# Emergency Stop System



## Morte615 (Oct 21, 2013)

I work for a Haunted House that has a bit of a problem, during the fire inspection the Fire Marshal decided that the emergency stop for the house needed to be more accessible. To accomplish this I took the EStop switch and extended the wires and placed it in a box where we could get to it. The Fire Marshal was ok with this but to make it work I had to remove the original switch, when I added another one it just would not work. What I would like to do is add another switch (you can never have to many!)

I am very comfortable with power and electrical but its a rat's nest in the box and I don't have the time till after the season to de-power the system to sort it out. I have looked around on the internet trying to find a common diagram (or at least some samples) of a system that will transfer power from one set of breakers to another set when a stop button has been pressed, but I am not able to find one.  Everything I have found so far has been about EStops on machines but this is an entire building I am looking for.

So can anyone point me in a direction or offer some help?


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## Footer (Oct 21, 2013)

What does the E-stop do? Typical simple e-stops are wired in series and will only work when all switches are open (or closed depending on system design). How many throws are in the current switch? Is there a way to replace the throws in the switch with relays? This would allow you to pretty simply put the switch or switches wherever you want and still have all the control of as many circuits as you need.


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## Morte615 (Oct 21, 2013)

The estop turns off power to all of the effects sound and lighting while turning on the work lights and playing a recorded message through the audio system. 
From what I could tell the brief time I had the power off to the system it is set up with relay modules but I could not tell if I could just add a switch on or if I had to add a new module. Though when I just wired a new switch in parallel it would not trip when pressed, neither switch would work then. 
I have seen these systems used before in other haunted houses but I just have not been able to find anything online about this type of system. 

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## JChenault (Oct 21, 2013)

I would expect that if you wired the second e stop in series instead of in parallel, it would be more likely to work.


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## venuetech (Oct 21, 2013)

i am sure someone will correct me if i am wrong, but to me it sounds like you want something like a transfer switch that would normally be hooked into an emergency generator
but that would hardly be a quick, easy or inexpensive solution.


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## Morte615 (Oct 21, 2013)

I tried both serial and parallel and same response, both had to be off for the system to switch. The system is already installed I just want to add an extra stop switch, and btw there are two stops already so I want to add a third, that's where the problem is at I think. 
I will try to get pictures this weekend but I may or may not be able to, depends if I can get enough time before others arrive to shut down power for the entire house! 

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## Morte615 (Oct 21, 2013)

I kind of assume that this is a modified version of the generator transfer system. But this is a system that is becoming common in haunted houses and thought it may be entering theaters also

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## Chris15 (Oct 21, 2013)

Classical design for an E stop system is to place all E stops in series and, for low power systems, have that directly controlling the mains feed, and for higher power systems, have that control a contactor with the mains feed.
Obviously this application is not quite the traditional "I need to stop this machine before any more damage happens the person who's caught in it".

It sounds a bit like this E Stop is more of a control input to a show control system?
What's directly connected to the switch you tried to augment and can you tell (either by multimeter or by part number referencing etc. ) if the siwtch is NO or NC or multiple contacts?

There is a part of me that were I designing this, I'd use a double pole changeover switch, with one NC pole to cut power to the non essentials and one NO pole to connect it to the safety systemns...


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## Morte615 (Oct 21, 2013)

Think of it like a system tied into a fire alarm in a club or other gathering place. When the fire alarm goes off the system cuts power to the audio system and lighting, while activating a second system that has emergency lights and audio, just instead of the fire alarm being the trigger it's the E-Stop switches. (Actually that's probably how I should look this up and see if I can find it.) I want to add another fire alarm pull to the system, but when I do it breaks the system.

I am not able to get into it safely till after the season is over. I do know it is running high voltage so I do not want to enter the system till I can shut off all the power to it and lock it out. The control box for the entire thing has a few modules similar to this inside it, http://www.tesch.de/english/sicherheitsrelais/html/000028-1 I can not tell what the model or manufacture is till after the season is over (it's functioning and approved, I just want to make it right {in my eyes} when I can.) When the system was installed they left a lot of wire in the box and nothing is labeled so I am not able to properly sort through right now. I was hoping to find a sample wiring diagram for an entire system and see if I can figure out what it is supposed to do that way when I clean it up and install the extra switch I would have an idea what to do instead of figuring it out blind. (Though I have had to do that before with different animations and such before!)

I agree I would probably use a series of relays to trip the power over, but that is pretty much what this is doing just with more reliability and information.


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## Footer (Oct 22, 2013)

Sounds like the switch you added was normally open when the other switches were normally closed or vice versa. Ideally an e stop system uses normally open switches so it fails to a safe state.

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## FMEng (Oct 22, 2013)

Put a voltmeter across the switch when it is in the run position. Check both AC and DC voltage, since we don't which it is. If there is little to no voltage across, the contacts are closed. I that case, the second switch also needs to be closed in the run position, and the two would be wired in series.

If there is voltage across the contacts, then the second switch needs to be open contacts in the run position and the two would be wired in parallel. Simple enough?


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## BillConnerFASTC (Oct 22, 2013)

Footer said:


> Sounds like the switch you added was normally open when the other switches were normally closed or vice versa. Ideally an e stop system uses normally open switches so it fails to a safe state.
> 
> Sent from my Nexus 7 using Tapatalk 4



I believe a normally closed loop is considered fail safe, so if something is cut or removed, the circuit opens and the systems stop. The contactor is held closed by a closed loop and any interruption drops the contactor and power is cut off.


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## Traitor800 (Oct 22, 2013)

BillConnerASTC said:


> I believe a normally closed loop is considered fail safe, so if something is cut or removed, the circuit opens and the systems stop. The contactor is held closed by a closed loop and any interruption drops the contactor and power is cut off.



This is correct, an estop system should use one or more maintaied red mushroom head buttons with 2 NC contacts. Both of these contacts should be wired in a closed loop to a safety relay like what the OP linked in one of his post. The most basic safety relay will monitor both contacts on your estop button and only activate if both inputs go low (are opened). More complicated safety relays will send test pulses down one line and monitor to ensure that they are getting the same test pulses back on the other line. This prevents you from wiring straight to a voltage source to bypass the button or from mis wiring the estop button loop. In either case if you want to add additional buttons they should all be wired in series.

For having a second system turn on when the system goes into estop what the OP needs to do is find the relay or contractor that is fired by the output of the safety realy and either tag off the NO side of a changeover contact or, since it appears to be a high voltage system, add an aux block to the main contactor and use a NO contact to fire a second contactor that powers the stuff you want to turn on when the estop is hit.

As usual all wiring changes should be done by a qualified individual and especially since this is an estop system any changes should be approved by the appropriate AHJ.

If you have any other questions let me know.


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## BillConnerFASTC (Oct 22, 2013)

To help the OP, what is the actual E-stop action or device? is it a contactor held closed or a shunt trip breaker or something else? I could be wrong but if a shunt trip - not a device i would allow for overhead lifting equipment or a stage lift - the normally closed switches and fail safes don't fit so well.

I guess if a shunt trip breaker has been accepted in the past, then normally open switches in parallel could be used - but hardly fail safe.


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## Footer (Oct 22, 2013)

Footer said:


> Sounds like the switch you added was normally open when the other switches were normally closed or vice versa. Ideally an e stop system uses normally open switches so it fails to a safe state.
> 
> Sent from my Nexus 7 using Tapatalk 4



Yup, correct, my mistake. You always want the system to shut down even if the power is cut to the e-stop switches...


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