Fault finding & troubleshooting
Does weather affect your internet connection?
Yes, on some types of connection. Rain, wind and heat cause faults on the copper types of NBN and on HFC, because their cables and joints are outdoors and many are old. Fibre to the premises is barely affected. An internet fault that follows the weather is a fault in a cable or a joint, and it can be found.
Does weather really affect the internet?
It does, and how much depends on what your connection is made of. Anything that relies on old copper cable outdoors is exposed to water, heat and movement. Anything that travels through the air is affected by heavy rain. Fibre is close to immune. Where the weather does cause a fault, it is in a cable or a joint, and a fault that comes and goes can be traced and repaired.
| Type of connection | Rain | Wind | Heat | Lightning and surges |
|---|---|---|---|---|
| Fibre to the node (FTTN) | Wet joints and pits cause dropouts | Overhead lead-ins can open up | Old joints fail as they warm | Can damage the modem |
| Fibre to the curb (FTTC) | The lead-in and its joints | Overhead lead-ins can open up | Joints fail as they warm | Can damage the NBN box |
| Fibre to the building (FTTB) | Little, unless the frame room is damp | None | Little | Can damage the modem |
| HFC | Water in outdoor fittings and at the tap | Overhead cable can be damaged | Little | Can take out the isolator and the box |
| Fibre to the premises (FTTP) | None | Only if a cable is brought down | None | The box's power supply |
| Fixed wireless and satellite | Heavy rain weakens the signal | Can move the antenna or dish | Little | The equipment's power supply |
Where the weather gets in
Rain. Water gets into old copper joints and cables in the pits along the street. The line drops when they are wet and comes back as they dry. More on rain and moisture
Wind. On an overhead lead-in, the wind opens hairline fractures in old copper, so the service drops and returns in gusts. More on wind and aerial cables
Heat. A corroded joint in the street can open up as it warms, and a modem shut in a cupboard or sitting in the sun overheats and restarts. More on extreme heat
Lightning. A nearby strike or a surge can damage whatever is at the end of the line: the modem, the NBN box and the devices plugged into them. More on lightning and surges
Not sure which you have? See which NBN connection you have.
Rain and moisture
Rain causes more internet faults than any other weather, and nearly all of them are on copper.
A copper phone line is a pair of wires, and the signal depends on those two wires staying insulated from each other and from the ground. Water in a joint or a cracked cable lets the signal leak between them. The modem loses its connection, and when things dry out it comes back.
Heavy rain also weakens satellite and fixed wireless signals for as long as it lasts. Light rain makes little difference. Ordinary WiFi inside the house is not affected by rain at all.
Water, pits and joints on fibre to the node
On fibre to the node, and to a lesser degree fibre to the curb, the last stretch of your connection runs through the old copper network: cables joined together in pits along the street. Much of it was laid decades ago.
Bag joints
When a joint in a pit fails, the lasting repair is to rebuild it. The quick repair is to cut the cable underneath the joint and connect the customer’s pair there, which gets the service going that day. A joint made like that has no proper enclosure. It is wrapped in a plastic bag and taped, and it is known in the trade as a bag joint.
The bags are not waterproof. When the pit fills, the joint soaks, and the faults follow: wires touching that should not, connections that have gone high in resistance, voltage leaking from one pair to the next. We still find bag joints in pits across Sydney.
Pits that no longer drain
The pits were built to drain themselves, set on layers of sand and gravel. Over the years, fine silt carried in by rainwater has clogged many of them. Now they hold water after rain, and because conduits link one pit to the next, the water travels along the street.
A line through a wet pit works on a dry week and fails on a wet one. That pattern is the signature of this kind of fault.
In this job, an HFC service had been dropping out in the rain for more than ten years.
Watch: NBN HFC Keeps Dropping Out When It Rains? This 10-Year Fault Finally Makes Sense
Strong winds and old aerial cables
Where the lead-in runs overhead from a pole to the house, wind is the problem. Storms bring down branches and cables, which is obvious. The less obvious fault is in old aerial cable that looks intact.
Old copper lead-ins develop hairline fractures inside the insulation. In still air the broken ends touch and the line works. When the wind moves the cable, they part and the service drops, then touch again and it returns. It comes and goes in gusts. A fracture does not heal: where the cable is on your side to replace, the answer is a new lead-in cable.
There is a worked example in fibre to the curb dropouts when it is windy or raining.
Extreme heat
Heat does two things.
- In the network, a copper joint that is already corroded can open up as it expands. The dropouts come on hot afternoons and clear in the evening.
- In the house, a modem or NBN box shut in a cupboard, or sitting in the sun, overheats and restarts. Give it open air.
Lightning and power surges
A nearby lightning strike or a surge on the power can damage whatever is at the end of the line: the modem, the NBN box, and the devices plugged into them.
On HFC there is a small fitting in the cable called an isolator, which keeps stray voltage on the street cable out of your equipment. A surge can destroy it, and the service then drops out or stops while the box itself is fine. The isolator belongs to NBN and is reported through your provider. See what HFC is.
In the days of the plain old telephone service, each line had a lightning arrester at the exchange. Homes today have less protection of that kind, so a surge-protected power board for the NBN box and the modem is worth having.
What to do about a fault that follows the weather
- Keep a log. Date, time, what the weather was doing, what the lights on the box did. Two or three weeks of entries shows the pattern.
- Report it every time and collect the reference numbers.
- Ask for the fault to be tested in the conditions that cause it, or for the lead-in and the pit to be inspected, not only tested remotely.
- Have your own side checked. A joint at the house wall, a socket on an outside wall or a cable under the house can be the wet spot, and those are yours. An internet technician tests your side and the line as it arrives.
- A home phone that plays up in the wet is on the same copper. That side is phone line repair.
If the dropouts follow no weather at all, start with why a connection becomes unstable.
Our part is testing the line where it arrives at your property and the wiring inside it. If the fault is on your side, it is repaired. If the line is already faulty as it arrives, that finding goes in writing, and it gives your provider a reason to send someone to the pit. There is more on how these faults get missed in faults in the Telstra network.
Frequently asked questions
Why does my internet drop out when it rains?
Usually because water has got into an old copper joint or cable between the street and your house. Water lets the signal leak between the two wires of the pair, so the modem loses its connection, and it comes back as things dry out. It is a fault in a cable or a joint, and it can be found.
Does extreme weather affect all types of internet?
No. Copper connections, such as fibre to the node and fibre to the curb, are the most affected, because water and heat get into old joints and cables. HFC is affected at its outdoor fittings. Satellite and fixed wireless fade in heavy rain. Fibre to the premises is the least affected, short of a cable being physically broken.
How can I protect my internet from bad weather?
Keep the NBN box and modem on a surge-protected power point, and unplug them in a severe electrical storm. Have a mobile hotspot as a backup. Above all, do not accept a fault that returns with every rain as normal: log the dates and report it, because it is a repairable line fault.
Is satellite internet more affected by weather?
By heavy rain, yes. The signal travels a long way through the atmosphere, and dense rain weakens it, an effect called rain fade. It usually passes with the storm. Wind can also move a dish off its alignment.
Why does my internet drop out when it is windy?
Usually an overhead lead-in cable. Old aerial cables develop hairline fractures in the copper, and when the wind moves the cable the fracture opens and closes. The service drops and returns in gusts. It is tested and then replaced; it does not heal.
Need this fixed rather than explained?
This is written from the field. When the fault needs a technician on site, this is where to go next.