---
kind: "section"
citation: "30 C.F.R. § 75.1323"
title: "30"
number: "75.1323"
heading: "Blasting circuits."
url: "https://uscodex.org/cfr/30/75.1323"
---

# §75.1323. Blasting circuits.

- (a) Blasting circuits shall be protected from sources of stray electric current.
- (b) Detonators made by different manufacturers shall not be combined in the same blasting circuit.
- (c) Detonator leg wires shall be shunted until connected into the blasting circuit.
- (d) Blasting cables shall be—
  - (1) Well insulated, copper wire of a diameter not smaller than 18-gauge; and
  - (2) Long enough to permit the round to be fired from a safe location that is around at least one corner from the blasting area.
- (e) Blasting cables shall be shunted until immediately before firing, except when testing for circuit continuity.
- (f) **Wire used between the blasting cable and detonator circuitry shall—**
  - (1) Be undamaged;
  - (2) Be well insulated;
  - (3) Have a resistance no greater than 20-gauge copper wire; and
  - (4) **Be not more than 30 feet long.**
- (g) Each wire connection in a blasting circuit shall be—
  - (1) Properly spliced; and
  - (2) **Separated from other connections in the circuit to prevent accidental contact and arcing.**
- (h) Uninsulated connections in each blasting circuit shall be kept out of water and shall not contact the coal, roof, ribs, or floor.
- (i) When 20 or fewer boreholes are fired in a round, the blasting circuit shall be wired in a single series.
- (j) Immediately prior to firing, all blasting circuits shall be tested for continuity and resistance using a blasting galvanometer or other instrument specifically designed for testing blasting circuits.

## Notes

### Amendments

[53 FR 46786, Nov. 18, 1988; 54 FR 27641, June 30, 1989]

### Source

Source: 53 FR 46786, Nov. 18, 1988, unless otherwise noted.

### Authority

Authority: 30 U.S.C. 811, 813(h), 957.

### Source

Source: 35 FR 17890, Nov. 20, 1970, unless otherwise noted.

### Amendments

[53 FR 46786, Nov. 18, 1988; 54 FR 27641, June 30, 1989]