Abdullah Shoaib
Managing Director
4 min read
Last Updated September 01, 2025
How to avoid voltage drop
Voltage drop is a common yet often overlooked issue that can have a significant impact on the efficiency and running costs of your business. When electrical current travels through cables, resistance causes a small loss of voltage along the way – known as voltage drop.
While this may seem minor, even a small drop can reduce equipment performance, increase energy consumption and shorten the lifespan of valuable machinery. For businesses, this not only means higher electricity bills but also the potential for costly downtime and maintenance.
At Energy Solutions, we understand that controlling overheads while maintaining smooth operations is a priority for every business. That’s why preventing voltage drop is so important. By identifying the causes and implementing simple, effective measures, you can protect your systems, save money and improve overall efficiency.
How much voltage drop is acceptable?
Voltage drop is a natural part of any electrical system, but excessive losses can be problematic. Knowing how much voltage drop is acceptable helps businesses maintain efficiency while staying compliant with regulations.
In the UK, the Wiring Regulations (BS 7671) set clear guidance on permissible voltage drop levels. For most installations, the recommended maximum is 3% for lighting circuits and 5% for other uses, such as power and heating. This means if your supply voltage is 230V, lighting should not drop below 223V, while power circuits should not fall below 219V. Staying within these limits ensures that equipment runs safely and efficiently without straining components.
However, best practice for businesses is often to aim even lower than the maximum allowance. Keeping voltage drop at 2–3% across circuits can reduce unnecessary strain, prolong the life of electrical assets and optimise energy efficiency. Factors such as cable length, size and load demand all influence voltage drop, so regular monitoring and professional assessment are recommended.
How to reduce voltage drop
To help your business keep energy use efficient and equipment running smoothly, here are five practical and cost-effective strategies to reduce the impacts of voltage drop.
1. Use the right cable size
Choosing the correct cable size is one of the simplest ways to control voltage drop. When cables are too small, resistance rises and efficiency falls. A slightly larger cable may cost more at installation, but the benefits far outweigh the expense as, over time, businesses gain from reduced energy waste, fewer breakdowns and longer-lasting equipment.
2. Shorten cable runs
The further electricity has to travel, the greater the resistance it encounters. This makes cable length a key factor in voltage drop. If possible, placing equipment closer to the power source can deliver big gains in efficiency, cutting unnecessary strain on both your system and your budget.
3. Balance electrical loads
Overloaded circuits are one of the main culprits behind excessive voltage drop. When too much demand is placed on a single line, performance suffers. Spreading loads evenly across circuits avoids this issue. Not only does this help maintain voltage levels, but it also reduces overheating risks and extends the life of your electrical infrastructure.
4. Maintain and upgrade connections
Loose or corroded connections quietly increase resistance and waste energy. Left unchecked, they can even cause costly downtime. Regular inspections of cables, junctions and terminals keep systems running smoothly and minimise voltage drop without major expense.
5. Invest in energy-efficient equipment
Old equipment often demands more current than modern alternatives, making voltage drop more likely. Upgrading to energy-efficient machinery lowers the load on circuits, improving stability and reducing costs. The upfront spend may seem daunting, but the long-term payback – lower bills, fewer repairs and better performance – makes this a smart, future-focused investment.
Minimising voltage drop is not just about meeting regulations – it’s about protecting your business from unnecessary costs, downtime and inefficiencies. By taking simple steps such as choosing the right cables, maintaining connections and investing in efficient equipment, you can keep your systems performing reliably while reducing wasted energy. And, for small and medium-sized businesses especially, these strategies can deliver noticeable savings over time.