by Tobie van Schalkwyk, Business Unit Manager

At first glance, Power over Ethernet (PoE) seems like one of networking’s simplest innovations. Think about it, a single cable providing both data and power. But there’s a catch. Just because a switch has 24 PoE ports doesn’t mean it can simultaneously power 24 high-draw devices. In South Africa’s often unpredictable networking environments, understanding and planning your PoE budget is essential for system reliability, customer satisfaction, and long-term scalability.

The importance of PoE budgeting

Power outages, energy-conscious clients, and rapid digital adoption are just a few reasons why PoE budgeting has become a business necessity. We regularly assist local installers dealing with support calls not because the equipment failed, but because the power draw exceeded the switch’s budget, causing devices to shut down or misbehave.

Here’s what you need to know.

Every PoE switch has a maximum power budget. For example, a 24-port switch with a 240W PoE budget averages 10W per port. But in real-world scenarios, not every device draws the same power. IP phones and basic IP cameras might only need 5 to 7W, but add a few power-hungry PTZ cameras, Wi-Fi 6 access points, or PoE lighting units, and you’ll blow the budget halfway through the rack.

We’ve compiled several best practices to guide you along the way:

1. Know your switch’s PoE budget: Before deployment, always check the total power available and understand how it divides across all active ports. This information is listed on the switch datasheet and should never be guessed.
2. Don’t mix high-draw devices blindly: Combining multiple PTZ cameras, intercoms, and advanced wireless access points on the same switch can create unpredictable draw spikes. Do the math. Or better yet, ask DuxNet Support to run a pre-deployment power assessment.
3. Leave headroom: A rule of thumb we recommend to all partners is to leave anything from 10 to 20% headroom in your PoE budget. This not only stabilises performance but also gives room for device additions later without causing disruptions.
4. Use a PoE calculator: Several vendors offer online tools to help map out power distribution based on the models you’re using. If you’re deploying a mixed environment, this step is essential.
5. Monitor live draw where possible: Many DuxNet switches come with built-in monitoring interfaces. Use them. After adding or changing devices, check your PoE usage stats and set thresholds or alerts where available.

Our reality

Unlike controlled environments in other parts of the world, South Africa’s networking landscape comes with unique pressures. Last-minute load shedding updates and unstable voltage conditions often push infrastructure to its limits.

In these conditions, any inefficiency is amplified. Worse still, many PoE-connected devices like security cameras and wireless access points are only added after the initial install. When the PoE budget gets maxed out, random devices drop off the network. Guess who gets the call? Yes, you, the installer.

Avoiding these situations means designing networks not from a functionality perspective, but with foresight. At Duxbury, we work closely with our resellers and integrators to conduct realistic PoE audits before rollout. The most successful deployments we’ve seen start with one simple question: “How much power will we need today and tomorrow?”

Beyond the basics

Even if you’ve nailed your budget, here are a few bonus tips:

• Use PoE injectors or mid-span units for high-draw outliers, so you don’t overload the core switch.
• Always label your switch ports with the device type and expected draw.
• When designing for scalability, assume future devices will need more power, not less.

PoE budgeting isn’t just about numbers. It comes down to ensuring uptime, delivering on SLAs, and preserving client trust. With the growing demand for connected systems in security, hospitality, education, and retail sectors, there’s simply no margin for error.

Duxbury Networking is here to guide you through the process. Whether you’re building out a smart campus or rolling out multi-tenant residential infrastructure, we’ll help you power your network the smart and reliable way.

Need help with your next deployment? Reach out to support@duxnet.co.za and let’s power your network the smart way, from day one.