Flickering lights or an unstable power supply in a commercial building is more than just an annoyance. It disrupts your team, affects productivity, and, more importantly, it’s often a sign that something in your electrical system needs attention.
If you’ve noticed the lights dimming, flickering, or power dipping intermittently, here are the most likely causes and what you should do about them.
Is It Just a Bulb?
Before assuming the worst, it’s worth ruling out the simplest explanation. A single flickering light fitting could be nothing more than a loose bulb, a failing lamp, or a faulty fitting. If the flickering is isolated to one light and goes away when you change the bulb or tighten the fitting, you can breathe easy.
But if the flickering is happening across multiple fittings, in different areas, or is accompanied by dimming or power dips, that’s a different conversation entirely.
The Most Common Causes of Power Flickering in Commercial Buildings
1. Loose or Deteriorating Wiring Connections
One of the most common and most serious, causes of flickering power is a loose or deteriorating electrical connection somewhere in the system. As connections loosen over time, electricity struggles to flow consistently, causing the voltage to fluctuate and lights to flicker.
Loose connections generate heat, and heat in an electrical system is a fire risk. This is not something to ignore or put off investigating.
What to do: If you suspect loose wiring is the cause, don’t attempt to investigate yourself. Call a qualified electrician to carry out a thorough inspection.
2. Overloaded Circuits
If your lights flicker or dim specifically when large equipment switches on an air conditioning unit, a compressor, a industrial machine, it’s likely that the sudden surge in demand is causing a momentary voltage drop on that circuit.
This is a sign that your electrical system is struggling to cope with the loads being placed on it. It may have been adequate when it was installed, but if your power demands have grown since then, the system may simply need upgrading.
What to do: A qualified electrician can assess your current load distribution and recommend the most cost-effective solution whether that’s additional circuits, load balancing, or a distribution board upgrade.
3. Voltage Fluctuations From the Grid
In some cases, flickering power isn’t caused by anything inside your building at all, it originates from fluctuations in the incoming supply from the grid. This can happen when large loads switch on and off nearby, or during periods of high demand on the local network.
A good way to test this is to check whether neighbouring businesses are experiencing the same issue. If they are, the problem likely lies with your Distribution Network Operator (DNO) rather than your own installation.
What to do: Contact your DNO to report the issue. If the problem is isolated to your building, the cause is almost certainly internal.
4. Failing or Outdated Distribution Board
An ageing or overloaded distribution board can cause inconsistent power delivery across your building. If your board is old, visibly worn, or has been patched and added to over the years rather than properly upgraded, it may no longer be capable of delivering stable power to all circuits reliably.
What to do: Have a qualified electrician assess your distribution board. In many cases, an upgrade is more cost-effective in the long run than continued patch repairs and it significantly reduces the risk of more serious faults developing.
5. Loose Service Connections
The connection between your building and the incoming mains supply the service connection can also become loose or deteriorated over time. This can cause voltage fluctuations that affect your entire building rather than individual circuits.
Service connection issues are the responsibility of your DNO rather than your own electrician, but a qualified electrician can help you identify whether this is the cause and liaise with the DNO on your behalf.
What to do: If widespread flickering across your entire building is the issue and internal causes have been ruled out, ask your electrician to check the service connection and contact your DNO if needed.
6. Faulty or Incompatible Lighting Equipment
If you’ve recently upgraded to LED lighting but are still experiencing flickering, the issue may be compatibility between your new LED fittings and existing dimmer switches or control gear. Not all dimmers are compatible with LED technology, and mismatched equipment can cause persistent flickering even when everything else is fine.
What to do: Ask your electrician to check that your control gear and dimmer switches are compatible with your LED fittings. In most cases, a straightforward switch replacement resolves the issue.
When Should You Be Concerned?
Occasional, very brief flickering during storms or periods of high grid demand is generally nothing to worry about. But you should seek professional advice promptly if:
- Flickering is persistent or getting worse over time
- It’s accompanied by a burning smell, warm fittings, or discolouration around sockets
- Multiple circuits or areas of the building are affected
- It started after new equipment was installed or electrical work was carried out
- Your circuit breakers are also tripping regularly
Any of these alongside flickering power is a sign that something needs professional attention sooner rather than later.
Could It Point to a Bigger Problem?
Persistent power flickering is sometimes a symptom of a broader issue with an ageing or inadequate electrical installation. If your building hasn’t had an Electrical Installation Condition Report (EICR) carried out recently, now is a good time to arrange one. An EICR will give you a full picture of your installation’s condition and identify any underlying issues before they develop into something more serious.
How Arrow Electrical Services Can Help
At Arrow Electrical Services, we diagnose and resolve power quality issues in commercial and industrial buildings across Cheshire and the UK every day. As NICEIC approved contractors, our engineers have the expertise to identify the root cause of flickering power quickly and put it right with minimal disruption to your operations.
Whether it’s a loose connection, an overloaded circuit, or an ageing distribution board, we’ll get to the bottom of it and give you an honest recommendation on the best way to resolve it.
Don't Ignore Flickering Power
It might seem like a minor irritation, but persistent flickering is your electrical system flagging that something needs attention. The sooner it’s investigated, the less likely it is to develop into something more costly or dangerous.
Arrow Electrical Services provide specialist industrial, commercial and Atex Electrical design, installation and maintenance solutions as well as manage projects across multiple trades using trusted specialist contractors across the UK.
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