PoE Distance: How Far Can Power over Ethernet Run?

One question often comes up when discussing PoE and smart building technology: What is the PoE distance for delivering power? A standard Power over Ethernet connection can run up to 100 meters, or 328 feet, over twisted-pair Ethernet cabling. This is the standard maximum Ethernet channel length and applies to common PoE, PoE+ and PoE++ installations.

The 100-meter limit includes the complete Ethernet channel, not necessarily 100 meters of cable installed between the network switch and connected device. A typical structured cabling installation allows up to 90 meters, or about 295 feet, for the permanent cable run, with the remaining distance available for patch cables and connections at each end.

Why Is PoE Limited to 100 Meters?

The 100-meter PoE distance comes primarily from Ethernet cabling standards rather than PoE itself. Copper Ethernet networks are designed around maximum channel lengths to maintain reliable data transmission. As the cable gets longer, signal quality can decline and electrical resistance increases.

PoE adds another consideration because the same cable is carrying electrical power. Resistance in the copper conductors causes some energy to be lost as heat while power travels through the cable. Longer cable runs have greater resistance, which can increase power loss between the Power Sourcing Equipment (PSE) and the Powered Device (PD).

IEEE PoE standards account for expected cable losses when specifying how much power must be available at the device. For more detail on those power levels, see How Much Power Can PoE Deliver?

Does PoE Lose Power Over Distance?

Yes. Some power is lost whenever electricity travels through copper cabling, and the amount of loss generally increases with distance. This does not mean a properly designed PoE connection becomes unreliable as it approaches 100 meters. Standards-compliant equipment and appropriate cabling are designed to operate within the established channel limits.

Cable construction also matters. Conductor size, material, temperature and installation conditions can affect resistance. This becomes increasingly important with higher-power PoE applications because more current is traveling through the cable.

For that reason, cable selection should be based on the PoE power level and installation environment rather than PoE distance alone. We cover those requirements separately in What Cable Is Required for PoE and PoE++?

Can PoE Run More Than 100 Meters?

A conventional copper Ethernet channel is generally limited to 100 meters, but that does not mean a PoE-powered device must always be located within 100 meters of the original network equipment. Several technologies can extend a network beyond the normal copper Ethernet distance.

PoE extenders or repeaters can regenerate the Ethernet connection and pass power farther along the route, expanding the PoE distance from the original source. Depending on the equipment and design, multiple extension points may be possible. However, every additional device introduces another component that must be powered, installed and maintained.

Fiber can also be used for the longer portion of a network connection. Fiber supports much greater distances than copper Ethernet but does not carry conventional PoE power. A design using fiber therefore requires a local source of power or equipment that converts the connection back to copper and provides PoE near the endpoint.

Can a PoE Switch Be Located Closer to the Device?

Yes, and in larger buildings having a PoE switch closer to the device is often more practical than trying to extend individual copper runs beyond their standard limits. Network switches can be distributed throughout a facility so that connected devices remain within the allowable Ethernet distance.

The appropriate layout depends on the building, number of connected devices, available telecommunications spaces, power requirements and network architecture. A large commercial building may therefore use multiple network locations rather than attempting to connect every device directly to one central switch.

This is one reason distance should be considered early in the design of a PoE system rather than after device locations have already been established.

Does PoE++ Have a Shorter Distance Limit?

The standard Ethernet channel length remains 100 meters for PoE++, including IEEE 802.3bt applications. Higher power does not automatically reduce the Ethernet distance limit to a shorter number.

However, higher-power PoE makes cable characteristics and installation conditions more important. A Type 4 PoE connection can carry substantially more power than an original Type 1 PoE connection, so conductor resistance and heat need greater consideration when selecting cabling and planning cable bundles.

The question is therefore not simply whether a cable is less than 100 meters. The cable also needs to be appropriate for the amount of power being delivered.

How Should PoE Distance Be Measured?

PoE distance should be considered from the PSE to the powered device across the entire Ethernet channel. Patch cables, connectors and other components are part of that channel and should be included when determining total length.

For a typical structured cabling system, using approximately 90 meters of permanent horizontal cabling leaves room for patch cords while keeping the completed channel within the 100-meter Ethernet limit. This provides a straightforward design target for most commercial PoE installations.

When devices must be located farther away, the solution is usually to adjust the network architecture, add appropriate extension equipment or transition to fiber rather than simply exceeding the standard copper Ethernet channel length.