§234.213. Grounds.
49 C.F.R. § 234.213
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.
Exception. Paragraph (a) of this section does not apply to the following:
Circuits that include track rail;
Alternating current power distribution circuits that are grounded in the interest of safety;
Circuitry internal to microprocessor-based appliances;
Circuitry internal to semiconductor-based memory; and
Common return wires of grounded common return single break circuits.
Notes, amendments, and revision history
Amendments
[79 FR 49715, Aug. 22, 2014]
Authority
Authority: 49 U.S.C. 20103, 20107, 20152, 20160, 21301, 21304, 21311, 22907 note; 28 U.S.C. 2461 note; and 49 CFR 1.89.
Source
Source: 61 FR 31806, June 20, 1996, unless otherwise noted.
Amendments
[79 FR 49715, Aug. 22, 2014]