Anyone with any electrical/wiring knowledge?

Is there some electrical/wiring reason I cannot buy a thermostat at Home Depot or Lowes, and wire it to my heat tape? I suspect there must be, because no one does it. Can anyone explain this to me, or explain how to wire it? The closest I can come to knowing anything about it is that there are more than two wires going out of the thermostat, right?
I'm kinda clueless, here! :oops:

Ok, Ok, I think I get this,
My husband just took a look at your post and If I can interpret this correctly:
Those type of thermastats cannot read the heat tapes heat, only the temperature of the envirnment.
Idon't know if that makes any sense,
like I said I could be saying it all wrong, i'm so damn tired..lol
Rusty

RustysDragons has it pretty close. Thermostats use a mercury switch to activate them (well MOST do, i've seen some that don't, but most do)... when the mercury cools down it moves to one side because its heavier or lighter (i forget which) and vice verse when it gets warm.

Heat tape uses a resistance type switch to activate/deactivate them... Heat makes resistance which reduces overall voltage thru the circuit which is how it controls the temperature.

While I can see it being possible (with some uhh... modification engineering) to make a household thermostat work with a heating pad, UTH, Heat Tape, etc... but the thermostat would HAVE to physically be (for lack of totally bashing it apart, in which case let me konw and i'll just draw u up a schematic and a parts list for what u'd need) in the tank. But then still it would only sense the temperature around where it is.

If that doesn't make sense (cause i mighta just rambled on I cant' tell) let me know and I"ll give it a second shot. Right now I'm goin out to pickup my new 40BR :) WOOOOOOT

-Chris

Randy, screw that, get a dimmer and hook it up :) I'll dig up a link when I get home, time to head off for a partay soon :)

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Thermostats use a mercury switch to activate them (well MOST do, i've seen some that don't, but most do)... when the mercury cools down it moves to one side because its heavier or lighter (i forget which) and vice verse when it gets warm.


Heat tape uses a resistance type switch to activate/deactivate them... Heat makes resistance which reduces overall voltage thru the circuit which is how it controls the temperature.

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Ok yes, sure, that's what I meant to say..lol
Rusty

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Originally Posted by BallKingdom

Randy, screw that, get a dimmer and hook it up :)

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I have a dimmer hooked up to it now. I am trying to figure out a better way to do an incubator setup than the hovabator I have now. I guess mounting it inside the incubator would work fine, huh? Would high humidity mess with the thermostat?

Chris, how hard would it be to build one from scratch with a remote temperature sensor probe? Would it cost less than the $100 most of them run at the reptile supply places?

Rustysdragons ;) I wasn't trin to step on toes, just merely elaborating on what u had said. Mechanics (and the sub classes under it like wiring, electronics, hydraulics, etc...) is what i did in the military and what i went to UTI for out in Phoenix, so I tend to ramble on about it :) What can I say.. once a snipe always a snipe ;)

RPlank, really wouldn't be that hard using just a household thermostat if my thinking is right. I've got an old one layin around in the basement so I'll give it a shot usin a test light and let u know what all would be involved.

-Chris

Last time I made an effort to wire something I didn't use a ground, and I had seriously no idea when I was doing. I looked at one already done when I made mine. I when to plug it in and there was an explosion of sparks...

Sure I'll tell ya how to wire some stuff!

That sound's like some of my experiences with wiring. All I know is that the kid's said to let them know ahead of time before I mess with electrical stuff again so they can make sure my life insurance premiums are up to date. Was a pretty good 4th of July firework's if you ask me. :shock: :lol:

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Rustysdragons I wasn't trin to step on toes, just merely elaborating on what u had said.

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Oh it's ok, I had no clue on what I was interpreting from my husband anyway. He always does those things. (I would just get electricuted if I messed around with that stuff.lol)
Thanks
Rusty

OK, being a PROFESSIONAL ELECTRONIC TECHNICIAN with experience in everything from microvolts to kilovolts, and at frequencies from DC to Daylight, let me add my 2 cents worth here.

First off, it depends on the type of thermostat you're using. Many inexpnesive thermostats use a bimetal system which makes and breaks a low voltage contact depending on thermal expansion/contraction. For most household furnaces, these contacts control a 24 - 28 VAC low current line which tells the furnace when to kick on and off. They work strictly on surrounding air temperature, with no real "feedback" from the furnace. They're cheap, usually effective, with minimal parts to go wrong. Fancier thermostats use a digital thermometer system to control a small relay inside, which likewise controls the furnace control voltage. In most cases, you do NOT want to run any kind of higher potential voltage through these contacts. The initial current surge when they make contact can start to burn and pit the contacts, resulting in loss of conductivity, or worse, welded contacts that never turn off. Always look that the contact rating of such a device, and make sure it well exceeds the power requirements of what you're controlling. Were I controlling, say, a 60 Watt ceramic heater, I would want a control system capable of handling at least 100 watts, preferably 150. You really don't want to run close to the ragged edge on such stuff.

Can household thermostats be used to control heat tape? Certainly, with a little extra parts thrown in for proper control. To do so, what I would do is to use a small low voltage AC adapter, such as would be used to power a personal electronic device like a CD player. This low voltage would be what was routed through the thermostat contacts. The thermostat applies or removes this voltage from the control contacts of a solid state relay. SSR's can be bought which use low voltage direct current to control high voltage or high current, either AC or DC. Unlike a mechanical relay, which uses a control voltage to set up a magnetic field to pull mechanical contacts together, a SSR uses a low control voltage to turn on or off an electronic "gate" for the voltage; no moving parts, and very low current draw on the control side.

The advantage of such a system is that your high current potential voltage (110 VAC for your heat tape) does not have to actually enter the reptile enclosure if the heat tape itself is on the outside radiating in. You have a low current potential low voltage in where the animals are (posing less risk in case something gets damaged or damp). Watching my BP nose around things in his enclosure, this can be a very good thing.

How reliable are such things? Well over ten years ago, I got sick and tired of the heat controller on our water bed, and using an electronic thermometer module I bought at Radio Shack, made a thermostat for our water bed. It utilizes the 1.5 vdc output logic of the thermometer to toggle a 5 vdc logic chip, which in turn controls the solid state relay. I set the thermometer to the temperature I want the bed to stay at, and it holds within 1 degree of that temperature year round, even when we lived in the High Desert of California, where our winters dropped well below the 20's range. It's been working flawlessly since I made it. Too bad Radio Shack doesn't sell those thermometer modules anymore. I'd use a couple of those to make controllers for the Reptile enclosures, too.

Back to what's available, though. For a reptile enclosure, I would spend a bit more money and buy a digital thermostat. They tend to be a lot more accurate and reliable, and a lot easier to set where you want them, instead of having to spend time with "hit or miss" calibration of where exactly the temperature trips the old bimetal contact system. As I recall, you can get digital thermostats from places like Walmart for under $20.

Well Randy, I think you found the answer to the Topic of Your post.

Hoomi.....Can you explain that in Layman's terms? Or was that? :lol:

I read your post like 3 times and still got lost......I guess that's why I spent almost 20 years in a china factory spraying toilets.

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Originally Posted by Ironhead

Well Randy, I think you found the answer to the Topic of Your post.
Hoomi.....Can you explain that in Layman's terms? Or was that? :lol:
I read your post like 3 times and still got lost......I guess that's why I spent almost 20 years in a china factory spraying toilets.

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Well said, Ironhead! LOL! :D

Hoomi, I'm just a public servant, so most of that went way over my head! Thanks for what I'm sure was a very information packed post, but could you dumb it down a little for me? I understood this part:

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As I recall, you can get digital thermostats from places like Walmart for under $20.

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Am I correct in saying that you are telling me that I CAN use a Walmart thermostat for heat tape? And you recommend a digital? And to really show off my IQ (or lack thereof), how many wires will be exiting the thermostat, and if there are more than two, which should I wire to the heat tape? And it WOULD have to be mounted inside the enclosure, yes?

Thanks for the post, Hoomi, but all the SSR, magnetic field, 110VAC, potential voltage stuff went zooming right over my poor, stupid head! :oops:

After spending quite a while typing out what I'd hoped was a more basic, "layman's terms" explanation, the forums decided I wasn't logged in and sent me to the login page, and my browser isn't letting me go back to where I had all the text typed in. Argh!

Quick summary. It isn't about being smart or "stupid". It's simply about what we're familiar with. I've been doing this electronics stuff for nigh on 25 years now. Sometimes I see this stuff in my sleep. To really simplify it, I'll draw up a basic sketch and scan it in to post here tomorrow.

Let's just say for tonight that, when it comes to electricity, we want to keep the dangerous levels of it out of reach of our scaly friends, lest our Ball Pythons become Great Balls of Fire.