Catagory "0" Stop

[Greg S.]

I hope another NFPA-79 question is OK with the readers. The last one got some good responses. --- NFPA 79 requires a Catagory 0 stop on all machines. My intent is to use the main disconnest as the Catagory 0 stop since all of the machine E-Stops are Catagory 1. They ramp down the motor controllers and take 5-7 seconds to deenergize the MCCs. The MCCs and the main disconnect are located in a seperate room from the machine since it is a very hostile enviornment. Can anyone cite a code article or ANSI standard that requires the Class 0 stop to be in a particular proximity to the machine. By the way, each motor has a Metrelec cord and plug connection that can be locked out.

Another quick one. Other being readily accesssable, is there a specific height a pull cord for an e-stop must not exceed? I expected to find a requirement of about 6' but could find nothing specific.

 

[pfalcon]

The "0" stop has no fixed position relative to the machine. Follow the rules for it being a disconnect.

The pull cord Estop height/location is based on risk assessment for how it'll be used. It doesn't look good in the after action report when the guy is trapped in the conveyor for 3 hours because the Estop cord was hangin "just beyond reach" in the other direction. That said, most control equipment is considered to be out of service reach over 84".