Lockable Emergency Stop Button?

D

Desert Sparky

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Location
Desert
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Electrical Engineer
I'm designing a shop classroom, and the owner has requested the installation of emergency pushbuttons in a few locations. These emergency pushbuttons will be wired to shunt the main breakers on the panels that are dedicated to feed all of the power in the space; essentially, the owner wants to be able to kill power to all shop equipment (lifts, cord reels, etc.) & lighting in the space. The only power in the space that will remain energized is the garage doors.

Question: can the emergency push button be provided with a lockable cover? The owner is now concerned about inadvertent tampering of the buttons, and wants to lock them, so the only person that can use them is the instructor who will have a key with him at all times :rolleyes:. The emergency push buttons are not required by code and are an owner request, but I can't find a reason why they can't be locked, even though it kind of defeats the purpose of having the buttons if only one person can use them and he needs a key to unlock them first. Thoughts?
 
Since they are not required they could be behind a locked cover
 
Desert Sparky said:
I'm designing a shop classroom, and the owner has requested the installation of emergency pushbuttons in a few locations. These emergency pushbuttons will be wired to shunt the main breakers on the panels that are dedicated to feed all of the power in the space; essentially, the owner wants to be able to kill power to all shop equipment (lifts, cord reels, etc.) & lighting in the space. The only power in the space that will remain energized is the garage doors.

Question: can the emergency push button be provided with a lockable cover? The owner is now concerned about inadvertent tampering of the buttons, and wants to lock them, so the only person that can use them is the instructor who will have a key with him at all times :rolleyes:. The emergency push buttons are not required by code and are an owner request, but I can't find a reason why they can't be locked, even though it kind of defeats the purpose of having the buttons if only one person can use them and he needs a key to unlock them first. Thoughts?
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I don't know why he would want the lights to drop.

Mark
 
Dont call them Emergency Power Off if they can't be used in an emergency.

Call them Remote Power Off instead. They can be lockable and any color you want.
 
Kind of pointless to have any kind of emergency off control that is locked. My suggestion is have a Emergency stop switch but one that needs a key to reset. If there is a problem with students turning them off when not necessary, intervention is needed by the keyholder to reset and hopefully will lessen such problems yet makes them available for an emergency shutdown. They do the same with manual pull stations for fire alarms.
 
ron said:
These are the guys. You might want a lockable box and you put the switch in it.
www.sti-global.com

Safety Technology International

Safety Technology International cages, covers, alarms and others help deter theft, vandalism, damage and false fire alarms. Rely on STI®.
www.sti-global.com www.sti-global.com
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The STI products are pretty good. We use them frequently. If the concern is inadvertent activation of the shutdown versus malicious activation, a Stopper II cover is all you need. It's obvious that any activation will have to be a deliberate act.

The problem with a lockable EPO is that if something happened and someone was injured or worse because the keyholder was taking a piss, or whatever, liability would almost certainly attach, regardless of what you call the button. You wouldn't have an EPO if you didn't recognize the hazard, and then you deliberately made it more difficult to respond to the hazard in a timely fashion. You'd be better off not installing it at all.
 
I can just imagine a lawyer having a field day with this if someone gets injured by a machine, and the person with the key was slow on the uptake. Sure, the E-stop isn’t required, but if it IS THERE, and cannot be used, someone could construe that as negligence or even depraved indifference.

I vote for a break glass or similar version. Some of the IEC 22mm E-stops have an optional thin membrane hard cover that breaks when you activate it so that you know which button was pressed.

But what’s the goal here? True “emergency” situations, or a “master kill switch” for when they leave the room?
 
Desert Sparky said:
I'm designing a shop classroom, and the owner has requested the installation of emergency pushbuttons in a few locations. These emergency pushbuttons will be wired to shunt the main breakers on the panels that are dedicated to feed all of the power in the space; essentially, the owner wants to be able to kill power to all shop equipment (lifts, cord reels, etc.) & lighting in the space. The only power in the space that will remain energized is the garage doors.

Question: can the emergency push button be provided with a lockable cover? The owner is now concerned about inadvertent tampering of the buttons, and wants to lock them, so the only person that can use them is the instructor who will have a key with him at all times :rolleyes:. The emergency push buttons are not required by code and are an owner request, but I can't find a reason why they can't be locked, even though it kind of defeats the purpose of having the buttons if only one person can use them and he needs a key to unlock them first. Thoughts
Click to expand...
Maybe suggest that the lights not be included in the loads to be powered off. Then include a kill switch for the shop equipment, that can be actuated to turn off the equipment without a key, but with key required to enable power-up. Probably best to just have one kill switch that locks out all the shop equipment loads. With this arrangement, safety will be maximized.
 
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