Ảnh hưởng của tiêu chuẩn National Electric Code (NEC ®) 2017 tới cáp đồng trong việc hỗ trợ POE

Mục lục

Impact of 2017 National Electric Code on Power over Ethernet Cabling

Introduction
The 2017 National Electric Code (NEC ®) has been revised and will now impose new requirements on cables running the highest power level of the next generation Power over Ethernet (PoE) standard. The majority of
PoE installations will not be affected by the new rules due to their lower power levels. However, for those that do, the 2017 NEC recognizes a new UL listing for cables referred to as Limited Power, or LP. Per the 2017 NEC, LP is not required to run PoE but cables with this classification can simplify the installation and inspection of cables running next generation PoE. The 2017 NEC is focused on the overall bundling sizes of cables running the highest PoE power level and applies only to cables permanently installed. The goal of this document is to provide information on the new 2017 code and what the new UL LP cable listing means.

Next Generation Power over Ethernet

The next generation of Power over Ethernet (called PoE++ or 4PPoE) introduces Type 3 and Type 4 PoE. The new standard, IEEE 802.3bt allows power to be provided on all 4 pairs with up to 60W on Type 3 and 99W on Type 4 at the source. The 2017 NEC code and LP designation applies only for systems with power levels above 60W or PoE++ Type 4. Therefore, the NEC 2017 should only impose new requirements for a small fraction of installations as most PoE applications are Type 3 or lower.