If you are using a PoE (Power Over Ethernet) based system to deliver power over your network, you may be wondering how safe it is for you and your equipment. When dealing with electricity, it is always recommended to use caution and make sure you are safely handling your equipment.
PoE is usually safe for equipment thanks to its smart detection technology that negotiates how much power to send. There are types like passive PoE, however, which can damage your electronics if misused. Handling live wires can also pose a hazard.
PoE can add some great benefits to your system. If you’re worried about injury or damage to electronics, it’s always a good idea to make sure you have an understanding of what you’re working with. PoE is very ubiquitous today, especially for use with security cameras (our guide), but some can cause damage when improperly used. Read on to learn more.
How Much Power is a PoE Line Carrying?
When it comes to how much power a PoE enabled ethernet cable is carrying, you’ll first need to find out what type of PoE you are using and what device you intend on using it for as we’ve talked about before. Each type of PoE is designed to work with different classes of hardware that have different power needs. For most applications, you’ll most likely be dealing with PoE standard Type 1, but there are higher levels that transfer more power.
Here are the types of PoE:
| Name | IEEE Standard | Power Usage | Used For |
| PoE Type 1 | 802.3af | 15.4 watts | IP Cameras, VOIP Phones |
| PoE Type 2 (PoE Plus) | 802.3at | 30 Watts | PTZ Cameras, Alarm Systems |
| PoE Type 3 (PoE ++) | 802.3bt | 60 Watts | Video Conferencing, WAPs |
| PoE Type 4 | 802.3bt | 100 Watts | PoE Computers, Monitors |
As you can see, the higher your PoE rating, the more power the cable will be transferring. While the cable will shield this power in most cases, there are instances where there can be open ends to the line. If this is the case, and the cables are live, you can certainly harm yourself. Thankfully, most ethernet cables you are working with will be shielded and have an RJ45 connector to protect the inner wires and you.
With your equipment, though, this can be a different story. If you’re using a non-standard type of PoE, there is a possibility you could damage any devices connected to your system. This is where understanding the difference between active and passive PoE is essential, moreover, it’s important to know about passthrough (our guide) as well.
Passive vs. Active (Normal) PoE – Which One is More Dangerous?
Active and passive PoE have different ways of managing the power being sent to the network’s devices. This is essential when using both PoE enabled devices like the Armcrest 5MP (on Amazon), and those just accessing the network which don’t need to draw as much power. Active PoE requires more intelligent communication across devices but also tends to be more expensive. Passive PoE, however, can be cheaper but less intelligent when it comes to power management.
- Active PoE – Active PoE manages the power across the network by communicating with the devices that have access. It negotiates the proper voltage between the PD (powered device) and the PSE (power supply equipment).
- Passive PoE – Passive PoE equipment does not communicate with the devices that are connected. Instead, it sends power passively along the cable to any device that is connected, whether they want it or not!
When working with active PoE types, you have little to worry about when it comes to connecting non-PoE devices. Active PoE will be able to recognize the device as non-PoE and not send power to that device. This is not the case for passive PoE.
Passive PoE does not come with an IEEE standard; instead, it sends power over the network without regulating it. The IEEE standards don’t just tell the system how much voltage to transfer. It also tells the system how to send that voltage over the ethernet cable’s four-paired wires. With passive PoE, it is hard to know how many paired wires are being used and how much power is being sent.
As we’ve talked about in our guide all about it, if you’re connecting a non-PoE enabled device to your passive PoE system, you may be in a precarious situation: since the power is still running through the cable, it will most likely short circuit at the connection point. This results in what computer specialists call “magic smoke” as the wires’ voltage shorts across the device’s component, heating up and vaporizing some material.
If you connect a PoE enabled device to a passive system that requires a higher voltage than the system can offer, all that will happen is your device will not work. but if your device requires a lower voltage, you will send too much power to the device, causing damage over time. Not in the same way as the magic smoke, but still something you’ll wish you hadn’t done.
Conclusion
In most cases, you will be working with active PoE, and you won’t have to worry too much about damaging yourself or your equipment. To avoid the downsides of working with passive PoE, make sure you are researching what components you are adding to your system. If they are passive, they should be labeled as such.
If you are interested in using passive PoE due to the lower price, be aware of what you are adding to the system to ensure you aren’t going to damage any equipment or yourself. When working with any electrical system, you should be wary of uncapped or unshielded wires. This is the case for PoE as well.
While it may seem like PoE cables aren’t dangerous because they seem as safe as ethernet cables, connected PoE cables should be treated like live wires, because they are. So, always use caution when working with your PoE system and shut off the power before repairing anything or working to maintain your system.