All Marinco IG devices are orange, with an orange triangle-indicating isolated ground. Equipment requiring an isolated ground should use an isolated ground plug (orange housing) to show that the equipment should be connected to an isolated ground receptacle. Conventional receptacles have grounding contacts that are connected to the box, fittings, conduit and all other building ground system components, which can act as a large antenna for EMI and RFI. The ground terminals on Marinco IG-receptacles are designed to directly connect only to the service entrance grounding system, per NEC Article 250.146(D).