By Sarah Larson, Commercial Program Manager, Rockwell Automation
For global machine and panel builders looking to sell their equipment into North America, one of the bigger challenges is complying with local standards and codes. Building compliant machinery and control panels for North American end users requires understanding the electrical codes and standards, as well as staying informed about emerging changes. Machine and panel builders serving the North American market should consider these four steps:
1. Key Standards
Some North American electrical standards have been evolving to harmonize with global standards for more than a decade. However, much work remains as the two sets of standards still have a number of differences. The three standards that every machine or panel builder should be familiar with include:
UL 508A, Standard for Safety for Industrial Control Panels: Applies to general and special-use panels, including requirements to comply with NFPA 79. There is no exact equivalent European counterpart to UL 508A. Although EN/IEC 61439-1 and EN/IEC 60204-1 have similar requirements, there are differences between these standards. For example, the European and North American standards use different methodologies for determining a system’s short-circuit current rating (SCCR), and the scope of coverage is slightly different.
The Allen-Bradley Bulletin 140G molded case circuit breakers are UL-listed as current limiting and can help engineers achieve a higher short-circuit rating in the control panel.
NFPA 70 National Electrical Code (NEC): Provides guidance for the proper installation of electrical equipment and safeguarding of persons and property from electrical hazards. Its European counterpart is EN/IEC 60364-1.
NFPA 79, Electrical Standard for Industrial Machinery: Covers not only a machine’s control panel, but also its operating environment, operator interface, warning signs, documentation and testing. NFPA 79 has been undergoing harmonization with its European counterpart, EN/IEC 60204-1, since 2002. Differences exist, such as grounding, voltage and protection requirements. But by standardizing on the NFPA 79 requirements, builders will reduce the number of changes needed to comply with EN/IEC 60204-1.
2. Confirm Specifications and Requirements
While many customers have some type of design specification, not all do. Even if a customer does provide specifications, they may lack crucial details. Types of information that should be requested and confirmed with the end-user customer include the following:
Power supply, including voltage, phase, frequency, system grounding and required short-circuit current rating
Operating conditions, such as temperature, vibration and environmental factors
Loads for devices, such as motors, drives, heaters and transformers
Functional descriptions, including sequence of operation and operator interfaces
Applicable standards and certifications, including local requirements
3. Documentation
One of the most basic but important things a machine or panel builder can do is document important project elements as part of the proposal process. The documentation should include the customer’s specifications and requirements; national and local standards and codes that apply to the project; and the proposed machine solution and project estimate. Some of this can come from the standards. For example, NFPA 79 provides a helpful “inquiry form” in its Annex B that can be used to document a machine’s requirements.
Tools like the Global Short-Circuit Current Ratings (SCCR) Selection Tool from Rockwell Automation can provide coordinated SCCR ratings for all power devices used in a circuit.
4. Using Training and Resources
Design engineers shouldn’t hesitate to contact their automation vendors with questions. The industry sees itself as a collaborator (or an ally) for machine and panel builders, system integrators and end users.
Automation vendors and distributors also host a number of educational opportunities throughout the year that specifically address North American standards. These include individual classes, individual speaking engagements at customer locations, and seminars at trade shows.
Standards and codes can be daunting, but they shouldn’t be a barrier to success in a new market. By understanding the standards, confirming and documenting project details, and working with automation vendors, OEMs and panel builders will be primed to meet compliance requirements and improve their competitiveness in North America.
Rockwell Automation Inc.
www.rockwellautomation.com
Filed Under: TIPS SITES (EE World)
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