E-Stop ???

I see that PJ regularly includes an e-stop in his diagrams. Is this anything more than an "oh ****" button that throws the hot into the neutral to trip the GFCI or does it bring added protections?

Yes, it shunts hot to ground to trip the GFCI breaker. There are some religious arguments around whether that is a good approach, but it will work, assuming the GFCI is good. Another approach is to wire the e-stop to the coil of a normally open SPDT contactor, through which both hot lines pass upon entry into the control panel.

jeffmeh said:

Yes, it shunts hot to ground to trip the GFCI breaker. There are some religious arguments around whether that is a good approach, but it will work, assuming the GFCI is good. Another approach is to wire the e-stop to the coil of a normally open SPDT contactor, through which both hot lines pass upon entry into the control panel.

Click to expand...

How is such a thing useful though? I'm trying to imagine where things screw up so bad that this would be necessitated. Is it more if a cool add on or are there legitimate safety benefits?

I don't think the e-stop is necessary, but I do highly recommend having the "main power contactor" that I described above, triggered by a switch. When the switch is off, the only hot wires in the panel are at the switch and at the line terminals of the contactor. When you plug in or unplug the control panel, all of the other components are powered down. You may not be able to switch it off as quickly as an e-stop, but close enough, and you could use the e-stop for the switch if you so desired.

I'm planning on having a main power switch that jeffmeh mentions and also the e-stop. I figure the e-stop is just added protection, and it's not that expensive. It's easy to say that if it hits the fan, you can just turn the main power off but you never know how you're respond in any situation. To me, it's much easier to smack a big red button without thinking. It's also nice if someone else is around and you need them to kill the power. "Hit the big red button" is easier than telling them to turn a switch off, especially if all the switches look the same.

One other thing with PJ's method (not saying I agree or disagree with it) is that by tripping the GFCI breaker, you're killing all power to the panel. By turning off a main power switch, the panel will still be energized up to the switch.

Hopefully you'd never have to use the e-stop but to me it's worth adding if you have the space.

Arguments about which method to utilize aside, my thought is that I have a lot of money invested in the panel and equipment, and I'm mixing hot liquids, high voltage, and my body all in the same equation. If a pump siezes, or sparks start flying, or the magic smoke starts to escape from some electrical component, or really anything at all starts to go south - having a big red 'Oh ****' button to smack is totally worth the minimal cost.

Thanks for the thoughts all, I just wanted to make sure I wasn't missing anything in my thought process. I'm pretty calm under fire so if the "magic smoke" starts it won't phase me much...unless it is coming from me and then I won't be able to hit the "oh ****" button anyway because I will be dead. In the meantime I have a blue LED power button with the universal power symbol that will be a main power switch so it should be pretty obvious what the main power is to anyone looking at it.

Personally my spa panel is only a few feet away and if a pump started to spurt hot liquids all over the place I could easily switch off at the breaker.

But I find the big red panic button reassuring.

jeffmeh said:

I don't think the e-stop is necessary, but I do highly recommend having the "main power contactor" that I described above, triggered by a switch. When the switch is off, the only hot wires in the panel are at the switch and at the line terminals of the contactor. When you plug in or unplug the control panel, all of the other components are powered down. You may not be able to switch it off as quickly as an e-stop, but close enough, and you could use the e-stop for the switch if you so desired.

Click to expand...

I'd recommend having just an e-stop and use that for the main switch, if one is trying to cut down on unnecessary buttons / switches.

I have an e strop on a double pole contactor, I use it as the main power switch. I also run a rims set up. If the flow would go too low, I.E. stuck mash, I could cut the power, usually just stir and scrape the false bottom. I have not had to do this yet. I usually just monitor the flow on the rims and stir, etc. My BCS is still wired even with the E stop off. It allows me to measure temps in a crisis situation, but on start up it allows me to make sure that the elements are off before start up.

Think about your brew process, and what you would still want power running to in the event of an "emergency."

There's no one right answer here, although the religion seems to be centered around wiring code; many folks will suggest that e-stops are not to code (and many will suggest that they are to code), while a third group will suggest that these breweries are appliances (and subject to different code requirements).

As jeffmeh said, make sure you have GFCI. The decision to e-stop at a contactor, all the way back at the breaker, or both, is one you have to make for yourself.

Good luck!