Checking for power

[mjoekingz28]

I changed a outlet terminal and got to thnking my safety wasn't true.

I flip breakers until power is gone, then take a lamp and check to see that power has been interrupted.

But how can you be more sure? Like, say the outlet receptacle is totally shot. How can you assure the wires are not charged?

Name as many ways as you can think.........

thanks

 

[BgBmBoo]

Well, you could:

- Grab the black wire with your hand
- Place a paperclip across the wires
- Pee on the outlet

Or you could just use one of these:

The lamp or radio works well to locate a circuit, but you should plug it in before you kill the power to make sure the outlet is actually hot. Follow that up with a noncontact voltage tester and you should be good to go.

 

[Slowgsr]

When in doubt just turn off the main.

Unless you've got some worn out junk then it may not turn back on

 

[BgBmBoo]

When in doubt just turn off the main.

This too. For basic homeowner stuff, I turn off the house subpanel and the main panel just to be sure it is off.

 

[Old Engineer]

 

[justsam]

It is handy to have a pocket type non-contact tester that will flash or give an audible if in the proximity of power.

A more sure way would be to pull the outlet from the box, without making contact with the terminals and just measure the voltage where the wire terminates. Good plan to measure between all wire combinations, including ground.

Careful with duplex receptacles as there is the possibility that half of the duplex is one a different breaker.

Also if others are in the house make sure the breaker is not accidently restored while you are working on a distant receptacle.

 

[Rookie2]

If it is that much of a concern , then you shouldn't be doing electrical work ! IMO , take a class in your local vo-tech or community college to gain the knowledge you need to work safe.

 

[gungatim]

I changed a outlet terminal and got to thnking my safety wasn't true.

I flip breakers until power is gone, then take a lamp and check to see that power has been interrupted.

But how can you be more sure? Like, say the outlet receptacle is totally shot. How can you assure the wires are not charged?

Name as many ways as you can think.........

thanks

wires don't hold a charge. you either have power or not. use a 25 cent plug tester, if you don't trust the outlet, use a screwdriver, unscrew the plate covering the outlet and touch the tester to the wires themselves. if you don't trust the tester, maybe you should hire an electrician...

 

[theoldwizard1]

Non-contacting voltage detectors are great, but they are not 100% fool-proof.

Instead of a lamp, use a polarity tester (which every homeowner should have). It will fit in your pocket so it is portable. Besides testing polarity and ground, it will tell you if an outlet is hot.

Very old fashion. but cheap, is a 120V test light. You can probe around inside of an outlet with no fear of being shocked.

 

[jkwilson]

For outlets, I use a radio and a non-contact tester. Check with the non-contact to make sure it works and you know where it will sound off. Plug the radio in and make sure it plays. Go to the breaker box and flip until the radio quits. Try the radio in the other outlet of the duplex and then verify with the non-contact.

This should cover you even if somebody mis-wired the outlet.

 

[wyliesdiesels]

Outlet tester, non contact tester and a multimeter should have u covered for any situation.

 

[Old Engineer]

wires don't hold a charge. you either have power or not. use a 25 cent plug tester, if you don't trust the outlet, use a screwdriver, unscrew the plate covering the outlet and touch the tester to the wires themselves. if you don't trust the tester, maybe you should hire an electrician...

I was originally about to post a similar response. But, I think what the OP was saying was "what if there was some sort of internal failure in the socket". In that case, the wires in the box were live, but nothing was making it out of the socket. If that was happening, plugging is a outlet tester, or lamp, or anything else will not tell him if the wires behind the outlet were turned off by the breaker. If the outlet is dead, but the wires are not, he can not be assured the right breaker was shut off by plugging something in. This is why a Non-Contact tester is a nice check.

Taking off the plate, and touching the wire with just the plate off, makes it very easy to short the live wire to the side of the box while sticking in your probe. Yes, you could unscrew the outlet, pull it straight out, and then test the wires. But, you have to still be careful not to touch the side of the box while pulling it out. It is safer to check with a Non-Contact before pulling it out, to see if it appears dead. Once you pull it out, and if you don't trust a Non-Contact, then test the wire with an actual meter before "touching" the wire. This is the safest you can get, without having someone else do it for you.

 

[Mustang51js]

Call the power co and have them shut down the grid in the state

 

[ishiboo]

I changed a outlet terminal and got to thnking my safety wasn't true.

I flip breakers until power is gone, then take a lamp and check to see that power has been interrupted.

But how can you be more sure? Like, say the outlet receptacle is totally shot. How can you assure the wires are not charged?

Name as many ways as you can think.........

thanks

As mentioned, a plug-in outlet tester, a non-contact tester and a DMM can all be used to verify this. If you are working on an outlet, use the tester (or 2) of your choice FIRST to verify it is "on". Then shut off the power and verify it is "off". If the receptacle doesn't work, use the non-contact on the wires and then you can verify with the DMM. Each time you use the outlet tester or non-contact, test it on a known working source first.

 

[ABSTIFFGS]

Call the power co and have them shut down the grid in the state

Lol a tad bit extreme however effective.

 

[mjoekingz28]

For outlets, I use a radio and a non-contact tester. Check with the non-contact to make sure it works and you know where it will sound off. Plug the radio in and make sure it plays. Go to the breaker box and flip until the radio quits. Try the radio in the other outlet of the duplex and then verify with the non-contact.

This should cover you even if somebody mis-wired the outlet.

Thanks






Thank you ishiboo!


Old Engineer,
Precisely...a non-contact tester before disassembly then a multimeter. Do you care to state the proper procedure? A guess.....remove plate as you said and touch the tester to each wire (one at a time)... The black, the white, and perhaps the green- individually and each one will illuminate the tester if working or illuminate zero if the wiring is not live? Also, would there be a scenario where some wires in the box would light up the tester and some will not?



jkwilson,

Like on the Seinfeld show.
George: you never really know
Jerry: sometimes you do

 

[matt_i]

Typical procedure in our manufacturing plant is "live-dead-live". In other words plug your measuring tool (typically a Fluke meter) into any voltage source to verify meter operation. Then move the probes away, seeing change back to zero. Then place on live circuit you are about to work on. Cycle power to off-state. Verify zero voltage to confirm. Typically before working on a 480vac circuit, the meter function is confirmed on a 120vac circuit.

Any circuit where one is unsure of the status should be considered live until proven otherwise. The internal blades on a 120vac outlet are a good place to start, but its always wise to go do a measurement on the actual screw terminals on the back.

I always check hot to neutral first, the hot to ground next. Neutral to ground next. In case someone jacked up the wires on the panel end or tore off the identification over-tape and you are left looking at black, blue and orange jacketed wires and wondering if their screw terminals on the outlet actually mesh with where those wires are landed in the panel*.

The noncontact testers are cool and interesting but the battery always seems dead when I want to go use it. Also every one I've ever touched would light up and beep if you moved the point up your forearm in a medium-fast motion. Seems sketchy that I could create enough voltage to change the state of the indicator light.

The testers to confirm hot and neutral locations are valuable if you didn't do the initial wiring and are troubleshooting.


* a seemingly common choice where cable trays exist, and electrical contractors are employed, are to run a 7 conductor tray-cable, 12awg each, with 3 hot wires @ 120vac and 3 neutral wires, and a single ground which is chained to every circuit. So there are a lot of colors in the jackets, and a lot of overtape (hopefully) to show the next guy what is what.

 

[Pwrgeek]

The proper way to check for voltage before working on a circuit.

If the breaker is known then turn the breaker off
If the breaker is unknown then plug in a device that you can tell when it goes off from the breaker box (a radio works well) then turn off one breaker at a time until the device goes off.

Using a multimeter find a live outlet near the one you want to work on.
Place the multimeter on a live outlet and verify that it reads voltage between hot and neutral (the two thin blades) to make sure that your meter is working
Next check the outlet you want to work on three ways
Check from hot to neutral (the two thin blades) on both the top and bottom plugs
Check from each blade to ground (the smaller one is supposed to be hot but they get miswired all the time) on both the top and bottom plugs
Carefully pull the outlet out of the box and check from each of the insulated wires on the back of the outlet to the bare wire.
Go back to the outlet that is live and check from hot to neutral again to verify that the multimeter is still working.

Some people will say this is overkill but its the only way to be sure. Those non contact voltage detectors give false negative readings all the time and an outlet tester sometimes will not work if there is a problem with the neutral/ground.

 

[zmaxmotorsports]

When in doubt climb the pole out back and cut the service,or take a wooden bat to the electric meter.
Or you could just buy yourself a real multi meter.

 

[mjoekingz28]

matt i,

While we are on the subject, is there a similar procedure for checking capacitors (or is this getting into UL listed brotherhood of electrical workers type dtuff that only certified pros should be tampering with? If so, which electrical devices should we check?


Like I was cleaning inside the refrigerator (beneath the dust cover where the 'magic' happens and wondered if I was going to get shocked after I had already unplugged it.....the motor was still quite warm. But for things like microwaves, radios, receiver and who knows what else....what do you do? Do you just leave it unplugged for a certain time? Up to what length of time can a capacitor hold a charge?

 

[checkthisout]

matt i,

While we are on the subject, is there a similar procedure for checking capacitors (or is this getting into UL listed brotherhood of electrical workers type dtuff that only certified pros should be tampering with? If so, which electrical devices should we check?


Like I was cleaning inside the refrigerator (beneath the dust cover where the 'magic' happens and wondered if I was going to get shocked after I had already unplugged it.....the motor was still quite warm. But for things like microwaves, radios, receiver and who knows what else....what do you do? Do you just leave it unplugged for a certain time? Up to what length of time can a capacitor hold a charge?

Start working on it and see what happens. Just make sure that only one hand is contact with the live wires that way the shock is just amusing to bystanders and not deadly to you.

 

[gungatim]

I was originally about to post a similar response. But, I think what the OP was saying was "what if there was some sort of internal failure in the socket". In that case, the wires in the box were live, but nothing was making it out of the socket. If that was happening, plugging is a outlet tester, or lamp, or anything else will not tell him if the wires behind the outlet were turned off by the breaker. If the outlet is dead, but the wires are not, he can not be assured the right breaker was shut off by plugging something in. This is why a Non-Contact tester is a nice check.

Taking off the plate, and touching the wire with just the plate off, makes it very easy to short the live wire to the side of the box while sticking in your probe. Yes, you could unscrew the outlet, pull it straight out, and then test the wires. But, you have to still be careful not to touch the side of the box while pulling it out. It is safer to check with a Non-Contact before pulling it out, to see if it appears dead. Once you pull it out, and if you don't trust a Non-Contact, then test the wire with an actual meter before "touching" the wire. This is the safest you can get, without having someone else do it for you.

?? around here, boxes have been non-conductive since the '40's...Assuming we're talking a regular outlet in a wall of a house, not some commercial external mounted situation. even so, the probes are insulated and short, and tough to do what you say, but even if you did, you'd know you had power, and the breaker would trip. if it doesn't, you've got bigger problems...

 

[Pwrgeek]

?? around here, boxes have been non-conductive since the '40's...Assuming we're talking a regular outlet in a wall of a house, not some commercial external mounted situation. even so, the probes are insulated and short, and tough to do what you say, but even if you did, you'd know you had power, and the breaker would trip. if it doesn't, you've got bigger problems...

Many places (I'm looking at you Chicago) still require conduit installations. Some of them even require metal.


Sent from my iPhone using Tapatalk

 

[Jazz1]

Never assume tripping a breaker off stops power to outlet.. I ran into this a few weeks ago where power was coming from TWO sources to one outlet in my early colonial slum dwelling. Always test wires.

 

[zmaxmotorsports]

Never assume tripping a breaker off stops power to outlet.. I ran into this a few weeks ago where power was coming from TWO sources to one outlet in my early colonial slum dwelling. Always test wires.

Well if you have a 1/2 switched plug thats a differant story,look for the jumper cut between the screws on the hot side.

 

[Pwrgeek]

Well if you have a 1/2 switched plug thats a differant story,look for the jumper cut between the screws on the hot side.

Not necessarily the only way. I've seen cases where two circuits were (I think) mistakenly tied together out in one of the junction boxes. The outlets on these circuits had two 15A breakers feeding them. Luckily for whoever did this (and unluckily for me) they happened to be on the same leg so they didn't get sparks when it was turned on. Took a good bit of time to find the offending connection and remove it.

 

[zmaxmotorsports]

Not necessarily the only way. I've seen cases where two circuits were (I think) mistakenly tied together out in one of the junction boxes. The outlets on these circuits had two 15A breakers feeding them. Luckily for whoever did this (and unluckily for me) they happened to be on the same leg so they didn't get sparks when it was turned on. Took a good bit of time to find the offending connection and remove it.

I hate it when that happens,Always make think of the old movies with 2 old steam locomotives slamming head 1st into each other.

 

[TheEquineFencer]

Typical procedure in our manufacturing plant is "live-dead-live". In other words plug your measuring tool (typically a Fluke meter) into any voltage source to verify meter operation. Then move the probes away, seeing change back to zero. Then place on live circuit you are about to work on. Cycle power to off-state. Verify zero voltage to confirm. Typically before working on a 480vac circuit, the meter function is confirmed on a 120vac circuit.

Any circuit where one is unsure of the status should be considered live until proven otherwise. The internal blades on a 120vac outlet are a good place to start, but its always wise to go do a measurement on the actual screw terminals on the back.

I always check hot to neutral first, the hot to ground next. Neutral to ground next. In case someone jacked up the wires on the panel end or tore off the identification over-tape and you are left looking at black, blue and orange jacketed wires and wondering if their screw terminals on the outlet actually mesh with where those wires are landed in the panel*.

The noncontact testers are cool and interesting but the battery always seems dead when I want to go use it. Also every one I've ever touched would light up and beep if you moved the point up your forearm in a medium-fast motion. Seems sketchy that I could create enough voltage to change the state of the indicator light.

The testers to confirm hot and neutral locations are valuable if you didn't do the initial wiring and are troubleshooting.


* a seemingly common choice where cable trays exist, and electrical contractors are employed, are to run a 7 conductor tray-cable, 12awg each, with 3 hot wires @ 120vac and 3 neutral wires, and a single ground which is chained to every circuit. So there are a lot of colors in the jackets, and a lot of overtape (hopefully) to show the next guy what is what.

Best answer so far...other than peeing on the circuit....always verify your test equipment then verify the device you're checking.

Go get a decent meter and learn how to use it.

 

[MikeF2316]

After using his meter, my uncle likes to do his final verification with clip leads. Puts one on each wire then swings the unconnected ends together with his eyes closed. No sparks, no problem. Electricity just scares the **** out of some folks.