---
kind: "section"
citation: "49 C.F.R. § 234.213"
title: "49"
number: "234.213"
heading: "Grounds."
url: "https://uscodex.org/cfr/49/234.213"
---

# §234.213. Grounds.

- (a) **General.** Except as provided in [paragraph (b)](#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.
- (b) **Exception.** [Paragraph (a)](#a) of this section does not apply to the following:
  - (1) Circuits that include track rail;
  - (2) Alternating current power distribution circuits that are grounded in the interest of safety;
  - (3) Circuitry internal to microprocessor-based appliances;
  - (4) Circuitry internal to semiconductor-based memory; and
  - (5) **Common return wires of grounded common return single break circuits.**

## Notes

### 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]