UL 508A
UL 508A
OSHA defines the building owner, facility or property owner as the ?employer?. Employers must comply with OSHA requirements applicable to their operations. These requirements are within US laws.
Under the Occupational Safety and Health Administration (OSHA) Act of 1970, OSHA uses Federal regulation Title 29 of the Code of Federal Regulations, Paragraph 1910.303, Subpart S (29CFR 1910.303 (S)), which requires that all conductors and equipment are approved (listed), it also requires electrical equipment to be examined, to ensure it is free of hazards likely to cause harm to employees and be suitable for installation (by listing or labeling).
In addition to OSHA requirements, which cover only the workplace, the USA relies on local building codes to ensure safe electrical installations. These codes are based on the requirements of the National Fire Protection Agency, standard NFPA 70, also known as the National Electrical Code (NEC). This code is adopted universally by state and local inspectors who are empowered by their authority having jurisdiction (AHJ).
Some common AHJ (Authorities Having Jurisdiction) personnel known for their strict enforcement of local electrical codes. The legal requirement for acceptability to the local AHJ is derived from NEC Article 110 - Requirements for Electrical Installations. As a result, electrical inspectors will look for an NRTL listing, or a field label.
Electrical Inspectors have an ally in enforcing their local regulations and the National Electrical Code where there are requirements for products to be Listed and Labeled in accordance with Section 90.7 of the NEC. Electrical Inspectors are required to assure that all products installed in their jurisdiction are safe and comply with the NEC. To assure this compliance many Inspectors must rely on a label that appears on the product to make their determination of compliance. When the label does not appear the Inspector is usually left with the unpopular option of turning down the product or the installation.
This requires the Electrical Inspector not only to be very observant about the installation he/she is inspecting but also the products that are being installed. Additionally, he/she must also determine that the product is compliant with Section 110.3(A)(1) and 110.3(B) of the NEC. If an unlisted product goes undetected and it is a Hazard, the Electrical Inspector could be held accountable. This is an unreasonable burden to be place on an inspector.
OSHA Electrical Standard (Subpart S) requires that all electrical products installed in the work place be listed, labeled or otherwise determined to be safe by a Nationally Recognized Testing Laboratory (NRTL). OSHA places the responsibility of this squarely on the Employer. Nationally Recognized Testing Laboratories (NRTL) have the knowledge, wherewithal, and test equipment to test and evaluate products for safety. A NRTL will perform tests on a product based on a specific nationally recognized safety standard. After the product has been tested and found to comply with the safety standard, the product is considered to be free from reasonably foreseeable risk of fire, electric shock, and related hazards. The product is then ?listed? and will have a listing marking (label). As you work with electrical products, make sure the product has a listing marked on it from a NRTL.
One of the most important NRTL in USA are UL (Underwriters Laboratories, Inc.) and ITS (Intertek Testing Services). Those are highly qualified, nationally recognized testing laboratories with several testing laboratories in the United States and service locations in several other countries.
A control panel shall be designed, manufactured and tested by the last version of following codes or standards:
? Federal:
NEC, National Electrical Code, Art. 409 ? Industrial Control Panels
? Local codes: UL508A - Industrial Control Panels,
Those standards may apply:
NEMA ICS 1 - Industrial Control & Systems General Requirements
NFPA 70E - Standard For Electrical Safety In The Workplace.
NFPA 79 - Electrical Standard for Industrial Machinery
The NEC is the code accepted by most inspection agencies in the United States for safe installation of electrical equipment. While the UL standard looks at the construction of the OEM panel, the NEC looks at the manner in which this same panel is installed. The intent of Article 409 is to prevent the misapplication of control products and related equipment. This article will provide the minimum requirements to ensure safe installation and inspection of industrial control panels. Article 409 covers industrial control panels that are intended for general use and operate at a voltage of 600V or less.
UL 508A is the UL standard for the construction of Industrial Control Panels. This document gives guidelines to panel builders on various issues including proper component selection, wiring methods and calculation of short circuit current ratings. If a panel builder follows UL508A?s construction requirements and recommendations, they can apply to have their panel listed by UL. Upon successful inspection, the panel would bear the UL label. A UL label signifies that the panel builder has met the requirements of UL508A, and that their panels are subject to inspection by UL field representatives. Industrial control panels rated not more than 600 volts and for installation in ordinary locations are specified in UL 508A, the Standard for Safety of Industrial Control Panels. The requirements in the outline are based on UL 508, the Standard for Safety of Industrial Control Equipment; the national electrical code, NFPA 70; and the standard for industrial machinery, NFPA 79.
UL 508A - "Industrial Control Panels"
This category covers industrial control panels, which are factory-wired assemblies of industrial control equipment, such as motor controllers, switches, relays and auxiliary devices. The panels may include disconnect means and motor branch-circuit protective devices. An industrial control panel does not include the controlled loads, including motors, luminaires, heaters, or utilization equipment.
An enclosed industrial control panel is comprised of the enclosure, all components located within the enclosure, and all components mounted to the walls of the enclosure.
An open industrial control panel is comprised of a mounting sub-panel and all components mounted to the sub-panel, and is intended for installation into an enclosure in the field.
UL 698A - "Industrial Control Panels Relating to Hazardous (Classified) Locations."
Intrinsically safe circuit extensions, Class I, Groups A, B, C and D; Class II, Groups E, F and G; Class III. This category covers industrial control panels relating to hazardous locations which are factory wired assemblies of industrial control equipment such as motor controllers, switches, relays and auxiliary devices. The panels may include disconnect means and motor branch circuit protective devices.
Industrial control panels relating to hazardous locations are intended for installation in unclassified (ordinary) locations. They are provided with intrinsically safe (low energy) circuit(s) as indicated on the product, for extension into a hazardous (classified) location.
The UL Listing Mark on an industrial control panel provides evidence of third party certification to the municipal inspection authority and to the purchaser of the panel. It shows that the panel complies with an acceptable safety standard. The UL standard for labeling took effect in April 2006. AHJ Inspectors and RETIE inspectors /certifiers check for compliance with UL standards and they focus primary on standard UL 508A. An inspector will not allow or avoid the installation of a panel that it doesn?t carry a valid UL label listing.
A UL listed component bears the UL listing mark and has been subject to testing. The UL Listed label is evidence that the manufacturer submitted complete product samples for testing, witnessed by UL representatives. These products are subject to testing and evaluation by UL and were found to meet nationally recognized safety standards. Products can also be ?UL Recognized?, which means that the product was found to be safe in particular instances when reviewed and accepted by UL in the final application. OEMs utilizing UL Recognized components in a control panel must ensure that their application meets additional requirements described in their UL procedure.
In order to manufacture an industrial control panel, the panel builder needs a UL 508A license to be able to build electrical panels for costumers. The UL 508A certification is given through inspection by a Nationally Recognized Testing Laboratory (NRTL). This UL label, classified as UL-508A, when applied to an industrial Control System, is a symbol of Quality and Reliability, and also guarantees Compliance with NEC and NFPA standards as well as Safety standards. The UL-508A mark indicates to you that all details of the integration of the components within this enclosure were done consistent with the manufacturers' specifications and that the interconnecting of these components meets or exceeds any other Code requirements. UL Recognized components in a control panel must ensure that their application meets additional requirements described in their UL procedure.
An industral control panel shall be UL labeled and built by Panel Builder with an UL 508A license. A UL 508A panel should be marked "industrial control panel" with the UL logo. Need to be careful not to mistake the label of the enclosure for the label of the assembly.
