A Voltage Stabiliser for Your Computer and Electronics: When You Need One and How It Differs from a UPS and a Surge Protector

A socket should supply 220–230 volts. But in many Tbilisi buildings the voltage "wanders": in the evening, when the neighbours switch on heaters and air conditioners, it sags to 180–190 volts, and at night it can jump above 250. Lights flicker, the fridge relay clicks and the computer sometimes restarts by itself. These fluctuations gradually kill equipment: power supplies, routers and chargers run at their limits and fail early. Let's look at when you need a voltage stabiliser, how it differs from a UPS and a surge protector, and how to choose one.

Signs of voltage problems

• Lights noticeably dim or brighten, especially in the evening and when powerful appliances switch on.
• The computer restarts or shuts down by itself, even though there's nothing wrong with it.
• The router restarts from time to time and the internet drops for a minute or two.
• Power supplies, chargers and adapters fail one after another.
• The air conditioner or fridge doesn't start first time, or hums.
• The UPS keeps switching to battery and beeping.

Measuring the voltage at different times of day gives an accurate picture — a technician can check it with a multimeter or leave an inexpensive logging meter in place for a few days.

Stabiliser, UPS and surge protector — the difference

• A surge protector suppresses high-frequency interference and short spikes, for example from a lightning strike on the line. It doesn't protect against prolonged dips or high voltage. A cheap extension lead with a switch is not a surge protector.
• A stabiliser evens out the voltage: with 180 volts coming in, it supplies around 220 to your equipment. But in a complete power cut it's useless.
• A UPS keeps equipment running on battery when the power goes off. Line-interactive UPS units have a built-in stabiliser, but with a narrow range; with strong and frequent dips they keep switching to battery and wear it out quickly.

So with poor mains a combination often makes sense: a stabiliser for the whole flat or a group of equipment, plus a UPS for the computer and router.

Types of stabiliser

• Relay — inexpensive and compact; they switch transformer windings in steps. They click when switching, and small jumps can occur at the output. Usually fine for household appliances and computers with a good power supply.
• Triac (thyristor) — switch steps silently and quickly and last longer. A good choice for a flat or office.
• Servo (electromechanical) — smooth regulation, but slow to react to sudden surges, and with moving parts that need maintenance.
• Inverter (double-conversion) — the most accurate and fastest, working over a wide input voltage range. More expensive than the rest; justified for costly and sensitive equipment.

How to choose the capacity

Add up the power of all the equipment that will be connected to the stabiliser and add 20–30% headroom. Bear in mind that at low input voltage the real capacity of many stabilisers drops — this is stated separately in the specifications. For a computer, monitor and router a small 1–1.5 kVA stabiliser is enough. For a whole flat, 5–10 kVA, and installation at the mains intake must be done by an electrician. Fridges, air conditioners and pumps draw several times their rated power at start-up, which also needs allowing for.

One socket or the whole flat

A local stabiliser protects only the equipment plugged into it and needs no wiring work. A stabiliser at the mains intake protects everything at once: electronics, lighting and appliances. But it must be powerful enough, and it has to be connected through circuit breakers with correctly sized cables. Installing one at the intake yourself is dangerous.

Worth knowing

• A stabiliser doesn't replace earthing. In old buildings without earthing, spike protection works less well.
• If the voltage drops very low (below 150–160 volts), the problem may be in the wiring of the building or stairwell — a reason to contact the power company.
• Scorched or warm sockets and a burning smell are a sign of faulty wiring, not a stabiliser problem. That needs fixing immediately.
• A good computer power supply works across a wide voltage range, but regular surges shorten its life.

What our technician does

1. Measures the mains voltage and assesses how severe the fluctuations are.
2. Checks equipment that has failed and identifies the cause.
3. Selects a stabiliser, a UPS or a combination of both for your equipment.
4. Connects your equipment correctly and checks sockets and extension leads.
5. Brings in an electrician to install a stabiliser at the intake and check the wiring.

A real example

A family in Digomi had replaced two computer power supplies, a router and a laptop charger in a year. In the evenings the lights dimmed noticeably, and the computer sometimes restarted by itself. Our technician measured the voltage: in the evening it fell to 178 volts, and at night it rose to 248. We connected the computer, monitor and router through a triac stabiliser and a line-interactive UPS, and an electrician checked the distribution board and tightened loose contacts at the intake. In the following six months not a single device failed, and the spontaneous restarts stopped.

Call a technician

If your equipment switches off, restarts or fails because of electrical problems, we'll come to any district of Tbilisi around the clock. Learn more on our electrician services, computer keeps restarting and computer won't turn on pages.