Du behöver inte fästa den gröna svansen mot jordledningen i lådan. Genom att ordentligt fästa denna enhet på en korrekt jordad metalllåda ger du en tillfredsställande jordningsbana.
NEC 2011
404.9 Provisions for General-Use Snap Switches
(B) Grounding.
Snap switches, including dimmer and similar control switches, shall be connected to an equipment grounding conductor and shall provide a means to connect metal faceplates to the equipment grounding conductor, whether or not a metal faceplate is installed. Snap switches shall be considered to be part of an effective ground-fault current path if either of the following conditions is met:
(1) The switch is mounted with metal screws to a metal box or metal cover that is connected to an equipment grounding conductor or to a nonmetallic box with integral means for connecting to an equipment grounding conductor.
(2) An equipment grounding conductor or equipment bonding jumper is connected to an equipment grounding termination of the snap switch.