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I was stripping a hot ungrounded conductor while a 20A breaker was on by accident. When my wire strippers pierced the sheathing, a large spark blew out and tripped a breaker, but yet I felt nothing. There's a possibility that somehow that the hot wire got stripped AND the ground wire was touching the other end of my strippers and created a ground fault. I don't believe the ground wire was touching my strippers, but the idea of me creating a path for 20 amps to flow from my hand to the ground tells me that I wouldn't be here blabbing about this question. I just can't see how I wasn't shocked at all.

I've drawn out a highly realistic depiction of me on the day this happened. Please try not to get caught up on why things are the way they are and focus on the question at hand. There is a main breaker panel (grounded/bonded), then it feeds a sub panel (ungrounded / not bonded), and from there is where the circuit ends. enter image description here

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    Excellent point - no cAFCI/GFCIs are present anywhere in this situation. – Tony DiNitto May 13 '17 at 17:05
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    Some may criticize the realism of your drawing but I have seen this kind of thing happen and the expression on your face seems accurate beyond question. – A. I. Breveleri May 13 '17 at 17:08
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    If there was an over-current trip on a 20 A breaker and you didn't feel it, then it went through a path other than through any part of you. Do you see any burn mark on the strippers? – Jim Stewart May 13 '17 at 17:10
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    The strippers have a mild weld/blown-out spot in the slot/notch where I was stripping the wire. – Tony DiNitto May 13 '17 at 17:15
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    My father had an old pair of tin snips that had a blown out crater where he cut a live Romex cable. I asked him why he didn't throw them out and get a new pair. He said because every time he looked at them it reminded him how important it is to verify that the power is off before doing any electrical work. – Mark May 13 '17 at 21:38
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Power doesn't usually go through you

Because you're a lousy conductor. Also if you possess even the slightest amount of fieldcraft, you habitually and perhaps unconsciously position yourself so you are not a current path.

Electricity is not the black oil from X-files. It doesn't seek out human skin, it will seek out all possible current paths to return at the same time. If you're contacting L1, then neutral, ground or L2 are returns. L1 is not a return.

Current will take each path in proportion to its conductance (which is 1/resistance, Siemens = 1 / Ohm ). So typically you have shoes on, and are not leaning on a grounded panel, and have not carefully attached a grounding strap to any fresh piercings, so your conductance is very low (megaohms/microsiemens). Meanwhile those other wires have extremely high conductance (milliohms/kilosiemens).

So one of two things happens, either so little current flows through you (microamps) that you don't feel it, or a dangerous current (milliamps) flows through you. And then hundreds of amps also flows through the wire (as evidenced by the arc flash) and the breaker magnetic-trips, interrupting the current flow in milliseconds and so you never get to find out if it's lethal.

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    Also, the fatality of the current depends on how it flows throw you. Across your chest and you're dead from hardly any current. From your thumb to your index finger and you'll probably live to tell the tale if not damage some tissue in your hand in the process. This is why a lot of people recommend trying to work with one hand as much as possible to prevent creating a current path through your chest. – statueuphemism May 14 '17 at 9:58
  • @statueuphemism yes the one hand rule is good, no rings, watches, jewelry, no leaning and also the insulated screw driver. – Ken May 15 '17 at 4:23
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1: Your wire strippers the handles appear to be insulated !

2: You needed to be both touching the HOT and grounded AND be the least path of resistance- you may not have been. The least path was between your hot wire on the strippers and Neutral or Ground - it tripped instantaneously - you have been LUCKY.

Now on to that least path of resistance - is kind of a misnomer (about being shocked or electrocuted) but in this scenario - your two wires Hot and what ever had a dead short ZERO resistance current flowed instantaneously and tripped the breaker. If there was some resistance in the wire not a DEAD short - you definitely could have been shocked or electrocuted if you had touched at the same time. It is a matter of the current flowing to the one point over it flowing through you to ground - which is faster. I cite the GFCI operation here - it senses (means there is a path, and it trips with in x milliseconds - you feel nothing).

In cases where the voltage is higher the above will not spare you - you will get fried.

RULE #1:

When working on an Electrical Machine, Component or Wire - REMOVE ALL SOURCES OF POTENTIAL ENERGY! Batteries, Storage Capacitors, Circuit Breakers - turn it off!

Turn Circuits Off before working on them, treat all circuits as if they were live when working on them, verify that they are off and have no live voltage before working on them.

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  • I'm not a native speaker, but isn't it 'path of least resistance' rather than 'least path of resistance' ? – Artur Biesiadowski May 14 '17 at 11:08
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    @ArturBiesiadowski I've only ever seen the prior. Try Google'ing "least path of resistance". Pretty much every result says "path of least resistance". That wording is much more common. "least" is specifying how much resistance, not about the path. You might be able to get a better answer at english.stackexchange.com. Good luck in your learning! – seth10 May 14 '17 at 15:03
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    Whatever order you put the words in, the statement about electricity taking the "path of least resistance" is not an accurate description, yet for some reason it gets repeated over and over. Current will flow through every path back to the source proportionally to the resistance of that path. If you put a 100ohm resistor in parallel with a 1kohm resistor, current will flow through both of them proportionally, not just through the path of least resistance. – Tom Carpenter May 14 '17 at 16:23
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    @TomCarpenter - yes you are correct however if you are 1meg ohm - and the other path is less than 1 ohm the Current flowing in a parallel circuit will flow more easily in the 1 ohm path and therefore will cause the circuit to trip as the current draw will be higher in that circuit - if the roles were reversed - the circuit would trip but you will for sure feel the Shock. Which is why I said kind of a misnomer .. with out going into Electron Flow theory and Ohms Law - just wanted the OP to understand why he did not get shocked in simplest terms. – Ken May 15 '17 at 4:16
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If the strippers were touching ground when they also touched hot, that would create a short-circuit that would trip the breaker. Assuming the stripper handles are insulated, no current should have gone through you.

If the strippers were not grounded, nor insulated. Then I'd have to assume the breaker that tripped was a GFCI breaker, and you created a ground-fault. In which case, the breaker would trip at only a few milliamperes.

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  • There was no GFCI/cAFCI involved. Based on this, is the only conclusion that a) The hot wire HAD to have touched the ground, which perhaps touched the outside edge of my strippers by accident while stripping the hot wire and b) The rubber handles on my strippers (not officially marked 'Insulated') saved me from being shocked? – Tony DiNitto May 13 '17 at 17:18
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    If enough current flowed through you to trip the breaker, you'd know it. – Tester101 May 13 '17 at 17:29
  • Amen, there are many reason why you wouldn't be shocked, but next time why don't you kill the circuit before you work on it. 65 and still alive. – Retired Master Electrician May 13 '17 at 17:31
  • How are there many reasons I wouldn't have been shocked? It seems like there's only one reason I wasn't shocked to my understanding, and it was the rubber handles on my wire strippers since even if the current didn't pass through me to get back to the source via earth ground (through my shoes), I would have still felt a shock as it passed through my strippers I was holding. As for your advice, I'll consider not trying to electrocute myself in future endeavors. :) – Tony DiNitto May 13 '17 at 17:35
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Two possibilities:

1) You went through the neutral first. When you then cut the hot, bang.

2) You cut the hot first but you were sufficiently insulated (see other answers) that you felt nothing. When you then cut through the neutral, bang.

If you are sure you have no ground path it's safe to work with a hot wire. The guys who work the big wires do it routinely. Just be very, very sure.

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Welding 101

Your strippers created a more effective path to complete the circuit. So effective that too much current was able to cause an arc and trip the breaker.

Why not you

Suffice to say you got lucky not getting shocked.

Worst Case Scenario

They're quite a few scenarios to name that you could get shocked by. The most dangerous one is when current enters one hand and exists out the other. This is because the current passes by your heart and can cause a cardiac arrest.

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  • While this is true, the circuit was completed somewhere, or there wouldn't have been a spark and a trip of the breaker. So this doesn't really answer the question – Machavity May 14 '17 at 2:59

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