Shocking Flexwatt development!

[TraconSnake]

It's true ... Dan really is "the man" ... sorry, couldn't resist.

triple E or work in the trade?

-adam

If you mean Electronics Engineering Technology, yup, I took the course at ITT... though looking back I wish I took computer networking. I kinda sorta work in the trade, but hope to be back into a real electronics job in the future...

Well, no reply from SSS, so back to playing Oblivion!

[SnakeySnakeSnake]

Okay, here's the schematic which I will revise as I get more information.

REV A


Now, I know this is not accurate, so I need more information.

First, does each shelf have a strip of FlexWatt for each tub (as shown in the schematic) or one strip per shelf?

Second, does each shelf have an independant thermostat control, or is there just one main thermostat control for the whole thing?

Does each shelf have one long strip of foil tape (as shown) Actually, looks like in the picture there are two strips per shelf going the entire length. Is that correct?

Aything else on this schematic which needs to be corrected?

Once this schematic is correct, we can start getting some readings and both be on the same page.

-Dan

I did a reading from ground (wall outlet) to the foil, and got about 4-5 volts each... (I was wrong before, I was going from foil to foil)

I have one strip of flexwatt per shelf, 4' long

I have one extension cord per shelf, attached to the far right end of flexwatt

I have two power strips. One is for the top 6 shelves, One is for the bottom 5 shelves.

I have one thermostat for the top power strip, and one thermostat for the bottom power strip.

The two places that have been cut on the flexwatt are diagonally on each end, with the direction of the heating element.

That leaves only two spots on each end exposed, the spot with the wire on the outsides... both have been taped thoroughly.

The foil tape goes from 2 inches in on each side, down the length of the flexwatt, covering about 1 inch each side, leaving maybe a 1 inche stretch of exposed flexwatt down the center (exposed plastic, not wire)

Thanks again for your help, I am VERY confused on what I thought was some simple wiring.

[TraconSnake]

Okay, looks like editing is disabled once there have been replies. The picture is updated, but it still says Rev A on top. It is indeed Rev B.

I did a reading from ground (wall outlet) to the foil, and got about 4-5 volts each... (I was wrong before, I was going from foil to foil)

Okay, and this is a steady 4-5V AC? Hmmm.

Re-reading the first post, you said that this is occurring on just 10 of the 11 shelves. Which shelf is not "hot" (electrically speaking) The top shelf? Bottom shelf?

Induction may be what is going on, but I want to be certain first.

Okay, so, is there anything different about the one shelf that has no voltage? Any possible path to ground? Wired backwards from the other 10? Aligned with sunspots?

With the ten that are hot, unplug all but one. Do the 9 unplugged shelves still shock? Does the one plugged in shelf still shock?

Now, on an unplugged shelf that does shock, set the ohm-meter to it's highest setting, and measure between the foil and either side of the plug. Is there any resistance at all, or is it out of range?

Here's a possible solution based on some assumptions of what I expect the outcome to be.

PROVIDED the one good shelf is somehow grounded...
PROVIDED the shelves only shock when plugged in
PROVIDED there is infinite resistance between the cords and the foil

If the above three are all true, my fix would be to solder a wire to each foil strip, and connect that wire into the ground of the outlet.

You see, if the above is true, I think you were right in venturing that the voltage was being inducted. While the AC coming out of the wall is a very low frequency of 60Hz, it is still AC. As the voltage rises and falls, there is an electromagnetic field which is expanding and collapsing 60 times each second. Whenever a magnetic field is passed through a conductor, in our case the foil strips, a current is induced. Since these foil strips are not connected to ground, there is no way for this current to go anywhere. But when you touch it, the current finds you a good path to follow. Grounding all the foil strips will effectively rid us of this unwanted voltage.

This is why I suspect that the one good shelf is somehow grounded. Or possibly, you have a short in that shelf with the neutral side of the wire. But I'm more inclined to believe that it is somehow grounded.

Let us know what you find out!

MG: I couldn't find a site for the actual company that makes FlexWatt. I think it might be a good idea to call them and ask if they have heard from others about voltages being induced in the foil tape beneath long runs of Flexwatt. As far as the job goes, looks like the commute might be a little long...

Dan

[Adam_Wysocki]

I couldn't find a site for the actual company that makes FlexWatt.

www.calorique.com

Many years ago, when I lived in MA I actually got a tour of their place ... it was wicked awesome.

-adam

[TraconSnake]

www.calorique.com

Many years ago, when I lived in MA I actually got a tour of their place ... it was wicked awesome.

-adam

Thanks! I've E-mailed the following to their support team:

Support,

I’m trying to help somebody resolve an issue with some flexible warming elements used to heat reptile cages. All the connections to the elements are insulated, however there is about 4-6V on the foil tape between the heating elements and the cages. I’m thinking this could be due to voltage being inductively induced into the foil strips.

Please refer to this forum thread for more detailed information:

http://www.ball-pythons.net/forums/showthread.php?p=340852

If you could provide us with some clues or a definite answer as to whether or not induction is the correct conclusion, I’d appreciate it.

Thanks!

Dan White (TraconSnake)

I wouldn't expect anything back until Monday. Perhaps we'll have this issue resolved ourselves by then - but at least this will give them a heads up to the possible issue.

[ErikH]

Induction, huh? I guess that makes sense with all of the heating element involved. I really thought he was going to find a loose neutral someplace, or foil tape touching the contact strip on the end opposite the wiring. So tell me, not to hijack this thread or anything, but would one be better off making a rack out of metal, so that it could easily be grounded?

[SnakeySnakeSnake]

Going up to do the tests you asked..


Is there such thing as grounded flexwatt? I know my thermostats have a spot for ground, but id have to find extnesion cords with a ground wire

[SnakeySnakeSnake]

All 11 shelves shock, I was wrong to say only 10 did (I was going by feel at that point)

Both of the foil strips on all of the shelves has a charge.... it spikes when I first touch it, and then settles in the 1-5 range for the most part


Now here is the great part.... I unplugged everything, and the foil held a charge for one touch.... I would touch the other end of the multimeter to the foil and it would jump up to a few volts max, and then go down to 0.00 and stay there..

About half the shelves kept a charge until i touched them, unplugged, and then they stayed at 0....

Every shelf foil to plug = out of range on the highest resistance setting.

[ErikH]

I have two power strips. One is for the top 6 shelves, One is for the bottom 5 shelves.

I have one thermostat for the top power strip, and one thermostat for the bottom power strip.

Okay, I am going to ask a stupid question here.... Most power strips have a three pronged plug with a ground, I know my t-stat doesn't have room for a ground plug, How is your power strip connected to the thermostat?

[SnakeySnakeSnake]

Okay, I am going to ask a stupid question here.... Most power strips have a three pronged plug with a ground, I know my t-stat doesn't have room for a ground plug, How is your power strip connected to the thermostat?

Because my thermostat has room for a grounded plug


Helix Grounded , $5 more than the non grounded one.