{"data":{"id":"us/49-cfr-234.213","jurisdiction":"us","citation":"49 CFR 234.213","heading":"Grounds.","body":"(a) General. Except as provided in paragraph (b) of this section, each circuit that affects the proper functioning of a highway-rail grade crossing warning system shall be kept free of any ground or combination of grounds that will permit a current flow of 75 percent or more of the value necessary to retain a permissive state of a safety appliance.\n(b) Exception. Paragraph (a) of this section does not apply to the following:\n(1) Circuits that include track rail;\n(2) Alternating current power distribution circuits that are grounded in the interest of safety;\n(3) Circuitry internal to microprocessor-based appliances;\n(4) Circuitry internal to semiconductor-based memory; and\n(5) Common return wires of grounded common return single break circuits.","path":["Title 49—Transportation","Subtitle B—Other Regulations Relating to Transportation","CHAPTER II—FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION","PART 234—GRADE CROSSING SAFETY","Subpart D—Maintenance, Inspection, and Testing"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-49.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:34Z","sha256":"0589b4e5e609765e9c8f430540fd7c6e1c0d30b0fdcfef7c22c9926063dbdd33","source_id":"us-cfr","stale":true,"prev":"us/49-cfr-234.211","next":"us/49-cfr-234.215"},"notice":"GroundRules: Original legal text. Not legal advice."}