So who's worked in their main electrical panel?

[whoaru99]

I've always wondered that, say you have a hot 120 or 240 line with no load on it, and you grab the hot and neutral. How bad will you get shocked since there's no load?

You're going to get nailed just as hard (or harder) without a load on the circuit.

Also, in theory, you can grab the hot *as long as your not grounded* right? Just curious.

It's not theory. It's true. There has to be a complete circuit for current to flow. That said, it's a dangerous, perhaps deadly, game to play if you don't know what you're doing. A path to ground can present itself in unexpected ways and then maybe you're toast.

 

[dannylerch]

You're going to get nailed just as hard (or harder) without a load on the circuit.



It's not theory. It's true. There has to be a complete circuit for current to flow. That said, it's a dangerous, perhaps deadly, game to play if you don't know what you're doing. A path to ground can present itself in unexpected ways and then maybe you're toast.

You're right. Its simple really. When you touch two leads you complete the circuit. Just Dont do it. This is why I separate bus bars with dividers when adding breakers or tie ins. I disagree about getting hit harder if there is no load. Voltage is voltage, it stays relatively consistent and only drops as you add a load. The load is what kills you. It only takes .7 mili amps to stop your heart. Its because voltage typically flows at 60hz. The human heart beats roughly the same. This is one factor why humans make such good conductors. As a journeyman I can tell you that if you touch a 220 circuit without a load as opposed to one with 100 amps on it, the one with 100amps will kick your ass way worse.

So pop quiz everyone, what is more dangerous? 10,000 volts at .01 mili amps, or 110 volts at 30 amps?

 

[kal]

Its because voltage typically flows at 60hz. The human heart beats roughly the same.

Err, a human heart does not beat 60 times/second.

Kal

 

[whoaru99]

I can tell you that if you touch a 220 circuit without a load as opposed to one with 100 amps on it, the one with 100amps will kick your ass way worse.

Why would touching loaded circuit hurt you worse?

Typically the voltage on a loaded circuit will be slightly less, although not significantly so if the circuit is sized properly.

 

[dannylerch]

Err, a human heart does not beat 60 times/second.

Kal

Correct, I was wrong about the beats. Its the micro electronic system of the heart that is very similar. IE electrolytes. I've had a few too many home brews today.

 

[Huff360]

Holy crap this thread is full of bad info.

 

[dannylerch]

Why would touching loaded circuit hurt you worse?

Typically the voltage on a loaded circuit will be slightly less, although not significantly so if the circuit is sized properly.

Because higher amperage means the intensity of the current is higher. It is common knowledge.

Here is a simple way to see for yourself. Take a lamp, switch it to off. Plug it in to a 20 amp circuit. See, there is a passive patch into a hot circuit. Now un plug it and plug it back in to the circuit but make sure the lamp is turned on. You should see a small arc. Now you can see how much more volatile current is with a load. Now try to imagine that traveling through one arm, through your heart and lungs, and out through the other hand. That small arc is just a light bulb. Now imagine patching into a breaker box with your fridge, dish washer, washing machine, hair dryer, house lights, etc pulling a load. You definitely Dont want that because all that amperage runs through that box in your house. Make sense now?

 

[whoaru99]

No, it still doesn't make sense.

If I go touch one of the main lugs in my breaker panel and complete a path to ground I'm going to get the same shock, within a couple volts, regardless if there is zero electric load in my house at the time or if my 18kW of electric heat is on.

 

[AllanMar]

I hear the "its not voltage that kills, its amps!" line a lot, and while it is true most people seem to mis-interpert it.

6-10mA through your heart can kill, however you need significant voltage to produce 6-10mA across your heart. So there are many factors involved, including the path the current may take through your body. Grab both terminals of a AAA battery, did you survive? Surely a AAA battery can supply more then 10mA. So unless your dealing with circuits fused at 6mA, its the voltage that is going to detail the risk.

An unloaded circuit is capable of just as much damage as a loaded one, although loaded ones can become more dangerous when connecting/disconnecting. The only real difference is when you break the connection the arcing that will occur, if you touch both leads the damage will be the same.

EDIT: I said 6-10mA because it is mentioned the most, most studies have found this to be much higher though (50-100mA).

 

[Huff360]

preferably an electrician who is in a union. Because if they aren't union, they are probably a hack.

+1
As a union electrician. I've gone in after many "rats" throw stuff together and have to fix a lot of stuff.

So what do you union guys say about this?

As a journeyman I can tell you that if you touch a 220 circuit without a load as opposed to one with 100 amps on it, the one with 100amps will kick your ass way worse.

Union or not, means nothing. There are plenty of union guys out there that know pretty much nothing. As well as there are plenty of non-union guys out there that know just as much as a union guy.

What you should have said to the OP was "Hire an electrician that knows what he is doing."

 

[Huff360]

A word about this panel of yours.

I like that you have secondary surge suppression in there. Two installed, in fact. However, it's not installed properly and might not function when the time comes.

Those coiled white neutrals tied into the bus at the bottom need to be uncoiled and trimmed as short as possible while still connecting to that bus safely. Surges always take the path of least resistance to ground, and we want those neutrals to be that path. It would be a shame for a surge to go into the house searching and exit through electronics.

Or perhaps I'm just reading them wrong at 6 am with no glasses. But they sure look like secondary surges to me.

I'm pretty sure those are Square D Homeline GFI breakers, not surge suppression. If it were TVSS, the coiled neutral would be an issue, but if it is GFCI then the coiled neutral is not a problem. Without WroxBrew weighing in, we won't know for sure.

 

[thadius856]

I'm pretty sure those are Square D Homeline GFI breakers, not surge suppression. If it were TVSS, the coiled neutral would be an issue, but if it is GFCI then the coiled neutral is not a problem. Without WroxBrew weighing in, we won't know for sure.

Perhaps, but I have a Square D (edit: Homeline) load center with GFCIs, and mine don't look like those. As you said, we can only know if he comes back and posts.

Its because voltage typically flows at 60hz. The human heart beats roughly the same. This is one factor why humans make such good conductors. As a journeyman I can tell you that if you touch a 220 circuit without a load as opposed to one with 100 amps on it, the one with 100amps will kick your ass way worse.

What the hell is this? Humans make good conductors because we're big bags of salty water.

 

[dannylerch]

So what do you union guys say about this?



Union or not, means nothing. There are plenty of union guys out there that know pretty much nothing. As well as there are plenty of non-union guys out there that know just as much as a union guy.

What you should have said to the OP was "Hire an electrician that knows what he is doing."

I can't speak for the industrial/commercial electrician. But I don't even think a non union linesman exists. There are also no real good electrics in the film business that are worth a damn.

The thing about being union is, there are credentials and codes of safety that exceed the bare minimum of what the law see's fit for your non union guys. I worked non union is my industry for several years before going union. Once I did, I started working with bigger lights, more power, much more sophisticated equipment, and also many safety classes, etc. I had to work in the union for 2 years before I was considered a journeyman.

Being an electrician in the film industry is much more dangerous than being a commercial or industrial electric too. Because we deal with a hell of a lot of power. IE, 1.5 MEGAWATT generators, 480v runs. 220, we run dozens giant hot 18,000 watt lights that weight 150 pounds. Rigs that are pulling upwards of 1200 AMPS. We also run miles of 4/0t cable three phase, 9 wire and 5 wire. We have to put it far away because the sound department can't hear the generators when they are shooting scenes. And also we are expected to work very very quickly because the producers are trying to keep a schedule. I also work up to 60-90 hours a week, depending on the movie.

 

[dannylerch]

Perhaps, but I have a Square D (edit: Homeline) load center with GFCIs, and mine don't look like those. As you said, we can only know if he comes back and posts.



What the hell is this? Humans make good conductors because we're big bags of salty water.

what do you think salty water is? Electrolytes. You can charge a iphone with a potato soaked in Gatorade

 

[thadius856]

what do you think salty water is? Electrolytes. You can charge a iphone with a potato soaked in Gatorade

I called out the quoted text where a poster claimed humans conduct electricity well because our hearts beat near 60 hz. Maybe you read my post too fast?

Edit: I see that's you I quoted. Care to explain how heart rate affects conductivity?

 

[dannylerch]

Some people have theorized that the human body cycles at an average of 70 Hz at rest. That is our bodies resonant frequency. AC current cycles at 60 HZ. Electrolytes are carried through "salty water" as you put it. We aren't the greatest conductors but our resistance changes drastically when wet. Look it up for yourself. The heart beats on average 60-80 BPM. Point being, is that our body works in cycles of micro electromagnetic activity. Its the same principle why lightning will hit a running generator in a thunderstorm.

 

[thadius856]

Some people have theorized that the human body cycles at an average of 70 Hz at rest. That is our bodies resonant frequency. AC current cycles at 60 HZ.

I can find nothing related to this after 15 minutes of searching Google.

This was certainly a fun article though: http://www.eplasty.com/index.php?op...ticle&id=345&catid=170:volume-09-eplasty-2009

Electrolytes are carried through "salty water" as you put it. We aren't the greatest conductors but our resistance changes drastically when wet. Look it up for yourself.

This was never disputed.

The heart beats on average 60-80 BPM. Point being, is that our body works in cycles of micro electromagnetic activity. Its the same principle why lightning will hit a running generator in a thunderstorm.

I fail to see the connection between the two. What does arcing current from clouds to ground have to do with the conductivity of the human body?

 

[Bobby_M]

This thread as degraded down to tap room level antics.

 

[kevreh]

Indeed, its gone down a few different rabbit holes. But what the hey, its' an interesting read. :cross: Of course, I've been waiting for the union vs. non-union comments to turn into a tap room brawl.

 

[dannylerch]

I can find nothing related to this after 15 minutes of searching Google.

This was certainly a fun article though: http://www.eplasty.com/index.php?op...ticle&id=345&catid=170:volume-09-eplasty-2009



This was never disputed.



I fail to see the connection between the two. What does arcing current from clouds to ground have to do with the conductivity of the human body?

It is all the same. A generator is a small system of electromagnetic activity. The human body is the same except an an even more exponentially smaller level. Resonant frequency of a 120/110 circuit is very close to the resonant frequency of a human body. My only point is that it is super easy to become part of a circuit. Safety first folks. How is that hard to understand?

 

[Bobby_M]

It's probably good enough to say don't touch live stuff and if you have to, don't touch other stuff at different potential like ground. If you don't understand why, call an electrical because you might die.

I upgraded my panel and service from 100a to 200 amp and spliced the SEC into the live aerial drop cable. How's that for scary? I wouldn't recommend that, but no, I'm not scared to pop a new breaker into the panel with the main still on. One of my personal mantras when I'm working around the panel is to keep one hand in my pocket. Oh, and check for nails and tacks in the sole of your shoes. Nothing like thinking you're isolated when a tiny lightning rod is a millimeter from your toe.

 

[dannylerch]

Indeed, its gone down a few different rabbit holes. But what the hey, its' an interesting read. :cross: Of course, I've been waiting for the union vs. non-union comments to turn into a tap room brawl.

Just last week my buddy, a local 479 best boy electrician was shocked by an energized breaker box in a middle school we were shooting in. We popped the door and noticed that a wire breaking off the red bus bar was pinched and the exposed copper was sending 110 through the entire breaker box. We read 28 amps from the box to the ground. More than enough to kill ya. We asked the house electrician who was the last person to service the box. He said it was a small non union contractor. If one of my union brothers did a hack job like that, we would have expelled him in a heartbeat.

 

[thadius856]

Just last week my buddy, a local 479 best boy electrician was shocked by an energized breaker box in a middle school we were shooting in.

I read this wrong. Twice, in fact, each time a different way. :cross:

 

[dannylerch]

I read this wrong. Twice, in fact, each time a different way. :cross:

FILM shoot. hahahah. I work in the film business

 

[thadius856]

FILM shoot. hahahah. I work in the film business

Unfortunately, that's a type of film as well.

 

[dannylerch]

Dont do THAT type of movie. Never have never will.

 

[brewfreeordie]

Just last week my buddy, a local 479 best boy electrician was shocked by an energized breaker box in a middle school we were shooting in. We popped the door and noticed that a wire breaking off the red bus bar was pinched and the exposed copper was sending 110 through the entire breaker box. We read 28 amps from the box to the ground. More than enough to kill ya. We asked the house electrician who was the last person to service the box. He said it was a small non union contractor. If one of my union brothers did a hack job like that, we would have expelled him in a heartbeat.

Why didn't the breaker trip? Was the box not grounded?

 

[brewfreeordie]

Why would touching loaded circuit hurt you worse?

Typically the voltage on a loaded circuit will be slightly less, although not significantly so if the circuit is sized properly.

A loaded circuit is fighting the resistance of the circuit, which depending on the load and wire gauge could be substantial. Along comes someone to provide another path to ground and suddenly you've give the electricity another (perhaps easier) way to get back to Mother Earth. When resistiance is in parallel it will always follow BOTH sides, not just the path of least resistance.


The worst shock I ever received rang out at 40 VAC when we found it. A frayed cord on a refrigerated table (240v/30a) was energizing the chassis. Turns out the restaurant owner bought his fancy new table to replace one that broke, but he cut off the 4 prong plug end it came with and replaced it with the old table's 3 prong, leaving the ground disconnected and therefore the chassis ungrounded.

It could have been like this for a long time because we only noticed it when we replaced the fryer baskets with ones that had an all-metal handle, and when your hand was on the table (sopping wet, the table was full of fish) then dropped the basket you completed the circuit. First guy to get shocked almost pissed himself. We couldn't figure out what was happening until I decided to go through the motions of what he was doing......when it happened...... OWWWWWWWWWWCH!! That hurt! No plasma, no big bang. All it showed on the meter was 40 volts. That's low-voltage right? Don't need a license for 40 volts!

Everybody talks about Amps and Volts, but there's another letter to that triangle putting everything in perspective.

 

[whoaru99]

Edited to try a different approach -

A loaded circuit is fighting the resistance of the circuit, which depending on the load and wire gauge could be substantial. Along comes someone to provide another path to ground and suddenly you've give the electricity another (perhaps easier) way to get back to Mother Earth. When resistiance is in parallel it will always follow BOTH sides, not just the path of least resistance.


The worst shock I ever received rang out at 40 VAC when we found it. A frayed cord on a refrigerated table (240v/30a) was energizing the chassis. Turns out the restaurant owner bought his fancy new table to replace one that broke, but he cut off the 4 prong plug end it came with and replaced it with the old table's 3 prong, leaving the ground disconnected and therefore the chassis ungrounded.

It could have been like this for a long time because we only noticed it when we replaced the fryer baskets with ones that had an all-metal handle, and when your hand was on the table (sopping wet, the table was full of fish) then dropped the basket you completed the circuit

I'm not clear whether you're agreeing or disagreeing with the point that a loaded circuit won't hurt you any worse.

No disagreement that you got a shock due to some sort of voltage leakage to chassis that almost certainly got worse/increased when the fryer was turned on than when it was turned off. However, are you saying the shock resulting from 40V leakage was worse than if, with the same sopping wet hands, same surface area of contact, etc., you had grabbed hold of a bare 240V hot wire in the power circuit supplying the fryer?

I think not.

Ohms Law -

Body resistance: ~1,000 ohms, wet hand to wet hand

40V to ground across 1,000 ohms = 40mA

240V to ground across 1,000 ohms = 240mA.

Again, not saying you didn't get perhaps the worst shock you've had, but had you touched an unloaded but energized 240V wire under the same conditions it would have been much worse.

 

[brewfreeordie]

It wasn't 40 volts, it was one side of the hot leg frayed against the outside of the fridge. No doubt I was getting 120v, but there was too much resistance to jump from me to the floor, or the rubbber-coated handles of the old fryolator baskets. But the fryolator was grounded through the gas pipe, and that was enough to almost knock me out. Protective gear is built on the phenomenon on resistance, and people who work around electricity need to know how this stuff works because there's more than enough juice in a lamp cord to kill you. You don't have to go into the electrical panel to kill yourself.

I'm of the opinion that a circuit under load is more dangerous than one that is not.