Understanding Fault Managed Power

The advent of fiber optics and wireless technologies has enabled communications networks to achieve higher bandwidth and lower latency in part by moving the connectivity and computation electronics closer to the end user. This distribution of network electronics increases the number of sites that require power, adding a layer of cost and complexity not experienced in more centralized architectures. Often, the edge device can be powered by tapping directly into the grid when it is in close proximity. But more and more, a single grid tap connects to a centralized power conversion device that in turn delivers electricity to the remote devices over metallic cables.

This remote powering technique has been effective for over two decades. But wireless networks, particularly 5G, are utilizing newer small cell radios that consume considerably more power than previous generations. Moreover, small cell nodes often include 2-3 radios to supplement the coverage and capacity of the macro cell. The result is the need for a distributed power solution that delivers much more power than the remote line powered devices previously used.

In 2020, operators, manufacturers, and industry standards bodies began to investigate the potential for a new distributed power technique that could deliver much more power yet in a safe environment for technicians and the public. Spearheaded by ATIS® and supported by UL & NEC®, a new distributed powering technique called fault managed power was developed. Also known as Class 4 power, fault managed power systems impose no power limit under normal operation, but precisely limit energy transferred under a fault condition to mitigate shock and fire hazard.