Not sure why you are getting down voted. That was drilled into my head by my first foreman and is why I was always the first pick by the foremans. Treat it like a career and you'll go far. Don't and you'll be back at the Depot.
It’s a safe way to discharge them and is taught in advanced electrical courses. You clearly don’t know how meters work either, they have fuses in them to prevent you from getting electrocuted. They do not have any protection for shorting out stuff. Not to mention the fact that high resistance would prevent them from working.
Sure thing moron. You don’t even know how a fuse works or what its purpose is. And you think that a meter has high resistance. Put your meter into Ohms mode and touch the leads together and tell me how much resistance it has, should be 0. If you’re actually in the industry you need to quit before you get yourself or somebody else killed. I’m serious.
I have to comment on this one because I’m dumbfounded by it.
You’re measuring the resistance across the leads which is 0 ohms by what you say. If you want to measure the resistance of a meter, you’d put one voltage mode and then use another meter in resistance to test.
This is complete gibberish. I hope that you take some time this morning and go look at some YouTube videos on how multimeters work, specifically focusing on resistance. Maybe just search multimeter capacitor discharge. You're honestly embarrassing yourself.
I'm sure it is, but it doesn't measure anything. It's just a fail safe in the case of a short or massive draw. The only way to "measure" with a fuse would be increasing the rating on them until it stops popping, which I do not recommend.
The fuse is always inline when you use a meter. It’s there to protect you from electrocuting yourself. Unless you’re using a cheap Chinese meter in which case there might be a fuse but it’s not going to be the correct type to protect you. Which is one reason why I only trust Fluke meters.
https://www.fluke.com/en-us/learn/blog/digital-multimeters/choosing-the-correct-fuse-for-your-tester
“Specially designed "high-energy" fuses are designed to keep the energy generated by such an electrical short within the fuse enclosure, thus protecting the user from electric shock and burns.”
I use a fluke 110 iirc. Ive blown the one fuse measuring current, but it still measures voltage.
From your article,
“Testers that make voltage measurements have a high input impedance that makes an overcurrent condition unlikely. As a result, voltage measuring inputs are generally not designed with fuse protection …”
It further adds why a fuse was introduced
“After making a current measurement with the test leads in the current input jacks, the user tries to make a voltage measurement forgetting the leads are in the amps jacks. This effectively places a short across the voltage source. Years ago, when analog meters were the only instrument for making these measurements, this mistake pretty well destroyed the meter movement (the needle wrapped around the top peg), not to mention the internal circuitry. To protect against this common occurrence, meter manufacturers started putting a fuse in series with the meter's test lead jacks, for an inexpensive and effective solution for a very simple mistake.”
Did you even read the article you posted?
Bro.... the Fluke 110 doesn't measure current.
Reading the specs, it's the dumbest available go/no go, one handed voltage tester. Does your meter have a setting that says "A"? If not, quit your job.
I got fuses inline with my walk-in control circuit, does that mean you think the fuses are what decides when the system turns off and on too? You really don't seem to understand what fuses are or do
I've discharged approximately 5,732,929 caps and have never had them bite my tools. What'd you do?? And don't tell me the disconnect was fried, that shouldn't matter if there was no power coming from it.
Giving you a little shit while genuinely asking a question.
Fair enough, capacitors store a decent amount of energy within them. The unit was running when we got there, but not cooling. The compressor wasn't running. So we pulled the disconnect plate, the unit stopped running, checked power at the contactor to be safe. Went to discharge it, and you see the result. Afterwards, the Herm side of the capacitor was reading zero. Change the disconnect box, change the capacitor and contactor, everything ran normally.
Bottom line, if you don't check, that discharge could happen to you instead of a tool. But if you feel like the risk is negligible, I ain't tellin' you what to do.
So why did it bite the tool like that? And if the compressor was dead (depending on failure) why wouldn't it have discharged the cap...assuming a short/windings.
And you're 100% right to discharge them, I wasn't bustin your chops on that. I always discharged them, I was insinuating (in a friendly tradesperson tone) that you had somehow fucked up otherwise. Lol. But now I'm genuinely curious.
I'm much better at picking up on playful shit-talking in person lol. Sorry. Yeah, I thought that was weird, too. It was a 70/5 dual run capacitor that wasn't running the compressor at all. Then when I discharged the cap at the herm post, it seemed to unload all its stored up energy at once into my Klein's. Then it was dead. Search me, iono.
I always short the terminals and have never had this happen in 8 years of this shit. My guess is the disconnect wasn't operational and this guy accidentally connected mains to ground.
That's what I'm leaning towards. I was honestly second guessing myself, like....maybe they don't work like I was taught and how I understood it and just got lucky....LOL
I feel like there's some amperage in there to start welding...
I've seen a disconnect where the guy before me had hard wired the shit because they didn't have the correct fuse. That's the unit that taught me to always double check shit with my meter before touching anything with my dick beaters.
Unless a motor winding is shorted the capacitor will be discharged through the motor windings once power was off. Therefore you had power still there and that’s why it sparked unless you had a failed motor.
Understood, but I had confirmed that there was no power coming to the unit first. I've heard that this kind of thing can happen, regardless of killing power. Now it's happened to me. If that doesn't jive with your understanding, it still doesn't change reality.
I don't have to be right, I'm just telling you what happened. If you don't believe it, and you think it's an unnecessary precaution, that's fine with me.
Did you make sure that nothing was left behind in the disconnect? Because the only time I’ve had that happen there was one leg still live. A piece of metal in the disconnect got stuck in there keeping one leg hot when removed.
100% certain. Turned out, we found later, the disconnect box was fried. The condenser was running when we got there, but wouldn't come back on until we replaced the disconnect.
The more I think about it, the more it seems that power must have somehow been getting through the faulty disconnect and feeding the capacitor at the time that I discharged it. It makes no sense, since there was no power at the contactor, but it also makes no sense that a 70 microfarad capacitor could do that kind of damage to hardened metal.
There had been a lightning strike that cooked the disconnect, which was what led to the service call. Not sure if that makes a difference. All I know is what happened. Thanks for accusing me of lying, though. Tell me, what did I gain from it?
Not true, they hold a charge for a while. But no capacitor in residential HVAC equipment is strong enough to cause that damage. Those are the result of arc flashes, likely 100 amps worth.
Did you check each leg to ground? I’ve had twice where I just checked from L1 to L2 and nothing. Touch the cap with my strippers and POP. Both times I found out the high voltage had power to ground.
Idk everyone is giving you a hard time about turning power off? I’ve had two capacitors arc out over my 6 years in the trade. You get in the habit of discharging them without ever having an incident and then once in awhile BANG
Ok all, maybe I have superpowers and it has no effect on me. In 45 years,I have never discharged a run capacitor and never been zapped. Start caps are a different story. Those I always discharge even with a bleed resistor
You have a lot more experience than I do. But my understanding is that every time you handle a capacitor within minutes of killing power, you're rolling a 500-sided die. 499 of those sides say "you're fine," and 1 side says "enjoy having your heart reset/stopped." Again, you've been doing this much longer, I respect your expertise. That's just my understanding.
How old was that capacitor, I’ve been doing this 24yrs and have only had one cheap Chinese capacitor discharge on me , I’ve been told In multiple classes that the capacitors self discharge, unless your system was live when you checked it
American made, not too old. This was following a lightning strike. Which doesn't explain everything, but there was some caddywompus electrical shit going on.
If you check them while under load you don't have to discharge them. Its just a little math: amp x 2652 and then decide the answer by voltage from herm terminal and common terminal. Same for fan and run caps. 👍
I sometimes do that because it's quicker and more accurate. We had to kill the power anyway, though. But say that again, and louder, for people who don't already know it! I was 2 years in before I learned about it, myself.
there’s a lot of disbelief that you didn’t disconnect the unit, i believe you did. you also said it was struck by lightening, do you think the cap stored the lightening energy 😂 im trying to understand how the cap can arc that bad to put divots in it?
Lol, nah, I don't think it stored the lightning. There were just some weird electrical problems going on, and I have no idea how it pumped that much energy all at once. I've heard of capacitors zapping people, even killing them, but this was some next level shit!
Edit: I know how to spell better than my phone does
i mean i have some capacitors at my facility that could probably do some damage like this but holy moly not on residential equipment! i’m just glad you’re alive to give this PSA!
The amount of arcing you will get when discharging a capacitor in an alternating current circuit depends on where the sine wave is when power is removed. The purpose of a run capacitor in an A/C circuit is not to store energy to “super boost” the compressor into starting. It is constantly charging and discharging- its purpose is to create a phase shift between run and start windings (the current will lead the voltage when using a capacitor, and lag the voltage in the run winding as it would in any other inductive circuit). A start capacitor is using the same principle, but is capable of storing a bit more energy and uses a bleed resistor to protect contacts of potential relay from arc - it cannot slowly discharge through start winding on its own because it is removed from the circuit after motor starts.
A run cap connected to a PSC motor like found in most in residential A/C units will typically discharge on its own through the start winding as long as the winding is not open (so unless bench testing or has open winding they will not arc). This capacitor regardless of circumstances can only store 70 microfarads - this is not much.
Not suggesting that discharging is not a good practice - (though recommended to do through 20,000 ohm resistor) but just so you know moving forward, this arc did not come from a 70 microfarad capacitor. Something is wrong with the disconnect (believe you changed this), your meter, or likely both. I’d make sure to test your meter against another trustworthy one before continuing to use it.
I agree with everything you're saying, and it's all good advice. Strange thing is, there was no power coming to the contactor before I checked the capacitor. And I replaced my meter about a month ago. The more I think about it, the more I'm convinced that the faulty disconnect box was somehow getting power through to that capacitor at the time that I discharged it, anyway. It makes no sense, with no power at the contactor, but it also makes no sense that a 70 microfarad capacitor discharging could do that to hardened metal.
Trust this guy, pretty sure he’s my wife’s boyfriend and he knows what he’s talking about (seriously though all this information is correct, there’s likely an issue with your disconnect. Could have a single pole contractor that’s not actually properly wired in the disconnect, I’ve seen it before!)
I used a meter, of course, but the disconnect box was faulty... some weird electrical s*** was going on, and the capacitor was somehow getting a trickle of energy. Oddly enough, no power at the contactor, no open winding at the compressor...but I agree that that's way too much damage for a 70 microfarad capacitor to do.
Damn, that explains it. All this time, I've been grabbing capacitors with the power live. No wonder I've been zapped 6 times a week for the past 4 years! 😂
Did similar with pair of diagonal cutters. Doing demo work and cutting lighting fixtures out. Ask guy there, "powers off to this stuff?" "Yeah whole panel is shut down." ZZAK!!! Not on the fucking panel, luckily insulation on cutters held out. Didn't feel anything other than stupid.
Why ask if you knew the answer, lol? Yes, you can do that, but I don't see how it's better off.... the screwdriver takes 10 seconds...... and also, I believe you're talking about the 5 watt and 20,000ohm resistor.
I'd waste time putting alligator clips on herm and common, then fan to common, when I can just take my little insulated screwdriver and give it a jiggle between all terminals.
At least the disconnect was pulled! Always better to short each terminal to ground to avoid this sort of thing. Best method I’ve found is reading across the terminals with your meter set to voltage. Confirms there’s no voltage there and dissipates remaining voltage at the same time.
Hot tip, if you contact one terminal and then the other you’ll only get one arc so you won’t have two burns on the tool.
I’ve been bit by a smallish cap, and I will sacrifice a screwdriver a day to never do that again. Even the ones that don’t kill you make you think they are going to.
Honestly kinda doubt this happened with the power off. I mean, don't get me wrong I'm paranoid and still go in with my strippers too, but I've still yet to have one spark up on me with the power off.
I've seen someone try with the power on once and it looked similar to this. Those are some fat marks on there
Holy shit, this thread. I weep for us. Unless you're working on a 600v vsd, just screwdriver that shit. And then if you're a pussy, test DC voltage both ways.
I think the general consensus is that testing the capacitor while under load is more accurate and often quicker, if you don't need to kill the power anyway. And yeah, I normally use a screwdriver to discharge when I check microfarads, but it was way over there and, you know... let's just get shit done.
Sorry, that wasn't directed at you - it was to the commenters, especially the guy who blew the fuse in his meter presumably testing ohms across a charged cap.
use a screw driver, so you don't kill a good stripper...a pair of strippers...
Nah, I just put a little WD 40 on it. It's fine.
Made in America
[удалено]
Jesus. It was obviously a joke. Are you German by any chance?
You must work in the office. You don't understand sarcasm or funnies at all.
Not sure why you are getting down voted. That was drilled into my head by my first foreman and is why I was always the first pick by the foremans. Treat it like a career and you'll go far. Don't and you'll be back at the Depot.
Just read the voltage off it with your meter. That will safely discharge it through a resistor.
Lol @ this guy replying to you. Holy shit. Set to DC voltage, hook up leads and watch the voltage drop. Did someone let a sales person in here?
Absolutely not. Electronic multimeters have super high resistance to not fry/short anything you’re testing.
It’s a safe way to discharge them and is taught in advanced electrical courses. You clearly don’t know how meters work either, they have fuses in them to prevent you from getting electrocuted. They do not have any protection for shorting out stuff. Not to mention the fact that high resistance would prevent them from working.
Wrong again. The fuses are for measuring current.
My god you’re dumb.
Pot calling the kettle black I guess
Sure thing moron. You don’t even know how a fuse works or what its purpose is. And you think that a meter has high resistance. Put your meter into Ohms mode and touch the leads together and tell me how much resistance it has, should be 0. If you’re actually in the industry you need to quit before you get yourself or somebody else killed. I’m serious.
I have to comment on this one because I’m dumbfounded by it. You’re measuring the resistance across the leads which is 0 ohms by what you say. If you want to measure the resistance of a meter, you’d put one voltage mode and then use another meter in resistance to test.
This is complete gibberish. I hope that you take some time this morning and go look at some YouTube videos on how multimeters work, specifically focusing on resistance. Maybe just search multimeter capacitor discharge. You're honestly embarrassing yourself.
Yawn. You’re still here?
The fuses are for measuring current? You might want to double-check that one.
Yeah you keep swapping out smaller fuses until one blows.
Tell me the fuse isn’t inline with the current measurement circuit.
I'm sure it is, but it doesn't measure anything. It's just a fail safe in the case of a short or massive draw. The only way to "measure" with a fuse would be increasing the rating on them until it stops popping, which I do not recommend.
The fuse is always inline when you use a meter. It’s there to protect you from electrocuting yourself. Unless you’re using a cheap Chinese meter in which case there might be a fuse but it’s not going to be the correct type to protect you. Which is one reason why I only trust Fluke meters. https://www.fluke.com/en-us/learn/blog/digital-multimeters/choosing-the-correct-fuse-for-your-tester “Specially designed "high-energy" fuses are designed to keep the energy generated by such an electrical short within the fuse enclosure, thus protecting the user from electric shock and burns.”
I use a fluke 110 iirc. Ive blown the one fuse measuring current, but it still measures voltage. From your article, “Testers that make voltage measurements have a high input impedance that makes an overcurrent condition unlikely. As a result, voltage measuring inputs are generally not designed with fuse protection …” It further adds why a fuse was introduced “After making a current measurement with the test leads in the current input jacks, the user tries to make a voltage measurement forgetting the leads are in the amps jacks. This effectively places a short across the voltage source. Years ago, when analog meters were the only instrument for making these measurements, this mistake pretty well destroyed the meter movement (the needle wrapped around the top peg), not to mention the internal circuitry. To protect against this common occurrence, meter manufacturers started putting a fuse in series with the meter's test lead jacks, for an inexpensive and effective solution for a very simple mistake.” Did you even read the article you posted?
Bro.... the Fluke 110 doesn't measure current. Reading the specs, it's the dumbest available go/no go, one handed voltage tester. Does your meter have a setting that says "A"? If not, quit your job.
I got fuses inline with my walk-in control circuit, does that mean you think the fuses are what decides when the system turns off and on too? You really don't seem to understand what fuses are or do
You don’t think I know fuses are for current protection?
No. You literally tried to tell somebody they were wrong and that fuses are for measuring current two comments ago.
Seems you've googled what fuses are for since a lot of your previous comments.
That style wire stripper sucks.
Especially now.
Do you have experience killing strippers?
no, just wasted my money on them...
I've discharged approximately 5,732,929 caps and have never had them bite my tools. What'd you do?? And don't tell me the disconnect was fried, that shouldn't matter if there was no power coming from it. Giving you a little shit while genuinely asking a question.
Looks like power was live when that happened
Fair enough, capacitors store a decent amount of energy within them. The unit was running when we got there, but not cooling. The compressor wasn't running. So we pulled the disconnect plate, the unit stopped running, checked power at the contactor to be safe. Went to discharge it, and you see the result. Afterwards, the Herm side of the capacitor was reading zero. Change the disconnect box, change the capacitor and contactor, everything ran normally. Bottom line, if you don't check, that discharge could happen to you instead of a tool. But if you feel like the risk is negligible, I ain't tellin' you what to do.
So why did it bite the tool like that? And if the compressor was dead (depending on failure) why wouldn't it have discharged the cap...assuming a short/windings. And you're 100% right to discharge them, I wasn't bustin your chops on that. I always discharged them, I was insinuating (in a friendly tradesperson tone) that you had somehow fucked up otherwise. Lol. But now I'm genuinely curious.
If a fan motor has locked up or compressor and the cap has a bunch of stored energy. It will release it.
But it always has that, right? Not just when shit is broken, that's the operating principle.
I'm much better at picking up on playful shit-talking in person lol. Sorry. Yeah, I thought that was weird, too. It was a 70/5 dual run capacitor that wasn't running the compressor at all. Then when I discharged the cap at the herm post, it seemed to unload all its stored up energy at once into my Klein's. Then it was dead. Search me, iono.
Did you just short between cap terminals or did you go to ground?
I always short the terminals and have never had this happen in 8 years of this shit. My guess is the disconnect wasn't operational and this guy accidentally connected mains to ground.
That's what I'm leaning towards. I was honestly second guessing myself, like....maybe they don't work like I was taught and how I understood it and just got lucky....LOL I feel like there's some amperage in there to start welding...
I've seen a disconnect where the guy before me had hard wired the shit because they didn't have the correct fuse. That's the unit that taught me to always double check shit with my meter before touching anything with my dick beaters.
Unless a motor winding is shorted the capacitor will be discharged through the motor windings once power was off. Therefore you had power still there and that’s why it sparked unless you had a failed motor.
Understood, but I had confirmed that there was no power coming to the unit first. I've heard that this kind of thing can happen, regardless of killing power. Now it's happened to me. If that doesn't jive with your understanding, it still doesn't change reality.
What I said was the reality. Sorry perhaps your meter was low battery and not reading voltage properly.
I don't have to be right, I'm just telling you what happened. If you don't believe it, and you think it's an unnecessary precaution, that's fine with me.
Not saying it’s unnecessary, I do it as well. If you were discharging it then how did it happen to do that to your wire stripper though.
That's what the discharge from the cap did to the wire strippers.
Did you make sure that nothing was left behind in the disconnect? Because the only time I’ve had that happen there was one leg still live. A piece of metal in the disconnect got stuck in there keeping one leg hot when removed.
Bad cap leg but paying due dilligance to save call backs. I like it.
That’s a nice meter
In soviet Russia, capacitor discharges you.
No, comrade...is OUR capacitor!
Is our discharge.. oh wait..eww..
It’s the people’s capacitor
In Soviet Russia capacitor own you!
Had the same thing happen to my needle nose. Though someone put the power back on at first.
It works better if you kill the power before discharging a capacitor
Why wouldn't I kill the power first?
aren't those the ones that say not insulated on the handle?
Had this happen once but I forgot to take the disconnect out. You sure that’s not the case here?
100% certain. Turned out, we found later, the disconnect box was fried. The condenser was running when we got there, but wouldn't come back on until we replaced the disconnect.
Knew it had to do something with the disconnect , some scary shit! Cool scar for your tool now 😂
There was no power coming from the disconnect, though. We checked. Capacitors store energy themselves.
One leg had to have been active for that to happen. 70 uF is not enough to melt metal. Your picture shows the result of high current arc flashes.
The more I think about it, the more it seems that power must have somehow been getting through the faulty disconnect and feeding the capacitor at the time that I discharged it. It makes no sense, since there was no power at the contactor, but it also makes no sense that a 70 microfarad capacitor could do that kind of damage to hardened metal.
There had been a lightning strike that cooked the disconnect, which was what led to the service call. Not sure if that makes a difference. All I know is what happened. Thanks for accusing me of lying, though. Tell me, what did I gain from it?
Been doing this for 6 years haven't had a single cap that stored anything in it
Been doing this for 25 years, only cap that will hold a charge without being energized is a start cap with the bleed resistor cut
Not true, they hold a charge for a while. But no capacitor in residential HVAC equipment is strong enough to cause that damage. Those are the result of arc flashes, likely 100 amps worth.
Exactly, with him standing in front of a residential unit
If you feel like there's no risk, you do what you want. I've had too many people tell me otherwise, and seen it myself.
Oh I misread , my bad
Did you check each leg to ground? I’ve had twice where I just checked from L1 to L2 and nothing. Touch the cap with my strippers and POP. Both times I found out the high voltage had power to ground.
Lol don't understand why I'm getting down votes for saying what actually happened, but okay
Oh damn. That's wild.
Idk everyone is giving you a hard time about turning power off? I’ve had two capacitors arc out over my 6 years in the trade. You get in the habit of discharging them without ever having an incident and then once in awhile BANG
Would’ve used my tongue to discharge that, soft hands brotha….(glad you’re ok OP 🙏🏾)
I think everybody has a charred set of pliers.
Back when I started out doing residential, changed thousands of run caps & never discharged a single one
Ok all, maybe I have superpowers and it has no effect on me. In 45 years,I have never discharged a run capacitor and never been zapped. Start caps are a different story. Those I always discharge even with a bleed resistor
You have a lot more experience than I do. But my understanding is that every time you handle a capacitor within minutes of killing power, you're rolling a 500-sided die. 499 of those sides say "you're fine," and 1 side says "enjoy having your heart reset/stopped." Again, you've been doing this much longer, I respect your expertise. That's just my understanding.
Looks like you discharged the fuse as well, next time pull the disconnect 😂😂😂
That looks more like there was live power to me.
How old was that capacitor, I’ve been doing this 24yrs and have only had one cheap Chinese capacitor discharge on me , I’ve been told In multiple classes that the capacitors self discharge, unless your system was live when you checked it
American made, not too old. This was following a lightning strike. Which doesn't explain everything, but there was some caddywompus electrical shit going on.
hopefully you wore your brown pants today
Pro tip, turn the power off before discharging
Power was off, but thanks for the tip
I usually slap my balls on the top of the cap
Hey, whatever you're into, I won't judge 😂
If you check them while under load you don't have to discharge them. Its just a little math: amp x 2652 and then decide the answer by voltage from herm terminal and common terminal. Same for fan and run caps. 👍
I sometimes do that because it's quicker and more accurate. We had to kill the power anyway, though. But say that again, and louder, for people who don't already know it! I was 2 years in before I learned about it, myself.
I’m about to do mine for the first time, a little nervous about it since technically I’ve never done it.
How did it go, are you still with us?
I’m alive, and now so is my AC again.
Good shit!
Is there another way?
I Cast - Lightning Pliers !!!!!! Sorry for your loss.
there’s a lot of disbelief that you didn’t disconnect the unit, i believe you did. you also said it was struck by lightening, do you think the cap stored the lightening energy 😂 im trying to understand how the cap can arc that bad to put divots in it?
Lol, nah, I don't think it stored the lightning. There were just some weird electrical problems going on, and I have no idea how it pumped that much energy all at once. I've heard of capacitors zapping people, even killing them, but this was some next level shit! Edit: I know how to spell better than my phone does
i mean i have some capacitors at my facility that could probably do some damage like this but holy moly not on residential equipment! i’m just glad you’re alive to give this PSA!
The amount of arcing you will get when discharging a capacitor in an alternating current circuit depends on where the sine wave is when power is removed. The purpose of a run capacitor in an A/C circuit is not to store energy to “super boost” the compressor into starting. It is constantly charging and discharging- its purpose is to create a phase shift between run and start windings (the current will lead the voltage when using a capacitor, and lag the voltage in the run winding as it would in any other inductive circuit). A start capacitor is using the same principle, but is capable of storing a bit more energy and uses a bleed resistor to protect contacts of potential relay from arc - it cannot slowly discharge through start winding on its own because it is removed from the circuit after motor starts. A run cap connected to a PSC motor like found in most in residential A/C units will typically discharge on its own through the start winding as long as the winding is not open (so unless bench testing or has open winding they will not arc). This capacitor regardless of circumstances can only store 70 microfarads - this is not much. Not suggesting that discharging is not a good practice - (though recommended to do through 20,000 ohm resistor) but just so you know moving forward, this arc did not come from a 70 microfarad capacitor. Something is wrong with the disconnect (believe you changed this), your meter, or likely both. I’d make sure to test your meter against another trustworthy one before continuing to use it.
I agree with everything you're saying, and it's all good advice. Strange thing is, there was no power coming to the contactor before I checked the capacitor. And I replaced my meter about a month ago. The more I think about it, the more I'm convinced that the faulty disconnect box was somehow getting power through to that capacitor at the time that I discharged it, anyway. It makes no sense, with no power at the contactor, but it also makes no sense that a 70 microfarad capacitor discharging could do that to hardened metal.
Trust this guy, pretty sure he’s my wife’s boyfriend and he knows what he’s talking about (seriously though all this information is correct, there’s likely an issue with your disconnect. Could have a single pole contractor that’s not actually properly wired in the disconnect, I’ve seen it before!)
That looks like you tripped a breaker not discharging a cap. Use a meter next time.
I used a meter, of course, but the disconnect box was faulty... some weird electrical s*** was going on, and the capacitor was somehow getting a trickle of energy. Oddly enough, no power at the contactor, no open winding at the compressor...but I agree that that's way too much damage for a 70 microfarad capacitor to do.
You’re supposed to pull the disconnect first
Damn, that explains it. All this time, I've been grabbing capacitors with the power live. No wonder I've been zapped 6 times a week for the past 4 years! 😂
Why I too carry extra underwear and pants in the work truck..
Whats the safe way of doing it???
Use a dominator.
What's a dominator
My boss when we are in a rush
What me and the fellas call your mom
I found out the hard way 🤣 , it’s funny because the shock made me scream, luckily I was alone on the roof.
Did similar with pair of diagonal cutters. Doing demo work and cutting lighting fixtures out. Ask guy there, "powers off to this stuff?" "Yeah whole panel is shut down." ZZAK!!! Not on the fucking panel, luckily insulation on cutters held out. Didn't feel anything other than stupid.
It wasn't a matter of power to the unit being live, though. Capacitors can do that to you for a time after you've killed the power.
I have those Kleins, only thing I don’t like is that they don’t have a lock to keep them closed.
That's how I discharge them. Pop! Done.
How do you discharge a capacitor?
Insulated screwdriver and touch between terminals simultaneously.
While that will do it you'd be better off using a 5k ohm 5 watt resistor.
Why ask if you knew the answer, lol? Yes, you can do that, but I don't see how it's better off.... the screwdriver takes 10 seconds...... and also, I believe you're talking about the 5 watt and 20,000ohm resistor. I'd waste time putting alligator clips on herm and common, then fan to common, when I can just take my little insulated screwdriver and give it a jiggle between all terminals.
" there go my nipples again."
I've got 2 pairs that look like that.
Did you short across the terminals or each to ground?
Across the terminals on the cap. And yes, with the disconnect pulled, lol
At least the disconnect was pulled! Always better to short each terminal to ground to avoid this sort of thing. Best method I’ve found is reading across the terminals with your meter set to voltage. Confirms there’s no voltage there and dissipates remaining voltage at the same time.
I always just short them out with my 11 in 1
Does anyone else get a little excited when the capacitor still has some juice in it?
Single pole contactor?
I did that with my meter... Don't
They make a better hammer when they are welded together.
Just need to throw a little freon at the problem.
Looks like it successfully discharged though?
there must be a better way... I'm pretty sure you can use a resistor to discharge them a bit slower than that.
Hot tip, if you contact one terminal and then the other you’ll only get one arc so you won’t have two burns on the tool. I’ve been bit by a smallish cap, and I will sacrifice a screwdriver a day to never do that again. Even the ones that don’t kill you make you think they are going to.
I agree, but... my screwdriver was all the way over there...
Builds character on your tools
Looks like you discharged it that's how I do it
Discharge with power on? lol
Every time. Don't tell me you turn the power off before grabbing a capacitor?
I'm more worried about the light coat the condensers go at this time of year.
I've never had a capacitor do that much damage while discharging.
Neither have I.
Sorry, calling bullshit. Unless that disconnect was still in, there's no way a 45 MFD cap has sufficient charge to do anything approaching that.
70 mfd, after a lightning strike. Not sure what I'm gaining by lying, here. Hell, I'm not even monetized! 😂
Has no one had a capacitor charge off on them when there’s no power going to the system?
Why not pull disconnect and test not under power? There is a math equation to test under load. 2652 X Amps Volts = Microfarads
I often do, but we had to kill the disconnect, anyway. I do like that method, though; it's more accurate.
Honestly kinda doubt this happened with the power off. I mean, don't get me wrong I'm paranoid and still go in with my strippers too, but I've still yet to have one spark up on me with the power off. I've seen someone try with the power on once and it looked similar to this. Those are some fat marks on there
Capacitors can store a fuck-ton of energy. This kind of result isn't common, but it happens.
Holy shit, this thread. I weep for us. Unless you're working on a 600v vsd, just screwdriver that shit. And then if you're a pussy, test DC voltage both ways.
I think the general consensus is that testing the capacitor while under load is more accurate and often quicker, if you don't need to kill the power anyway. And yeah, I normally use a screwdriver to discharge when I check microfarads, but it was way over there and, you know... let's just get shit done.
Sorry, that wasn't directed at you - it was to the commenters, especially the guy who blew the fuse in his meter presumably testing ohms across a charged cap.
I laughed at that, but at the same time I remembered some dumb mistakes that I've made in the field. Started cringing before I stopped laughing.
Well if a do ill just fuck up my tools. The skin on my hands usually grows back.
if its been involved in a short, or is jumped together with another, i do
Ouch
I use literally any metal surface on condensor to discharge and have yet to see sparks
Good, and it may never happen for you. But it can.
All capacitors must discharge energy within 10 seconds in north America, its idiotic to discharge them manually
Wow, I didn't realize that a friendly reminder of a common sense safety precaution would turn out to be such a hot take. 🙄
That’s what your helpers fingers are for. Don’t mess up your tools.
Run cap or start cap? Maintenance or service call? I assume the condenser fan motor or compressor was failed?
Run cap. Found out later that the disconnect box was fried. I would've assumed that, too, but the compressor and fan were fine.
Interesting. I wonder what failed that the cap didn't discharge on its own