What is the difference between an “Emergency Shut-Off Switch” and an “Emergency Disconnect” as described in FBC 423.17.4 and .5 respectively?
In general terms, they both provide the same type function. To be a little more specific, an “Emergency Shut-Off Switch” is normally associated with use in a laboratory and disconnects power to all of the receptacles in the room. It can also shut off any gas supplied to a lab. It usually performs its operation through relay control. An “Emergency Disconnect” is generally associated with heavy equipment located in a shop, i.e., an arc welder, band or table saw, bench sanders, etc. It also shuts off power to all receptacles in the shop area. Based of what is connected, the “Disconnect Switch” may be a large manual pull switch that disconnects all 220 volt and all 3 phase power equipment and trigger relays to shut down all receptacles and 110 volt equipment. One important factor is that two “Disconnect Switches” are required where only one “Emergency Shut-Off Switch” is required.
