This article is about Non-Hazardous Indoor Enclosures, Installation and Pre-Commissioning Materials Selection & Requirements of Electrical Power System Systems as per International Codes and standards for Commercial Buildings, Plants and Refinery Projects.
Non-Hazardous Indoor Enclosures, Installation and Pre-Commissioning
Certification & 3rd Party Listing – General Purpose Boxes & Enclosures
- Boxes and Enclosure Certification:
In outdoor plant areas, boxes and enclosures shall be certified by the manufacturer as:
(a) NEMA 250/NEMA ICS 6 Type 4; or
(b) NEMA Type 3 manufactured copper free cast aluminum (0.4 of 1% maximum), or plastic (including fiberglass); or
(c) IEC 60529 Type IP54 or better” - Box and Enclosure Certification:
In outdoor plant areas, outside the perimeter of process units, and other industrial areas, boxes and enclosures shall be certified by the manufacturer as:
(a) NEMA Type 3 or 4; or
(b) IEC 60529 Type IP54 or better” - Box and Enclosure Certification:
In outdoor plant and other industrial areas located in severe corrosive environments, boxes and enclosures shall be certified by the manufacturer as:
(a) NEMA Type 4X (except galvanized and/or painted or coated carbon steel sheet metal enclosures are not permitted); or
(b) NEMA Type 3 or 4, manufactured of copper free cast aluminum (0.4 of 1% copper maximum), or plastic (including fiberglass); or
(c) IEC 60529 Type IP 54 or better, manufactured of stainless steel (Type 304 or better), copper free cast aluminum, or plastic (including fiberglass).
Commentary Note:
In outdoor plant and other industrial areas located in severe corrosive environments, paragraph 7.3 supersedes paragraphs 7.1 and 7.2.” - Box and Enclosure Certification:
In outdoor non-industrial areas, boxes and enclosures shall be certified by the manufacturer as:
(a) NEMA Type 3R, 3 or 4; or
(b) IEC 60529 Type IP34 or better” - Enclosures that are rated:
(a) NEMA Type 3, 4 or 4X, or
(b) IEC 60529 Type IP54, or better,
shall have Type 300 Series stainless steel hardware.
Exception: Aluminum enclosures may have aluminum or aluminum alloy hinges and operating handles.
Certification & 3rd Party Listing & Labeling – General Boxes & Enclosures
- Suitability: Suitability of identified equipment shall be determined by one of the following:
(1) Equipment listing or labeling
(2) Evidence of equipment evaluation from a qualified testing laboratory or inspection agency concerned with product evaluation
(3) Evidence acceptable to the authority having jurisdiction such as a manufacturer’s self-evaluation or an owner’s engineering judgment.
[NFPA 70, NEC 500.8(A)] - Cathodic protection junction box enclosures shall be certified, labeled or listed by an approved and recognized testing organization to indicate full compliance with NEMA ICS 6 and NEMA 250 for NEMA Type 4, 4X, 7, 8 or 9 enclosures, as applicable.
- Marking:
All boxes shall be durably and legibly marked with the manufacturer’s name or trademark.
[NFPA 70, NEC 314.44]” - Marking:
Nonmetallic wireways shall be marked so that the manufacturer’s name or trademark and interior cross-sectional area in square inches shall be visible after installation. [NFPA 70, NEC 378.120]
Material Requirements
- New and Unused – General Boxes, Enclosures and accessories shall be new and unused.
- As Designed – General Boxes and Enclosures and accessories shall be in accordance with the Saudi Aramco-approved project-specific design drawings, diagrams, schedules, lists, databases, and associated design documents.
- Free of Damage -General Boxes and Enclosures and accessories shall be free of damage.
- QC Before Installation – General Boxes and Enclosures and accessories shall conform to all applicable requirements, standards, and specifications prior to release to be used as part of the work.
- Traceability – General Boxes and Enclosures and accessories shall be traceable from the manufacturer and supplier through delivery, storage, fabrication, erection, installation, repair, modification and use.
- Severe corrosive environments includes:
a) Outdoor offshore locations
b) Outdoor onshore locations within one kilometer from the shoreline of the Arabian Gulf, all of the Ras Tanura Refinery and Terminal, and within three kilometers from the shoreline of the Red Sea
c) Location where chlorine or other corrosive chemicals are being handled (e.g., waste water treatment, water treatment, R.O. facilities)
d) Battery Rooms ”
Locations where chemicals are being handled, enclosures, conduit, fittings and wiring must be resistant to the chemicals present. - Types of Electrical enclosure rated not more than 1000 Volts:
a. Non-hazardous locations
1. Enclosures for indoor locations, Types 1, 2, 5, 12, 12K, and 13; and
2. Enclosures for indoor or outdoor locations, Types 3, 3X, 3R, 3RX, 3S, 3SX, 4, 4X, 6, and 6P.
b. Hazardous locations
1. Enclosures for indoor locations, Types 7 and 9;
2. Enclosures for indoor or outdoor locations, Type 8; and
3. Enclosures for mining applications, Type 10
Table 2-1 and 2-2 (Attachment 1) are guides for comparing specific applications of enclosures. [NEMA 250 Sec. 1.1] - The IP Code & Designations:
A coding system to indicate the degrees of protection provided by an enclosure against access to hazardous parts, ingress of solid foreign objects, ingress of water and to give additional information in connection with such protection. Designations of the degree of protection provided by an enclosure is indicated by the IP Code arranged (See attachment 2 & 3) [IEC 60529 Sec. 3.4 and 4] - Drainage Openings:
Type 2, 3R, and 3RX enclosures shall have provisions for drainage. Drainage openings shall not be less than 3.2 mm in diameter (1/8 inch in diameter) or more than 6.4 mm in diameter (1/4 inch in diameter) unless baffled or provided with a drainage fitting.
For Type 2, 3R, and 3RX enclosures that also meet the requirements of other enclosure types, the drainage openings shall be closed by a removable plug. The enclosure shall meet the requirements of the other enclosure types with the plug installed. [NEMA 250 Sec. 3.6.3]” - Gaskets: A gasket shall be secured with adhesive or by mechanical means. The gasket and its securing means shall not be damaged when the gasketed joint is opened. [NEMA 250 Sec. 3.14]”
- An enclosure shall completely enclose all live parts that may be housed in it. [UL 50 Sec. 6.1.1 and NEMA 250 Sec. 1.2]
- An edge on an enclosure shall not be sufficiently sharp to constitute a risk of injury in normal maintenance or use. [UL 50 Sec. 6.1.4]
- Verify that all junction boxes, pull boxes, and conduit bodies are correct (size/ type) in according to NEC 314.16 and table 314.6(A) (Attachment 4). [NFPA 70, NEC 314.16]
Installation and Pre-commissioning
- Working space shall not be required in the back or sides of assemblies, such as deadfront switchboards or motor control centers, where all connections and all renewable or adjustable parts, such as fuses or switches, are accessible from locations other than the back or sides.
[NFPA 70, NEC 110.26(A)(1)(a)]” - Where rear access is required to work on nonelectrical parts on the back of enclosed equipment, a minimum horizontal working space of 762 mm (30 in.) shall be provided.
[NFPA 70, NEC 110.26(A)(1)(a)]” - By special permission, smaller working spaces shall be permitted where all exposed live parts operate at not greater than 30 volts rms, 42 volts peak, or 60 volts dc.
[NFPA 70, NEC 110.26(A)(1)(b)]” - Junction boxes shall be leveled to the floor grade and sealed against the free entrance of water or concrete.
[NFPA 70, NEC 372.7]” - Junction boxes shall be of metal and shall be mechanically and electrically continuous with the header.
[NFPA 70, NEC 372.7]” - Sufficient access and working space shall be provided and maintained about all electric equipment to permit ready and safe operation and maintenance of such equipment. Enclosures housing electrical apparatus that are controlled by lock and key shall be considered accessible to qualified persons.
[NFPA 70, NEC 110.26]” - The width of the working space in front of the electrical equipment shall be the width of the equipment or 762 mm (30 in.), whichever is greater. In all cases, the work space shall permit at least a 90 degree opening of equipment doors or hinged panels.
[NFPA 70, NEC110.26(A)(2)]” - Indoor electrical installations that are accessible to unqualified persons shall be made with metal-enclosed equipment. Metalenclosed switchgear, unit substations, transformers, pull boxes, connection boxes, and other similar associated equipment shall be marked with appropriate caution signs. [NFPA 70, NEC 110.31(B)(1)]”
- Electrical installations in a vault, room, or closet or in an area surrounded by a wall, screen, or fence, access to which is controlled by a lock(s) or other approved means, shall be considered to be accessible to qualified persons only. The type of enclosure used in a given case shall be designed and constructed according to the nature and degree of the hazard(s) associated with the installation.
[NFPA 70, NEC 110.31]” - Where switches, cutouts, or other equipment operating at 600 volts, nominal, or less are installed in a vault, room, or enclosure where there are exposed live parts or exposed wiring operating at over 600 volts, nominal, the highvoltage equipment shall be effectively separated from the space occupied by the low-voltage equipment by a suitable partition, fence, or screen. [NFPA 70, NEC 110.34(B)]
International Standard and Codes for Non-Hazardous Indoor Enclosures
3. NFPA 70 – National Electrical Code (NEC), 2008 Edition
4. SAES-P-104 – Wiring Methods and Materials, 13 January 2008
5. SAES-P-100 – Basic Power System Design Criteria, 25 June 2007
6. ANSI/IEC 60529 – Degrees of Protection Provided by Enclosures (IP Code) (identical national adoption), 2004
7. NEMA ICS 6 – Industrial Control and Systems: Enclosures -1993 (R 2006)
8. NEMA 250 – Enclosures for Electrical Equipment (1000 Volts Maximum), 2008
9. UL 50 – Enclosures for Electrical Equipment, Non-Environmental Considerations.
1. Attachment 1: Table 2-1 & Table 2-2 – Guides for Comparing Specific Applications of Enclosures – NEMA 250
2. Attachment 2: Arrangement of the IP Code – IEC 60529
3. Attachment 3: Elements of the IP Code and their Meanings – IEC 60529
4. Attachment 4: Table 314.16(A) – Metal Boxes – NFPA 70
Discover more from PAKTECHPOINT
Subscribe to get the latest posts to your email.