Just Moved - seeking advice on adapting my setup

[johnnybrews12]

Ok, so scrap the 12v switch / relay for the element cut-off. I can either replace it with a 2-pole switch (like this leviton one) or a contactor (220v coil) with a switch.

Can the switch I use with the contactor be rated for 240v 3a (that's what I have on hand)? Is there any difference between these two options besides the wider array of switches available for the contactor? Also, what's the difference between having the switch before the SSR vs. after?

 

[doug293cz]

Ok, so scrap the 12v switch / relay for the element cut-off. I can either replace it with a 2-pole switch (like this leviton one) or a contactor (220v coil) with a switch.

Can the switch I use with the contactor be rated for 240v 3a (that's what I have on hand)? Is there any difference between these two options besides the wider array of switches available for the contactor? Also, what's the difference between having the switch before the SSR vs. after?

Yes you can use the Leviton 3032 type switch as an element power enable switch. The major drawback of this switch is the amount of space it occupies on the front of the control panel enclosure, as opposed to a smaller switch on the front, and contactor mounted on the back plane of the enclosure. Using the switch-contactor pair allows some additional flexibility such as implementing a "safe start" interlock, or allowing upgrading to computerized control. Just about any switch rated for the voltage of the contactor coil can be used to switch the contactor. Contactor coils typically draw much less than 1A current.

The only difference between putting the contactor/switch upstream of the SSR or downstream is how much circuitry inside the control panel is energized when the contactor/switch is off. Since the contactor/switch before the SSR leaves less circuitry powered when off, that is my preference.

Brew on

 

[johnnybrews12]

@doug293cz I put together an updated wiring diagram (rough sketch). I've decided to go with the leviton 3032 type switches for my main power to box as well as my element switch. The pump is running on 12v DC so I can use an old switch I have lying around.

 

[BeardedBrews]

Looks good from here

 

[johnnybrews12]

Looks good from here

Thanks @BeardedBrews!

 

[BeardedBrews]

Thanks @BeardedBrews!

I could have included a reminder that in-line fuses are super cheap and can save your expensive components.

DIGITEN 5x20mm AGC Fuse Holder Inline Screw Type with 16 AWG wire + 5x20mm Fast-blow Glass Fuses Quick Blow Car Glass Tube Fuses Assorted Kit Amp https://www.amazon.com/dp/B01I2MNRWK/ref=cm_sw_r_cp_api_i_gwY0Cb0T7Q43P

 

[doug293cz]

I would recommend adding an LED indicator light (240V) in parallel with the element. This light will tell you that the element is actually getting voltage when it should be, and is also the easiest method to determine if your SSR has failed. If the light is on when the PID output LED is off, then your SSR has either latched on, or hard failed in the on mode. In the case of a latch up, letting the SSR cool (turn the element power switch off) may correct the problem. If cooling the SSR doesn't correct the problem, then you have a hard fail. There is one bit of odd behavior with the LED in parallel with the element: if the element is unplugged, the LED will light (dimly) even when the SSR is in off mode. This is due to current leakage in the SSR, and is normal.

Brew on

 

[johnnybrews12]

It looks the trigger current for class A GFCIs is 5mA.
So a resistor with a value of 120V/5mA = 24kΩ from one of the hot poles (~120V nom.) to ground should trigger the GFCI.

However 24 kΩ (5% or 10% tolerance) is not a common value, 22 kΩ and 27 kΩ are.
So a common 22 kΩ (5% or 10% tolerance) resistor should do it with a trigger current of 5.5 mA at 120V.

Power dissipation is V * I = 120V * 5.5mA = 0.66 Watt. Now since it's supposed to be on 'load' for only a fraction of a second, 1/4 watt should suffice. As long as the circuit works as it should and shuts off fast.
Keeping the button down if it doesn't work will fry that 1/4 watt resistor in short time. Use a 1/2 Watt or 1 Watt resistor if you plan to do this.

How GFCIs work.

Quick question on implementing this test switch on my box. What kind of switch should I use? What voltage & current does it need to be rated for?

 

[IslandLizard]

Quick question on implementing this test switch on my box. What kind of switch should I use? What voltage & current does it need to be rated for?

There's line voltage across the open poles, so the switch needs a voltage rating of 120V. Or 240V if you want to test a 240V line voltage.
But the series resistor limits the current to 5.5 mA (at 120V), so current rating is pretty much a non-issue. Anything above 20-50 mA will do.

 

[johnnybrews12]

There's line voltage across the open poles, so the switch needs a voltage rating of 120V. Or 240V if you want to test a 240V line voltage.
But the series resistor limits the current to 5.5 mA (at 120V), so current rating is pretty much a non-issue. Anything above 20-50 mA will do.

Ok understood. I have a switch rated for 120v 20a laying around somewhere. The way I’m thinking about wiring this is like so: take one of my hot lines and run it to ground with a resistor in between.

Should it look like this?
120v —— resistor —— switch —— ground

Or this?
120v —— switch —— resistor —— ground

 

[doug293cz]

Ok understood. I have a switch rated for 120v 20a laying around somewhere. The way I’m thinking about wiring this is like so: take one of my hot lines and run it to ground with a resistor in between.

Should it look like this?
120v —— resistor —— switch —— ground

Or this?
120v —— switch —— resistor —— ground

Both will work equally well. I'd pick option 2 just because I have a bias towards having the least amount of circuitry energized when a switch is open.

Brew on

 

[IslandLizard]

Both will work equally well. I'd pick option 2 just because I have a bias towards having the least amount of circuitry energized when a switch is open.

I second this.

 

[johnnybrews12]

Thank you everyone for the help - couldn’t have done it without you. Just had our first brew day Saturday and the system worked great - NEIPA is fermenting now. I attached a couple pics - just the control box and the system on brew day. Now all I have to do is figure out a way to hold the grain bag up while draining / sparging. Caught a couple burns doing it by hand.