GR-3160-CORE, NEBS Requirements for Telecommunications Data Center Equipment and Spaces, is sometimes described as ‘NEBS Lite.’ It includes important reliability and safety requirements, without the full set of hurdles found in the NEBS telecom standards, like GR-1089-CORE and GR-63-CORE.
But what exactly are the differences for equipment evaluation? Following is a basic overview.
- Acoustic Noise
- Energy Efficiency
- Handling Shock
- Surface Temperature
In other areas, the test requirements for GR-3160 are looser or non-existent:
Bonding & Grounding
NEBS – Requirements for reliable ground methods as well as short-circuit tests
GR-3160 – Requirements for reliable ground methods, but no short-circuit tests
Corrosion, SSPI, DC Potential Difference
NEBS – Required
GR-3160 – No requirement
DC Power Compatibility
NEBS – Requires transient tests as well as DC noise emissions and immunity
GR-3160 – Requirements for grounding of return conductor of centralized sources and DC-I configuration of loads
Earthquake & Office Vibration
NEBS – Full scale tests in all cases
GR-3160 – Checklist review for redundant or non-critical sites; test for others
EMC – Emissions
NEBS – Only NEBS method
GR-3160 – FCC or NEBS
EMC – Immunity
NEBS – Testing from 10kHz to 10GHz
GR-3160 – NEBS only from 30MHz to 10GHz or EN 55024
NEBS – Required
GR-3160 – An Objective
Fire Resistance – Materials
NEBS – Materials level fire resistance tests required
GR-3160 – No test if facility has suppression, detection, and disconnection means and equipment is listed
Fire Resistance – Spread
NEBS – Full scale fire spread tests required
GR-3160 – No test if facility has suppression, detection, and disconnection means and equipment is listed
NEBS – Objective Limit
GR-3160 – No Objective Limit
Intra-building and AC Power Port Lightning
NEBS – Only NEBS method
GR-3160 – NEBS or EN 300 386
Mixed Flowing Gas & Hygroscopic Dust
NEBS – Required for all hardware
GR-3160 – No requirements
NEBS – Short-term -5C to 50C; 7 day test
GR-3160 – Narrower range requirement; 2 day test
NEBS – NEBS specific
GR-3160 – Listing to EN 60950
Transport & Handling Temperature & RH
NEBS – -40C, +70C, 40C+93% RH
GR-3160 – No requirement
GR-3160 was created with input from 19 participating companies, including Verizon, AT&T, Telcordia, Dell, Intel, Juniper Networks, and Brocade. The committee’s goal was to focus on critical, high-value areas, relying on popular commercial standards when possible, and encouraging the use of well-designed and robust COTS equipment. Where testing can be avoided (e.g. earthquake), alternatives like the checklist are utilized. This approach takes advantage of data center infrastructure and network architecture redundancy.
MET Labs is a pioneer in NEBS testing, and we are equally skilled in testing data center equipment for reliability, energy efficiency, and safety. Contact us today to determine if your equipment is best suited for full NEBS or a more limited program.
The only constant? Change. Product safety standards are almost always in some state of being updated. Here is a summary of changes afoot for some of the most popular UL lighting safety standards:
UL 1598 – Luminaires (Tri-national standard)
The next 2-year revision cycle has started. CSA (the Publication Coordinator) sent proposals to the Technical Harmonization Committee (THC) Chair and the proposals were reviewed and discussed during the February 2014 CANENA meeting. Contact MET for the status of UL 1598A (Marine Vessel Installation) or UL 1598B (Reflector Kits).
UL 1993 – Self-Ballasted Lamps and Lamp Adapters (Tri-national standard)
The next revision cycle has started. Multiple proposals went out, and comments have been sent to the THC for review and input. Here is a summary of topics.
UL 935 – Fluorescent-Lamp Ballasts (10th edition)
Proposals went out for 1) the addition of requirements for ballasts intended to be dimmed using solid-state dimming controls electrically wired in series with the mains supply and 2) revising the arcing test method in Section 30. The revisions were published on August 7, 2014. For the tri-national standard, the draft of Part 1 (covering general construction and test requirements) is being reviewed by the CANENA Harmonization Committee (THC34/SC34C). The Part 2 documents, which will include specific requirements for the various product types, still need to be developed.
UL 1786 – Direct Plug-In Nightlights (Bi-national standard)
The next revision cycle has started. Multiple proposals went out. Here is a summary of topics.
UL 1838 – Low Voltage Landscape Lighting Systems
A proposal went out for a revision to ambient temperature measurement method.
UL 48 – Electric Signs
Proposals went out for 1) clarification of drain opening requirements, 2) grounding and bonding marking, 3) addition of requirements for laminated or organic-coated glass and revision to test method, and 4) addition of requirements for signs with photovoltaic systems or modules. Three out of the four topics gained consensus – grounding and bonding marking did not. Revision pages will be issued in the near future. In development is a proposed 1st edition for UL 48B (Changing Message Signs and Displays).
MET Labs is OSHA-accredited to product safety test and certify to all of these standards for the U.S. NRTL program and SCC-accredited for many additional CSA lighting safety standards for Canada. Find out why MET has a reputation as the Better Service Alternative to UL – Contact us today.
Attend our free webinar on Safety Certification for Electric Sign Shops.
Here at MET Labs, we’ve been product safety testing electrical/electronic equipment in the field for over 55 years. Naturally, we see the same failures over and over again. We hope this list of Top 20 Field Failures for Panel & Motor-Operated Equipment will help inspectors identify and contractors fix the most commonly observed non-compliances.
1. Supplementary Protector Usage – Supplementary Protectors are used incorrectly as branch circuit protection. When used incorrectly, these components are known to fail – welding closed and causing fires/short circuits. These can either be replaced by UL 489 listed circuit breakers or branch circuit fuses (suitable for the circuit rating).
2. Risk of Electrical Shock – Covers over live electrical parts are not secured properly. A tool or key is required to access areas that pose a risk of electrical shock.
3. Dedicated Ground – The main incoming grounding conductor is not terminated at its own dedicated point (e.g. there were two wires in the grounding terminal). The secondary ground must be moved to another grounding terminal.
4. Motor Overload Protection – Overload charts are not provided in the panel to verify the rating of the overload protection.
5. Protection of Power Supplies – The manufacturer’s instructions for overcurrent protection are not followed.
6. Strain Relief – An internal terminal strain relief device is not provided.
7. Working Space – Control panels are located too close to the wall and are not able to be serviced properly. The panel doors must be able to open at least 90 degrees.
8. Emergency Stop – Emergency stops are not provided at control and operator stations where shutdown would be required. These E-stops are required to override all other functions and operations in all modes (unless it creates another hazard).
9. Protection of Motor Drives – Motor drives are improperly protected per the manufacturer’s installation instructions. These frequency drives require specific size and type primary fuses or listed circuit breakers depending upon the size of the drive.
10. Power Transformer Protection – Power Transformers are not properly protected on the primary or secondary, based on the appropriate tables in the related standards.
11. Control Transformer Protection – Control Transformers are not properly protected. In some cases, only primary protection was found when secondary protection was also needed.
12. Termination of Wiring – Some wires are not terminated or were improperly terminated. Improper multiple terminations is a common issue and could create overheating at the terminal.
13. Conductor Ampacities Based on Termination Ratings – Conductor sizing is done improperly. Conductors are sized based on conductor ampacity without consideration to termination ratings.
14. Wire Bending Space for Main Connections – Control panels don’t have adequate wire bending space for the main connections, risking snapping the termination completely off.
15. Component Information – Components are not marked as certified (MET, CSA, UL, FM, ETL, VDE, JIS, etc.). Some components have CE marking, which is not acceptable.
16. Flexible Cords – Flexible cords are used improperly per NEC Article 400, which restricts the use of flexible cords for specific applications.
17. Multiple Power Sources – Panels that are fed with more than one source of power are not marked with a cautionary marking to protect the individual servicing the panel. This marking is required: “Caution, more than one disconnect, disconnect all before servicing.”
18. Area Classification – The environment where the product is installed is inappropriate. For example, a product intended for Ordinary Locations cannot be installed in a Class 1 Division 2 location.
19. Panel Only Certification – A control panel is certified but the load served by the panel is not.
20. Equipment Markings – Marking labels are not suitable for the surface material and temperature applied or text is not of adequate size and of good contrast.
What electrical equipment field failures do you see most often? Please leave a comment.
The requirements for HVAC/R equipment safety have changed. UL 1995/CSA 22.2 No. 236 has been updated with the release of the 4th edition. This new edition came into effect October 14, 2014. If your products are currently certified to the 3rd edition, you must have your file updated to reflect 4th edition changes.
UL1995 covers a broad range of HVAC/R equipment, including both residential and commercial fan coil units, heat pumps, liquid chillers and more.
Following are some of the significant new testing requirements in the 4th edition:
- Loading test for ceiling/wall suspended equipment
- Electric heat back-up protection tests for free air discharge units
- Hydrostatic pressure test for hot water/steam coils operating at 93°C and below
- Short-circuit test for some conductors of crankcase heaters
- Wire flexing tests for high voltage/safety circuit conductors that are periodically moved
Here are important revisions to the motor section of the standard:
- With exceptions, ungrounded conductors must open on controllers for motor compressors to interrupt current
- UL 60730 may now be used as a component standard in conjunction with UL 991, UL 1998 and UL 508C for electronically protected motors
- With exceptions, electrically protected motor circuits must comply with their applicable UL/CSA standards
And here are new testing requirements that apply specifically to components:
- Air filters and media wheels/plates must comply with flame test requirements of UL 900, which is now spelled out further
- Contactors used in pressure-limiting circuits must have an endurance rating of 100,000 cycles or more
- Interlock mechanisms must comply with UL 353/CSA C22.2 No. 55 or meet new cycling requirements
For new products, contact us for a free Lunchtime Review to discuss the new testing requirements as they apply to your equipment.
For existing equipment safety certified to Edition 3, contact us for a Gap Analysis. This service evaluates a current file to determine where it stands with respect to the new requirements. The fee varies depending on the complexity of the file to be reviewed. A portion of this fee can be applied to a project that is opened as a result of a completed gap analysis.
Three weeks ago, MET Labs joined other C12 Accredited Standards Committee members in St. Louis, MO at the EEI Transmission, Distribution & Metering Conference to discuss revisions to ANSI C12.1, which provides the basic requirements for all kilowatthour metering devices, both electronic and electromechanical.
This post highlights changes from the ANSI C12.1-2008 revision to the soon to be released ANSI C12.1-2014, as presented at the meeting by Jim Reed, MET’s Meter Accuracy Lab Manager. ANSI C12.1 was modified in several sections to keep pace with industry trends and to provide clarity for tests.
A number of definitions were added.
188.8.131.52.2 (Performance requirements) – Tightened the % errors for portable and reference standards at reference conditions including a specific voltage and current.
184.108.40.206.3 (Variation for reference condition) – Gave additional percent errors for Portable and Reference Maximum Percent Errors @ 23°C over the designed range of voltage and current.
4.7.1 (Test conditions under performance requirements) – Adds some clarity for the calibration level of the meters prior to entering into testing.
4.7.2 (Accuracy tests – internal influences) – A host of changes in this section, including the addition of a 0.5% accuracy classification. Contact MET for all of the changes in this section.
220.127.116.11 (Insulation) – A few changes, including the addition of a requirement to disconnect components providing a path in parallel with the insulation to be tested.
18.104.22.168 (Effect of high voltage line surges) – Adds an allowance for performing the accuracy performance check once after the completion of both a ring wave test and combination wave test.
22.214.171.124 (Effect of operating temperature) – A few changes, including ramp timing change from 6 to 5 hours.
126.96.36.199 (Effect of relative humidity) – A couple changes, including specifying test current between light load and class amps (same as 188.8.131.52).
A number of changes in this section, including:
- Restructuring to provide clarity, guidelines and generally better reflect updated practices within the industry for in-service and new meter deployment.
- A test plan must be in place for metering devices at various set intervals (periodic interval plan, variable interval plan or a statistical sampling plan).
- Provides details for corrective actions that must be taken for any metering device or group of metering devices failing to meet performance criteria.
- Added recommendations on test data that should be recorded for the annual performance test programs.
- An Acceptable Quality Limit or AQL of 1.0% or less will be used to develop the acceptance criteria for all metering devices.
- Service switches to fall under a statistical sampling plan.
- Performance tests for integrated communication devices.
Appendix D (Periodic testing schedule) – Recommended periodic test program cleaned up to reference AMI meters specifically, and then all other meters.
Appendix F (Variable interval plan) – Includes an example of appropriate test rates based on failed meters.
Questions about the changes? Ask Pat, our meter approvals expert.
Authorities Having Jurisdiction (AHJs) in the United States have typically used the National Electrical Code, NFPA 70, as the basis for approving electrical equipment installations in the United Sates. Much of the Code relies on having products manufactured and certified by a recognized testing laboratory to consensus-based U.S. product safety standards.
In Canada, the AHJs use the locally adopted Code and rely on products certified to that country’s adopted product safety standards.
However, this approach has historically proved challenging for AHJs, so industry organizations have created additional guidance documents. Here is a short history of this effort:
2003 – The American Council for Electrical Safety (ACES) publishes the Recommended Practice and Procedures for Unlabeled Electrical Equipment Evaluation. It became the de facto guide for delivering field evaluations.
2005 – ACES approves the Recommended Competency Guidelines for Third-Party Field Evaluation Bodies. It uses ISO Guide 65 as its foundation with input from ISO/IEC 17020.
2006 – The International Accreditation Service (IAS), a subsidiary of the International Code Council (ICC), issues AC 354, Accreditation Criteria for Field Evaluation of Unlisted Electrical Equipment.
2008 – The National Fire Protection Association (NFPA) forms the Technical Committee for Electrical Equipment Evaluation (EEE).
2011 – The 2012 editions of NFPA 790, Standard for Competency of Third-Party Field Evaluation Bodies and NFPA 791, Recommended Practice and Procedures for Unlabeled Electrical Equipment Evaluation — are adopted.
2013 – IAS adopts an updated AC 354 that references NFPA 790 & 791.
2013 – The 2014 editions of ANSI/NFPA 790 and ANSI/NFPA 791 are issued.
NFPA 790 and NFPA 791 provide AHJs with the ability to qualify who can complete field evaluations for electrical products. Read more about what is specified in these standards in a previous Compliance Today blog post.
As of September 10th, 2014, the U.S. Environmental Protection Agency’s (EPA) ENERGY STAR Version 6.1 requirements took effect. This newer version expands the scope of the computers program to include two new product types and a subtype of Notebook Computers. EPA chose to add Slates/Tablets, and Portable All-In-One computers to their product list and a Two-In-One Notebook subtype. Power management and energy efficiency criteria have also been added to the two new product types.
Note to manufacturers: These changes to the ENERGY STAR scope do not have an effect on previously certified products.
MET Labs is an EPA-recognized lab and/or certification body for 15 ENERGY STAR product categories. Get a free quote now to evaluate your product to Version 6.1 or any other energy efficiency standard.
The electromagnetic compatibility (EMC) requirements for telecom and military equipment are considered among the most difficult to meet for any industry. Not many electronics manufacturers conduct testing for both requirements, but it happens occasionally. For those who do, it’s an advantage to pursue both at the same time, as there is some overlap. Following is a short MET Labs overview on some of the primary similarities and differences.
MIL-STD-461 is the primary EMC standard for military approvals. The current version is MIL-STD-461F, but previous versions may still be specified in U.S. military contracts.
GR-1089-CORE is the primary EMC standard for telecommunications (NEBS) equipment. The current version is Issue 6.
MIL-STD-461 is similar to section 2 and 3 of GR-1089 in that they both include EMC conducted and radiated emissions and susceptibility requirements, however the test methods are quite different.
For emissions, MIL-STD-461 requires use of a peak detector and the limits are more stringent for some platforms, like Army Ground. On the other hand, the radiated emissions test method could be considered less thorough because the test antenna and EUT are placed in one position, while for GR-1089 radiated emissions, the EUT is rotated 360 degrees and the antenna height is adjusted to find the maximum radiated emissions.
For susceptibility testing, MIL-STD-461 test method CS114 is similar to GR-1089 conducted susceptibility. Test method CS115 is somewhat similar to GR-1089 section 2 EFT. RS103 is similar to GR-1089 radiated susceptibility, however, for some military platforms, the test level is much higher than GR-1089 (up to 200V/m).
MIL-STD-461 does not include ESD testing, although many military test programs include IEC 61000-4-2 ESD testing along with -461. GR-1089 includes ESD testing in section 2 and references IEC 61000-4-2 for the test procedure.
Another occasionally-referenced military standard – MIL-STD-1399-070 DC Mag Field – is not like any GR-1089 test. This is a 1600A/m DC field, which is quite strong. If the EUT has no magnetic sensors, compass, or other magnetically sensitive components, it shouldn’t be a problem. If the EUT does have those components, it would have to be specifically designed to withstand this test.
Electrical/electronic equipment manufacturers often ask if it is acceptable to use uncertified or improperly rated components in their products. The following Frequently Asked Questions address the implications of using these components for North America product safety approvals.
What is an uncertified component?
Any safety critical component that is not certified by a suitably accredited agency and that does not provide surveillance comparable to that required by United States and Canadian regulatory schemes.
What is an example of an uncertified component?
Some examples include power supplies, transformers, plastics, insulation, adhesives, potting compounds and more.
Is an improperly rated component the same as an uncertified component?
No. An improperly rated component is any safety critical component that, though it may be certified by a suitably accredited agency that does provide surveillance comparable to that required by United States and Canadian regulatory schemes, is not rated for the end-product application.
What is an example of an improperly rated component?
Some examples include power supplies connected to supply voltages greater than for which they are certified or flammable plastics rated for HB but required to be V-2 or better.
You used the term safety critical component – what does that mean?
Safety critical components are any component, material or substance that, if its performance or features change, can affect compliance with the essential safety requirements of the applicable standards.
Ok, I have equipment with uncertified/improperly rated components in it, what do I do now?
Usually the easiest route is to replace the component in question with one properly rated and certified for the end product application. Second easiest is to have the component certified by its manufacturer, if that’s possible. The final option is to have the component evaluated and tested by MET Labs, with a schedule for continued compliance.
I understand it may take more time and money to safety certify a product with uncertified/improperly rated components in it, but are there other implications also?
Yes. If using uncertified components, there is no assurance of continued compliance even after evaluation and testing in product. If certified but improperly rated, there is no assurance of continued compliance even if tested in product. Changes may be made by the manufacturer that allow the item to remain compliant with original certification but that might cause it to become non-compliant in the end product application.
Is continued compliance a regulatory requirement?
Yes. The United States and Canadian certification schemes require surveillance to assure continued compliance. Surveillance applies to the end product and its components.
How is continued compliance enforced for a MET-certified component?
If a repeat of testing is not necessary and the item is not too complex to inspect at the same time as the end product inspection, the item may be described in detail in our report and our follow up inspector will verify continued compliance during the end product factory inspection. It is necessary that the report contain sufficient product description and instructions for effective surveillance.
More complex components are returned to the laboratory on a minimum of an annual basis for reevaluation and perhaps some retesting. Some components or circumstance might require more frequent surveillance.
Contact us for a question about component integration into your equipment, or for a free quote for an upcoming product evaluation.
MIL-STD-461 is the standard that defines the test limits, test levels, and test procedure for various electromagnetic phenomena for electronic equipment used by the U.S. Army, Navy, and Air Force on all platforms (ground, sea, and air). MIL-STD-461F is the latest version. Following are answers to common questions about this often-utilized military EMC standard.
Where can I find MIL-STD-461 and how much does it cost?
The standard is free and approved for public release. It can be downloaded from a number of sites, but we recommend using the official U.S. Defense Logistics Agency (DLA) ASSIST site. This site requires registration and a wait for approval.
What is included in MIL-STD-461?
Test methods cover electromagnetic emissions, which are an unintended, but unavoidable byproduct of every electronic device, as well as electromagnetic susceptibility, which is a measure of the equipment under test’s (EUT) ability to withstand electromagnetic disturbances.
Test methods include specific types of conducted, radiated, transient, and continuous emissions and susceptibility tests. See a full list of test methods on MET’s Military EMC Testing page.
The first few sections define general aspects of the standard and testing, such as terminology, test facilities, test equipment, setup of the EUT, applicable tests for equipment to be used on various platforms, etc.
Section 5 contains a test procedure for each test method, which defines the test equipment needed, instructions for setup, and a procedure for how to conduct the test.
Is compliance with MIL-STD-461 mandatory?
MIL-STD-461 is usually only required when part of a specific military contract between the U.S. military and an electronic equipment manufacturer.
The contract would specify the specific test methods within -461 which need to be performed and passed by the equipment being built for the military.
MIL-STD-461 testing is sometimes voluntarily performed by electronic equipment manufacturers for marketing purposes, to attract possible military contracts and/or for quality purposes, to ensure a rugged design.
I want to voluntarily perform MIL-STD-461 testing and am not worried about my EUT’s susceptibility to electromagnetic disturbances. What are the best test methods for determining compliance with the standard’s electromagnetic emissions requirements?
CE102 and RE102 are the most applicable test methods for this.
CE102, conducted emissions, power leads, 10 kHz to 10 MHz, is performed to verify that electromagnetic emissions from the EUT do not exceed the specified requirements for power input leads, including returns.
This will ensure that the EUT does not cause interference to other electronic equipment operating from the same power source, since the emissions can conduct along the supply lines.
A special piece of test equipment called a line impedance stabilization network (LISN) is connected in series with each conductor of the input power lines to the EUT.
The LISN establishes a 50 Ohm impedance on the power line and has a coaxial measurement port, which allows for connection to a 50 Ohm spectrum analyzer for measurement of the RF emissions.
The EUT is exercised in a way typical of its normal use and the emissions are compared to the limit. If CE102 emissions exceed the limits, the tests are considered not compliant.
RE102, radiated emissions, electric field, 10 kHz to 18 GHz, is performed to verify that electric field emissions from the EUT and its associated cabling do not exceed specified requirements.
This will ensure that radiated emissions from the EUT do not cause interference to other electronic equipment operating nearby.
The EUT and test antenna are set up within a shielded test enclosure, which is internally lined with RF absorbent material.
The shielded enclosure prevents RF ambient noise from entering the test area, while the RF absorbent material reduces RF reflections from the metallic chamber walls, allowing for accurate radiated RF measurements of the EUT emissions with a test antenna.
The test antenna is connected through coaxial cable and chamber wall bulkhead connectors to the spectrum analyzer outside the test chamber.
The EUT is exercised in a way typical of its normal use and the emissions are compared to the limit. If RE102 emissions exceed the limits, the tests are considered not compliant.
For MIL-STD-461 testing for marketing purposes only, does MET issue a test report?
MET can issue a test report and a one-page certificate upon completion of testing.
The test report and certificate would not guarantee acceptance of the product by the U.S. military. However, you are free to use your engineering judgment to make claims of compliance for similar projects, based on the test report and certificate provided.
MET Labs has a reputation for high quality test results and our test reports will increase the credibility of your marketing claims.
Request a free quotation for MIL-STD testing for military or marketing requirements.