30 CFR § 7.66 - Output energy test.

---
identifier: "/us/cfr/t30/s7.66"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "30 CFR § 7.66 - Output energy test."
title_number: 30
title_name: "Mineral Resources"
section_number: "7.66"
section_name: "Output energy test."
chapter_name: "MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR"
subchapter_number: "B"
subchapter_name: "TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS"
part_number: "7"
part_name: "TESTING BY APPLICANT OR THIRD PARTY"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "30 U.S.C. 957."
regulatory_source: "53 FR 23500, June 22, 1988, unless otherwise noted."
cfr_part: "7"
---


# 7.66 Output energy test.

(a) *Test procedures.* The blasting unit shall be tested by firing into each of the following resistive loads, within a tolerance of ±1%:

(1) The maximum blasting circuit resistance.

(2) Any resistive load between 3 ohms and the maximum blasting circuit resistance.

(3) One ohm.

(b) *Acceptable performance.* (1) The voltage shall be zero at the firing line terminals 10 milliseconds after operation of the firing switch.

(2) The electric current from the blasting unit shall be:

(i) Less than 50 milliamperes except during firing of the blasting unit.

(ii) Available only through the firing line terminals.

(iii) At least an average of 2 amperes during the first 5 milliseconds following operation of the firing switch.

(iv) Not exceed an average of 100 amperes during the first 10 milliseconds following operation of the firing switch.