Low voltage is a common complaint, and the first instinct is usually to push the number back up. That’s the wrong first move. Before you buy anything, you need to know why the voltage is low, because the right fix depends on the cause: the type of system, the load, the wiring, the transformer, and what the equipment actually needs.
This guide covers what a voltage upgrade involves, what equipment can raise or steady voltage, and what to check before changing anything.
What does “upgrading voltage” mean?
Usually it means getting equipment the voltage it was designed for. A system built around a given nominal voltage can deliver much less at the machine because of long cable runs, undersized conductors, heavy load, a transformer that’s too small, swings in the utility supply, bad connections, or unbalanced three-phase loads.
In three-phase systems, keep line voltage and phase voltage apart. Line voltage is measured between two phases. Phase voltage is measured between one phase and neutral. Mixing them up leads to wrong readings and wrong conclusions.
Why voltage gets too low
Find the cause before you install any voltage-boosting equipment.
Voltage drop. Voltage falls as current travels through a cable, and the longer the run and the higher the load, the bigger the drop. A workshop far from its main distribution board will notice this when large machines start up.
Undersized cables. A cable that’s too thin for its load has higher resistance. Under heavy current that means more voltage drop and more heat.
High demand. Large motors, compressors, pumps and air conditioners pull a lot of current, sometimes only at startup and sometimes all the time.
Utility fluctuation. Sometimes the problem is outside your building. Local network conditions or transformer loading can make the incoming supply vary.
Transformer capacity. A transformer that’s too small for the load will struggle to hold voltage when demand rises.
Poor connections. Loose terminals, damaged cables, corroded joints and worn switchgear all add resistance.
Ways to fix it
No single fix works for every installation. Here are the main options.
Voltage stabiliser or AVR
If the incoming voltage fluctuates, an automatic voltage regulator (AVR) is a common answer. It monitors the input and adjusts its output to keep voltage steadier, using transformer taps, servo mechanisms or electronic switching depending on the design. When the supply sags, a suitable unit can boost the output within its rated range.
Stabilisers are used with industrial machinery, CNC equipment, pumps, compressors, office equipment and commercial buildings. They have limits, though. The unit has to be sized for the load and rated for the input and output range you need, and it can’t fix every kind of electrical problem.
Step-up transformer
A step-up transformer converts AC from a lower voltage to a higher one. You’ll find them in factories, commercial buildings and distribution systems.
Choosing one takes more than picking the output voltage you want. You also need the input voltage, kVA rating, frequency, phase configuration, load characteristics and protection requirements.
Better cabling
Sometimes the supply is fine and the cable between it and the equipment is the weak link. If measurements show a large voltage drop along a run, a larger conductor can reduce it. An electrician or engineer will look at cable length, conductor material, cross-sectional area, installation method, ambient temperature, current demand and the maximum voltage drop allowed.
A thicker cable is often a better answer than a voltage booster, especially in big buildings and workshops where equipment sits far from the main board.
Transformer or incoming supply upgrade
If the building’s transformer or incoming supply is simply too small, a stabiliser won’t fix the capacity shortfall. The infrastructure itself may need work: a bigger transformer, a higher-capacity incoming supply, better distribution, extra distribution equipment, rebalanced loads or new switchboards. This calls for an engineering assessment and, in many cases, coordination with your electricity distributor.
Phase balancing
Commercial and industrial sites mostly run on three-phase power. When loads are spread unevenly across the phases, you get poor voltage conditions and wasted efficiency. A qualified electrician can measure current and voltage on each phase and redistribute loads. Balancing can improve performance without raising the supply voltage at all.
Check whether you need an upgrade at all
Measure first. A proper assessment records:
- incoming voltage
- voltage at the distribution board
- voltage at the equipment
- voltage under light load and under full load
- current drawn by the major equipment
- voltage drop across cables
- phase-to-phase and phase-to-neutral voltage
- frequency and general power quality
Those readings show whether the cause is the utility, the wiring, the load, the transformer or something else. Power-quality monitoring is worth having, since sags, surges and harmonics can disrupt equipment and operations without being obvious.
Voltage upgrade vs voltage stabilisation
People mix these up, but they’re different things.
A voltage upgrade changes the system to operate at a different voltage level. That might involve a transformer, a new supply arrangement or new switchgear.
Voltage stabilisation holds the output steady while the input varies. If your equipment is designed for 240 V and the supply sometimes drops well below that, stabilisation is probably what you want. If the whole installation needs a different voltage level, you’re looking at a broader upgrade.
Sizing a voltage stabiliser
Choosing by voltage alone is a common mistake. The kVA rating has to match the load.
Motors are the usual trap. Their starting current is far higher than their running current, so a stabiliser that looks fine for normal running can be undersized the moment a motor starts. Consider total connected load, maximum demand, motor starting current, input voltage range, required output voltage, single or three-phase operation, hours of continuous use, the environment, and the protection features you need.
Manufacturers offer many capacities with different input ranges and regulation accuracy. A professional load assessment beats picking from an online capacity chart.
Can you do it yourself?
No. Changing voltage isn’t a DIY job. A wrongly chosen transformer, stabiliser, cable or protection device can cause electric shock, fire, insulation failure, overheating, short circuits and motor damage. Anything that touches fixed wiring, switchboards, transformers or distribution equipment should be assessed and done by licensed electrical professionals.
What low voltage does to equipment
How badly equipment suffers depends on its design and on how severe and long-lasting the problem is. Typical effects:
- Motors can draw more current at low voltage, which means more heat and weaker performance.
- Lights dim or flicker.
- Sensitive electronics reset, malfunction or shut down.
- CNC machines, pumps, compressors and production equipment fault or stop.
- HVAC compressors and motors are especially sensitive to poor supply conditions.
What too much voltage does
Overvoltage is just as bad. It can cause component failure, overheating, insulation stress, electronic damage, a shorter equipment life and safety hazards. The aim isn’t the highest possible voltage. It’s the correct voltage, within the range the manufacturer specifies.
A practical process
A professional assessment usually runs like this.
- Define the problem. Note when the low voltage happens. Is it constant, or only when large equipment starts?
- Measure the supply. Take readings at the incoming supply and at the affected equipment.
- Work out the load. Establish connected load and maximum demand.
- Inspect the cabling. Check size, length, connections and installation conditions.
- Assess power quality. Look for fluctuations, sags, surges and phase imbalance.
- Choose a solution. Depending on the findings, that could be a cable upgrade, load balancing, a stabiliser, a step-up transformer, a transformer upgrade, an incoming supply upgrade, or new switchboards and distribution.
- Add protection. Circuit protection, isolation, earthing and surge protection belong in the design from the start.
- Test the result. Measure voltage and load again afterward to confirm the system does what it should.
When to call a professional
Get an assessment if you see any of these:
- frequent equipment shutdowns
- flickering lights
- motors struggling to start
- machinery faults
- repeated breaker trips
- large voltage swings
- unusual smells or heat
- voltage readings outside equipment specifications
- problems that show up whenever big equipment runs
For businesses, catching voltage problems early can save you production downtime and damaged equipment.
Solar Panel Installers in Pakenham – EcoRun Energy
If you’re looking to improve your property’s energy efficiency and reduce reliance on grid electricity, installing a solar power system can be a worthwhile investment. EcoRun Energy, a trusted provider of solar solutions in Pakenham, offers solar panel installation, battery storage, and energy solutions tailored to residential and commercial properties. With a focus on quality installations and reliable service, EcoRun Energy helps homeowners and businesses in Pakenham and surrounding areas make better use of solar energy. If you’re considering solar panels for your property, contact EcoRun Energy to discuss your energy requirements and find a suitable solar solution.
Bottom line
Raising voltage isn’t about making a number on a meter go up. The right fix depends on why the voltage is low and what your equipment needs. Sometimes that’s a stabiliser or AVR. Just as often it’s undersized cable, an overloaded circuit, a bad connection, phase imbalance or a transformer that’s too small.
Measure first, find the cause, calculate the load, then pick the solution. If low voltage keeps happening at your property or business, have a qualified electrician look at the installation.