain in the rear end will it be for maintenance to fix it? Where the hell is the thermal cutout on it anyway? I'm more curious if they're going to have to cut the light out of the ceiling or if they'll somehow be able to fix it without ripping the ceiling apart. Or did the previous tenant stick a flasher behind the switch to drive me crazy?

some texas redneck posted:

So I'm moved into my new apartment (well, new to me). I'm sure the place will eventually burn down on its own, since it has an early 80s FPE Stab Lok panel . But that's not why I'm here.

There's a recessed can light above the bar. Seems like a standard 6 inch can. Problem is, it turns off on its own after a few minutes. It'll cycle back on and off several times for a minute, then goes off for 5 minutes or so. It's doing this with incandescent, CFL, and LED bulbs installed, regardless of wattage (with one of the LEDs it would start flickering rapidly instead of going off completely). When it goes off for 5+ minutes, there's an audible "click".

I'm assuming this is a bad thermal safety, but I can't see one inside the can - the socket just has 2 wires leading out of the can. How much of a pain in the rear end will it be for maintenance to fix it? Where the hell is the thermal cutout on it anyway? I'm more curious if they're going to have to cut the light out of the ceiling or if they'll somehow be able to fix it without ripping the ceiling apart. Or did the previous tenant stick a flasher behind the switch to drive me crazy?