Critique / Let me know if I am wrong

[Laurabobaura]

I've decided, after this past winter and trying to brew outside in -10 degree weather unsuccessfully, to go with a simple electric system in the basement.

I will be going to buy this stuff this weekend so my electrician friend can wire it up, and don't feel like making 20 trips to Home Depot/wherever if I can help it, so if people could look my plan over and let me know if anything needs changing I would appreciate it. The bits with asterisks are already there; the bits in bold I am not sure of.

300amp Panel
>*30amp nonGFCI breaker to
>*4 prong, 4 wire receptacle to
> *50amp GFCI Spa panel to
> Analog control box (kind of like the Still Dragon one but made with parts the electrician had) with 60amp SSR, on/off toggle switch, potentiometer, ridiculously oversized heatsink, to
>3 prong locking receptacle wired into analog control box
>*two 20 gal aluminum kettles,
> each with a 3 prong locking plug and 10/3 (8/3?) wire installed in a waterproof box on each kettle with a ground going up to a to machine screw well above liquid line in each kettle
> 4500watt ULWD element mounted in each kettle

Questions:
1) If going from 4 wire to 3 wire, neutral can be capped off. Where? In the spa panel or in the analog control box? Changes the wire I need to buy.

2) Placing the ground in the kettle above the liquid line is still fine even with Aluminum kettles? If I can avoid replacing 20gal aluminum kettles with SS, I will. I've never had a problem using them with my propane system, but I am not sure of the grounds on aluminum.

3) My sparge system is copper to PVC--do I need to buy stuff to ground the copper bit? Or will the kettle being grounded suffice? Would it be worth it to make a new one with high temp tubing and PVC?

4) Where can I find a DPDT switch big enough for the control box?? Certainly not radio shack, but would I be able to find it at home depot? Or should I use some other kind of on/off switch?

5)Sort of unrelated--do I have to ground a CFC? I usually hook it up before the boil, but I am not sure if I do that if I'll have to ground it as well. Or just leave it not hooked up until after the boil finishes.

To clarify: I already have a temp probe system that I am used to and I like, and a gravity fed three tier system so I don't need pumps or a PID system. I mash in a 100qt cooler that holds temps within 2 degrees so I am not wiring that or making a recirculation system.

Thanks!

 

[Brewpupil]

If your using a GFCI Breaker in your spa panel you need 4 wire to your control box for the GFCI to function correctly. from your Control box to your heating element is where you can use 3 wire. Most people i see on here and myself included all have grounds in the control box and at the pot where the element housing is.

 

[Laurabobaura]

Thanks! That makes sense. A lot of the threads about this get derailed by opinions about what is and isn't code.

 

[kal]

1) If going from 4 wire to 3 wire, neutral can be capped off. Where? In the spa panel or in the analog control box? Changes the wire I need to buy.

No need to cap it off, simply don't pull a neutral from the spa panel. Ie: Don't hook one up.

2) Placing the ground in the kettle above the liquid line is still fine even with Aluminum kettles? If I can avoid replacing 20gal aluminum kettles with SS, I will. I've never had a problem using them with my propane system, but I am not sure of the grounds on aluminum.

As long as the kettle is grounded, doesn't matter where. Water level does not come in to play.

3) My sparge system is copper to PVC--do I need to buy stuff to ground the copper bit? Or will the kettle being grounded suffice? Would it be worth it to make a new one with high temp tubing and PVC?

You only need to ground things that contain power. If your sparge system does not have power, no need to ground.

4) Where can I find a DPDT switch big enough for the control box?? Certainly not radio shack, but would I be able to find it at home depot? Or should I use some other kind of on/off switch?

For high currents you do not usually switch directly. You switch indirectly with a relay.

Most small switches cannot handle the large amounts of current required so current does not actually flow through the switch. Instead, a power switch is used to control a large relay which is capable of handling up to 30-50 amps (whatever you need). A relay is simply an electrically operated switch. So you have a power switch to activate a coil in the relay which closes contacts able to handle up to the 30-50 amps of current. Current is then able to flow into the rest of the control panel to power the other devices including the high power devices like the heating elements.

Generally speaking, high power switching such as this is always controlled remotely in electrical panels where a smaller 'control' switch on the door is used to activate a larger switch (such as a high power relay or a definite purpose contactor) that is permanently installed on the back plate. This is done for ergonomic reasons (smaller switches are easier to operate) and for safety reasons (high power wires are not required to move or bend when the door is opened/closed).

More info/pictures here in my instructions: http://www.theelectricbrewery.com/control-panel-part-2?page=7

5)Sort of unrelated--do I have to ground a CFC? I usually hook it up before the boil, but I am not sure if I do that if I'll have to ground it as well. Or just leave it not hooked up until after the boil finishes.

Same answer as with your sparge arm: If there's no power to it, no need to ground it.

Good luck!

Kal

 

[Laurabobaura]

Thank you the reply, Kal. Your site's been lovely, BTW, even if what I'm doing isn't exactly the same. So thank you for that as well--lots of help there.

What I meant for the on/off switch was a switch to cut all power to the control box. Just to avoid accidentally cooking the elements by dry firing them--or if something goes wrong it would be a way to stop everything. Kind of like an extra bit of safety between spa panel and control panel. Sort of like the E-stop in The Electric Brewery control panel, but on/off and mounted before the control panel altogether.

Everything is wired up and working, as is, though, so I may just leave it alone and be careful while brewing. Seems easier that way.

 

[jeffmeh]

Thank you the reply, Kal. Your site's been lovely, BTW, even if what I'm doing isn't exactly the same. So thank you for that as well--lots of help there.

What I meant for the on/off switch was a switch to cut all power to the control box. Just to avoid accidentally cooking the elements by dry firing them--or if something goes wrong it would be a way to stop everything. Kind of like an extra bit of safety between spa panel and control panel. Sort of like the E-stop in The Electric Brewery control panel, but on/off and mounted before the control panel altogether.

Everything is wired up and working, as is, though, so I may just leave it alone and be careful while brewing. Seems easier that way.

Personally, I think a main power switch in the panel itself (like Kal's) is good enough, even though you would still have live wires at the switch and the main contactor line contacts. P-J's e-stop design trips the GFCI, so you don't have any live power at the panel itself, but a GFCI can fail. If you really wanted to get fancy, you could have an e-stop that both trips the GFCI and opens the main power contactor in the panel, but that's overkill, IMO.