This is one of my biggest pet hates*. When an electrical component is described as "Normally x", this should always describe the off, de-energised, unactuated, (usually) out-of-the-box state of the contact. That's how electrical devices have always been. It's how they're (supposed to be) drawn. If it's a pushbutton, you draw it and describe the state when the pushbutton is not pressed. If it's a limit switch, you draw it and describe the state when the limti switch is free to spring to whichever is its "neutral" position and it's not actuated by any other object. If it's a pressure switch, you describe the state when no pressure is applied to the switch (or more accurately, when atmospheric pressure is applied to the switch). If it's a tongue-and-groove door switch, it's the state when the switch is not actuated by the tongue. If it's a coded magnet switch, it's the state when the switch not actuated by its coded partner.
What I think happened somewhere along the way is that someone who knew just enough about 'lectrical stuff to be dangerous, came along and claimed that "all safety devices must be failsafe" (which is true) and "failsafe means normally closed" (which is total BS). And thus, proclaimed that all guard switches are normally closed. Unfortunately, it stuck. So now, "normally open" and "normally closed" are almost completely meaningless because they threw away the definition of "normally" in pursuit of an incorrect idea (normally closed is failsafe).
When I draw something, I draw it in the non-actuated, de-energised, out-of-the-box state. Always. I will fight anyone who says that my guard switch has normally closed contacts. It ******* does not.
Anyway, I better get off my soapbox before I burst a blood vessel.
/rant
*(if you really want to see me get worked up about normally closed and safety, ask me why safety contactors come with so many normally closed auxiliaries)
I guess so. Is there an industry standard for this or does it depend on manufacturer?
