UL & NFPA Standards
USA UL and NFPA Standards for machineries
UL 891 is a tristandard. That means it is exacly the same content in the following three norms:
- CSA Group: CSA C22.2 No. 244-05
- Underwriters Laboratories Inc: UL 891
- Association of Standardization and Certification: NMX-J-118/2-ANCE-2012.
The subjects are the SWITCHBOARDS, also called in North America "dead-front switchboard". In Europe the equivalent standards are the EN 61439-1 and EN 61439-2. However the approach is different. EN 61439 puts a lot of emphasis on the Design Verification and cabinet testing. UL 891 is mainly about how to design the switchboard.
The Standard applies to switchboards nominally rated at 600 V or less and intended for use in accordance with the Canadian Electrical Code, Part 1 (CE Code, Part 1), the National Electrical Code (NEC), ANSI/NFPA 70, and the Mexican Standard for Electrical Installations (Utility), NOM-001-SEDE.
These requirements cover switchboards for use on circuits having available RMS symmetrical short-circuit currents of not more than 200 000 A.
NFPA 79
On 8th January 2021 the new edition of Industrial Machinery NFPA 79, the electrical standard for industrial machineries in the USA, was published. That will be valid for the next three years
Although the standard has many parts in common with IEC 60204-1 (alignment started with 2002 edition), there are still several differences.
Unlike IEC 60204-1, NFPA 79 does not recognize the advantage of class 2 insulated conductors, so the criteria for bonding metal parts is different. An excellent standard for bonding criteria is C22.2 No. 0.4 of 2017: Bonding of electrical equipment. Although it is a
UL 891
UL 891 is a Tristandard. That means it is exactly the same content in the following three norms:
CSA Group: CSA C22.2 No. 244-05.
Underwriters Laboratories Inc: UL 891.
Association of Standardization and Certification: NMX-J-118/2-ANCE-2012.
The subjects are the SWITCHBOARDS, also called in North America "dead-front switchboard". In Europe the equivalent standards are the EN 61439-1 and EN 61439-2. However the approach is different. EN 61439 puts a lot of emphasis on the Design Verification and cabinet testing. UL 891 is mainly about how to design the switchboard.
The Standard applies
NFPA 70
NFPA 70 or NATIONAL ELECTRICAL CODE is the reference standard for electrical installations in premises and buildings in USA.
Being an Installation Code, it is addressed to the installer, more than to the Electrical Engineer who designs the electrical installation/distribution.
The first National Electrical Code was developed in 1897. In 1911, the National Fire Protection Association (NFPA) became the sponsor, and the Code has been revised on numerous occasions since that date. Now it is revised every three years. The latest edition is 2020. The NEC is available for adoption as the electrical
UL 508A
UL 508A is the technical standard for Industrial Control Panels in the USA. Starting from the basics of electrical safety, stated by the NEC and looking at the prescriptions stated in NFPA 79, it gives indications for the design of industrial control panels.
While the NFPA 79 provides prescriptions for industrial machinery control panels, UL508A has a broader scope and it focuses on the criteria that guarantee the safety of a control panel. It also provides a well recognised method to calculate the Short-Circuit Current Rating of an Intustrial Control Panel.
In Europe, there is no equivalen
IEEE 1584
IEEE 1584 is a guide that aims to provide models and analytic processes for calculating the caracteristics of an electric arc flash.
It is essential to know these characteristics because, depending on these, the necessary PPE and the measures to be taken to ensure the safety of electrical maintenance personnel during live work are chosen.
It is emphasized that the guide deals with electric arcs in alternating current systems, with operating voltage between 208 V and 15.000 V. Single-phase electric arcs or direct current electric arcs are not covered by the guide, even if the latter still pro
