Why Does My NBN Drop Out During Heavy Use?
Most FTTN and FTTC dropouts happen because of hidden internal wiring faults especially bridge taps or star wiring that disrupt your NBN signal during heavy use.
If your NBN works fine in the morning but starts disconnecting in the afternoon or drops out when your team begins video calls or heavy online tasks you’re not alone. This is one of the most common problems in homes connected using FTTN and FTTC.
What many customers don’t realise is:
The issue is usually inside your home/office, not the provider.
A hidden wiring fault called a bridge tap or star wiring may be the real reason your modem struggles.
What Is a Bridge Tap
A bridge tap is an unwanted extra branch of copper wiring inside your home that causes signal reflections, noise, and dropouts on FTTN/FTTC NBN lines.
A bridge tap is created when:
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Old phone sockets remain connected
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Alarm wiring was never removed
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Multiple outlets share the same copper line
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Past owners added extensions or secondary points
Instead of one clean line from the street to your modem, the signal hits a T-junction and splits.
This causes reflections, echo, and instability especially when the line is busy.
What a Bridge Tap Looks Like (Visual Identification)
What Is Star Wiring and How Is It Different?
Star wiring is when one copper line splits in multiple directions, creating several bridge taps and heavily weakening your NBN performance.
Star wiring is like a spiderweb:
One main cable branches out into many cables, often to multiple phone points.
This multiplies the interference and is one of the biggest causes of poor NBN performance.
Why FTTN & FTTC Are Affected the Most
FTTN and FTTC connections rely on VDSL2, a technology that uses high-frequency signals to deliver speed. These high-frequency signals are extremely sensitive to issues inside a building especially extra wiring, old copper, or hidden bridge taps.
Here’s how it impacts your business:
Low frequencies → Keep the connection alive
Used when the network is quiet or only basic activity is happening.
High frequencies → Deliver speed for business tasks
Activated during activities such as:
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Video conferencing
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Cloud backups
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Large file downloads
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VoIP phone systems
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Multiple staff working online
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Busy afternoon usage
These high frequencies are the ones most affected by wiring faults.
The Business Impact
This is why many workplaces experience issues only during peak activity:
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“The internet drops out when the team logs in after lunch.”
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“Video meetings freeze when more staff get online.”
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“Speed tests or cloud syncs disconnect our modem.”
When your modem activates the high-frequency channels to meet business demand, those signals hit the bridge tap or star wiring.
The signal reflects back, creates noise, and the modem becomes overloaded leading to:
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Dropouts
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Slower speeds
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VoIP call issues
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Disruptions to cloud systems
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Productivity loss
FTTN and FTTC work acceptably when your business is quiet but become unstable when you actually need speed and performance.
How Bridge Taps Cause Dropouts
Bridge taps make your modem’s high-frequency signals bounce back, creating noise that forces the modem to disconnect under load.
Here’s the simple breakdown:
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Your modem sends high-frequency signals down the copper line.
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The signal hits the extra branch (bridge tap).
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The signal splits and bounces back (echo).
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Noise increases, error rates spike.
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The modem gets overloaded → it disconnects.
Signs You May Have a Bridge Tap or Star Wiring
If your NBN drops out during streaming, peak hours, or speed tests and your home has multiple phone sockets you likely have a bridge tap.
Common symptoms:
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Dropouts during peak times
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Internet cuts out when someone streams Netflix
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Speed test disconnects the modem
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NBN works fine at low usage
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Random sync losses throughout the day
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Home has multiple old phone outlets
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Alarm system wiring still present
These symptoms match 90% of bridge tap cases.
What Bridge Taps Look Like
Multiple cables on one socket, branching cables in junction boxes, or leftover alarm/phone wiring are strong signs of a bridge tap.
A licensed technician might find:
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More than one cable connected to a phone socket
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Split wiring running in different directions
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Multiple phone points still electrically active
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Old alarm system cabling
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Junction boxes with two or more outgoing cables
Anything that creates a branch is considered a bridge tap.
Who Is Allowed to Fix Bridge Taps?
Only ACMA-licensed cablers and NBN-approved technicians are legally allowed to fix or remove bridge taps in Australia.
This is important:
Allowed to fix:
✔ ACMA-licensed telecommunications cablers
✔ NBN field technicians
✔ Licensed cabling contractors (Open Registration)
Not allowed:
✘ Homeowners
✘ Electricians without telecom endorsement
✘ Handymen
✘ Security alarm installers (unless certified)
Illegal wiring work can cause safety hazards, fines, and even worsen the problem.
How a Technician Removes a Bridge Tap
A technician removes bridge taps by isolating unused wiring, simplifying the line to one clean socket, and testing the signal for stability.
The process is simple:
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Identify the primary socket
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Trace and locate all wiring branches
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Disconnect and isolate unused wiring
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Re-terminate the correct cable pair
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Ensure only one cable runs to the modem location
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Test the line for errors, speed, and stability
Once the extra wiring is removed, the line performs significantly better.
Benefits After the Fix
Removing bridge taps gives you fewer dropouts, higher speeds, and more stable NBN especially during peak hours.
Most customers see immediate improvements:
✔ Fewer dropouts
✔ Higher sync speeds
✔ Stable evening performance
✔ Less buffering on streaming
✔ Better video call & gaming stability
✔ Lower error rates
✔ Faster uploads (FTTC especially)
Many times, fixing internal wiring improves NBN more than changing modems or providers.
When Internal Wiring Isn’t Enough
If your copper line is too old or damaged, upgrading to FTTP is the best long-term solution.
Some homes have:
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Very old copper
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Corroded joints
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Damaged lead-in cables
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Severe internal wiring faults
In these cases, the most reliable fix is upgrading to Fibre to the Premises (FTTP).
FTTP gives you:
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Near-perfect stability
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No copper interference
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Higher download/upload speeds
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Better performance for business/home office
Your address may be eligible for a free or low-cost NBN fibre upgrade depending on availability.
FAQs
Q: Can I fix a bridge tap myself?
No. Only licensed cablers are legally allowed to work on NBN wiring.
Q: Will a new modem fix the problem?
Not if your internal wiring has faults the issue will return.
Q: How long does bridge tap removal take?
Usually 20–60 minutes depending on the home layout.
Q: Does NBN fix bridge taps for free?
Internal wiring is the homeowner’s / business owner’s responsibility.
Q: How do I know if I need FTTP instead?
If your wiring is too old or unstable, FTTP is the long-term solution.
