# Sorry for another STC thread - want to make sure I understand this



## Nizmoose (27/10/15)

Hi guys I know the wiring for an stc has been done to death and the many diagrams seem easy enough. My questions dont so much relate to the how part of wiring it up but the whys. I hate just doing things without a sound understanding of how things work whether thats wiring, brewing, pulling cars apart, etc. I have a reasonable amount of experience with wiring in cars but haven't done anything 240v and appliancy (definitely not a word). I want to make sure I've got this right using the below diagram.




Firstly Im not sure if this diagram is from the US and if we have slightly different colours but I think its right?

So we have the brown(ish) which is live?

Blue which is neutral?

and green which is earth?

Our stc power terminal has a live wire from the mains and a neutral wire back to the mains?

Our sensor terminal has both sensor wires in it, nothing from mains.

Both our heating and cooling has power from mains going in and a power line coming out and going to its respective plug?

Both our heating and cooling plugs have a neutral and ground wire running from the mains to the heating/cooling plug or from the heating/cooling plug back to the mains depending on how you look at it?


Hopefully someone can fill in those blanks with yes and no! I know theres a heap of diagrams out there but sometimes I find it helpful to spell out where each wire is going and what it is doing to get a sound understanding of how the unit is working, I havent seen a good detailed explanation of each wire and its function so hopefully (assuming the above is correct) it'll be helpful to others.

Cheers

EDIT: also as more of a general electrical question. The difference between neutral and ground is that neutral is the usual return for electricity back to the mains and the ground ensures that if a neutral or power wire hits the fridge and makes it live the current will travel through the ground wire and trip the breaker in the house preventing crispy humans?


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## MHB (27/10/15)

It looks the goods, the way I remember the colours is
Red and Redish Brown - Active - the colour of blood dry/blood because the active can kill me
Black and Blue - Neutral - as in bruises, can hurt me but less likely to be fatal

Not exact and all but it makes sure I keep my big fat fingers out of active circuits...

Earth is Yellow/Green striped.
The modern house hold protectors don't look at the earth, they compare the power in the active and neutral and if there is a difference it shuts off. It would be quite easy to set up a situation where lots of power is going through you and not going down the earth wire, leading to crispy critters = bad place to be.
Mark


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## Nizmoose (27/10/15)

MHB said:


> It looks the goods, the way I remember the colours is
> Red and Redish Brown - Active - the colour of blood dry/blood because the active can kill me
> Black and Blue - Neutral - as in bruises, can hurt me but less likely to be fatal
> 
> ...


 Thanks mark especially the last bit, so what is the ground doing essentially in terms of its necessity for a safe circuit?


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## Crusty (27/10/15)

I'm about as useless as tits on a bull but I've wired up 7 of these now & used this diagram.
Even colour coded for special people like me.


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## dannymars (27/10/15)

^^ both these are exactly the same....



Nizmoose said:


> Our sensor terminal has both sensor wires in it, nothing from mains.
> 
> Both our heating and cooling has power from mains going in and a power line coming out and going to its respective plug?
> 
> Both our heating and cooling plugs have a neutral and ground wire running from the mains to the heating/cooling plug or from the heating/cooling plug back to the mains depending on how you look at it?


Yes

Yes

Yes, funny way of wording it though... 

The diagram you posted is correct.


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## idzy (27/10/15)

http://aussiehomebrewer.com/topic/66428-stc-1000-in-pictures/ Stc-1000 in Pictures is good even for people a bit derp...


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## Nizmoose (27/10/15)

idzy said:


> http://aussiehomebrewer.com/topic/66428-stc-1000-in-pictures/ Stc-1000 in Pictures is good even for people a bit derp...


yeah this was the first thread I read, its sort of helpful for the assembly but besides the wiring diagram it explains f all about the wiring and why things are going where


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## sponge (27/10/15)

Brown/Active is being switched (opened/closed) by the heating/cooling contacts in the STC (closing the circuit for current flow) and thus does not require a neutral connection, unlike the mains supply which requires the potential (between active and neutral) to power up the actual STC unit.

Once the heating/cooling contact closes on the STC, the current can then flow through to the load where the potential will power a fridge/heat an element/etc.

In an absolutely perfect world an earth would never be required as it really is only a safeguard against faulty connections/equipment/wiring/etc and provides a path of least resistance to earth for stray current instead of going through a person. Because of human error (and of course other factors), *earth wires/connections are an absolute necessity*.

This is a very basic summary of why/how an STC does what it does.



*As a side note, NEVER fcuk with electricity!!*


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## Nizmoose (27/10/15)

sponge said:


> Brown/Active is being switched (opened/closed) by the heating/cooling contacts in the STC (closing the circuit for current flow) and thus does not require a neutral connection, unlike the mains supply which requires the potential (between active and neutral) to power up the actual STC unit.
> 
> Once the heating/cooling contact closes on the STC, the current can then flow through to the load where the potential will power a fridge/heat an element/etc.
> 
> ...


Haha good side note and one I'm a big believer in thus the thread! Excited to get the stc in the mail and finally have temperature control now


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## dannymars (27/10/15)

This is the same (but different).. I find it easier to wire like this...


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## Camo6 (27/10/15)

dannymars said:


> This is the same (but different).. I find it easier to wire like this...


Maybe if you're Mr Squiggle. Out of interest, what sized wire are you using to be able to fit two into a single STC terminal and how are you splicing those earths?


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## TheWiggman (27/10/15)

Why he would be using a double screwed connector of course!


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## Camo6 (27/10/15)

If you can tell that from that diagram you must be Blackboard!


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## Barge (27/10/15)

Camo6 said:


> If you can tell that from that diagram you must be Blackboard!


Hurry up! Hurry up!


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## spog (27/10/15)

Settle down Bill.


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## MartinOC (27/10/15)

Nizmoose, that's definitely the BEST wiring diagram I've seen (in your OP) for wiring these things up. Someone should put this up as a "keeper" somewhere here.

Common Neutral.

Common Earth.

The Active powers the unit itself & is switched for the heat/cool relays.

Use Terminal blocks for all the common connections & you can't go wrong.

Dead simple! Pardon the obvious pun..... h34r:


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## Nizmoose (27/10/15)

MartinOC said:


> Nizmoose, that's definitely the BEST wiring diagram I've seen (in your OP) for wiring these things up. Someone should put this up as a "keeper" somewhere here.
> 
> Common Neutral.
> 
> ...


Just the diagram or explanation below? It is fairly simple once you get used to what wires are what. I find it so much easier to understand when I know what each wire is as opposed to brown here and there and green here blue here etc.


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## BradG (27/10/15)

If you have to ask what the wires are for, then perhaps seek professional advice before attempting this.


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## Nizmoose (27/10/15)

I think to be fair it's more about double checking with people who have done it for piece of mind. Nothing dangerous about attempting something you know thoroughly. But it sometimes takes a bit of confirmation from others to know that you do understand the set up and it'scomponents. I definitely understand the concern but if I had no idea what I was doing I wouldn't be touching the thing.


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## MartinOC (27/10/15)

Nizmoose,

The COLOUR of the WIRES doesn't matter once it's in a closed box.* It's the connections that matter.*

I've used bits of green for this & bits of blue for that for some of my wiring...whatever I have at the time.

*Follow the wiring diagram you put up in your OP* & it's all good. What you posted-up is correct.

If it makes you feel better, use the appropriate coloured wires for your connections so you get it right the first-time. After that, it's a breeze & you can just follow the diagram when you do your next one. 

RDWHAHB....etc...etc...


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## SBOB (27/10/15)

MartinOC said:


> Nizmoose,
> 
> The COLOUR of the WIRES doesn't matter once it's in a closed box.* It's the connections that matter.*


true, but colours matter should someone come along and (wrongfully) make assumptions on a wires purpose based on its colour... there is a reason colour standards exist


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## MartinOC (27/10/15)

SBOB said:


> true, but colours matter should someone come along and (wrongfully) make assumptions on a wires purpose based on its colour... there is a reason colour standards exist


Agreed. That's why I suggested Nizmoose use the appropriately-coloured wires in his first try.

Edit: Try/fail/death from electrocution etc...etc.... :huh:


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## Nizmoose (27/10/15)

MartinOC said:


> Nizmoose,
> 
> The COLOUR of the WIRES doesn't matter once it's in a closed box.* It's the connections that matter.*
> 
> ...


haha yeah I understand the colours sort of dont matter haha but when I pull apart an extension cord I'm glad someone decided to colour code the wires in a predictable way and I shall wire the STC up using the same thought process  Keeping everything standard will definitely make it easier should things be pulled apart.


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## MartinOC (27/10/15)

Cut yourself 10cm out of an extension cord & use whatever pieces of appropriately-coloured wire you choose to make you feel confident that you're doing the right thing.

I'm confident that you're doing the right thing....


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## mrp64 (27/10/15)

Hi Nizmoose,

No mention has been made of the enclosure type for the STC1000. If using a plastic box with no exposed metal parts your circuit is fine. However, if using a metal box or even a plastic box with a metal lid, the exposed conductive parts must be earthed to comply with Australian Standard wiring rules (AS3000).

This is in case a fault occurs such as the active wire comes loose inside the box and touches the exposed metal. Could be lethal.

MRP


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## Nizmoose (27/10/15)

mrp64 said:


> Hi Nizmoose,
> 
> No mention has been made of the enclosure type for the STC1000. If using a plastic box with no exposed metal parts your circuit is fine. However, if using a metal box or even a plastic box with a metal lid, the exposed conductive parts must be earthed to comply with Australian Standard wiring rules (AS3000).
> 
> ...


Hi MRP good pick up, I plan to use a fairly thick walled project box from jaycar for ease of cutting and lack of conductivity  important part of the project for sure!


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## Nizmoose (9/11/15)

Okay so I have the stc all wired up and it's been doing its thing for a week. Incredibly easy to wire up in the end and I'll post a few photos to see if people agree it's all been done properly. I do have a question for anyone who has their fridges in a shed. How hot is too hot? My poor fridge is black which does not give it a good start and the compressor is getting fairly warm. From the attached photos you can see the set up, there a deep freezer and a fridge in a similar place and they've been running in there for years at much colder temps than I'm asking of my fermentation fridge but it is a tiny compressor. It's first test has been the last couple of days in adelaide where we've had 35ish degree days, as you can see in one of the photos ambient in the shed is around 40c and the metal outside of the fermentation fridge is pretty hot. Is there any way or any benefit to cool the outside of the fridge a little for the sake of efficiency? A wet towel over the top and sides but not back or front? As you can also see from the photos it's right up against the bloody metal sheet wall which gets nice and warm, I'd try and shove a polystyrene box lid back there but don't want to restrict airflow to the compressor. Any suggestions would be greatly appreciated!


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## wobbly (9/11/15)

Nizmoose

Are both ends of your earth wires (the green and yellow ones) secured under* both screws* in the terminal block. Regulations require the earth wire to be secured by a connector with double screws so as to avoid a possible loose connection should a single screw come loose

Wobbly


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## Camo6 (9/11/15)

wobbly said:


> Nizmoose
> 
> Are both ends of your earth wires (the green and yellow ones) secured under* both screws* in the terminal block. Regulations require the earth wire to be secured by a connector with double screws so as to avoid a possible loose connection should a single screw come loose
> 
> Wobbly


Unless the screw has an outside diameter not less than 80% of the tunnel diameter, or if bootlace ferrules are used.


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## Nizmoose (9/11/15)

wobbly said:


> Nizmoose
> 
> Are both ends of your earth wires (the green and yellow ones) secured under* both screws* in the terminal block. Regulations require the earth wire to be secured by a connector with double screws so as to avoid a possible loose connection should a single screw come loose
> 
> Wobbly


Hi wobbly they aren't both under each screw just the one coming in is screwed down on that side and the one coming out in that side. Might have to strip back more insulation and rectify this thanks. Regardless of code if it's a good idea consider it done!


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## Nick the Knife (19/11/15)

FWIW from a complete newbie (both to anything to do with electrical wiring & homebrewing) this thread and in particular the wiring diagram in post #1 was very handy to getting my STC-1000 all wired up and working perfectly!

The diagram does differ slightly from several others in both the STC in Pictures thread and also a few other posts - not that this is either a good or bad thing BUT I found it a very straight forward diagram & was user friendly to wire route within an enclosed space.

Haha for fellow novices don't half wire up the controller and THEN realise that you still need to put it through your project box's slot!

Nice thread, much thanks to all that contributed and the OP.


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