---
kind: "section"
citation: "30 C.F.R. § 23.9"
title: "30"
number: "23.9"
heading: "Special requirements for complete devices."
url: "https://uscodex.org/cfr/30/23.9"
---

# §23.9. Special requirements for complete devices.


Telephones and signaling devices will be considered nonpermissible if used under any of the followings conditions:

- (a) **Without the approval plate, mentioned hereafter.**
- (b) **With unprotected openings in any of the explosion-proof compartments.** This condition refers to any openings in these compartments, but especially to those equipped with removable covers.
- (c) If not complete with all of the parts considered in the approval.
- (d) If installed or connected otherwise than in accordance with the instructions furnished by the manufacturer.
- (e) If modified in any manner not authorized by MSHA.

## Notes

### Authority

Authority: 30 U.S.C. 957, 961. Sec. 23.2(f) also issued under 30 U.S.C. 811.

### Source

Source: Schedule 9B, 4 FR 1555, Apr. 11, 1939, unless otherwise noted.