..and the answer may have been lost in the midst of time..
Plastic bit on pull cord switches is for insulation/saftey reasons?
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..and the answer may have been lost in the midst of time..
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OK - I just sacrificed 20 minutes of my life to finding the answer. It's in BS EN 60669-1:2000+ A2:2008
10.7 Where cord-operated switches are provided with a pull cord, which can be fitted or
replaced by the user, they shall be so designed that it is impossible to touch live parts when
fitting or replacing the pull cord in the normal way.
EDIT: A further reference in the standard says:
- breakage of the replaceable pull cord, not involving the part entering the cord-operated
switch, shall not be considered a failure to pass the test.
10.7 Where cord-operated switches are provided with a pull cord, which can be fitted or
replaced by the user, they shall be so designed that it is impossible to touch live parts when
fitting or replacing the pull cord in the normal way.
EDIT: A further reference in the standard says:
- breakage of the replaceable pull cord, not involving the part entering the cord-operated
switch, shall not be considered a failure to pass the test.
Last edited:
That's an absolutely brilliant find...
However if that is the reason for fitting the insulator I can think of a glaring error in every single currently available pull switch.
I still firmly believe that part of the design criteria was to enable the the cord to snap at the joint, if pulled to hard. I vaguely remember a report of child playing and becoming entangled with a pull cord round their neck and either dying or almost so.
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Not sure that can be true. One of the tests is to load the cord with 100N for 1 min without it breaking.
That's just over 10kg, most people who might get tangled in a hanging cord weigh quite a bit more than that.
Another probably fairly far-fetched idea, I suspect! I've just tried with a couple of current ones and, try as I may, I cannot get anything to 'snap'.
It may be a different case you're referring to, but I do recall one of a tragic death of a child who got the pull cord of curtains (or blinds), not an electrical switch, around their neck. That led to a lot of campaigning, suggestions about 'safety measures' and maybe changes in design, but I've never seen any such 'joint' in a curtain pull cord - and nor do I see that it would be practical to have one (without stopping the functionality of the cord).
Kind Regards, John
I remember the blind/curtain cord as a separate issue. The suggestion was to ensure they were short enough that it prevented a child becoming entangled. Kids can be expected to need to turn a bathroom light on, so the cord needs to be long enough for that.
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Yes, I was too quick. Going from the Newton being the weight of a large apple, I incorrectly estimated the weight of a large apple. Nevertheless they require a minimum strength but not a maximum.
... and, as I said, although I haven't tried supporting my weight with one (which would require me to somehow fix it to a ceiling or something), I have tried, 'on the bench', pulling as hard as I possibly can on a couple, and nothing snapped or broke - and I'm not particularly a 'weakling'.
Kind Regards, John
Just found this: https://www.bathroom-trends.co.uk/a...room-Ceiling-Pull-Switch-FPK4-CH-29-8796.html
Not saying it's compliant or legal of course.
Not saying it's compliant or legal of course.
That rather defeats the whole concept of the string providing the user with good insulation from any live parts. Probably a Chinese import.
Well, it would do, IF the concept (of the 'string' and/or the plastic cord connectors) were as you suggest - but, as you know, I am far from convinced that such is/was the case.
Kind Regards, John
As metal 'normal' switches are permitted, it would seem highly unlikely that that pull-cord would not be - assuming it is earthed properly.
Remember the discussion has been about water causing any problem; not the design of the switches.
Remember the discussion has been about water causing any problem; not the design of the switches.
I wonder if its Class I or II - I'm not sure that one could reliably earth (all of) a 'cord' consisting of metal beads presumably strung on something non-conductive. Mind you, are we even certain that they are metal beads (rather than plastic with 'chrome paint')?
Sort of, but all the recent discussion has not been about water causing a problem with the switch but, rather, water potentially turning a pull cord into a conductor (which a metal one already would be).
One thing that hasn't been mentioned is that, for very many years, the cords have (presumably) been made of 'man-made-fibres', sot any sort of string/cotton/wool/yarn/whatever - so probably far less inclined to get 'soaked in water', even if submerged in the stuff?
Kind Regards, John