NEC Article 500 Code Sections
(500-516) Hazardous Locations/Special Occupancies
BRIEF DESCRIPTION:
This course is based on Article 500+ of the National Electrical Code (Hazardous Locations/ Special Occupancies). The course reviews the Class, Division and Group categories of the NEC and the NEC additions and restrictions on the IEC Zone System (Articles 504, 505 and 506). The course will explain the protection techniques of both systems as they apply to conduit systems, enclosures and luminaires. In addition, the changes in the 2014 code that expand the IEC methods (i.e. the use of TC-ER-HL cable) will be explained.
COURSE OUTLINE:
1. Listing and Review of Articles 500-516
a. Class, Division, Group
b. Intrinsically Safe Systems
c. Zones
d. Special Occupancies
2. Examples of Accidents in Hazardous Locations
a. Deep Water Horizon
b. Savanah River Sugar
c. Exxon Torrance Refinery
3. Definitions
a. Lower Flammable Limit
b. Upper Flammable Limit
c. Flash Point
d. Auto-Ignition Temperature
e. “T” Rating
4. Combustion Triangle
a. Fuel, Air, Ignition
b. Potential Ignition Sources
5. NEC Classes
a. Gasses/Vapors
b. Dusts
c. Fibers/Flyings
6. Divisions
a. Constant Presence
b. Presence by Exception
7. Groups
a. A, B, C, D Gasses and Vapors
b. E, F, G Dusts
8. NEC Protection Techniques
a. Maximum Experimental Safe Gap
b. Minimum Ignition Current
c. Third Party Testing/Standards Organizations
9. Zones, (Equivalent Divisions and Groups)
a. 0, 1, 2 Gasses and Vapors
b. 20, 21, 22 Dusts and Fibers
c. IIC, IIB, IIA Groups of Gasses only
10. IEC Protection Techniques
a. Intrinsic Safety
b. Flameproof
c. Increased Safety
d. Encapsulation
e. Non-sparking
f. Oil Immersion/Powder Filled
g. Purged and Pressurized
11. NEMA/IEC Comparison
a. Protection Techniques
i. NEC: Explosion Proof Enclosures, Rigid Conduit
ii. IEC: Limited Power, Cable
b. NEMA Enclosures/ IP Numbering
12. Luminaires
a. Label Contents
b. “T” Rating
c. Enclosed and Gasketed
d. Restricted Breathing
e. Explosion Proof
13. Miscellaneous Notes
a. Categories
i. ATEX
ii. AEx
iii. EEx
iv. Ex
b. Wire nuts permitted in NEC, Prohibited in IEC
COURSE OBJECTIVES:
The objectives of this course are to insure that the student understands the NEC Hazardous Location Classes, Divisions and Groups and how they relate to the IEC Zone System. Contractors and Manufacturers may follow either method depending on the AHJ (not mixed) so electricians must understand that there are two methods and what the differences are between them in approvals, wiring practices and equipment.
LEARNING OUTCOMES:
Licensed Electricians will be able to install electrical products in hazardous locations according to either the NEC or IEC requirements (subject to certain restrictions the NFPA places on the IEC method in the territories where the NFPA has jurisdiction).
INSTRUCTOR: Ralph Bliquez (Previously Approved)
COURSE PREREQUISITES: Licensed Electricians
SPECIFIC STATEMENT ON CODE CHANGES: The course focuses on the code changes in the 2014 code both harmonizing and distinguishing the two construction methods (NEC and lEC) for Hazardous Locations but the NEC is the authority in the United States. Some examples of changes in the 2014 Code: allows the use of tray cable in hazardous locations (TC-ER-HL) up to 1” in diameter; a “qualified person” in some cases is permitted to do plans instead of an engineer; the prohibition on wire nuts in the IEC, U.L. listing on cable glands in the NEC but not the IEC, etc.. The code requirements are set by the National Fire Protection Association for the NEC and they deviate in some areas from the International Electrotechnical Commission requirements.
PROGRAM MATERIALS: NEC 2014 CODE REVIEW, A Guide for the use of Electrical Products in Hazardous Locations.