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!

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!

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?

Well the definition of 'emergency switching off' in Part 2 of BS7671 is quite broad and does not even require the hazardous situation to be electrical in nature - although the note to 537.3.3 seems to say that it does.  I'm not sure I get the subtlety of your distinction Graham.

'My consumer unit has started fizzing and smoking a bit and it seems to be getting worse'.  This would seem to fall under the definition of needing to be 'emergency switched off' to me.....

If your CU is fizzing then perhaps you might wish to fit a 100A DP contactor in the tails coupled to a remote E/stop button? Or better still, why not switch off at the isolator and investigate the cause of the 'fizzing' instead?