The PoE distance limit is 100 metres (328 feet) of copper cable, from the switch port to the device. That figure is the same for 802.3af, 802.3at and 802.3bt, and it includes every patch cable in the link. Real runs often fall short of it, because cable quality, device power draw and heat all eat into the margin. You can go further, but only with the right extra hardware, and the switch itself has to be sized for the power budget as well as the port count.
TL;DR
- Plan every copper PoE run at 100 metres or less, counting patch leads at both ends, not just the cable in the wall.
- Higher-power devices (PTZ cameras, 802.3bt access points) are the first to struggle on long runs. Cable quality and voltage drop matter well before you hit 100 metres.
- Past 100 metres, use a PoE extender for one extra hop, or convert to fibre and inject power at the far end. Don't chain cheap repeaters.
- Size the switch on its total PoE power budget in watts, then add at least 20% headroom.
- In Australia, cabling must meet ACMA requirements, and copper clad aluminium (CCA) cable is not acceptable for PoE.
Table of Contents
- What the 100 metre limit actually covers
- Why a run can fail before 100 metres
- Quick reference: how distance interacts with power
- How to go beyond 100 metres
- Sizing the switch: the other half of distance planning
- What this means for different properties
- Australian compliance: what to check
- Our perspective: why we design PoE around the worst night, not the best day
- Getting a PoE network designed and installed
- FAQ
- Sources
What the 100 metre limit actually covers
The limit comes from Ethernet copper cabling rules, not from PoE itself. The same 100 metres applies to data, which is why a data electrician designing an office fitout treats it as a ceiling for horizontal runs.
The standard link is usually broken down like this:
- Up to 90 metres of fixed cable inside the walls, ceiling or conduit.
- Up to 10 metres in total for the patch leads at each end.
If you buy a 10 metre patch lead and also run 95 metres of solid cable, you are over. The device might still work on a bench test, then drop out in summer or when a camera switches its infrared lights on at night.
The limit is the same for every PoE standard
IEEE 802.3af (PoE), 802.3at (PoE+) and 802.3bt (PoE++) all share the 100 metre ceiling. What changes is how much power the switch must push into the cable to deliver a usable amount at the far end.
Power is lost along the way, so the switch (the power sourcing equipment) supplies more than the device receives. Under 802.3af, the switch supplies 15.4 W and the device gets 12.95 W at 100 metres. Under 802.3bt Type 4, the switch supplies 100 W to deliver 71.3 W at the device (Netgear).
So a long run does not simply "work or not". It costs you power, and the higher the load, the more that cost matters.
Why a run can fail before 100 metres
A cable that is 70 metres long can still misbehave. These are the usual causes we see on a job.
Cheap or non-compliant cable
The most common culprit is copper clad aluminium cable. It has higher DC resistance than solid copper, so voltage drops faster and the cable warms up under load. The ACMA states that customer cabling work must follow the Wiring Rules and the customer cabling product standard, and CCA does not meet the required resistance levels. If you are buying cable for a PoE job, it should be solid copper from a supplier who can show it meets the standard.
If you are weighing whether a cable is genuine, our guide to checking cabling certification covers six checks you can do before you sign off a job. The ACMA cabling rules for on-site cablers are also worth a read if you hire trades.
The wrong cable category for the load
Cat 5e can technically carry all current PoE standards, but Cat 6 is the recommended minimum for 802.3bt installs, with better heat dissipation and signal integrity. Cat 6A is preferred for 10 Gbps over a full 100 metres. If you are choosing between them, see our comparison of Cat6 vs Cat6A.
Heat in bundled cable
Energy lost along a cable becomes heat. In a tight, unventilated bundle with many high-power runs, that heat can become a real design problem, especially for 802.3bt. Spread high-power runs out, avoid packing them into a single hot conduit, and leave the bundle somewhere it can lose heat.
Too many joins and poor terminations
Every join adds resistance. Couplers, wall-plate keystones, a patch panel and two patch leads can all sit in one link. A badly punched-down jack at 30 metres can cause more trouble than a clean 95 metre run. Testing the finished link with a certifier, not just a continuity tester, is the way to find these faults.
Quick reference: how distance interacts with power
| Standard | Switch supplies (per port) | Device receives at 100 m | Max length |
|---|---|---|---|
| 802.3af (Type 1) | 15.4 W | 12.95 W | 100 m |
| 802.3bt Type 4 | 100 W | 71.3 W | 100 m |
Figures are from Netgear's PoE cable length guide. The 802.3at figure sits between the two. Always check the device's datasheet for the power it actually needs.
How to go beyond 100 metres
There are three sensible options. Which one you pick depends on how far and what you are powering.
Option 1: Put a switch partway
The simplest fix is to add a small PoE switch at the 80 to 90 metre point, powered locally. It starts a new 100 metre segment for data and power. The catch is that you need a mains power point and a weatherproof, secure enclosure at that spot, which is not always possible on a paddock or along a driveway.
Option 2: A PoE extender
A PoE extender repeats both the data and the power, and can typically add another 100 metres per unit. It draws its power from the cable it receives, so there is no mains needed at the midpoint. The trade-off is that performance can degrade if you chain too many in a row, and each extender takes some of the power budget for itself. We treat extenders as a fix for one extra hop, not as a way to cover a whole property.
Option 3: Fibre, with power injected locally
For long distances, converting the link to fibre removes the electrical limit entirely. Some SFP modules reach 10 km up to 160 km, depending on the module and fibre type. At the far end, a media converter or a ruggedised industrial switch with PoE output powers the camera or access point locally. That far-end unit still needs a power source, such as mains or a solar and battery setup.
Fibre is usually the right answer for outbuildings, sheds and gates on rural properties, and for sites with electrical noise or lightning exposure. Our write-up on SFP vs RJ45 explains where copper stops being the sensible choice.
| Option | Best for | Watch out for |
|---|---|---|
| Mid-point PoE switch | Run of 100 to 190 m with mains at the midpoint | Needs power and a protected enclosure |
| PoE extender | One extra hop of about 100 m | Daisy-chaining reduces performance, uses some power budget |
| Fibre plus local PoE | Long runs, outbuildings, noisy or exposed routes | Far end still needs power; more design work |
Sizing the switch: the other half of distance planning
People searching for distance limits often turn out to have a power problem. A camera that reboots at night is a classic one. The cable is within limits, but the switch cannot supply enough at peak.
The most common planning mistake is treating port count as capacity. A switch should be sized on its total PoE power budget in watts, not on the number of ports or the maximum a single port can deliver. A 24-port switch might only have a budget for a dozen high-power devices.
A simple method
- List every powered device and its maximum power draw from the datasheet, not the typical figure. For cameras, include the infrared illuminators running at night.
- Add them up.
- Add at least 20% headroom.
- Compare that total with the switch's stated PoE budget.
- Check that every port serving a device supports the right standard (af, at or bt) for that device.
Switches are rated in the power they source, while devices are rated in the power they receive. That gap is why you budget on the higher switch-side figure, as the Servnet sizing guide explains.
A worked example
Say a rural home has eight cameras that each draw up to 12 W at night, and two outdoor access points that each draw up to 25 W. This is an illustrative example, so check your own datasheets.
- Cameras: 8 x 12 W = 96 W
- Access points: 2 x 25 W = 50 W
- Total peak: 146 W
- With 20% headroom: about 175 W
A switch with a 150 W budget would look fine on the box, since it has plenty of ports. At night it would run out of power. You would want a switch with a budget comfortably above 175 W, and long runs push the figure up further because of cable losses.
For camera-specific detail, see our guide to matching IEEE PoE classes for CCTV, which covers the random reboots that come from a mismatch.
What this means for different properties
Suburban home. Most runs are well under 50 metres. The practical risks are cheap cable, poor terminations and a switch that is too small. Distance is rarely the problem.
Small office or retail. Runs typically stay within the 100 metre ceiling, but they are often bundled together in ceiling spaces. Plan cable categories, bundle sizes and the switch budget together. Our overview of network cabling costs in Australia explains what drives the price of a job like this.
Rural property. Sheds, gates, dams and pump sheds are often well past 100 metres. Fibre with local power, or a carefully designed combination of extenders and mid-point switches, is the norm here. A pole-mounted camera at the end of a long driveway is a good candidate for fibre.
Australian compliance: what to check
Customer cabling in Australia is regulated. The ACMA lists the standards that apply, including the Wiring Rules and the customer cabling products standard. Practical consequences for a PoE job:
- Cable should be genuine solid copper, not CCA.
- The installer should be registered to do cabling work, and should be able to show it. Our guide to licensed cablers in Australia explains how to verify.
- You should get test results for each link at handover, not just a verbal "it works".
Our perspective: why we design PoE around the worst night, not the best day
We design and install networks, cabling and security systems for homes, businesses and rural properties across South East Queensland, and PoE distance faults make up a lot of the call-outs other people ask us about. They rarely come down to one thing. A cable that is a bit long, a bit cheap and a bit crowded, feeding a switch that was bought on port count, adds up to a camera that drops out at 2 am.
So we design in the opposite order. We start with the devices and their peak draw, choose the switch for its power budget, then plan each run against the 100 metre limit with the patch leads counted. Anything that looks marginal gets a different answer: a shorter route, a better cable, a mid-point switch or fibre.
Because the same licensed team scopes, installs and configures the work, with no subcontractors, there is nobody to point the finger at when a long run misbehaves. We also quote to a fixed scope, so the cost of a fibre leg to the back shed is clear before we start, not discovered halfway through.
— Dylan
Getting a PoE network designed and installed
If you have a run that is near or over the limit, or a switch you are not sure about, we can survey the site and scope it. Our networking and cabling service covers data cabling, PoE network installation, switch and rack work and wireless access points. If the job is mainly cameras, see our security camera and alarm systems. Prices depend on the site, so we quote each job on its scope.
FAQ
How far can PoE reach on Cat6?
The limit is 100 metres for Cat6 and Cat6A, the same as for Cat5e, because the limit comes from the Ethernet standard rather than the cable category. Cat6 is the recommended minimum for high-power 802.3bt devices because it handles heat and signal quality better. Count patch leads in the 100 metres.
What is the difference between a PoE injector and a PoE extender?
An injector adds power to a data line from a non-PoE switch, and does not lengthen the run. An extender repeats the data and the power so the cable can go roughly another 100 metres. Use an injector when your switch lacks PoE, and an extender when the distance is the problem.
Can I run PoE over 100 metres without extra equipment?
Not reliably. Some products claim longer reach by lowering the data speed, but the standard stops at 100 metres, and cable quality and voltage drop affect what you actually get. For a dependable result, use a mid-point switch, an extender or fibre.
How do I size a PoE switch?
Add up the maximum draw of every device, then add at least 20% headroom, and compare that with the switch's total PoE power budget. Do not rely on port count. For cameras, include the night-time infrared load.
Sources
- Netgear: PoE cable length standards
- Eaton: Overview of Power over Ethernet technology
- Packetsaver: PoE switch guide
- ACMA: Australian cabling standards
- Network World: The power over Ethernet
- Optcore: Gigabit RJ45 to SFP fibre media converter
- Voltora Industries: The data electrician's job explained
- Servnet: PoE switch sizing calculator