Wire gauges for control panel?

[rknerem]

I plan on using this schematic for my control box wiring (special thanks to PJ). I can figure everything out but the correct wire gauges for the internal wiring. Wondering if someone can tellme what wire to use throughout?

Thanks in advance.

 

[kal]

Anything that carries over 15 up to 30 amps should be 10 ga.

Anything that carries between 0-15 amps should be 14 ga.

The DC signal wires to the SSRS can be much smaller if you like, 18-22 ga.

There's never any harm using anything larger.

Make sure the wire's also rated to the voltage you want to carry.

Kal

 

[nhwrecker]

And stranded copper wire is easier to work with than solid core.

 

[HHP]

Use lots of zip ties and those sticky pads they attach to.

 

[rknerem]

So 12 gauge stranded will work for everything but the wires for the elements? Which will be 10 gauge stranded.

 

[audger]

So 12 gauge stranded will work for everything but the wires for the elements? Which will be 10 gauge stranded.

that will be overkill for the control circuits, but yes that will work.

 

[brewhokie]

Any particular reason you couldn't use 16awg on the 120v circuits? Everything is fused at either 10amps or 1 amp.

 

[rknerem]

Just happen to have a bunch of 12 gauge wire to use up.

 

[BWN]

Anything that carries over 15 up to 30 amps should be 10 ga.

Anything that carries between 0-15 amps should be 14 ga.

The DC signal wires to the SSRS can be much smaller if you like, 18-22 ga.

There's never any harm using anything larger.

Make sure the wire's also rated to the voltage you want to carry.

Kal

Just to be clear when you say carries, do you mean how much the device is pulling? Do the ground wires going to the pump need to be 10 gauge? If the ground wire coming in is from the bus bar from the 50 amp service could I still use 14 gauge to the pumps.

 

[amb1935]

Any particular reason you couldn't use 16awg on the 120v circuits? Everything is fused at either 10amps or 1 amp.

16 awg wire has a max ampacity of 13 A. Even if you fuse a circuit below that ampacity, you should still have an agreement between wire size and breaker size. A 15 A breaker won't trip until about 12 A or so, meaning your wire should be fine, but I wouldn't bet my house/garage on it. I would always use a minimum of 14 awg for residential wiring. It would be against code to use 16 awg with a 20 A breaker at 120v.

 

[kal]

Just to be clear when you say carries, do you mean how much the device is pulling?

Yes. Same thing. If the device pulls up to X amps of current, the wire will carry that X amps of current.

Do the ground wires going to the pump need to be 10 gauge or possibly If the ground wire coming in is from the bus bar from the 50 amp service could I still use 14 gauge to the pumps.

No. The pumps only pull 1-2 amps and the cord they came with is likely only 14 ga at the highest. It may also be 16 ga. The ground wire to the pumps doesn't need to be bigger (10 ga).

Kal

 

[brewhokie]

16 awg wire has a max ampacity of 13 A. Even if you fuse a circuit below that ampacity, you should still have an agreement between wire size and breaker size. A 15 A breaker won't trip until about 12 A or so, meaning your wire should be fine, but I wouldn't bet my house/garage on it. I would always use a minimum of 14 awg for residential wiring. It would be against code to use 16 awg with a 20 A breaker at 120v.

Yes but if you are running your pump off one of the 120volt legs of a 240 volt circuit with a 30amp breaker you are already violating this rule, hence why the 120volt components are fused at 1amp or 10amps for the pump.

Please excuse my ignorance, but is there any difference between the functionality of a fuse and a breaker. Their function is to protect the wiring and devices in an overload situation, and both are designed to break the circuit if a certain amperage is reached, correct?

I ask because I already have a bunch of 16awg wire, and every little bit of savings helps on these projects. Obviously I won't do this at the detriment of safety, which is the reason I'm asking more experienced people.

One other quick note, could you use cat5e wire for the RTD signal wires? That would be awesome I could wire my house to china and back with the extra Ethernet cable I have around the house.

 

[yjfun]

There is no difference in the functionality of a fuse and a breaker. Breakers are just more user friendly since you can reset them instead of having to replace them. Fuses are actually safer than breakers since they will blow no matter what and a breaker has the possibility of a mechanical failure internally and not tripping.

Use the 16 awg wire and just fuse it down to 5 amps and you'll be able to run your pumps and controls without the chance of melting the wire.

It might be possible to use the cat 5 wire for the RTD signal wire but I wouldn't. It's just to small. You could probably use some shielded speaker wire and you can definitely use shielded fire alarm cable though.

 

[bagpiperjosh]

I plan on using this schematic for my control box wiring (special thanks to PJ). I can figure everything out but the correct wire gauges for the internal wiring. Wondering if someone can tellme what wire to use throughout?

Thanks in advance.

is there an original thread for this pic? because i have a few questions about it.

for instance.. why is there only 1 switch for the hlt and boil kettle elements? why would you want/need them to be on at the same time? why not have 2 switches?

 

[yjfun]

There is only one switch because the supply is only 30 amps. The two 5500 watt elements would try and draw 45 amps if you ran them at the same time so this switch setup only lets one run at a time.

 

[BWN]

In a schematic like this what size wire would you use for the emergency stop switch if it had 50 amp service coming in? Would that have to be 10 gauge?

 

[bagpiperjosh]

There is only one switch because the supply is only 30 amps. The two 5500 watt elements would try and draw 45 amps if you ran them at the same time so this switch setup only lets one run at a time.

Is that a 3 position switch then? like hlt|off|bk ?

 

[yjfun]

That particular switch is on/on so there is no off feature but you could use a on/off/on switch instead.


The service size doesn't matter when wiring up an e stop in this manner. You could use 16 awg wire if you wanted. I know that this is the way many HBT members have wired their systems but a GFI breaker is not designed to be used as an emergency stop like this. They wear out a lot quicker if you do this to shut your system down. It's better to run your service through a contactor at the beginning and wire in the e stop to the contactor's coil. That's how any commercial or industrial system is done.

 

[P-J]

My mind is just plain boggled with the questions about the diagram.

Question for the questioners: Doesn't anyone read the Legend: at the bottom of the diagram?

Switch #1 is clearly referenced as a DPDT Center Off 25A unit. I even reference the source.

 

[yjfun]

Didn't even see that line on the legend P-J even though it is obvious when you look at it. I just went off what I saw on the line diagram.

 

[P-J]

In a schematic like this what size wire would you use for the emergency stop switch if it had 50 amp service coming in? Would that have to be 10 gauge?

The E-Stop is fused with a 1A fuse.

You mention 50A service "coming in". The particular diagram in this thread is drawn for a 30A 240V service feed. If your intent is to power it with a 50A service feed, you MUST provide circuit breaker protection within your power panel.

If you short cut it here - You Are Playing - You Bet Your Life.!

 

[BWN]

The E-Stop is fused with a 1A fuse.

You mention 50A service "coming in". The particular diagram in this thread is drawn for a 30A 240V service feed. If your intent is to power it with a 50A service feed, you MUST provide circuit breaker protection within your power panel.

If you short cut it here - You Are Playing - You Bet Your Life.!

I understand that. I had seen another one of your diagrams that had the same setup(for the emergency stop) for 50 amps. It went from the line2 distribution block to the 1a fuse to the resistors to the switch to the ground. I just assumed that the emergency stop setup would be the same. I guess I should have started my own thread.

 

[bagpiperjosh]

My mind is just plain boggled with the questions about the diagram.

Question for the questioners: Doesn't anyone read the Legend: at the bottom of the diagram?

Switch #1 is clearly referenced as a DPDT Center Off 25A unit. I even reference the source.

i looked at that legend no less than 100 times,lol i even printed it out. im not good at understanding schematics and such yet. but i'm learning.. i apologize in advance for all of the other stupid questions I will ask in the future.