Anything that only requires a single gesture to operate - e.g. a push button covered by a flap (like on the missile launch systems in films) which requires two actions (1. lift flap, 2. press button) would be out.

   - Andy.

So, what is a single gesture?

Z.

e.g. push, pull, twist, or is it? Normally you would push (hit, kick) an emergency stop button. Arguably, if you have to grip it first, and then pull or twist, it is 2 actions. Rotating a lever could be achieved in one action because it would not necessarily have to be gripped first.

I think that a lever has first to be gripped then pressure applied to rotate it. So that is more than one simple action. The same applies to a rotary switch.

Z.

If you think of a (modern) door handle (as opposed to an old-fashioned knob), it can be operated by pressing one's knee or foot on it if, for example, you are carrying something with both hands. Of course, that doesn't help if you are on the same side as the hinges; and it is not the intended means of operation in any case. If it was intended to be foot-operated, it would be a door pedal rather than a handle.

Oh dear - that means that Main Switches in domestic consumer units up and down the land that have a nice lift-up lid over everything (which presumably helps a little with stopping fire escaping if the devices inside melt....) are non-compliant then!  Quick, somebody get a manufacturer to design a new CU with the main switch not under a flap and then tell most of the householders in the UK they need a new one.  Should keep the boys in jobs for a few years!

I had the very same "discussion" many years ago with what I would call and over zealous NICEIC inspector who basically stated that unless its a push button then no other device was for "Emergency switching". Now my discussion was around a lever operated device i.e a firefighter/firemans switch. So what some people have said on this thread, you need to grab the lever then push it up, the spring pin then latches it off.

Now , when I then showed him what the regs indicated but also the standard description, the definition indicated and emergency stop can be either a button, rod or lever operated device, so with that definition Im still waiting on that NICEIC inspector to draw me or show me an example of a lever operated device that you dont grab then push up or down?

Too many people focussing on one single action, to me its not the single action of what your hand does its the single operating action of one electrical accessory that latches in the off position and isolates all forms of energy etc from the installation/equipment/machine.

Also with possible flames licking my backside then me activating that device would be so fast it would be classed as one action!!

Cheers GTB

Agreed, Regulation Groups 537.3 and 537.4 ought to help sort that out. 537.3.3 does sort of lead you down the e-stop route, although there is a complete separate standard for e-stops.

GTB said:

Now , when I then showed him what the regs indicated but also the standard description, the definition indicated and emergency stop can be either a button, rod or lever operated device, so with that definition Im still waiting on that NICEIC inspector to draw me or show me an example of a lever operated device that you dont grab then push up or down?

Agreed.

GTB said:

to me its not the single action of what your hand does its the single operating action of one electrical accessory that latches in the off position and isolates all forms of energy etc from the installation/equipment/machine.

Again, agreed ... BUT we need to be careful to limit that to the switch that the person presses, rather than the actuator that removes power, otherwise e-stops operating on drop-out contactors (to the e-stop standard BS EN ISO 13850, or per  BS 4163 Health and safety for design and technology in educational and similar establishments) wouldn't be permitted, which I think adds weight to your argument.

jbrameld said:

Oh dear - that means that Main Switches in domestic consumer units up and down the land that have a nice lift-up lid over everything (which presumably helps a little with stopping fire escaping if the devices inside melt....) are non-compliant then!

Whilst that is an isolator, I don't see it being the same function as a device for emergency switching off as discussed in BS 7671.

Yes, you might need to use it to remove power in a situation that might be itself an emergency, but it's not a device for emergency switching off?

And grabbing the firefighter's pole to reach the 2.75m high fire fighters' switch involves more than one single action.

Z.