Wireless E-stops for industrial use?

[MichaelA1965]

Has anyone had any luck with, or is it even legal/code compliant, to install wireless transmitters to operate an E-stop? Specifically, I would be tripping the rectifier circuits that supply my DC bus.

I'm working with an industrial (smelter) DC bus system that is 1000 VDC, and 150KA. There is a request by the customer to install wireless E-stops. It is against my better judgement to do something like this, but I must at least explore the options.

I'd love to hear your thoughts, but more importantly, I'd love if someone might have experience, or can point me to documents/code sections that will support or not support this method of de-energizing a bus/power.

Thanks.

 

[hillbilly1]

I would think they would be legal, as long as it's a supervised signal. You may have some unwanted tripping though if there is interference from another source interupting the supervisory signal. I know they use wireless ones with truck cranes.

 

[pfalcon]

SHORT ANSWER: Legal yes; We don't use them though.

LONG ANSWER: Estops are poorly covered under federal and state regulations. NFPA79 is a national consensus standard you can use to answer the OSHA General Duty Clause in case you run into difficulties. I suggest that your company adopt it. In any case, as a device being used for safety, it must be listed for the purpose. That means it will have a version of a heartbeat signal. Loss of signal will trigger the Estop. Generic wireless devices cannot be used.

Now you can play find the remote at work too!