The Canadian Electrical Code for Hazardous Locations Has No Class—But it Does Have Significant Changes
Bibliographic record
Abstract
The world moved one step further from the U.S. National Electrical Code (NEC) [2]. For decades, both the CEC and NEC have used the term “Class” to identify the various types of hazardous materials. The 23rd edition of the CEC has removed the term “Class” from Section 18 and replaced it with the International Electrotechnical Commission (IEC) Zone system. Class I, which was changed in 1998 to include Zones, becomes simply Zones 0, 1, and 2. Class II and Class III were merged to become Zones 20, 21, and 22. Fig. 1 shows the introduction of hazardous location requirements into the CEC. All new construction must use the new system for area classification. The legacy “Class” and “Division” system was relocated to Appendix J. The CEC does allow for continued use of the Class/Division System in existing facilities. However, all new facilities must use the Zone System for all Explosive Atmospheres. This change does not prevent the use of Class/Division equipment in the Zone System. Tables were added that identify the types of Class/Division electrical equipment that can be used in the various Zones designated locations. The CEC approach differs considerably from the NEC. Although the NEC contains a variation of the IEC full system in Article 505 and Article 506, it permits the user to select either the Class/Division or Class/Zone system. This paper will explain the changes to the CEC and highlights the differences between it, the IEC system and the NEC.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.004 | 0.018 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.005 |
| Science and technology studies | 0.006 | 0.004 |
| Scholarly communication | 0.006 | 0.004 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.004 | 0.006 |
| Insufficient payload (model declined to judge) | 0.053 | 0.047 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".