E-Stop to Contactor?

[vikingsfan]

I'm in the process of building my first panel. The goal is to have the ability to start with a single element and pump with a timer, but grow out to two elements / pumps when I get a bit more space. Anyway, looking at what most people are doing here, the consensus seems to be that wiring the E-stop up to a couple of resistors to trip the GFCI is the best way to go. I would rather not have to go outside and flip the breaker if I don't have to, should I ever need to hit the E-stop, and I would prefer to wire it up to a contactor in-line instead (probably along with a two position key switch). Is there some reason that using a resistor to trip the breaker is preferred, or is that there something else that I'm not seeing?

Thanks in advance!

 

[iijakii]

The reason for the e-stop is to have all power cut from your panel. Do you need it? That's up to you. Personally in my last build I had both an on/off power + an estop, in my upcoming build I have neither. Plenty feel it gives a safety benefit. I don't want to sway you one way or the other.

 

[vikingsfan]

Thanks! I definitely want to have the E-stop, but I was wondering why most people seem to be relying on the GFCI breaker to trip when they hit it? I would prefer to wire it to a contactor or relay instead, but no one here seems to be doing that. Any ideas why?

Thanks again!

 

[Facinerous]

Aside from the actual GFCI breaker, I don't know why the E-stop is typically done that way. I think tripping the breaker removes all power from your brew panel. Even the feed. Where if you hit the e-stop that only operates the contact in the panel, you still technically have power at the panel, just not the equipment.

I don't know if that level of safety is necessarily required, but technically neither is the GFCI breaker. The GFCI breaker just makes things safer for you.

As long as you have the "Oh S$!t" button working properly to clear your stuff, maybe not the entire panel, I think you are fine.

 

[vikingsfan]

Great answer! Thanks, I didn't think about having the panel still energized. I suppose that could be a problem in certain circumstances, and in those cases it would be preferable to have all power off to the area.
Now I have some more thinking to do!
Thanks again.

 

[Bobby_M]

A side benefit to tripping the GFCI for the Estop is that it provides a consistent way of testing that the GFCI is still functioning. All of the GFCI receptacles have a test button on them and the directions suggest testing monthly. With the breaker, there really is no way of doing that easily. I plan to use this Estop feature and hit it at the end of brew day every so often to test it.

 

[MagooBrew]

If the circuit is built as it should be with an effective ground fault current path, the gfci breaker will trip anyway. It is not good to constantly trip a breaker.

 

[evanmars]

It will only trip for an electrical issue. What about a hose coming loose and spraying hot wort all over, or some other non-electrical snafu?
That big red button (that should be on a yellow background) is very easy to see and hit in an "Oh ****!" moment.

But I guess that's back to "Why trip the breaker when you can just cut power to the equipment?"

 

[MagooBrew]

Exactly. Use an e-stop for what its designed for. Let the Gfci handle electrical issues.

 

[stevehaun]

I have a contactor controlling all power coming into my panel. The E-stop shuts this contactor off. If I happen to fill my control panel with water, I hope that my GFI breaker would trip. I guess I can't think of a scenario where using the E-stop to trigger the GFI breaker would be advantageous. That said, it is an effective way of cutting power to the panel and I can't think of a reason it would be a wrong way to install an E-stop. Take your pick, I think both ways will work.

 

[summerofgeorge]

One reason I've seen to not use the GFCI tripping is that you also need to make sure your fuse isn't blown (at least most diagrams I've seen have a fuse and resistors). I have seen someone mention using different resistors and skipping the fuse so that would eliminate this concern.

Is there any harm in doing both? Would the GFCI still trip if you were cutting power to the main contactor at the same time? I don't know what happens quicker - GFCI trips or main contactor shuts off.

 

[atoughram]

I'm not a big fan of tripping the GFI as an e-stop either. IF I had an estop button, It would simply power a contactor and shut the power off to the pumps and elements. I'd still leave the PIDS on. But I dont think that an estop button is necessary on equipment without motion either..

 

[Satisfaction]

In my panel build I used the E-stop to kill the power to the PID's, which in turns kills power to the contactors and subsequently the elements.

Dealing with inline fuses is a pain and if you decide to skip that step there is a real risk for arch flash using the e-stop as a short to ground.

 

[CoolZone]

I put an e-stop circuit on my system to cut power to hazardous components (gas flow solenoids, and pumps) that, when power is removed, eliminates the hazard; but not to control voltage (PLC, touch screen, level sensors, etc). Other componets, like automated ball valves still need power to close. The E-stop circuit sends a signal to the PLC which then closes the ball valves (in case of a hose rupture like someone mentioned above).

If there is the "Oh ****" moment, in my opinion, you want to eliminate what generates the hazard, and also take the system to a safe state.

If you want to remove power from the entire panel, you may want to consider a disconnect switch (rotary disconnect switches like this: http://www.ebay.com/itm/like/200127124033?lpid=82 (BTW, no relation to the eBay seller)). Most contact blocks for pilot devices are not suited for "disconnect" purposes. There are a variety of ways to remove power from a panel, this is just one option.

 

[Bobby_M]

No one ever suggested direct shorting to trip the breaker. It's usually done with a resistor so that there's a small leakage current that the GFCI is looking for.

 

[atoughram]

Dealing with inline fuses is a pain and if you decide to skip that step there is a real risk for arch flash using the e-stop as a short to ground.

Implementing an E-Stop with a fuse and resistors going to ground is a bad idea. Remove the fuse and it's a dangerous idea.

 

[nightrider069]

That is the way I have mine wired you can wire it to the neutral side of the circuit so you kill all power in the panel