stc-1000 questions

let me start this out by saying I have no electrical experience and after reading the 300 sum od pages of info on this topic im still lost. I am trying to build a temp controller for my garage fridge so I can ferment in it and im not sure on a few things

1. Can I use an extension cord with #16 wires on it or do I need to get another?

2. Can I use the wires from the extension cord to wire up the stc to the outlet?

Any help will be much appreciated.

 

I'm no electrical expert either, but I personally wouldn't use 16ga to run a fridge/freezer. A quick search showed 16ga is good to 13 amps. Thats probably plenty to run your fridge(and the stc1000 is good for 10amps at 110v anyway), however, if your circuit breaker is a 15 or 20 amp, the 16ga wire becomes the weakest link and would burn up before the breaker tripped.

I am also building a ferm chamber with the stc1000 and plan to use 14ga wire for my internal wiring, and 14ga minimum for my extention cord.

 

thanks for the quick reply. I figured that was the case. I bought the extension cord without even looking and later realized it was so small. looks like its back to lowes

 

I suggest you buy a three prong extension cord. (I didn't and wish I had) I wired it with a heat plug , a cooling plug, and an always hot on a 14" section of the extension cord i wired it with. It might simplify your build if you read the amp draw of your freezer/fermentation cabinet on the tag to check the load so you be sure to use the right gauge wires.

 

I disagree, if this were the case you would never use anything less than a 14 gauge wire for your standard 15 amp circuit. Amperage is drawn, not pushed so unless you are plugged into something that draws more amperage than the wiring can handle you are fine. If you are greatly concerned about this condition you can put an inline fuse in to protect from over amperage like they do with Christmas lights, I presume the only reason is so some knuckle head doesn't use an old strand if multi color as an extension cord to a table saw. Anyway, your determining factor is the rating of what you are plugging in, check that to determine how much amperage is being drawn and then size the wire accordingly. I have 3 ranco etc111000 controllers all wired by butchering a common 16 gauge extension cord and none if them have ever found a chest freezer or fridge that draws more than that gauge can handle.

 

Use 14-gauge throughout the build, including the chord.

 

Can you explain the logic of using wire that has double the amp capacity of what it is being used for?

 

Look at the cord to the fridge. What gauge is it? Betcha it is 16. Mine is.

I used a 16 gauge cord for my STC-1000 based controller as well. I sleep at night.

 

16 is fine, i wouldnt go 18 though...

 

So 16 is good for the wiring and the cord?

 

Yes!, 16 is fine... if you find a fridge that takes more than 10 amps to run then there are other issues you need to worry about. Besides the controller will burn up before the extension cord will.. im pretty sure the controller even has a fuse in it to protect it so worst case you blow the fuse and have to take the controller apart to replace fuse.

using a cord that has a amperage rating greater than the breaker for loads way less than that is like wiping before you poop... it dont make sense.

 

Going to be using the stc as well for my outdoor fridge kegerator. be easier than having to go out there and turn on/off a light bulb or on/off the fridge all winter. Good info thanks.

Sent from my SGH-T769 using Home Brew mobile app

 

thanks for the help fellas. I should have this thing done by tonight so I'll post some picks later on

 

hey everyone, I see two types... 220V and 110V, which one is the one can can be used for our purposes? Oh I see the 220 is a euro one... correct?

 

Yup.. 110v is what's running through your standard plugs

 

Yes. 110V AC for most of us here in the US.

 

No. It doesn't have an internal fuse associated with the relays.

 

When I opened mine, the relays were actually labeled 15A, I still used 16 gauge throughout all of my STC's

 

got it all put together. it powers up and gives me a temp but I haven't tested it fully. everything good so far tho. thanks for all the help guys I really appreciate it. pics coming soon.

 

if anyone needs the info on what I used or where I got it from hit me up. if you sign up for amazon's free 30 day trial period for prime you can get free 2 day shipping fyi. just don't forget to cancel it before the 30 days is up.

 

pics

 

Amazon Prime in general is so worth it if you order off them often...

Nothing like paying 0 dollars to get a 30lb Miter saw shipped to my house in 2 days for half the price it'd cost at HDepot or Lowes...

If/when they ever open up a Grocery store i'll be all over that.

 

https://fresh.amazon.com/welcome

Mind... blown! Kabooooom!

 

so I testing out the controller this evening on the free fridge I got which I planned to use for my ferm chamber. controller works great but now the damn fan in the freezer isn't pushing air down into the fridge area. im gunna let it run for a while to see what happens but if it doesn't start to work I want to take the panel that separates the fridge and freezer off and see if it will get cold enough like that. Any thoughts or advice? I think ive see someone else do this on here I just cant seem to find it.

 

If it's a standard kitchen fridge you'll need that fan to move air thru the evaporator coil. The fan is not just there to share air between the freezer and refrigerator compartment.

 

what does that mean

 

What it means is that the fan is required for operation. Your post appeared to indicate that the fan was not operating. Maybe I misinterpreted. If that is not what you meant, please correct me.

FWIW, a standard kitchen refrigerator/freezer has an evaporator coil in the freezer, usually behind the interior rear wall. A fan circulates air thru this coil in order to remove heat in the freezer compartment. There is usually some type of air ducting/damper system that allows a small flow of this freezer air into the refrigerator compartment for cooling. If the fan is not circulating the air, the system will not function. The evaporator will quickly turn into a block of ice.

There is another common type of refrigerator that just has a cold plate evaporator with no fan but that design is usually relegated to dorm size refrigerators.

 

Yea the fan wasn't working. I took the aluminum plate and styrafoam out from in between the fridge part and freezer. Seems to be working for the moment. So you think its gonna freeze in there? What's going to happen if it does? I have no clue how a fridge works BTW so please excuse my ignorance.

I really appreciate the help btw

 

Well, it's supposed to freeze in the freezer, however, once the evaporator builds up some ice, because of the lack of air movement, cooling (removal of heat) will be steadily reduced.

Which is why dismantling the interior may not have been the best course of action.

 

Fridge was free. If it goes out on me I'll just spend some money and get a nice one.

 

Just built mine, and used 16GA throughout. According to the label on my chest freezer, it only draws 5 amps, so I figure 16GA ought to cover it. Haven't actually tested it with a full load yet though. Might just add a 10 amp inline fuse just as a precaution. And for what it's worth, check out this link. This guy has an AWESOME and easy-to-decipher diagram showing you how to wire up the entire project, including some LED bling.
http://loudmouthbrewer.wordpress.com/2013/12/10/diy-stc-1000-2-stage-temperature-controller-wiring-diagram-with-indicator-lights/

 

NOOOO!! AND NOO!!

IMO 16 gauge wire is generally FAR to small to run a refrigerator compressor! 16ga is only good for 12-13 amps. In all seriousness if you run 16ga to a refrigerator that draws over the amperage a 16ga wire can handle you're running a risk of burning your place down!

And I highly recommend AGAINST permanently using extension cords for anything! There is a reason it is against fire code!

For a refrigerator you are going to want a 14ga wire and a 110v 15 amp circuit and the least!

I just built a fermentation chamber and I actually wired a 25 foot plug using 14/2 with a ground using outside wire. The STC-1000 can only handle a 10amp draw on it so a 15 amp circuit would be fine as long as what is drawing on the controller is less than 10amps.

But If your refrigerator draws less than 10 amps then go for it. Otherwise don't let your wiring job become your weakest link!

I really feel you are far better off over sizing the wire and not needing the capacity then trying to skimp on the wire and need the extra capacity.

Sent from my DROID RAZR HD using Home Brew mobile app

 

acafro, forgive me for being thick...i'm not an electrician (nor do i play one on TV), but if the STC-1000 is, in fact, only rated to 10 amps, and a 16GA extension cord to 13 amps, wouldn't the OP be perfectly fine building his controller with wire from a 16GA extension cord??? Cause it seems to me that the STC-1000 would be the weakest link (and fail first, 3 amps worth of draw before his extension-cord-build would give out)...

 

By using your reasoning you should not be using a STC-1000 that is rated only for 10A on a 15A circuit. What is your reasoning for saying the you can not use cable with a lower ampacity, but you it is ok to use other electrical componants with lower current ratings. By the way from what I have read the relays are in fact rated for 15A @ 120V.

 

I am not running a 15 amp system, I am running a 10 amp system on a 15 amp circuit. The circuit is the wiring going from the outlet to the breaker panel and that particular system, is on a 15 amps breaker, thus it is a 15 amp circuit (as is most of the circuits in my house other than 220 volt circuits). Now for the record I am not an electrician and my terminology could be off, but the licensed electrician who helped my with this system seems to feel it is an appropriate set up. The 15 amp circuit merely means that circuit that the fermentation chamber is plugged into can handle up to 15 amps

The system I have set up does not draw more than 10 amps on the controller. So yes, the STC-1000 is appropriate for this particular application.

as far as the STC-100 rating go, here is a picture of the wiring diagram that came with the STC-1000.

10A/220VAC to me indicates the STC-1000 can only handle 10 amps up to 220 Volts AC. Though I could be mistaken...

 

the STC-1000 is only rated for 10 amps and yes it may be the weakest link depending on how it is wired, if the wiring between the heater / Air conditioning and the STC-100 is too small then that could be the weakest link, and if the controller does not fail and draws too much on the extension cord then that may become the weakest link. Why even chance it and use wiring that comes close to max capacity?

Just because the STC-1000 is rated for 10 amps doesn't mean it will shut itself down. There is no fuse or circuit breaker in the STC-1000 to shut itself down, so if the system draws above 10 amps you are chancing a dangerous situation.

also extension cords are not designed to be used as permanent wiring, that is why there are fire codes against using them in such manner

 

Thanks for the really entertaining thread everyone! I've enjoyed reading it.

I am currently using a stc-1000 for a ferm chamer myself, but its not a fridge or freezer.

I fear saying so, but I am an electrician.

First off to cover the extension cord topic. Have you ever looked at the wires in an extension cord to a vacuum, or even for the fridge or freezer you are using? The wire size that is supplied by a manufacturer for a device is rated for the amperage the thing will use. When I turn on my vacuum at home if I feel the cord I can physically tell the cord is warm, but it is not burning up or ready to cause a fire. This is simply because by design there is no way for the average user to overload the wire.

If the nameplate on your device (fridge) says it draws 8 amps then 16 awg wire is safe to use. Its safe because you have purposed the wiring to only that device. The unfortunate part about it is simply the temptation of having power supplied at the receptacle. I would recommend not plugging anything else into it. Leave it as a single purpose plug.

If I were to be wiring this myself the way you did I probably would have used 14 (15 amp) or 12 (20 amp) awg wire to the receptacle, whatever the breaker supplying the power is rated at. I would do this simply for the fact that I would then know that I could plug anything into the plug and it would be protected.

Second is your wiring of the box you created, and addressing the fan not running.

There are 9 terminals on the stc-1000. Three for the power input, 4 for the heat and cool contacts, and two for the thermostat. The power terminals simply do what you think they would do. You hook up the three wires from the cord and it will turn on. You don't need to have anything else hooked up and the thing will still turn on.

The heat and cool are simply contacts. They open, or close when the stc-1000 tells them to do so and that is all they do. Which is of course governed by the thermostat.

The way things look from your picture. The stc-1000 is turning off and on the power to the plug in the same box. So the fridge will turn on when the stc tells it to, but turns completely off when the temperature setting is met. The stc contact has broken and stopped supplying power to the fridge at all. That is why the fan does not run all the time.

There are other ways to wire the stc into a fridge replacing the fridges thermostat with the one supplied with the stc. That involves drilling into the fridge though and I don't blame a guy for shying away. I'm not going to write about how to do that as it is well documented on the net, (including videos) if one were to simply google it.

Sorry for the lengthy post, but I hope I was descriptive in enough to help, and stop the wire guage bickering.

 

Firstly sorry, you are right that all the documentation states 10A limit - it is only those that have opened up that have found that the relays are actually also rated for 15A @ 120V.

Your reasoning does not make sense - the cable can handle the expected current, the STC-1000 can handle the expected current. Why would you need to use cable that can handle more current than the breaker can handle for appliance cord. As someone said above if that was the case no appliances would be wired with anything less than 14 AWG.

Why are you distiguishing between two componants both rated below the CB rating and so could potentially (but not likely) be overloaded. You are basically saying that for some reason you trust the STC-1000 to stay together even though the rating says it should, but you don't give the same level of trust to the cable... personally I would trust the cable more

A fair as I am aware most warnigns about contious use of extention cords are due to the fact their is not control over the general publics use of them - i.e. people can easily plug loads over the rated current, if not used continously you would notice your cable is stating to burn/melt/etc. when you put it away.

 

The system is plugged into a 15 amps circuit, why would I not use 14 GA wire? If you would like to use wire that is smaller than go ahead, I simply do not feel comfortable using wiring that cannot support the total use of the circuit it is plugged into.

I also have other outlets and lights running in the same system that are not connected to the STC-1000, the potential is there to draw up to 15 amps from the system. But the heater and AC I have wired into the STC-1000 draw under 10 amps. I really fail to see why the concept is so difficult to understand nor do I see why it's an issue.