Internet and electricity are essential for a functioning garden room. When running cables for both, be sure to take steps to avoid electrical interference with the data connection.
When it comes to getting the most out of a garden building, we recommend installing both internet and electricity. Whether the outbuilding is a summerhouse, shed or log cabin there are plenty of applications that require connectivity to both.
A number of options are available when it comes to extending an internet connection to a garden building. Wi-fi extenders are great but often not suitable if the garden building is far away or requires a high bandwidth internet connection. Use as a garden office is a typical example that requires the internet connection to be fast and extremely stable.
For our garden office room, we installed a Cat6 ethernet cable from the router in the house, which terminates on the interior wall of the summerhouse. This allows us to use a wireless access point inside to connect all of our devices.
The best time to install an ethernet cable is often at the same time as digging the trench to install electrical power cables. This allows for a tidy installation and keeps all of the wiring out of sight in the garden. But when installing both cables, we need to take some additional precautions for both safety and data integrity reasons.
Can I run an ethernet cable next to an electrical power cable?
You can run both ethernet and electrical cable to a garden building, but they should be separated by at least 20cm and a shielded ethernet cable should be used.
Don’t make the mistake of placing the ethernet cable next to the power cable inside a conduit that runs to the outbuilding. This may result in a poor quality connection and could even lead to safety issues.
Instead, install the electricity cable and then partially fill the tench to create a sufficient gap before laying the ethernet cable. This will reduce any interference to the data connection from the electricity, allowing for the best possible connection.
What can happen when running power and ethernet cables together?
Both data integrity and safety are important concerns when running cables, even to an outbuilding. We don’t want to see issues appear once the garden room is completed and it’s not easy to access cables once buried underground.
Safety
Ethernet cabling is classified as a low-voltage communications cable, whereas the electrical power cabling is high-voltage. When running these two types of cable together, there is a risk of voltage induction occurring. This is when the voltage from the high voltage cable can jump across to the other cable. Ethernet cable is not designed to handle the high voltage and neither will the devices be that are connected at either end of the ethernet connection.
This poses a safety risk of high voltage getting into a device that’s not designed to handle it, potentially leading to a fire or damage to the equipment.
Data integrity & performance
The main reason for installing an ethernet cable instead of a wi-fi extender is to get a faster and more reliable connection. Lots of electromagnetic interference (EMI) can affect the integrity of the data inside the cable, reducing the connection performance and bandwidth.
Leaving a sufficient gap between the cables reduces any interference from the electricity cabling, allowing us to take advantage of the maximum throughput available through the cable.
Power over Ethernet
A Power Over Ethernet (POE) connection uses an ethernet cable to send power as well as data to the connected device. This type of technology is commonly used for CCTV cameras where a single cable can be used instead of multiple cables connected to the camera.
Running a POE cable next to an electrical cable can cause potential safety issues due to the difference in voltages between both cables. We don’t recommend running Power Over Ethernet cables from a house to a garden building. Instead, any POE devices inside the garden building should be connected from inside.
Guide: How to install wired internet in a garden room
Which type of ethernet cable should I use?
Lots of different ethernet cables are available and it’s important to choose a suitable cable to make the connection between the house and garden building. Replacing a cable that has failed after a year can be expensive and time-consuming if it has been buried underground.
Cat5e or Cat6?
Both Cat5e and Cat6 cables are widely available and we recommend using a Cat6 cable. Both can support a gigabit connection, but Cat6 has a lot more bandwidth available, allowing more data and offsetting any degradation in performance.
The interior of a Cat6 cable also contains more isolation at the twisted pair wiring. This reduces interference and cross-talk further, allowing for fewer data errors and a more reliable connection. A distance of up to 100m is supported on both, which is plenty for connecting to a garden building.
The price difference between both has reduced in recent years, making Cat6 the best option considering how long the cable will be in position.
Exterior grade cable
A common mistake when choosing an ethernet cable for connecting an outbuilding is to not use an exterior grade cable. This can result in the outer coating of the cable breaking down and the connection becoming damaged and unreliable.
When a cable is outside it has to contend with a lot of elements that can cause potential damage. Above ground, UV rays from the sun can cause the plastic to fade and begin to break down over time. Below ground, moisture and insects causing damage to the cable can become a challenge.
Exterior cables are designed to provide increased protection to avoid damage to the cable. An exterior cable will feature UV protection so that the cable does not begin to go break down with age. The outer layer is often slightly thicker to stay protected if buried underground. Some cables also use a gel inside to prevent moisture from running down the interior of the cable.
How is shielded ethernet cable different?
Both unshielded and shielded versions of ethernet cable are available and most of the time unshielded cable is used. But when we are running the cable in parallel with an electricity cable, it’s recommended to use a shielded cable.
A shielded ethernet cable contains aluminium foil that is wrapped around the twisted pair wiring inside the cable. The shielding protects data integrity by blocking electromagnetic interference from nearby devices or cables.
While shielding blocks most of the interference, some can still get through so it’s still important to leave a suitable gap around the cable. Shielded cables are slightly thicker compared with unshielded cables, which can make them slightly more difficult to work with.
A shielded cable should be terminated into a wall box inside the outbuilding. A thick exterior jacket and aluminium foil inside can make it difficult to terminate into an RJ-45 connection. The cost of shielded ethernet cabling can also be higher compared with a similar unshielded cable.
Best results when installing ethernet and electricity in an outbuilding
Both ethernet and power cables are commonly run to garden buildings such as summerhouses, sheds and log cabins. When doing so, be sure to follow best practise so that the installation is safe and maximises the performance of the internet connection.
Leave a suitable gap between the cables
Leaving enough space between both cables can prevent voltage induction and electromagnetic interference. If a shielded ethernet cable is used, it’s recommended to leave at least a 20cm gap. If an unshielded cable is used, a 30cm minimum gap is recommended.
When the cables are being buried in an underground trench, the electricity cabling is often installed first, allowing the void to be partially filled before the ethernet cable is installed into position.
Always use a qualified electrician
In the UK, a qualified electrician is required to carry out electrical works, including connecting a garden building to a power supply. Installation by a qualified professional ensures the outbuilding is connected safely and follows the recommended guidelines.
In 2005, part P of the building regulations was introduced with electrical safety rules. Any works carried out must be designed to reduce electrical shocks and homeowners need to be able to prove the work carried out complies with part P. A qualified electrician can provide a certificate, that may be required if the property is sold in the future.
Consider running an additional ethernet cable
Ethernet cabling is relatively low cost over a short run such as to a garden building. It can be a good idea to run an additional redundancy cable at the same time, in case the main cable becomes damaged in the future.
Unlike power cables, ethernet cables are not usually armoured, leaving them vulnerable to insect attack or damage from gardening equipment. Replacing the cable can become a big job and require digging up the original cable that needs to be replaced.
Laying a redundancy cable means that if the first fails the connection can be quickly swapped over. The second cable does not need to be connected until it is required and can simply be left in position in case it is ever needed in the future.
Alternative internet solutions
While ethernet provides the best connection, it’s usually the most challenging to install. If you don’t need mega high bandwidth, it may be a good idea to consider simpler solutions first.
Powerline Networking
Powerline technology has been around for a long time, but it’s not widely used and often misunderstood. The best way to think of Powerline is a hybrid between a wi-fi extender and an ethernet connection.
Instead of requiring a separate cable, Powerline takes advantage of the existing electrical cable to send data across. If the garden building already has electricity installed, the cable is usually suitable for a powerline connection.
Powerline adapters are placed at either end of the connection, so one next to the router and another inside the garden building. Installation takes minutes and the internet connection can be up and running without any additional cables.
Wi-fi extender

If the outbuilding is close to the existing property, a wi-fi extender (Amazon) is often suitable for boosting the connection enough to get a reliable signal. A wi-fi extender just repeats the existing signal to push it further away from the original router. Ideally, the extender should be positioned halfway between the router and the garden building.
The challenge many users experience is when purchasing low-cost Wireless N standard extenders. These provide a slow connection that is going to result in buffering. Opting for a high-quality wi-fi 6 extender will offer a vastly increased range and higher performance speeds.
Guide: Extending Wi-Fi to an outbuilding
Summary
It’s common for all types of garden buildings to feature both electricity and ethernet installations. The Internet can transform the use of the outbuilding into a room in the garden that is ideal for relaxing or working from.
When installing both, be sure to leave a sufficient gap and use the correct type of cable. An outdoor shielded ethernet cable will protect the wiring from the elements and shield against electromagnetic interference. A gap needs to be maintained between the power and internet cabling to avoid voltage induction and interference causing errors in the data inside the cabling.
- The Lowdown on Shed Ventilation: What is the Deal?
- Creating Your Dream Music Studio: Discover the Best Sheds for Music Studios
- Cheapest Way to Build a Shed: Buy or Build?
- How to Make Decking Non-Slip: 6 Steps to Stop Slippery Decking
- Best Metal Sheds & Garages for Your Garden
Leave a Reply