What causes broadband connection problems?

Last updated: 12 July 2022   By Lyndsey Burton

Broadband connection issues are a frustrating part of life for many customers.

Common problems include slow broadband and connections dropping in and out, as well as difficulties getting a service running in the first place.

We can try to address the issue ourselves by moving our router and checking internal connections.

If we need to escalate the matter to our broadband provider, we can expect them to run diagnostic checks or send an engineer around to our home.

broadband connection problems
Credit: Andrey_Popov/Shutterstock.com

What causes slow broadband speeds?

Broadband advertising regulations have been tightened in recent years, yet many customers still aren't getting the speeds they expect from their broadband.

Providers must advertise speeds that can be received by at least 50% of their customers at peak times, but that still leaves up to half that might not be receiving those speeds due to issues such as:

  • Network congestion - Speeds are slowest during peak times (evenings and weekends) when lots of people are trying to use the same infrastructure.
  • Distance from an exchange - Copper and fibre to the cabinet (FTTC) connections lose speed if customers are further from the exchange.
  • Hardware issues - Some wireless routers are better than others.
  • Type of broadband connection - Full fibre broadband connections are the fastest while copper-based lines are the slowest.

These are some of the main causes of slow broadband speeds and there are things we can do to mitigate some of them.

For example, upgrading our router to a better model or simply optimising its place in the home can help.

We've got more on router placement and other ways of improving home broadband speeds in our dedicated guide.

However, even if we optimise our home broadband set-up, we might still suffer from slow broadband speeds.

Capacity problems

A common cause of slow broadband is when the combined bandwidth of many customers strains or exceeds the capacity of the local exchange.

Capacity crunch generally has two main causes:

When an exchange hits capacity, all customers in the area will suffer either very slow broadband speeds, dropouts; or they may get disconnected entirely.

When it happens, the only remedy for providers is to install more capacity to handle the increased demand.

Invoking fair use and traffic management policies on bandwidth hogs used to be a strategy employed by ISPs, but these have largely been phased out in recent years due to improved regulations.

Universal Service Obligation

Customers in areas where average speeds are below 10Mb should be aware of the Universal Service Obligation (USO).

This was first introduced in March 2020 and gives households receiving ultra-low broadband speeds the legal right to request an upgrade.

It was previously hoped the universal minimum would be set at 30Mb but, in practice, thanks to providers upgrading areas with full fibre broadband, eligible households are getting speeds in excess of the basic 10Mb.

There are caveats to the USO:

  • If a build is planned in the future, customers will need to wait for that
  • If a build will cost more than £3,400 per eligible household, BT can refuse the application

On this last point, BT agreed changes to the USO in 2021 that mean multiple houses should be considered together for expensive builds, but it still means some might miss out on fixed line connections and be provided with 4G broadband instead.

The USO is a useful tool, especially for those in rural areas who may struggle to get a decent broadband connection.

Broadband keeps dropping or losing the connection

If our broadband speeds meet expectations but we keep losing our broadband connection, this can be another frustrating experience.

Solving the issue is a case of problem solving, trial and error, and trying to locate the problem.

Technical support will typically take the same approach, starting with asking for checks on wiring and equipment around the property, before running remote tests to try and locate the cause of the dropped connection - more on this process below.

The most common causes are either faulty or poor wiring in the home, including microfilters; or, slightly more problematically, poor wiring between the home and the local exchange.

Dropping can also be due to overcapacity, although it's unlikely to cause a frequently recurring dropped connection.

No broadband connection

When the broadband connection is not working at all, the first port of call should be the provider's status update page or social media accounts.

This only works if customers have access to mobile data or someone else's wi-fi connection, but it is the quickest way of finding out if the problem's a widespread one or not.

Alternatively, calling a provider should garner the same results (just a bit slower).

If there are no reported problems for an area, meaning it's an isolated issue, it's back to trial and error troubleshooting.

There can be multiple causes for a broadband outage, but it's often down to line or exchange connection problems. Other causes could include:

  • New electrical devices interfering with signals
  • Moving the router may have disrupted the signal
  • The router itself might be broken

If a broadband provider can't fix the problem remotely, they have to call out an engineer.

New broadband or phone line provision delays

For several reasons, the part of the process broadband providers are heavily invested in - getting the connection going in the first place - can prove to be a stumbling block.

New line trouble

A perennial problem is getting a new line installed in a property.

If equipment needs to be installed it requires an engineer visit which can be tricky to arrange.

If the property has a stopped line instead of a truly new line that might also cause problems (see below).

Switching problems

Another common issue is that broadband providers need to communicate with one another during a switch - something that doesn't always work as it should.

One of the most common technical issues is known as a 'tag on the line'. This indicates that a line has been stopped, perhaps by the broadband provider of the property's previous owners and a notice served to stop supply by other ISPs.

To get it going again, the new provider needs to remove this tag.

Tag on the line and communication issues typically take a few weeks to clear up as we explain in our guide to reconnecting with BT.

When it's not a problem...

Finally, it's worth noting that new line problems are sometimes no one's fault.

New lines need time to stabilise while the exchange runs tests on the line to determine the best speed. That means that a new connection can be more prone to speed fluctuations and even dropping service before it finds its feet.

New line fluctuation can take a month to right itself.

Getting broadband tech support

If we're in one of those situations where we need to enlist the technical support of our broadband provider, the process for fixing issues can itself be frustrating.

This is because broadband providers, especially those with large customer bases, have a series of stages to go through to diagnose and address the problem effectively.

When multiple customers in an area complain, broadband companies might look at installing additional capacity at an exchange (as discussed above), but they are only likely to do this if they get lots of customers saying the same thing.

This is a situation where a provider knows what the issue is but might not be rushing to fix it.

However, if everything looks fine from the provider's end, the following process should begin with technical support.

1. House check

This is the first line of troubleshooting (usually over the phone). Customer service will focus on tech inside the caller's home - the router, the wireless network, microfilters, and internal telephone wiring.

Tech support will typically start by asking you to attempt to solve the problem by:

  • Checking/restarting the router
  • Bypassing the wi-fi with an ethernet cable
  • Switching microfilters
  • Using the master socket to rule out any problems with your secondary telephone wiring (that's any telephone wires inside your house)

These are all minor fixes but can be surprisingly useful for many customers.

2. Diagnostic check

If they can't find a problem at stage one, the provider can run remote fault diagnostics and line checks to try and pinpoint where the fault is.

Once they've had you exhaust all options in your home, they'll start running these diagnostic tests remotely.

The tests can help detect where on the connection the problem is occurring, as well as the type of problem (e.g. connection dropouts or slow broadband caused by packet loss).

Once the provider has an idea of where the problem might be, they can start trying to resolve it. Some solutions include splitting the signal into 2.4 and 5GHz bands or moving your connection over to a different channel.

If a provider is unable to work out exactly what the problem is, however, they can't fix it, and thus technical support becomes particularly delayed.

Providers will ensure they exhaust all possible avenues at this stage, as the next step is to involve physical support or assistance at the local exchange, street cabinet or your home via an engineer.

This is costly and time consuming, so your broadband provider is likely to have you try out other options for days before resorting to sending someone out.

3. Engineer involvement

If the problem can't be resolved, or it requires an in-person engineer at the local exchange, street cabinet or customer's home a provider has to pass the fault over to Openreach (formerly BT Openreach) or, for companies with their own infrastructure (e.g. Virgin Media), their own engineer department.

However, providers are generally reluctant to get to this stage.

Delayed technical support resolutions can therefore be because providers will ensure they've taken all steps necessary to fix the problem remotely before handing over a fault to the engineers.

While that's often a sensible way of doing things, providers can drag their heels too much and we've seen repeated complaints about this in the past.

There have also been complaints about missed engineer appointments which Ofcom sought to remedy with the introduction of automatic compensation for those left without broadband by their provider.

Customers will receive:

  • £8.40 for each calendar day that a service is not fully repaired when it has stopped working (after two working days)
  • £26.24 per missed engineer appointment or when it is cancelled with less than 24 hours' notice
  • £5.25 for each calendar day if the start of a new service is delayed

12 broadband providers in the UK are signed up to these compensation rules, so many of us will be covered by them.

These rules mean we should receive some recompense for prolonged broadband inconvenience, yet many will still be irritated that companies have two working days to sort out the problem when it feels as though it could be solved much more quickly.

Summary: Tech support takes time

Broadband issues can be incredibly frustrating, especially if we've chosen a broadband provider based on how reliable they are.

The basic process for dealing with broadband issues should be along these lines:

  1. Check routers and connections around the home to see if it's just you
  2. Check whether a broadband provider's status page is reporting problems
  3. Contact a provider directly
  4. Go through their steps to check the connection yourself
  5. Wait for the provider to run external diagnostic checks
  6. Receive an engineer's visit

It can be a take a while to get a satisfactory resolution to our issues, although we can always make a complaint about our broadband provider if we don't feel things are moving quickly enough or that the problem isn't being taken seriously.

Some providers are better at handling complaints than others, but it remains the case that being able to leave a provider because the broadband isn't living up to expectations remains a rarity. In addition, leaving before our minimum term is up can be an expensive business.

In most cases, if we don't feel our broadband provider is addressing our connection issues effectively, we may have to escalate the complaint to a third-party to get some action.


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