Our Fearless Leader Mike

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I watched it yesterday when he was doing the live stream playing the video. I knew he was fine but it still made me kind of on edge.lol

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I understand the bird on the wire concept. A person can assume the voltage and yet not be shocked ...Unless they close the circuit.
But water always has me baffled. How is it that there are cases When a swimmer enters the water that has been energized (such as a swimming pool or near docks) and their muscles contract. How are they closing the circuit? I would think that they are assuming the voltage and will not be shocked at all.
Mike entered the water with 120 V and assumed the voltage .
Secondly Mike’s pool had a equal potential bonding system around the perimeter of the pool. How is it that he did not feel any tingling when he entered the water since the pool is bonded.
There’s a case of a seven-year-old boy who jumped in the pool in Miami and swim towards the niche(light). As he got closer to the light his muscles contracted and he died. I just don’t understand if the young boy swimming assumed the voltage and had no contact with a grounding conductor how did he close the circuit in order to be shocked?


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Peter Furrow said:
I understand the bird on the wire concept. A person can assume the voltage and yet not be shocked ...Unless they close the circuit.
But water always has me baffled. How is it that there are cases When a swimmer enters the water that has been energized (such as a swimming pool or near docks) and their muscles contract. How are they closing the circuit? I would think that they are assuming the voltage and will not be shocked at all.
Mike entered the water with 120 V and assumed the voltage .
Secondly Mike’s pool had a equal potential bonding system around the perimeter of the pool. How is it that he did not feel any tingling when he entered the water since the pool is bonded.
There’s a case of a seven-year-old boy who jumped in the pool in Miami and swim towards the niche(light). As he got closer to the light his muscles contracted and he died. I just don’t understand if the young boy swimming assumed the voltage and had no contact with a grounding conductor how did he close the circuit in order to be shocked?


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If you take switch / breaker and dunk it in chlorinated pool water, then with the switch in the open position connect 120 to one side, you to the other, and then ground yourself to the equipment ground, you will get shocked. So actually, don't do that as it is an immediate death hazard. The chlorinated pool water will conduct right across the open switch and through you to ground.

If you are swimming in the pool, the chlorinated water brings the exposed voltage to you and then through you as you are one of the paths for it, to ground. Disclaimer, I did not watch the video.

The equipotential grid purpose is that there should exist no potential voltage difference within the coverage area.

If you are inside of a contiguous tin can, lightning can strike the can's exterior and you will see no potential voltage difference (or shock hazard) from inside the can. There is a famous Ben Franklin experiment of the type that he did with the exposure of his own body to the lightning strike.
 
Peter Furrow said:
I understand the bird on the wire concept. A person can assume the voltage and yet not be shocked ...Unless they close the circuit.
But water always has me baffled. How is it that there are cases When a swimmer enters the water that has been energized (such as a swimming pool or near docks) and their muscles contract. How are they closing the circuit? I would think that they are assuming the voltage and will not be shocked at all.
Mike entered the water with 120 V and assumed the voltage .
Secondly Mike’s pool had a equal potential bonding system around the perimeter of the pool. How is it that he did not feel any tingling when he entered the water since the pool is bonded.
There’s a case of a seven-year-old boy who jumped in the pool in Miami and swim towards the niche(light). As he got closer to the light his muscles contracted and he died. I just don’t understand if the young boy swimming assumed the voltage and had no contact with a grounding conductor how did he close the circuit in order to be shocked?


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If there is current flowing through the water, there will be a voltage gradient across positions in the water.
A human body in the water becomes a current path.
This is minimized by a proper equipotential grid because most of the stray current will flow through the bonding system instead of the water.
 
So if you took a #12 wire single wire from 120 V 20 amp breaker and dropped it in the pool You would create a voltage gradient around that wire. If a person swims within that voltage gradient zone they would receive a shock
IF the pool is properly bonded back to the source. The person swimming in that voltage gradient would assume the voltage & there would be parallel paths , in the chlorinated water, through their body & back to the source resulting in death.
However, same scenario but this time the pool is not bonded at all. The person swims within the voltage gradient zone but they would not receive a shock because the pool is not bonded and there’s nothing returning back to the source.
Correct me on this or expound.


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To me it just seems like the safer pool is the one where the equipotential bonding is not attached to the equipment grounding conductor. 680.26 (b) last sentence says ‘that the bonding conductor from the equipotential bond shall not be required to be extended or attached to panel boards’.
This would mean that the equipotential bonding system is completely isolated from the electrical grounding system.
However, the pool motor is the only area where the equipotential bonding system and the grounding conductor system can meet.
The equipotential bonding conductor# 8 Bonds to the outside casing of the motor.
The equipment grounding conductor from the panel board bonds to the grounding terminal inside the motor casing. There would now be continuity between the two points.

My point in this is that equipotential bonding system is good however When the equipment grounding conductor is connected to this system it becomes a potential hazard.
IMO These two systems should be completely isolated from each other.


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Peter Furrow said:
To me it just seems like the safer pool is the one where the equipotential bonding is not attached to the equipment grounding conductor. 680.26 (b) last sentence says ‘that the bonding conductor from the equipotential bond shall not be required to be extended or attached to panel boards’.
This would mean that the equipotential bonding system is completely isolated from the electrical grounding system.
However, the pool motor is the only area where the equipotential bonding system and the grounding conductor system can meet.
The equipotential bonding conductor# 8 Bonds to the outside casing of the motor.
The equipment grounding conductor from the panel board bonds to the grounding terminal inside the motor casing. There would now be continuity between the two points.

My point in this is that equipotential bonding system is good however When the equipment grounding conductor is connected to this system it becomes a potential hazard.
IMO These two systems should be completely isolated from each other.


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You're forgetting that everything, including the EGC, is at the same potential once bonded. If you lift the EGC on the motor (if it's not double insulated) you present more of a risk if there is a fault at the pump motor.
 
I was at a Mike Holt seminar about ten years ago, the comment came up, "Water and Electricity Don't Mix". Mikes answer was to take powered up plug strip and put it in a pitcher of water and drink from it. It does make a difference the type of water, pure water is not a conductor.
Not really related to the orginal post, but hey, its like getting in the pool with 120V
 

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I did an experiment with a plastic bucket filled with water. I install a 120v wp bulb to a 2 wire circuit and dropped it in the bucket. Everyone thought it would trip the gfci but, as you know, it won't. I then stuck my hand in the bucket..... a bit safer then what Mike did....but it was a good demonstration on understanding gfci. I took a wire from the water in the bucket to a ground and the gfci immediately tripped.
 
I saw him do it on his live stream when he was making his new videos for 2020 code cyc
Peter Furrow said:
So if you took a #12 wire single wire from 120 V 20 amp breaker and dropped it in the pool You would create a voltage gradient around that wire. If a person swims within that voltage gradient zone they would receive a shock
IF the pool is properly bonded back to the source. The person swimming in that voltage gradient would assume the voltage & there would be parallel paths , in the chlorinated water, through their body & back to the source resulting in death.
However, same scenario but this time the pool is not bonded at all. The person swims within the voltage gradient zone but they would not receive a shock because the pool is not bonded and there’s nothing returning back to the source.
Correct me on this or expound.


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The whole idea of the grid and the bonding of all the parts is to eliminate voltage gradiants in the water if it becomes energized
 
Peter Furrow said:
So if you took a #12 wire single wire from 120 V 20 amp breaker and dropped it in the pool You would create a voltage gradient around that wire. If a person swims within that voltage gradient zone they would receive a shock
IF the pool is properly bonded back to the source. The person swimming in that voltage gradient would assume the voltage & there would be parallel paths , in the chlorinated water, through their body & back to the source resulting in death.
However, same scenario but this time the pool is not bonded at all. The person swims within the voltage gradient zone but they would not receive a shock because the pool is not bonded and there’s nothing returning back to the source.
Correct me on this or expound.


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You’re not wrong, but consider this - in a swimming pool environment wired to current code. That #12 would be protected by GFCI. The GFCI would trip before enough current would flow to create a dangerous voltage gradient.

The pool is safer with the equipotential than without in virtually all common fault scenarios. Your example is intentionally designed to defeat the safety aspects instilled by a code-compliant environment.
 
Peter Furrow said:
...
However, same scenario but this time the pool is not bonded at all. The person swims within the voltage gradient zone but they would not receive a shock because the pool is not bonded and there’s nothing returning back to the source.
Correct me on this or expound.


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There can be no assumption the pool is not bonded even if constructed with no metal. The assumption would have to be that there is continuity, some unintended conductive path to the earth, and it is just a question of resistance and current carrying capacity, so in the range of what we are discussing, enough to kill you, the pool is sufficiently connected to Earth.

Same scenario but now your (120) power source is floating ungrounded and you drop any *one* lead into the water, the power source will only reference to ground but not pass any current, in theory, and so in theory is swimmable (note not safe to swim in, safe for the mouse test subject to swim in).

Same scenario but now ground the *other* lead and do the same mouse test. That mouse may float but he won't be swimming.
 
I did watch a bit of the video and did see the point where Mike is doing the step potential test with himself as the meter. I saw him say "I'll let you know when I feel it". That was over my limit.

I did want to see the actual hands on of how they floated the equipotential grid, and then connected the 120, and especially with a clamp on Amp meter on the power source because even floating I am pretty sure there was still some current flow (to earth and then to the system bonding jumper). Unless they also floated the system bonding jumper, and if so, I would say "A good magician never reveals his secrets".

If the source 120 had a system bonding jumper, even floating the grid will still give some current flow, but maybe not (through the pool water while someone is swimming in it). Floating the power source, then floating the grid, connecting the two and swimming in it, that's a magic trick.
 
Dennis Alwon said:
I did an experiment with a plastic bucket filled with water. I install a 120v wp bulb to a 2 wire circuit and dropped it in the bucket. Everyone thought it would trip the gfci but, as you know, it won't. I then stuck my hand in the bucket..... a bit safer then what Mike did....but it was a good demonstration on understanding gfci. I took a wire from the water in the bucket to a ground and the gfci immediately tripped.
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I do the same.
 
Dennis Alwon said:
I did an experiment with a plastic bucket filled with water. I install a 120v wp bulb to a 2 wire circuit and dropped it in the bucket. Everyone thought it would trip the gfci but, as you know, it won't. I then stuck my hand in the bucket..... a bit safer then what Mike did....but it was a good demonstration on understanding gfci. I took a wire from the water in the bucket to a ground and the gfci immediately tripped.
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So when you stick your hand in, are you being careful not to be earthed? Or does it still work safely even if you are earthed, because the water resistance plus your resistance plus earth resistance is high enough?

Cheers, Wayne
 
wwhitney said:
So when you stick your hand in, are you being careful not to be earthed? Or does it still work safely even if you are earthed, because the water resistance plus your resistance plus earth resistance is high enough?

Cheers, Wayne
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I am wearing shoes so I am not earthed otherwise the gfci would trip. My point was to show how a gfci worked. As I stated I put a wire in the water and touched it to a ground and the gfci tripped. I assume it would do the same if I were connected to ground.
 
This is like underwater welding. Never get between the stinger and ground. Otherwise totally safe. Ask a hard hat diver.
 
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