Emergency stops for other purposes

[LARRY POTTER]

Is it code compliant to use another set of contacts on a emergerncy stop button to turn on a light that indicates that the switch has been pushed using the same control voltage and circuit the light will be on a pilot in seperate control box

 

[augie47]

I know of nothing that would prohibit that use.
Illuminated pushbuttons are often used in just such a manner.

 

[StephenSDH]

That is the normal way to indicate an E-Stop is pressed in.

 

[billsnuff]

the systems I've worked on have a light at the e-stop that has been actuated and an illuminated 'reset' which is required to return the e-stop circuit to monitoring.

 

[eric7379]

Systems that I have worked on in the past usually have had a different circuit for the light, but I have seen in done both ways.

Another system that I have worked on in the past had a "redundant" e-stop circuit in which the normal e-stop circuit is on a NC contacts, but another part of the circuit is on a NO contact. If both contacts do not change state within a defined amount of time, then a fault of "e-stop mismatch" would be given.

Other setups I have seen have been where once the e-stop button is pushed, then the light is illuminated on every e-stop button on the machine, but another set of contacts is used to tell the PLC where at on the machine the e-stop button is pushed in at, then a fault message can be annunciated on a display.

Don't know for sure if any of these is specifically addressed in the NEC. Probably the NFPA 79 or other industrial standards would come in to play.