Conformity Magazine - November 2007 - (Page 30)

Field Evaluation FAQ UL 508A Panel Q: The machine in question has a control panel that has been constructed by a UL 508A panel shop and has a UL 508A panel listing. Is this sufficient for the United States? A: No! While the electrical panel is an important element of the machine, it is not the entire machine. The full machine must be assessed to applicable safety standards. Often, this means the overall machine is assessed to NFPA 79. UL 508A is a good standard for electrical panels (for which it is intended) but does not address questions of overall machine safety. Multiple Machines Q: Multiple identical machines are being manufactured. Is a full field evaluation examination required on each machine? A: No. A preliminary field evaluation and final field evaluation is required on one representative machine. After this, only a final field evaluation inspection is required for each subsequent identical machine. CE Marked Machines Q: A machine is CE marked per the European Union’s Machinery Directive. Do additional requirements for the United States apply? A: Yes. The CE mark has no legal standing in the United States. In addition, for technical reasons related to the way the power system is designed in the United States and the manner in which factory power systems handle fault currents, a system designed for the European Union is not suitable for use in the United States. A field evaluation performed by an NRTL which is also a Notified Body for the European Machinery Directive allows the field inspection process to focus on those areas of the machine that must be modified for use in the United States. Parts of the machine which are approved for use in Europe and which are acceptable in the United States need not be modified. Inspection Documents for Used Machines Q: A field inspection is performed for used machinery, and the requested documents for the preliminary inspection are not available. What can be done? A: The NRTL normally recognizes that the full requirements of a field inspection become difficult for machines which are used, or which have been in service for a long time. In these cases, the minimum requirement is an electrical schematic. If an electrical schematic does not exist, and the machine electrical system is simple, the inspecting engineer can normally make a sketch of the wiring system in the field inspection notes, which are included in the compliance file. If the electrical system is complex, it may be necessary to hire an outside technical firm to trace the electrical system and produce a schematic. Programmable Electronic Safety Devices Q: The machine uses programmable electronic safety devices. What are the requirements for field labeling? A: The hardware is required to comply with UL 991. This cannot be assessed during a field evaluation, so if non-UL 991 hardware is used, the manufacturer will either need to: a) have the hardware independently tested in the laboratory of the NRTL; b) replace the hardware with UL 991 approved hardware; or c) retrofit electromechanical safety systems in place of the programmable electronic safety devices. The software running on the programmable device is required to comply with UL 1998. If the software is already compliant with IEC 61508, no further actions are required, since the requirements of IEC 61508 exceed those of UL 1998. If the software is not IEC 61508 compliant, the field engineer will need to examine a source code printout of the software and verify operation of all safety functions identified in the software. Non-NRTL Approved Wiring Q: The machine is being imported into the United States and does not have NRTL approved wiring. What can be done? A: In general, hazardous voltage wiring and wiring used outside of protective enclosures (control cabinets, conduit, etc) are required to be NRTL-approved for the rated voltages and conditions of use. Low voltage wiring which is not NRTL-approved but is approved by a non-U.S. testing agency is acceptable for field inspection use. Where wiring is required to be NRTL-approved, it is also possible to accept non-U.S. agency approvals if the NRTL engineer can verify that the standard used for approval is equivalent to the U.S. standard. If all else fails, the NRTL can subject a sample of the wiring to laboratory testing. 30 Conformity noVEmBEr 2007

Table of Contents Feed for the Digital Edition of Conformity Magazine - November 2007

Conformity - November 2007 Contents Editor’s Note Commission Sets Date, Terms for 700 MHz Auction FCC Reaffirms Roaming Obligations Commission Moves to Improve USF Management FCC Proposes Fines for Violations of E911 Handset Requirements Commission Levies $1 Million Plus Fines for Unsolicited Fax Advertisements GR-3150 - Lithium Battery Certification Levels Based on Criteria for General Product, Safety, and Performance, Part 2 ESD Open Forum Machinery Field Evaluation for the United States Validation, Verification, and Immunity Testing Techniques for EMC for Functional Safety Thermal/EMC Simulation Addresses New Mechanical Design Challenges Product Safety Equipment Buyer’s Guide FCC Releases Report on Telephone Numbering Resource Utilization Canada Still Has PCS Spectrum to Assign Updated Standards List for the EU’s Medical Devices Directive Updated Standards List for EU Directive on Active Implantable Medical Devices Call for Papers for the 2008 EOS/ESD Symposium Announced Mobile Phone Use in Hospitals May Be Dangerous CPSC Actions in the News IEC Standards Update UL Standards Update Telcordia Standards Update From Our “You Can’t Make This Stuff Up” Department Product Reviews Looking Back: Items from Past Issues of Conformity Upcoming Events Advertisers

Conformity Magazine - November 2007

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