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Comprehensive information about LP certification

by:FOT     2020-07-16
Comprehensive information about the LP certification you may have heard about Ethernet power supply ( 坡) LP certification cable update dynamically, and want to know the PoE facilities installation yourself whether you need this kind of cable. We can understand a little bit about the following the new UL certification and its relationship with the national electrical code 2017, introduced the reason of the certification, and why you still need to test. An optional alternative and the upcoming 60 w ( 3 classes) And 100 w ( 4 class) IEEE 802。 3 bt PoE standards related to the PoE equipment is higher and higher, more and more power levels caused people concern about wire temperature. When the number of cable harness, wiring harness in the middle of the cable will not be able to send out PoE caused by heat, causing the working temperature of cable in excess of the prescribed, and lead to network performance is poorer, because the heat is directly related to insertion loss. Under the installation environment of higher temperature, which is especially worrying. After high toward a harness cable in PoE after actual investigation, the influence of UL launched a limited power ( LP) Certification, designed to help simplify the cable selection of PoE application. LP authentication said cable tested and worse under the condition of PoE, as to not more than the temperature rating of the cable. Certification takes into account the large wire size, high temperature and other environmental impacts, such as confined space or a pipe. Understand the LP is a certification rather than a column or rating is very important. So, with other UL listed or NFPA 70 the national electrical code ( NEC®) Requirements higher, or higher level cable is different, the LP certification cable is optional - — Not mandatory. As for NEC ®, 2017 edition also includes new requirements for temperature rising problem - — But is only applicable to power higher than 60 w ( 3 classes) At the right time. For this kind of situation, NEC including the current-carrying capacity table, which regulates at 30 ° C ( 86°F) The environment temperature, the installation of more specific cable allows the current-carrying capacity, the current-carrying capacity and wire size corresponding to the specifications, wire and cable temperature level. Because NEC ® is a regulation, requires that must conform to the current carrying capacity of the table. However, NEC indeed allows the use of a LP attestation cable as a substitute for follow the current-carrying capacity of the table. The good news is that only you plan for the deployment of more than 60 w PoE didn't need to care about the problem, and most of PoE, including LED lights, equipment is less than the value; The bad news is, you never know how much more will come through the cable transmission power, so follow the current-carrying capacity table or using LP certification cable is a good way to adapt to after proofreading. Other options also include the use of large diameter wire, high temperature level or block structure, and simply choose not to use of cables. Resistance unbalance is still very important no matter you choose how to deal with the problem of temperature rise is higher when PoE cable is need to test the dc resistance unbalance that cannot be ignored. Resistance unbalance will cause the Ethernet data signal waveform distortion, cause error, resend even data cable will not work. When through a pair of dc power line transmission, should use the common-mode voltage, the current uniform distribution, and the resistance between the two wire should be close to zero. So the standard IEEE Std. 802. 3 - 2012 rules between wire more unbalanced dc resistance is 3%. Despite the high temperature rating or own the high quality of the dc resistance of the cable certification of LP balance is not a problem, but poor process can cause resistance unbalance is too high. Fortunately, DSX CableAnalyzer ™ series of unbalanced dc resistance test function can verify whether the resistance of the conductor is equal, in order to ensure that the common-mode current can effectively support the PoE, to avoid the same line of the distortion of the transmitted data signals. As the power is more and more high, support gigabit Ethernet continues to increase, the number of PoE equipment that has become more and more important. If you have any questions or problems, you are welcome to contact us at any time
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