Shocking Flexwatt development!

Crap. I really gotta get a Helix. O.k., never mind, I thought I was on to something.....

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Originally Posted by ErikH

Crap. I really gotta get a Helix. O.k., never mind, I thought I was on to something.....

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No problem! I appreciate any input.

The problem is my extension cords are only 2 pronged, so im not using that ground anyway (I only have 2 spots to hook wires too on the flexwatt anyway)... I suppose if i had an extension cord with a ground wire, I could split it and attach to the two piece of foil...

Im just wondering if the inducted current in the foil tape is worth worrying about, or if i should use some other kind of tape in the future.

Found an old post describing a mild electric shock


http://forum.kingsnake.com/caging/messages/13941.html



though he never responds back, he said that the seller told him that this is normal... wonder who the seller was.

Definitely sound like induction. The reason you get a shock even after unplugging is the flexwatt is acting like a giant capacitor. (a capacitor being two conductors separated by a thin strip of insulation) Technically speaking, even after the flexwatt is unplugged, there is either an excess or deficiency of electrons stored up on the foil tape which is released only when it finds a way to get to ground. Kinda like how static electricity works.

There is no way to ground the flexwatt itself - it just has two sides for voltage. Grounds are used on equipment where voltages can find their way into the chassis, such as a computer case, metal power tools, and some AV equipment. (really, ALL AV equipment should have a ground. We had a 60hz hum once that went away when we grounded the equipment)

Don't worry, you don't need to re-wire everything. Just take a piece of wire, connect all the foil strips together, and connect that wire to ground. The wire doesn't even have to be insulated. Just find a way to get a good solid connection to each strip of foil tape, and plug it into a ground somewhere. Either wire it into the cut off end of an extension cord with a grounding prong (it will be the green wire), or plug it straight into the ground receptacle of the outlet.

You could go to Radio Shack and get some of the microclips with the flat jaws, and just solder all those together, then put a bananna jack on the end of the wire to plug into the ground of the outlet. There's a lot of ways you can accomplish it. Just ground it all, and you should be good to go.

On an aside, my E-mail to Calorique bounced back to me undeliverable. But sounds like we got this under control.

Let us know how it turns out!

Dan

P.S. Here's a site that has a neat little JAVA applet that helps explain what's going on. The wire is like the foil. The magnet is like the AC current in the FlexWatt. Even though the foil is not coiled, there is enough of it that current is being induced into the foil by way of electromagnetic induction.

http://micro.magnet.fsu.edu/electromag/java/faraday2/

And a Wikipedia article:

http://en.wikipedia.org/wiki/Electromagnetic_induction

Thanks bud, I will try to get the ground setup wednesday.


Is there a reason why it doesnt have to be insulated? I understand its a ground but wont it have the juice running from the foil in it?

The ground wire prevents current from ever building up in the foil. It is acting like a lightning rod.

bryan, I don't know anything about this stuff at all but I did have the same thing happen to me. After called the Bean Farm(where I purchased the tape) they told me the provided instructions are not correct and you need to cut the tape in the clear band and not in the black band. I made this correction and my tingle problem disappeared. I have not idea if it was because I rewired everything or because I changed the cut point but it worked. I hope this helps. Awesome info from the forum smarties!

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Originally Posted by cueball

bryan, I don't know anything about this stuff at all but I did have the same thing happen to me. After called the Bean Farm(where I purchased the tape) they told me the provided instructions are not correct and you need to cut the tape in the clear band and not in the black band. I made this correction and my tingle problem disappeared. I have not idea if it was because I rewired everything or because I changed the cut point but it worked. I hope this helps. Awesome info from the forum smarties!

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When you say the clear band versus the black band, what exactly are you referring to? (I haven't yet actually handled a piece of flexwatt) Isn't the black band the conductor?

If the conductor is cut as shown here:

http://www.mgreptiles.com/FLEXWIRING.html

Then Yes, if the edge is not taped, current could get to the foil. But SSS did affirm multiple times that all edges are insulated with electrical tape.


In reply to why the ground wire doesn't require insulation, the ground acts as an electrical short to ground, so all the current will follow the wire. The only way somebody could get shocked by touching a ground wire is if their body offered less resistance to the flow of current.

In reality, it's a lie that current follows the least path of resistance. Current follows ALL PATHS. But if you do the math, the resistance offered by the wire, which would be in the tenths of an ohm, is much less than the resistance offered by your body. So if you're grounding a charge of 6 volts, and there is 1 ohm of resistance in the wire, you'd have a 6 amp current flow in the wire. If you touched the wire, the resistance offered by your body is usually at least 100,000 ohms. So you'd get 60 micoramps (.00006A) worth of that current.

Now, while SSS was measuring upwards of 6V, there won't be 6A flowing through the wire as the charge won't have a chance to build up to that amount once the ground is applied. But it would be interesting to take a current reading between the wire and ground to see how much current is being bled off.

To do that, set the multimeter to measure AC Amps, disconnect the ground, and connect one wire to the ground wire, and the other end to the outlet ground. Turn everything on and you'll see how much current is being bled off. This might be a good thing to know as if you are getting significant current bleed off, you'll need a heavier gague wire to handle the increased load. If the wire gets warm, you need thicker wire. But I highly doubt this will be the case. Of course, we are grounding 11 strips...

The black band is the conductor and is listed in the instructions as the cut point. The clear portion seperates the black bands and was the logical cut point, I should have just listened to reason :P


I have the same basic setup. MDF rack, 4" flexwatt and Helix thermo

So, have you tried it out yet? Is there resolution?