NEMA (www.nema.org) has recently posted its updated Application Guide for Isolated Ground Wiring Devices on its website for free download – www.nema.org/stds/appguide-isoground.cfm. This publication covers wiring devices and accessories intended to help protect sensitive equipment from malfunction due to noise on the equipment grounding path. Devices include receptacles, single or duplex with straight blade or locking NEMA configurations, rated 15A to 60A and 125V to 600V. Accessories include color-coded mating plugs and wall plates to identify isolated ground receptacles.
In addition to indicating devices and accessories available for isolated ground installations, this guide covers National Electrical Code® requirements, applications for isolated ground circuits, and troubleshooting and maintenance of such installations.