Unlike metal boxes, plastic boxes cannot be grounded because they are non-conductive. What should I do? What if the grounding wire is too short to reach the device? What are the relevant electrical codes that govern grounding in plastic boxes? Can I daisy chain grounding wires in a plastic box? How to Ground a Plastic. The answer is yes – if you want to ensure the highest level of safety, proper grounding of your plastic box is the way to go. Preparation: First, you need to prepare some necessary tools, including grounding wire, grounding rod, voltmeter, insulating gloves and insulating tools. You must use approved materials, choose the right size box.