Page 18
ManageMent
www.us-tech.com
Harting Qualifies Connectors for Use in UL 508-Certified Control Cabinets
By Cory Jenkins, Senior Product Manager, Harting, Inc. I
n order to better serve its cus- tomers, Harting, a provider of in- telligent and high-performance
connection technology, recently had its connectors certified to UL 508 standards. This certification allows the company to provide connectors and assemblies that are recognized as safe across the industry. UL 508 (508A and 508C) is a
certification standard for electrical control cabinets and switchgear. It provides assurance to machine builders and their customers, as well as regulators and insurers, that the cabinet can be operated safely and reliably. Globally it is not the only standard covering control cabinet safety, but it is the one most often used in North America. Nearly all industrial connectors
used in North America are UL-certi- fied for general use from the time they are introduced. The same con- nectors also are used widely on other continents in electrical control cabi- nets certified to other major certifica-
tion standards. However, until re- cently, their assigned UL status did not pre-qualify them for use in UL 508-certified cabinets.
Certification’s Obstacles Industrial equipment complying
with UL 508 has had to contain compo- nents and sub-assemblies whose prod- uct groups are listed in UL 508 Appen- dix A, “Standards for Components.” Connectors have been relegated by UL (Underwriters Laboratories) to histori- cal electrical interface categories such as ECBT2, which uses UL 1977 as their base standard. With this category rating it was the responsibility of the machine builder to demonstrate to UL’s satisfaction that ECBT2-class connectors could be used safely in a UL 508 application. The OEM’s UL field representa-
tive would conduct a thorough investi- gation of the application, including the overall electrical transmission path, for possible safety issues. The uncer- tain cost and duration of this supple-
mental approval process was usually enough to cause a machine builder to take the path of least resistance and hardwire all electrical connections, foregoing the cost and time savings of- fered by plug-and-play connections. Now, that procedural deterrent has been removed, clearing the way for us- ing connector-based wiring as an alter- native to hardwiring. At the request of Harting, UL
created a new section of UL 2237, a complementary standard to UL 508 that governs multi-point connections of power cables. This new section is under the category PVVA2 which al- lows for approved “recognized” con- nectors to be used and still be compli- ant with the UL508 standard. By having this second option, customers now have the ability to purchase rec- ognized components from the compa- ny and build their own assemblies, or to purchase the more traditional “UL-Listed” cable assemblies. When Harting took on the task
of having its connectors tested by UL, it transferred the testing burden from the machine builder to the con- nector manufacturer. It effectively pre-clears them for UL 508 applica- tion without additional time and money for UL testing and certifica- tions. This is possible because PVVA and PVVA2 components can be used in UL 508-certified cabinets without a lengthy additional safety investiga- tion, provided they are being used in the prescribed manner.
UL-Recognized Once they pass supplemental
testing, these well-established con- nectors earn the “UL Recognized” mark allowing them to be employed in user-created, field-assembled con- trol cabinets. By using UL-recog- nized connectors, OEM’s can fast- track UL 508 certification since the traceability and documentation of these connectors has already been es- tablished. These recognized connec- tors are the same ones that Harting uses to manufacturer “UL Listed” ca- ble assemblies under the PVVA cate- gory. The assemblies bearing a UL Listed certification mark can be used virtually without restriction where UL 508 certification is being sought. With two offerings, “recognized”
components and “listed” assemblies, it gives users the flexibility to assem- ble the connectors however they de- cide is best for them. If a custom so- lution better suits the application, the OEM can create it using UL-rec- ognized (PVVA2) connectors and still be compliant, provided that they fol- low the applicable UL standards of building such assemblies. The connectors and components
must be installed by trained techni- cal professionals following the “Con- ditions of Acceptability” (CoA). For
example, the power distribution ca- bles should be selected in accordance with the TC-ER declaration and the approved wire AWG cable cross-sec- tion choices. Also, protective devices (fuse types RK5, CC, J or T) must be used on the cable path. In addition, the short circuit current rating (SC- CR) for the connectors must be com- pared against the requirements of the cabinet. UL-recognized connectors are
by default, given the lowest SCCR rating (5 kA) by UL unless addition- al testing is done. The SCCR rating of each cabinet may vary depending on the components used, and can po- tentially require additional current protection devices if components do not match to the overall level that the cabinet requires. Harting opted to test, and passed, to the highest SCCR value (65 kA) rather than a lower level such as 5 kA and as such, does not limit its customers in their use of its components.
Connectors vs. Hardwiring Hardwiring only really com-
petes economically with connectors when a cabinet is to be wired only once. As soon as it has to be unwired and rewired a second time, which of- ten happens at some point prior to customer acceptance, the cost advan- tage shifts decisively to connector- based wiring. A machine large or complex enough to have an external cabinet or cabinets often is assem- bled at the plant and tested, then dis- assembled and shipped to the cus- tomer’s location and re-assembled. With hardwiring, each connec-
tion has to be individually unmade for shipping, then remade in the field at a significant additional labor cost. Dur- ing field setup, it is common for hard- wiring errors to occur, delaying start- up, even causing damage in extreme cases. Connectors are plug-and-play; the same wiring can be unplugged and plugged in again in seconds. With a connector-based wiring assembly, if it worked correctly at the plant, it will work in the field from the get-go. Each OEM has its own labor
costs, but end user benchmarking suggests that each subsequent de- taching and re-attaching of multiple hardwired connections during the op- erational life of a machine can add hundreds, even thousands of dollars, in extra labor and ancillary costs. This is a cost saving for the OEM and potentially for the end user when maintenance or upgrading is per- formed. As a result, connectors are increasingly the go-to wiring ap-
proach in modular machine design. Contact: Harting, Inc. of North
America, 1370 Bowes Road, Elgin, IL 60123 % 847-717-9217 E-mail:
christina.chatfield@
harting.com Web:
www.harting.com r
August, 2016
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88