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  #51  
Old 07-30-2010, 03:40 PM
Joey P is offline
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LOTO = lock out / tag out

The way it is supposed to work is the guy doing the work turns off the breaker and installs the lock or tag on the breaker so that no one else will turn it on. When the guy is done working, he removes the lock/tag and turns the breaker back on.

Only the guy who installed the lock or tag can remove it. It doesn't matter if Mr. Doofus is the site supervisor, president of the company, or whatever. He can't remove the tag and flip the breaker on since he's not the one who put the tag on in the first place. At least that's the way it is supposed to work. Obviously it didn't work in this case.
To expand on that, most lockout devices have multiple holes. So when I go to work on a machine, I can put the device on the power supply and my padlock. If then you need to work on the same circuit, you can put your lock on it also. So even when I'm done, I still can't turn it back on.
  #52  
Old 07-30-2010, 03:55 PM
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Every two outlet circuit in my kitchen (there are three of them) is wired to two separate circuits (the same two). The electrician who did this said the code required it. The reason he gave was that in a kitchen you might be tempted to plug in a toaster in the top and a coffee maker in the bottom and that would exceed the 15 amps of one circuit. Of course, there is no reason I couldn't plug the toaster into the top of one of the outlets and the coffee maker into the top of a different one, with the same effect. Nonetheless the point above is well taken. Unless you have tested every outlet, don't assume that if one is off, so is the other.
in the USA the code would require that the circuit breakers feeding the two circuits be tied together so that both are off at the same time.
  #53  
Old 07-30-2010, 04:00 PM
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So I open up the box. Unscrew the hot grab it with my hand and move it over to the new outlet and screw it on, no problem.
On the neutral side there are two wires, one comes in the bottom of the box, and the other comes in the top. I unscrew the lower wire and move it to the new outlet. I unscrew the top wire and grab it, and get the mother loving shock of my life. It traveled up my right arm, around my rib cage and out my back where it was leaning against my new gas stove. I say gas, because gas pipes are buried in the ground and are well umm grounded.
It turns out that I got shocked by a shared neutral. That wire that went out the top of that outlet went to the light on the ceiling that was on another circuit. When I disconnected the lower wire I broke the ground connection, and that upper wire became live with 120V looking for a ground. It found one though my body.
I hate shared neutrals.
using a device (receptacle in this case) to provide neutral conductivity is an electrical code violation in the USA
60 year old house. That section has been rewired sans shared neutral anyway.
  #54  
Old 07-30-2010, 04:37 PM
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your story is incomplete as to how the fire department turned off the power; did they do so with a switch or disconnect wires.
I don't know about other jurisdictions, but around here, firefighters will cut power with what looks like a set of fiberglass-handled branch loppers. I've also seen at fire scenes where someone sawed through the main conduit, wires and all, with a Sawzall. Presumably this was done after the power was off further up the line.
  #55  
Old 07-30-2010, 05:06 PM
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[QUOTE=Joey P;12745020]
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it is dangerous to change the outlet if you leave the power on, but it is impossible to change the outlet if you turn the power off. One solution is to get a good flashlight, but that might not be easy. So instead, leave the power on, and be very careful.
There was a Handy Manny episode about exactly that. They ended up using a bunch of mirrors to reflect light from the kitchen on to the work area.
Wouldn't it be simpler to use a table lamp from elsewhere in the house & an extension cord into an outlet in the next room?

Actually, many electricians now have a portable work light (like this) for just such situations. A big, adjustable, hands-free light like that is much safer than a flashlight.
  #56  
Old 07-30-2010, 05:17 PM
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This is why you should never flip breaker switches till the unit you are gonna work on is "off". If you are not sure of what you are doing, please shut off the entire home at the main.
But that can cause much more problems elsewhere.

First, hope that power cut didn't hurt any computers, home theatre systems, stereos, etc. that are in the house.

Then think about all the items that will have to be reset once you turn the main power back on: clocks, bedroom alarm clocks, computer clocks, VCR/DVD clocks, TV clocks, thermostat clock, microwave clock, etc. And then there are all the the items that need to be reset/reprogrammed: re-program/rescan your digital TV channels, re-program stations on your radio, re-record your answering machine message, reset your kitchen stove, reprogram the individual setting on your washing machine, etc., etc. (Some of the newer ones might have batteries that will last for a few hours -- assuming the batteries aren't dead.)

This will involve a whole lot of work for you (or the homeowner) to do afterwards, to get the house back working as it was before you came to 'fix' the wiring.

A better action is to study the situation until "you are sure of what you are doing" before starting to do the work.
  #57  
Old 07-30-2010, 05:18 PM
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For the benefit of anyone coming into this thread, you never, ever, want to use your water pipe as a ground. It used to be that you were required to ground the house through the cold water pipe. That was changed many years ago and now a separate ground is required. A lot of folks back then used to use water pipes as their ground, but what you really want to do is keep your protective grounds from your circuits completely separate from your water pipes. However, you also want to ground all of your metal water pipes for safety.

You want your water pipes grounded, but you don't want to use the water pipes as grounds for anything else.
An electrician I had out just a few weeks ago claimed that you must ground the breaker box to the cold water pipe inlet as a secondary ground under code. Was he incorrect?
  #58  
Old 07-30-2010, 05:26 PM
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An electrician I had out just a few weeks ago claimed that you must ground the breaker box to the cold water pipe inlet as a secondary ground under code. Was he incorrect?
Depends on your location, and the code in effect there.
  #59  
Old 07-30-2010, 05:35 PM
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An electrician I had out just a few weeks ago claimed that you must ground the breaker box to the cold water pipe inlet as a secondary ground under code. Was he incorrect?
He was incorrect. You are required to ground the pipe to the panel. But it's not like wires only let power go one way, so if the houses actual ground failed the piping would function as a secondary ground. That isn't the intent of the code however. The code wants you to ground any metal components of the structure in case a wire comes lose or what not and touches the metal it will ground out and throw the breaker.

If a live wire hit metal that was ungrounded nothing would happen until some poor sap came along and completes the circuit to ground electrifying themselves in the process.


The largest topic of the electrical code book is 'grounding and bonding' it is simple in theory but put to print it gets very complex even very experienced pros get the terms mixed up, then there is the ever popular mistranslation of customers or electricians attempts to translate the language into something they can follow.
  #60  
Old 07-30-2010, 05:41 PM
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I used to do it all the time, along with hot wiring ceiling fans and light fixtures. I probably have swapped out more than 500 outlets hot but in 2008 my good friend Jim Hilton was working on our friends condo and was electrocuted swapping an outlet in the kitchen.

Since that day, I haven't touched any electrical work other than the stuff on my motorcycles.
  #61  
Old 07-30-2010, 05:42 PM
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Yes, it is not only possible, but even a lot of electricity providers have men in elevated "buckets" working on high voltage lines with no fear of electrical shock. Electricity needs a path back to ground. If one isn't available then no hazard exists. Take a look at birds perched on 10 gazillion volt lines.
I have to voice some suspicion on this - are you sure those aren't 240V wires, or maybe high-voltage wires that have been de-energized?

I used to work with Utilities. In one instance, I know they employed devices called 'hot sticks' that were like 6 foot long poles that were extremely non-conductive. (They had to be discarded every couple months just because they built up a slight amount of conductivity) These sticks were used when they needed to throw the large breakers/switches that activate/deactivate the high voltage lines.

Given how *extremely* careful they were just in touching (supposedly not hot) switch handles, I would not have expected anyone to touch an actual hot wire.

Now maybe they would do that on the 240V wiring running down the street, but that's very different from the 4KV and up 'high voltage' referred to.
  #62  
Old 07-30-2010, 05:48 PM
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My dad decided to work on a heating element of the water heater with the power on once. The screw driver got blasted across the room and half the shaft in one spot vaporized. The upside was that after that we had a pretty nice magnetized screw driver to hold and pick up screws and whatnots.
  #63  
Old 07-30-2010, 05:55 PM
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An electrician I had out just a few weeks ago claimed that you must ground the breaker box to the cold water pipe inlet as a secondary ground under code. Was he incorrect?
He was incorrect. You are required to ground the pipe to the panel. But it's not like wires only let power go one way, so if the houses actual ground failed the piping would function as a secondary ground. That isn't the intent of the code however. The code wants you to ground any metal components of the structure in case a wire comes lose or what not and touches the metal it will ground out and throw the breaker.

If a live wire hit metal that was ungrounded nothing would happen until some poor sap came along and completes the circuit to ground electrifying themselves in the process.


The largest topic of the electrical code book is 'grounding and bonding' it is simple in theory but put to print it gets very complex even very experienced pros get the terms mixed up, then there is the ever popular mistranslation of customers or electricians attempts to translate the language into something they can follow.
IANAE, but I think it can be summed up this way:

Let's say you're installing a new 120 VAC receptacle. There are three connections to the receptacle: hot, neutral, and ground.

The hot connects to a circuit breaker inside the breaker box. The neutral connects to the neutral/ground bar inside the breaker box.

What to do with the ground?

Let's say you go outside, pound a 4-foot copper rod into the soil, and run a wire between the receptacle's ground connection and the copper rod. Would this be O.K.?

No - there would be too much resistance between the receptacle's ground connection and the neutral/ground bar inside the breaker box.

When installing a receptacle (or anything else), there must be a good, low resistance path between the receptacle's (or device's) ground connection and the neutral/ground bar inside the breaker box. In other words, you need to run a copper wire between the receptacle's (or device's) ground connection and the neutral/ground bar inside the breaker box.

The ground connections of all receptacles, appliances, devices, etc. must be connected (via copper wires) to the neutral/ground bar inside the breaker box.

Once this is all done, the neutral/ground bar inside the breaker box must be connected to the earth (using a copper rod) in one or more places.

Last edited by Crafter_Man; 07-30-2010 at 05:56 PM.
  #64  
Old 07-30-2010, 06:04 PM
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This is why you should never flip breaker switches till the unit you are gonna work on is "off". If you are not sure of what you are doing, please shut off the entire home at the main.
But that can cause much more problems elsewhere.

First, hope that power cut didn't hurt any computers, home theatre systems, stereos, etc. that are in the house.

Then think about all the items that will have to be reset once you turn the main power back on: clocks, bedroom alarm clocks, computer clocks, VCR/DVD clocks, TV clocks, thermostat clock, microwave clock, etc. And then there are all the the items that need to be reset/reprogrammed: re-program/rescan your digital TV channels, re-program stations on your radio, re-record your answering machine message, reset your kitchen stove, reprogram the individual setting on your washing machine, etc., etc. (Some of the newer ones might have batteries that will last for a few hours -- assuming the batteries aren't dead.)

This will involve a whole lot of work for you (or the homeowner) to do afterwards, to get the house back working as it was before you came to 'fix' the wiring.

A better action is to study the situation until "you are sure of what you are doing" before starting to do the work.
As I said upthread I always do work while everything is "hot" but I will not advise others to do so.
  #65  
Old 07-30-2010, 06:08 PM
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As for working on a live line to keep you safe because you'll be more carefull...well, I think thats macho BS IMO.
Not macho in my case, just lazy disrespect of the danger, pure and simple.
  #66  
Old 07-30-2010, 06:18 PM
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You unhook the wires one at a time from the old outlet and attach to the new socket- first the two white, then the two black; do the ground last or first; don't touch anything. I still burned one outlet when it touched the side of the box while being pushed in.
I was an electrician for a lot of years and I believe that you are incorrect here. It's been a long time, but some things stay with you. In addition to touching one wire at a time, you want to avoid an open neutral while the hot wire is still connected. Disconnect the hot wire first, the neutral second, the ground last, never first.
  #67  
Old 07-30-2010, 06:22 PM
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The largest topic of the electrical code book is 'grounding and bonding' it is simple in theory but put to print it gets very complex even very experienced pros get the terms mixed up, then there is the ever popular mistranslation of customers or electricians attempts to translate the language into something they can follow.
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Originally Posted by Crafter_Man View Post

IANAE, but I think it can be summed up this way:

The ground connections of all receptacles, appliances, devices, etc. must be connected (via copper wires) to the neutral/ground bar inside the breaker box.

Once this is all done, the neutral/ground bar inside the breaker box must be connected to the earth (using a copper rod) in one or more places.
The grounded connections of receptacles, appliances, devices, etc. must be connected to the ground bar inside the breaker box, they are not connected to the neutral bar.

There is a difference in a service entrance and subpanels and other structures for the above issues as well.

Grounding and bonding is a complex issue and that is why it occupies so much of the electrical code.
  #68  
Old 07-30-2010, 08:28 PM
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[QUOTE=johnpost;12747207]
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The grounded connections of receptacles, appliances, devices, etc. must be connected to the ground bar inside the breaker box, they are not connected to the neutral bar.
Correct me if I'm wrong, but inside a home's primary electrical panel, aren't the neutrals and grounds connected together via a common bus bar?
  #69  
Old 07-30-2010, 08:33 PM
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Well in my panel at least the neutral and ground are two different bus bars in the box, but they are connected electrically.
  #70  
Old 07-30-2010, 08:42 PM
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[QUOTE=UncleFred;12747107]
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Given how *extremely* careful they were just in touching (supposedly not hot) switch handles, I would not have expected anyone to touch an actual hot wire.

Now maybe they would do that on the 240V wiring running down the street, but that's very different from the 4KV and up 'high voltage' referred to.
Watch as they get near the wire. They use the stick to bring themselves, the helicopter and the wire all to the same potential. They get on to the wire and you can see as the helicopter potential drops.

Also, on an episode of This Old House, they had to cut the main wires running into the house to move the service entrance. Their electrician climbed up the ladder, cut the wires, did what he needed to do (touching bare copper the whole time) and reconnected them. When Kevin asked who you call to have the power to the house shut off, he replied that it was live the entire time, but he was very careful to only have one exposed wire at a time and he was on a fiberglass ladder so getting a shock really wasn't an issue....of course he was still very careful.

Last edited by Joey P; 07-30-2010 at 08:42 PM.
  #71  
Old 07-30-2010, 09:17 PM
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Also, on an episode of This Old House, they had to cut the main wires running into the house to move the service entrance. Their electrician climbed up the ladder, cut the wires, did what he needed to do (touching bare copper the whole time) and reconnected them. When Kevin asked who you call to have the power to the house shut off, he replied that it was live the entire time, but he was very careful to only have one exposed wire at a time and he was on a fiberglass ladder so getting a shock really wasn't an issue....of course he was still very careful.
on electrical forums i saw many people saying what he did was poor. he was leaning the ladder against the structure and he was leaning over structure. so it wouldn't take much movement of him or his clothes for him to be grounded. he was careful and lucky.
  #72  
Old 07-30-2010, 09:32 PM
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The largest topic of the electrical code book is 'grounding and bonding' it is simple in theory but put to print it gets very complex even very experienced pros get the terms mixed up, then there is the ever popular mistranslation of customers or electricians attempts to translate the language into something they can follow.
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Originally Posted by Crafter_Man View Post

IANAE, but I think it can be summed up this way:

The ground connections of all receptacles, appliances, devices, etc. must be connected (via copper wires) to the neutral/ground bar inside the breaker box.

Once this is all done, the neutral/ground bar inside the breaker box must be connected to the earth (using a copper rod) in one or more places.

Quote:
Originally Posted by johnpost View Post
The grounded connections of receptacles, appliances, devices, etc. must be connected to the ground bar inside the breaker box, they are not connected to the neutral bar.

There is a difference in a service entrance and subpanels and other structures for the above issues as well.

Grounding and bonding is a complex issue and that is why it occupies so much of the electrical code.
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Correct me if I'm wrong, but inside a home's primary electrical panel, aren't the neutrals and grounds connected together via a common bus bar?
the neutral bar and the grounding bar are different entities. at a service entrance, and no where else (including breaker panels) in your electrical system, they are bonded together with a bonding conductor.

your first statement above is incorrect as you wrote it.
  #73  
Old 07-30-2010, 10:23 PM
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In a pinch I have done it. It is not something someone with out experience should do at all. And with experience it should not be done.
  #74  
Old 07-31-2010, 12:06 AM
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Also, on an episode of This Old House, they had to cut the main wires running into the house to move the service entrance. Their electrician climbed up the ladder, cut the wires, did what he needed to do (touching bare copper the whole time) and reconnected them. When Kevin asked who you call to have the power to the house shut off, he replied that it was live the entire time, but he was very careful to only have one exposed wire at a time and he was on a fiberglass ladder so getting a shock really wasn't an issue....of course he was still very careful.
on electrical forums i saw many people saying what he did was poor. he was leaning the ladder against the structure and he was leaning over structure. so it wouldn't take much movement of him or his clothes for him to be grounded. he was careful and lucky.
His safety practices were lacking but that is how it is done. When upgrading or changing a service those wires are live. You use a fiberglass ladder cut the old wires and connect them to the new wires. You are supposed to use rated gloves for the procedure. Many old timers don't use the gloves as they are a pain in the ass to work with. They are thick and limit your dexterity. The gloves have a listed expiration date before you need to get a new set.

I usually opt to use the gloves but I've done changeovers without them a couple times. I don't own a set,. I borrow one if needed. Electrical is not my primary gig. I avoid this type of work.

Doing the change over reminds you how heavy wire is. The aerial wire is much thinner then the service drop but is still a heavy gauge. When you are up on a ladder holding a hundred feet of wire taught trying to clip the neutral into the tension clip it demands some strength. That wire hitting you will kill you almost without a doubt. The thing that's going to stop that current is the transformer exploding. Same goes for dropping the wire. It hitting the ground is going to leave you with some explaining to do.

New construction is much easier. You run the drop up the side of the house and from there it is the power companies problem. They run the wire across dead then connect it on the house side. After the wires secured on both sides they can connect the power at the pole. The last connection being live.

Last edited by boytyperanma; 07-31-2010 at 12:07 AM.
  #75  
Old 07-31-2010, 12:19 AM
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I have worked on hot wiring, but never on purpose. In one case, I had turned off the wrong breaker, and found out when I melted the tip of my inadequately-insulated screwdriver. In another, we were removing a wall. I called out to the fellow I was working with to turn off the breaker. He yelled, "Okay, it's off." I cut the wires, made a spectacular show of sparks, and left a hole in my cutters. I felt it, even through the insulated handles, and fell over backwards--mostly out of surprise.

There was a pause, and then I heard his voice say, "Oh. That breaker."

He got me a nice new pair of diagonal cutters for Christmas.
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Old 07-31-2010, 01:52 AM
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Every transformer around here has a fuse and an disconnect. Only one customer to each transformer. They will come disconnect for you. In the cities that is not necessarily true....
  #77  
Old 07-31-2010, 04:40 AM
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I think some of you need to treat electrical energy with a little more respect. Electrocution kills quite a lot of DIYers every year. Don't screw around with it.

When I studied power engineering years ago, I was taught that if you were unsure whether wiring was hot, work with one hand behind your back to make sure you weren't providing a path to ground that went through your chest.

That may have saved me this year - I bought a new dishwasher and range, along with a new over-the-range microwave to replace the old range hood, and installed them myself. When i removed the old appliances, i went to the breaker box and flipped off the breakers marked 'dishwasher' and 'appliances.'. Then I tested the wiring for the range hood and dishwasher, and both were off.

I installed the new microwave, but was missing some plumbing bits for the dishwasher, and couldn't get them until the next day. So, I capped the wiring for the dishwasher and flipped the breaker on for the range hood.

The next day I got the plumbing bits and pushed the dishwasher into place and plumbed it. Then I checked to make sure the dishwasher breaker was still off, removed the caps from the wiring, and hooked up the ground wire. When I started to hook up the hot wire, it touched the grounded box, and sparks flew everywhere. At any time I could have electricuted myself, except that I still treated the wires as 'hot', even though I didn't think they were. I made sure I wasn't grounding my left hand or body, and used insulated pliers for everything.

So what happened? The electrician who wired the box mislabeled the breaker. The dishwasher was wired into the 'appliance' circuit. The day before I had switched both off, and tested both to have no power. It was a fluke that I happened to turn off the other breaker at the same time. If I had replaced only the dishwasher, I would have caught the mislabeled breaker the day before.

But this is how accidents happen. A fluke, a combination of unlikely events that catch people napping. It's easy to tell yourself that you're smart enough or experienced enough to take safety shorcuts, and you might get away with it for a long time. But you're playing Russian Roulette with fate. So don't cut corners.

Last edited by Sam Stone; 07-31-2010 at 04:44 AM.
  #78  
Old 07-31-2010, 08:11 AM
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Sam Stone has the word, If you play around with live electricity without strict need and training, you will at best get surprised, and at worst get toasted to obituary.
As a plumbing/heating guy, I've been restoring houses and flats for about 25 yrs. I have been surpised so many times by electrical defaults(defects) that ONE rule is imperative: NEVER TRUST ANYTHING. Treat every wire as hot, any voltmeter will do, but you need 30 seconds to test hot, neutral, and ground, half a second more to check an independant ground, DO IT
We have seen everything you couldn't imagine, circuits wired to neighbors, hot grounds running current to appliances, hot grounds running full voltage with welded circuit breakers, etc etc If you put your paltry flesh in there...
Don't forget that a live circuit also may have .. microwave capacitors (blast you crisp) old TV caps, tubes, faulty transformers, (a gas furnace igniter will tickle you with 30 to 50 000V) a ground fault in an oven or heat plate can run quite high without showing if the installation is "rusty"
If you don't care so much for your own well being (and thos of your loved ones) don't forget all those appliances with circuit boards (boiler, furnace, fridge, TV etc...) that do not at all appreciate ground faults, or jolts up a neutral wire, (that beautiful spark you made when wirering your outlet)
  #79  
Old 07-31-2010, 09:21 AM
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Also it only takes about three seconds to jam the leads of your meter into a receptacle that is known to be working to get a reading. This way you know your meter is working. I have seen digital meters with bad batteries that give false readings.
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Old 07-31-2010, 09:58 AM
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Also, on an episode of This Old House, they had to cut the main wires running into the house to move the service entrance. Their electrician climbed up the ladder, cut the wires, did what he needed to do (touching bare copper the whole time) and reconnected them. When Kevin asked who you call to have the power to the house shut off, he replied that it was live the entire time, but he was very careful to only have one exposed wire at a time and he was on a fiberglass ladder so getting a shock really wasn't an issue....of course he was still very careful.
on electrical forums i saw many people saying what he did was poor. he was leaning the ladder against the structure and he was leaning over structure. so it wouldn't take much movement of him or his clothes for him to be grounded. he was careful and lucky.
His safety practices were lacking but that is how it is done. When upgrading or changing a service those wires are live. You use a fiberglass ladder cut the old wires and connect them to the new wires. You are supposed to use rated gloves for the procedure. Many old timers don't use the gloves as they are a pain in the ass to work with. They are thick and limit your dexterity. The gloves have a listed expiration date before you need to get a new set.

I usually opt to use the gloves but I've done changeovers without them a couple times. I don't own a set,. I borrow one if needed. Electrical is not my primary gig. I avoid this type of work.

Doing the change over reminds you how heavy wire is. The aerial wire is much thinner then the service drop but is still a heavy gauge. When you are up on a ladder holding a hundred feet of wire taught trying to clip the neutral into the tension clip it demands some strength.
sometimes a service entrance change over has to be done hot.

he could have used gloves, put a mat down on the roof, moved the ladder he was working from to the other side to put himself a bunch more inches away from the structure in a safer vertical manner.

i would have done at least one of the three things.

pulling a hundred feet or better of triplex taut is a hard task. good reason to take a break after its done.
  #81  
Old 07-31-2010, 10:06 AM
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don't trust other people's work (at least those you don't know to have done quality work at that point).

only test for one condition/state/fault at a time.
  #82  
Old 07-31-2010, 10:40 AM
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Also it only takes about three seconds to jam the leads of your meter into a receptacle that is known to be working to get a reading. This way you know your meter is working. I have seen digital meters with bad batteries that give false readings.
OR have the leads not work. Always test but never trust.
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Old 07-31-2010, 10:47 AM
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Yeah, my father-in-law helped me change the outlets in my house when we remodelled. It was an old house, and we needed to change to 3-prong. He had worked with electricians and showed me how to do it carefully. Fortunately the wiring had been 3-wire (grounded) to the metal outlet boxes even if the plugs weren't, so it was easy to hook up a safe ground.

Theoretically, you never touch anything to anything (or to yourself) to complete a circuit, so it's no different than the wires just sitting in the wall - until you go "oops".

You unhook the wires one at a time from the old outlet and attach to the new socket- first the two white, then the two black; do the ground last or first; don't touch anything. I still burned one outlet when it touched the side of the box while being pushed in.

So if you really don't know for sure what you are doing, don't. Or, in the words of John Belushi from Animal House - if you can't fly, don't f*ck with the eagles.
If you have two black and two white wires connected to outlets in your house you are headed for trouble, unless they are to seperate circuits to the outlets. And as stated before then the breakers need to be tied together. Daisy chaining outlets over time usually leads to an outlet failure and is against code in most areas.
  #84  
Old 07-31-2010, 12:02 PM
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If you have two black and two white wires connected to outlets in your house you are headed for trouble, unless they are to seperate circuits to the outlets. And as stated before then the breakers need to be tied together. Daisy chaining outlets over time usually leads to an outlet failure and is against code in most areas.
I'm confused by this.

Almost every outlet in a residential is going to have two black and two white. Dedicated circuits are only found in specific locations and rarely is an electrician going to pigtail in every box. So any outlet in series except the last one will have 4 wires.

If only using 2 wires on each outlet became standard practice the cheap pricks that made outlets would be scrambling to cut the cost of their outlets and save money by only including 2 screws. To date 2 screw outlets are the rarity and 4 screws are the most common. I'd expect to find all 4 used on most outlets.
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Old 07-31-2010, 12:09 PM
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If only using 2 wires on each outlet became standard practice the cheap pricks that made outlets would be scrambling to cut the cost of their outlets and save money by only including 2 screws. To date 2 screw outlets are the rarity and 4 screws are the most common. I'd expect to find all 4 used on most outlets.
My house was built (I assume to code) about 11 years ago, and all the outlets on a circuit are like this (connected in parallel). At my work, the electrician they hired years ago when they put on on of the additions just stripped off part of the insulation, bent the wire around the terminal and the continued on to the next outlet, all without cutting the wires. (But he did leave plenty of slack in the boxes to work with at a later time).
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Old 07-31-2010, 12:49 PM
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Most circuits should only be 15 amps, right? Why wouldn't the cheap bastards just get rid of the screws entirely and use the plug-in terminals on the back?

Quote:
Originally Posted by Joey P View Post
My house was built (I assume to code) about 11 years ago, and all the outlets on a circuit are like this (connected in parallel).
Well, it's a parallel circuit in the strict sense, but an electrician would still probably describe the outlets as being run in series. It's not a series circuit, but the outlets aren't in a star.
  #87  
Old 07-31-2010, 12:59 PM
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devices can be used in ways that are poor practice or in violation of rules.

duplex receptacles have 2 hot and 2 neutral terminals.

the configuration allows the receptacle to be wired to feed another receptacle (the receptacle acts as a splice for the next one). using it in that manner is not allowed in the USA for a multiwired circuit.

quality wiring is pigtailed and never back wired IMHO.
  #88  
Old 07-31-2010, 12:59 PM
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Quote:
Originally Posted by Snnipe 70E View Post
Quote:
Originally Posted by md2000 View Post
Yeah, my father-in-law helped me change the outlets in my house when we remodelled. It was an old house, and we needed to change to 3-prong. He had worked with electricians and showed me how to do it carefully. Fortunately the wiring had been 3-wire (grounded) to the metal outlet boxes even if the plugs weren't, so it was easy to hook up a safe ground.

Theoretically, you never touch anything to anything (or to yourself) to complete a circuit, so it's no different than the wires just sitting in the wall - until you go "oops".

You unhook the wires one at a time from the old outlet and attach to the new socket- first the two white, then the two black; do the ground last or first; don't touch anything. I still burned one outlet when it touched the side of the box while being pushed in.

So if you really don't know for sure what you are doing, don't. Or, in the words of John Belushi from Animal House - if you can't fly, don't f*ck with the eagles.
If you have two black and two white wires connected to outlets in your house you are headed for trouble, unless they are to seperate circuits to the outlets. And as stated before then the breakers need to be tied together. Daisy chaining outlets over time usually leads to an outlet failure and is against code in most areas.
This is completely wrong.

I'll amend that to say that some local codes may have this provision, but I've never run into it.

Last edited by Chefguy; 07-31-2010 at 01:03 PM.
  #89  
Old 07-31-2010, 01:06 PM
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Quote:
Originally Posted by johnpost View Post
devices can be used in ways that are poor practice or in violation of rules.

duplex receptacles have 2 hot and 2 neutral terminals.

the configuration allows the receptacle to be wired to feed another receptacle (the receptacle acts as a splice for the next one). using it in that manner is not allowed in the USA for a multiwired circuit.

quality wiring is pigtailed and never back wired IMHO.
Where? what? when? how?
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Old 07-31-2010, 01:10 PM
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Quote:
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Quote:
Originally Posted by johnpost View Post
devices can be used in ways that are poor practice or in violation of rules.

duplex receptacles have 2 hot and 2 neutral terminals.

the configuration allows the receptacle to be wired to feed another receptacle (the receptacle acts as a splice for the next one). using it in that manner is not allowed in the USA for a multiwired circuit.

quality wiring is pigtailed and never back wired IMHO.
Where? what? when? how?
300.13(B)
  #91  
Old 07-31-2010, 01:38 PM
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Quote:
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Quote:
Originally Posted by boytyperanma View Post
Quote:
Originally Posted by johnpost View Post
devices can be used in ways that are poor practice or in violation of rules.

duplex receptacles have 2 hot and 2 neutral terminals.

the configuration allows the receptacle to be wired to feed another receptacle (the receptacle acts as a splice for the next one). using it in that manner is not allowed in the USA for a multiwired circuit.

quality wiring is pigtailed and never back wired IMHO.
Where? what? when? how?
300.13(B)
Some misunderstanding on my part. That would be a multiwire branch circuit. You can't wire it in a way that device removal would break the neutral for the other circuit as it is a shared neutral. You could still include the outlet as a splice for the hot wire.

If you are running a standard circuit as almost all circuits in a residential are you aren't dealing with multiwire branch circuits and 300.13B wouldn't apply. You can use all 4 screws.

Last edited by boytyperanma; 07-31-2010 at 01:40 PM.
  #92  
Old 07-31-2010, 02:37 PM
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Quote:
Originally Posted by Balthisar
Most circuits should only be 15 amps, right? Why wouldn't the cheap bastards just get rid of the screws entirely and use the plug-in terminals on the back?
Because back-stabs suck.

I've replaced enough burnt receptacles to never use those wretched things. They make a connection that's good enough for a 60-watt light bulb, but it's when someone plugs in a high-draw load like a clothes iron or a vacuum cleaner that 12+ amps are trying to flow through a point-contact and that connection gets hot and sooner or later fries to a crisp.
  #93  
Old 11-03-2019, 10:28 PM
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For those who dont know, it's not the voltage that will kill you it's the amperage. Yes technically voltage does have current but for the most part amps do more damage than the actual voltage.
  #94  
Old 11-04-2019, 02:19 AM
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Yet under the right circumstances, less than 50 volts can allow enough current to do the job. Even zombie volts.
  #95  
Old 11-04-2019, 06:43 AM
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"It's not the volts that kill you, it's the amps" is a meaningless statement, because for any given resistance (such as the human body), there will be a 1 to 1 relationship between the two.

And it's more accurate to say that it's neither the volts nor the amps that kill you, but either the watts or the hertz.
  #96  
Old 11-04-2019, 08:37 AM
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"It's not the volts that kill you, it's the amps" is a meaningless statement, because for any given resistance (such as the human body), there will be a 1 to 1 relationship between the two.
I agree there is a one to one relationship between the voltage and the current through a human body but only if the voltage is measured while the current is flowing.

Most of the time, people measure voltage (EMF)in an open circuit and the actual current through the human body depends on the resistance of the human body AND the internal resistance of the source.

I agree watts maybe a better unit.

So a 50kV taser will give you a bad shock but a 50kV power line will fry you to char.
  #97  
Old 11-04-2019, 09:50 AM
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Yes, I know this is a zombie....

Funny story, I was having trouble with a 3way switch at our apt. The electrician hired by the complex was on property so I asked him to take a look at it. He launched right into it without flipping the breakers and seemed to be being less than careful.

I asked him if he wanted me to cut the power for him but he declined. Thinking he was being a bit sloppy I asked him if he ever got shocked. His answer?

“Every fucking day.”
  #98  
Old 11-04-2019, 09:51 AM
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Quote:
Originally Posted by Chronos View Post
"It's not the volts that kill you, it's the amps" is a meaningless statement, because for any given resistance (such as the human body), there will be a 1 to 1 relationship between the two.

And it's more accurate to say that it's neither the volts nor the amps that kill you, but either the watts or the hertz.
It's not the volts or amps or watts or hertz that kill you, it's the part where your heart stops beating. That's what kills you.
  #99  
Old 11-04-2019, 02:38 PM
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Because back-stabs suck.

I've replaced enough burnt receptacles to never use those wretched things. They make a connection that's good enough for a 60-watt light bulb, but it's when someone plugs in a high-draw load like a clothes iron or a vacuum cleaner that 12+ amps are trying to flow through a point-contact and that connection gets hot and sooner or later fries to a crisp.
I guess since electricity awakened this Frankenstein's monster nine years dead, I'll clarify, that we were talking cheap bastards eliminating extra screws. If they wanted to be really cheap, they could use the back terminals. Christ, I'd never buy that product.
  #100  
Old 11-04-2019, 06:02 PM
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the neutral should only be switched if the hot wires are also switched at the same time, a ganged switch.

your story is incomplete as to how the fire department turned off the power; did they do so with a switch or disconnect wires.

what you've said doesn't make sense to me as you've stated it.
To answer this just a little bit late. I don't know the details, but from what he told me - the guys who wired the house originally switched the neutral and the live from the house feed (or maybe on one phase) so what everyone though was neutral was in fact the hot and vice versa. the subdivision wasn't built by the brightest bulbs and had lots of problems.
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