# STC-1000 wiring - check my work



## BrewDaddy (17/6/13)

So - I've wired up my STC-1000 and plugged it in. Everything works as expected.

However, SWMBO still isn't convinced and doesn't want me burning down the garage / electrocuting myself, so I thought I'd start here and post a picture of my work to see if anyone can see anything obviously wrong.

Cheers.


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## np1962 (17/6/13)

I will only say all your wiring appears to be correct.
But, I cannot say by looking at a pic whether your plugs and sockets on the end of the cables are wired correctly or that all your connections are secure or if there is a chance a cable could be pulled loose from your enclosure.


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## BrewDaddy (17/6/13)

Thanks Nige - I should have mentioned, the plugs are actually cut off extension cords, so I've done no wiring at the other ends.


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## dmac80 (17/6/13)

Are the cables secured where they go through the jiffy box? This stops the connections being stressed, good to see that you've used a jiffy box too.


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## Truman42 (17/6/13)

I think you need to swap over 5-6 and 7-8 so your actives are switched not your nuetrals.

I know there was 2 wiring diagrams going around for these. One with active to 5 and 7 like you've done and another with active to 6 and 8.


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## Yob (17/6/13)

Huzzah!!! another STC1000 thread!!  Sweet, there hadnt been one for at least a week.. No offence meant to the OP but there are (or soon will be) 1000 of these threads with the same question, photo's, explanations, issues etc, 

@ Truman, I dont believe it really matters, it's just a switch after all.

ed: Proof my search skiiz are up to par http://aussiehomebrewer.com/index.php?s=deece206577b9f244934fae702d40a5c&app=googlecse#gsc.tab=0&gsc.q=STC 1000


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## dmac80 (17/6/13)

I think you'll find that he has switched the Active Truman, just used some blue wiring instead of brown coming out of the switch.

It's a switch, it doesn't matter which side of the contact the unswitched active is wired to.

Cheers


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## Truman42 (17/6/13)

@Dmac..he hasnt switched the actives. They go to 5 and 7, the switch is on 6 and 8. But yes true it probably wont matter in this. Just trying to teach hm good wiring practices in case he decides to wire up a caravan one day. Then it would matter.


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## spudfarmerboy (17/6/13)

Truman, he has switched the actives, have a closer look at the picture.
He should have used brown wire coming from the switch to the heating and cooling cables, but he has still switched the acitives.
Remember it is switch, in this case the switch doesn't have polarity. Yob had to be told this several times on another STC 1000 thread.
It doesn't matter if he brings an active in 5 and out of 6, or in 7 out of 8 compared to bringing the active into 6 and out of 5, and in to 8 and out of 7. You are still switching the actives to the heating and cooling cables.
I'll say it again, contacts 5 and 6, and contacts 7 and 8 are switches, no polarity.


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## Yob (17/6/13)

_*oi!*_.. in my defence.. one of the earlier posts I made did say that it was a switch and possibly didnt matter... admittedly I wrongly jumped the gun and I also humbly apologised


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## dmac80 (17/6/13)

Truman said:


> @Dmac..he hasnt switched the actives. They go to 5 and 7, the switch is on 6 and 8. But yes true it probably wont matter in this. Just trying to teach hm good wiring practices in case he decides to wire up a caravan one day. Then it would matter.


I'm an electrician Truman, when i want help from someone who has just enough knowledge to be dangerous, i'll ask.

It is bad electrical practice to switch neutrals.

Cheers

Edit:Quoted wrong quote


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## Truman42 (17/6/13)

dmac said:


> I'm an electrician Truman, when i want help from someone who has just enough knowledge to be dangerous, i'll ask.
> 
> It is bad electrical practice to switch neutrals.
> 
> Cheers


No need to get narky about it. I showed the pic to our electrician here and he said that he had the actives on the wrong side as well. But he said it wouldnt matter as its just a switch and gave the analogy that if it was a caravan for example the whole thing would be live, but in this case it wouldnt matter.

But I humbly apoligise if Ive upset you at all.

EDIT: Ive just seen what your saying. I showed the electrician and on closer inspection he agreed that the actives are switched. So our bad.. Carry on..


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## dmac80 (17/6/13)

i'm not upset Truman, it's important to get these things right when people are wiring up 240 V.

If you look at his picture you'll see that the wiring to the switch originates from the Brown incoming wire, and the Blues are commoned up as they should be for a Neutral.

I'm just concerned that there's a lot of people out there doing their own wiring and i don't want anyone to end up dead.

Cheers

Dan


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## spudfarmerboy (17/6/13)

Truman, the caravan analogy you've used is abit out of whack, maybe you misunderstood him.
240 volt gpo's on caravans have double pole switching, thats why you don't use a house gpo in a caravan as house gpo's are only single pole.
One of the reasons this is done is because caravans are supplied with power via extension leads. So, if for some reason the active and neutral are swapped over in the extension lead, by using double pole gpo's, the active and neutral are both switched, thus no live actives.
Now, where that ties in to the STC wiring debate I'm not sure as the op HAS switched the actives.


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## Truman42 (17/6/13)

dmac said:


> i'm not upset Truman, it's important to get these things right when people are wiring up 240 V.
> 
> If you look at his picture you'll see that the wiring to the switch originates from the Brown incoming wire, and the Blues are commoned up as they should be for a Neutral.
> 
> ...


Yeh I agree, but even if he had swapped them over like I said it wouldnt have made a difference. He would still be switching the actives either way and his blue nuetrals are all tied in together.


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## BrewDaddy (17/6/13)

Wow - didn't want to start a fight here.

I had seen diagrams for wiring both ways and actually bookmarked what Yob posted about it not actually mattering.

I'm not sure what to take from the discussions but I think I'll leave it as it is.

Thanks all for the feedback.

The cables are secured. The holes i drilled are really and tight and a bit of tape prevents them from putting pressure on the connections.

I also never intend to wire up a caravan


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## glaab (17/6/13)

since you asked, it's wired right in theory but in practice it's a bit sloppy.
no need for the top terminal block , you shoulda cut the wires longer.
you only need a screw terminal for the earth [the manufacturer could've provided an earth loop on the device imo ], put the active into term 1 on the controller
and loop it from there to 5&7, and use the neutral in as loop terminal for all 3 blue wires. the less unnecessary mechanical connections the better
[more reliable/ tidier/ safer] from a radio engineers point of veiw. don't use tape for stress releiving, get some glands
or better yet mount the female outlet straight on the box. single unswitched outlets are only a couple of bucks ea or use a double with switches.
if you do that use the outlets earth terminal to loop then theres no screw terminals. the coin you spent on a pkt of them and the extra ext cord you butchered wouldve paid for the outlets with change.
I know, I'm a picky prick but you asked .,..


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## Bridges (17/6/13)

Or call a sparky to come look at it. I agree with your wife. Burning down houses or electrocutions are not fun options.


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## np1962 (17/6/13)

glaab said:


> since you asked, it's wired right in theory but in practice it's a bit sloppy.
> no need for the top terminal block , you shoulda cut the wires longer.
> you only need a screw terminal for the earth [the manufacturer could've provided an earth loop on the device imo ], put the active into term 1 on the controller
> and loop it from there to 5&7, and use the neutral in as loop terminal for all 3 blue wires. the less unnecessary mechanical connections the better
> ...


The problem with looping using the devices screw terminals is that they are so small it is a pain to get two wires in there securely let alone the three you require for the neutral.


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## Yob (17/6/13)

Bridges said:


> Or call a sparky to come look at it. I agree with your wife. Burning down houses or electrocutions are not fun options.


The amount of sparkies that have wired these wrong defies belief


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## Crusty (17/6/13)

This is very easy to follow.


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## Crusty (17/6/13)

Regarding the compressor delay ( F3 ) does the compressor delay activate every time the differential ( F2 ) is reached or not?
When I wired mine up & testing it out, I set desired temp to 18.0deg, differential to 0.5deg & compressor delay to 3mins.
Everything works perfect, 18.5 & the fridge comes on, 18.0 it turns off & 17.5 the heating switches on. I held my hand over the temp probe & when it hit 18.5, delay light flashes for 3mins & on comes the fridge, perfect. Now that I have it in use & a fermenter bubbling away, I noticed that the compressor delay doesn't activate any more. Is this due to the fridge holding temps for long periods & the compressor delay is not required due to it exceeding the 3mins or should it still activate even though the fridge is off for an hour or more.
When testing, I see that the delay activated only if the temperature fluctuated between heating, off & cooling in the 3min time frame from when the fridge actually turned off.


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## glaab (17/6/13)

it won't delay if it's been off for more than 3mins already. thats normal


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## chewy (17/6/13)

Lol I love ATC threads...


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## Crusty (17/6/13)

glaab said:


> it won't delay if it's been off for more than 3mins already. thats normal


Thanks glaab.
I assumed that was the case as it had obviously exceeded the 3min delay that was set.
Working as it should then.
Cheers.


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## chewy (17/6/13)

You should leave it at 10min delay... The idea is to let the fridge rest between startups and not fk the compressor....


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## Crusty (17/6/13)

chewy said:


> You should leave it at 10min delay... The idea is to let the fridge rest between startups and not fk the compressor....


Well here at the moment, even at 3min delay, the fridge is staying off for an hour or more so I think the compressor will be fine.
If I had it at a tighter differential & warmer ambient temps, I'd probably look at setting the delay higher.
Thanks for the tip though.


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## chewy (17/6/13)

0,o


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## ploto (19/6/13)

I can't work out how to repost an image but here's how to do it neatly.

http://aussiehomebrewer.com/topic/70395-help-with-stc-1000-controller-wiring-help/?p=996586

Using the wrong coloured wire even when 'it doesn't matter' is never a smart idea. You never know who might end up playing with it one day. Even what seems obvious to you now may well leave you scratching your head years from now. And no I am not an electrician nor am I affiliated with any.

Perhaps there should be an 'official' STC-1000 sticky thread with a collection of diagrams and photos deemed correct by the AHB hive mind.


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## godzillalad (31/7/13)

I've jiust wired one of these up too and was wondering why in the instructions does it say



> Both heater and cooler must have *external AC power*


and elsewhere it says to



> Safely distinguish the sensor down-leas, power wire and output relay interface


Is there a problem with using the cross wiring like above? Should we be using relays and separate power supplies for heater/cooler?


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## Yob (31/7/13)

The unit only has one power input so I should think not, essentially it's a switch so no need to make it overly complicated.


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## booargy (31/7/13)

"Both heater and cooler must have *external AC power"*

The heat and cool interface are just switches. the unit activates the switch to supply power to the appliance.

"Safely distinguish the sensor down-leas, power wire and output relay interface"

This just means make sure you get the right hole or might be in the pooh. If you run 240V through the sensor the smoke will leak out and it will not work.


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## QldKev (31/7/13)

godzillalad said:


> I've jiust wired one of these up too and was wondering why in the instructions does it say
> 
> 
> and elsewhere it says to
> ...



Is there a problem with using the cross wiring like above
No, pins 1 and 2 are power supply to the stc. The remaining active wires are only getting switched via an internal relay.

Should we be using relays
No need if the load is <=10amp, the device has 2 x 10amp relays built in. If you wanted this to switch a load greater than 10amp then this unit could switch an external relay of greater capacity and the wiring would change to reflect this.


separate power supplies for heater/cooler
No, the device will not run both at one time. So as long as the load does not exceed the source capacity. Ie The device can only switch 10amp. The device itself uses very little power, but should be taken into the entire load.


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