Power cord on Lee 4-20

[shuckinthecorn]

I put a GFI outlet where I planned to cast, then my new pot gets here and only has a two wire cord on it, just like a metal cased electric drill sold in 1960.:???:
I think this will be getting changed soon.

[Frozone]

I change out the cords on my LEE pots.
I like a grounded chassis.

[el34]

I change out the cords on my LEE pots.
I like a grounded chassis.

Dittos .

[Idz]

The gfci outlet measures the imbalance of the current going out and returning. They assume any difference is leakage to ground. A 2-wire cord works just fine on a gfci as long as the gfci is functional. The outlets should be designed to fail open so if the gfci isn't working the outlet is disconnected from the mains.

[shuckinthecorn]

I assumed (and you know what they say about that) that it monitored the ground and killed the power if there was anything on the ground. Guess that was my lesson for today. I'm still grounding the chassis anyway. I can't believe something made from all metal that works in the temperature range of a lead melting pot, doesn't get this from the factory.

[Zymurgy50]

To quote an old instructor of mine, "The purpose of the ground conductor is to facilitate operation of the overcurrent device."
In plain english it means that the ground conductor is present to ensure the fuse blows (or the breaker trips) in the event of an overcurrent situation. Go ahead and put a 3 wire cord on the pot and ground the chassis, it will not make a difference in how the GFCI works with a 3 wire appliance vs. a 2 wire appliance.

[Idz]

The purpose of the gfci is to protect you, not the equipment. The ground lug on the gfci outlet is the same as regular 3-wire outlets. The only reason (other than cost) I can see for not using a 3-wire cord is that older style heating elements got electrically leaky with age. A grounded pot would trip the gfci where the 2-wire pot would only trip if you barehanded grabbed hold of the operating pot and a grounded pipe at the same time.

[shuckinthecorn]

I've never had much electrical training but well remember my instructor in high school beating in our heads, that electricity was always looking for a ground, and would always take the path of least resistance.
If something were to happen to it's normal path, I would much rather it use the additional ground, than to possibly use my body.
The chassis will be grounded.

[el34]

Current flow will take all available paths, proportional to the resistance of each. Same as if you hook two hoses of different diameters to a Y adapter at a faucet, water would come out of both but more would flow through the large one than the small.

Ground protects you not only by causing a fuse/breaker to blow, it channels current away from what you might be touching while the fuse is being blown.

[dikman]

If you're using anything that has a metal case/body then always make sure it has a ground connection. Trust me, you do not want AC flowing through your body - it hurts!!!

[454PB]

All the outlets in my shop are GFCI protected. I use 3 different Lee casting pots with no problems, but I agree, the pots should have a ground.

[Mal Paso]

GFIs are a government plot to prevent people from feeling their electricity. The extra letter was put in by Democrats just to inflate things and I won't use it.

Seriously, a GFI is plenty. I would worry more about all the 2 wire lamps with no GFIs scattered through the house. Been shocked by several 2 wire refrigerators.

Why are the plugs on Double Insulated tools Polarized? If it doesn't matter electrically it must be about control.:wink:

Many of the older GFIs failed closed ( Hot) and not all have been replaced. Don't Rely on safety equiplent

[AggieEE]

el34, I like your explaination of parallel current flow. Mind if I steal it the next time I have to teach a parallel class?

[el34]

el34, I like your explaination of parallel current flow. Mind if I steal it the next time I have to teach a parallel class?

Sure. It's not really mine, a really long time ago electricity was explained to me using water as an analogy. Very easy to understand that way-

Voltage = pressure, or how hard is the push (psi, volts) that's trying to move water/electrons through what it's flowing through (the plumbing)

Resistance = the nature of the plumbing (pipe, wire, whatever will be conducting the stuff) that determines the difficulty of getting water/electrons to flow through it.

Amps = the amount of water/electrons that passed through the plumbing, the result of how hard is the push and how much resistance to the flow.

Amps (the result) = volts (pressure) divided by ohms (resistance to flow)

It's the same story for each and every parallel path where flow is possible. Each path would feel the same pressure (volts) but the Amps through each path would vary based on the individual resistance of it.

[montana_charlie]

I put a GFI outlet where I planned to cast, then my new pot gets here and only has a two wire cord on it, just like a metal cased electric drill sold in 1960.


I'm still grounding the chassis anyway. I can't believe something made from all metal that works in the temperature range of a lead melting pot, doesn't get this from the factory.
That drill made in the sixties didn't shock you because the metal body was insulated from all of the current carrying components in the tool. It was fine as long as nothing shorted around the insulation.
Even if the short existed, you wouldn't be injured if the plug was placed in the socket so that the neutral side of the circuit was connected to 'your hand' through the metal case.

People tended to plug the tool in with the connector turned the other way, and they got shocked with varying degrees of seriousness, if there was a problem with the insulating medium.
The advent of the three-way connector cured the problem. The ground wire kept current away from the operator, but the physical design of the plug also regulated in which direction it was stuck in the outlet.

As it turns out, a polarized plug - with one blade wider then the other - does the same trick.

And, as long as the wiring is done by someone who knows what the deal is (like the factory) the neutral lead will be the only side of the circuit you can possibly 'get hold of'.

Neutral is already firmly connected to ground at your breaker box.

CM