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Joined: Sep 2005
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SOmeone help me out with a real life situation where using this familar saying will hurt someone??
Line work, where someone is using a grounding set for protection. The set has to be sized adequately for the fault current available and placed correctly to protect the lineman. To give that worker the impression that "any" type of ground applied in "any" manner will save him "because it takes the path of least resistance" would get him killed.
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Joined: May 2003
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Is the 'Nailed by Neutral' thread? (The one that doesn't exist yet)
I too hate the 'least resistance' idea, and often tell people to rethink it as a water analogy. Every available path, and think of wires as garden hoses.
BigB, I tell people that the problem will always in be the last place I look while troubleshooting..... It always is!
Mark Heller "Well - I oughta....." -Jackie Gleason
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Joined: Jul 2002
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Line work, where someone is using a grounding set for protection. The set has to be sized adequately for the fault current available and placed correctly to protect the lineman. To give that worker the impression that "any" type of ground applied in "any" manner will save him "because it takes the path of least resistance" would get him killed.
I assume linemen know their job and understand what it takes to make themselves safe while working. I also assume electricians unserstand current will flow in any path it can. So how is this saying making the world unsafe??
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Joined: Aug 2001
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a real life situation where using this familar saying will hurt someone?? Let's say a receptacle is feeding an 1800-watt load. That's a resistance of 8 ohms (at 120V). Now assume that you put one hand on the neutral terminal and the other on the hot terminal of the receptacle. Your hand-to-hand body resistance will be many times greater than the 8 ohms of the load, but would you still believe that electricity will only take the path of least resuistance?
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Joined: Apr 2006
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Fair point trekkie.... it took me a while to get to grips with earthing arringements here in the UK. electure. I am all for making things as visual as poss. It is hard to explain things that you just can not see (we dont have many ants in scotland....the haggi keep eating them ) Reno true funny but true The one saying I was told by an old tradesman and I dont think anyone can refute is "Electricity is a good slave but a bad master" Kenny
der Großvater
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Joined: Sep 2005
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I assume linemen know their job and understand what it takes to make themselves safe while working. I also assume electricians unserstand current will flow in any path it can.
A very unsafe assumption. An awful lot of people learn from the guy, that learned from the guy, that learned from the guy before him. This applies to linemen and electricians. It's important that those who teach, teach correctly. Now, having said that, I agree it'a a fine point to argue this phrase. However, when someone's new to a technology, it's not always predictable how they will interpret a phrase. Better to be safe than sorry.
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Joined: Nov 2004
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This is a really interesting thread. I have a question to ask. Since electricity does take every possible path that it can, why is it that one can't (or doesn't) get shocked when in contact with the neutral of a circuit that is off in an electrical system with other circuits that are still under load. Wouldn't another circuit under load and returning it via the main neutral actually back feed the neutral of the dead circuit a bit? Or is the answer to this have to do with the fact that the neutral is grounded?
Just wondering here... sorry if the question is confusing.
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Joined: May 2003
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There is always a potential difference from neutral to ground. Often barely measurable. Depending on a wide range of factors as to how much. If the neutral wasn't grounded, there would be a much larger potential difference.
See the "nailed by neutral" thread...
Mark Heller "Well - I oughta....." -Jackie Gleason
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Joined: Dec 2003
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Grounding and Bonding works by that very principle. The voltage available to shock you is equal to the voltage drop between the point where you grab the grounding conductor and the point where your feet are touching. This voltage will be small if the resistance is small, which can be acomplished by establishing an equipotential grid for your feet, and bonding it to any exposed grounded surfaces that may have voltages.
Earl
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