Short answer
An RCD, known locally as a FID/FI (residual current) device, is a unit in the distribution board that cuts the power within 30 milliseconds when as little as 30 mA leaks to earth, protecting people from electric shock. It is mandatory under modern standards. Fitting one in an existing board costs under 5.000 MKD in total (device 1.500-3.500 MKD + fitting 1.500-3.000 MKD). Elektro TR fits and tests an RCD in 1-2 hours - 070 393 045.
If you live in an old building with no RCD protection, you are exposed every day to the risk of a fatal electric shock. We mean that seriously. We do not want to frighten anyone - but the statistics are clear: these life-saving devices have been around for 50 years, and yet many homes in North Macedonia still do not have this protection.
In this article you will learn: what a FID/FI device is, how it works, why modern standards make it mandatory, and what fitting one costs.
What is a FID/FI device?
FID is short for Fault Current Device, and FI comes from the German Fehlerstromschutzschalter. Both mean the same thing: a residual current protective device, or RCD.
It is a small electrical unit (roughly the width of 2 circuit breakers) that is fitted in the distribution board. Its only job is to cut the power the moment it detects a leakage - that is, when current is “escaping” through a person, a wet surface or a faulty appliance.
How does it work, in plain language?
An RCD measures how much current enters the home (through the live conductor) and how much leaves it (through the neutral). In normal operation these two values are equal. If there is a difference - even of just 30 milliamps (0.03A) - it means the current is “leaking” somewhere through a person or a faulty appliance. The RCD reacts within 30 milliseconds and cuts the power. That is before the current can cause cardiac arrest or a fatal injury.
Why exactly 30 mA?
The RCD's settings are not arbitrary - they come from medical studies on the effect of electric current on the human body:
- 0.5 - 2 mA: you start to feel a tingle
- 5 - 10 mA: you may not be able to let go of the cable (the let-go threshold)
- 10 - 30 mA: pain, muscle contractions, difficulty breathing
- 30 - 100 mA: high risk of heart fibrillation (the heart stops pumping blood properly)
- over 100 mA: a high probability of death within a short time
An RCD with a sensitivity of 30 mA reacts before the current reaches the dangerous level. That is the gold standard for safety at home.
When does an RCD protect me?
Scenario 1: Water sprays onto a fridge or washing machine
Water + electricity = danger. If the drain hose leaks and the water reaches the metal parts of the machine, then without an RCD the metal body of the machine becomes live. The moment you touch it, the current passes through you into the ground. With an RCD, the leakage is detected instantly and the power is cut before you get a shock.
Scenario 2: Children with a nail in a socket
Children experiment - the statistics for injuries and deaths caused by nails, scissors or metal toys pushed into sockets are considerable. An RCD cannot stop a child doing something dangerous, but it can prevent a tragedy.
Scenario 3: A damaged appliance cable
A toaster, a hairdryer or a hob with a bare (visible) wire or damaged internal insulation is a hidden killer. The moment you touch the bare part, the RCD reacts immediately.
Scenario 4: Damp bathrooms / outdoor lighting
Bathrooms and outdoor areas are critical zones for electric shock. Today's standard requires a separate 30 mA RCD for those circuits alone.
Why is it mandatory under the standard?
According to Macedonian and European safety regulations:
- All new installations MUST have a 30 mA RCD on every circuit that supplies sockets
- For bathrooms and outdoor areas - a separate 30 mA RCD
- For buildings used by children (nurseries, schools) - a 10 mA RCD (stricter)
- Older installations must be upgraded when the property is renovated or sold
Since 2020, insurance companies in North Macedonia have increasingly refused to cover damage from an electrical fire if there is no modern RCD protection in place. That means you are running a double risk: to your life and to your finances.
What does fitting an RCD cost?
Indicative prices in 2026:
- 30 mA RCD (standard): 1.500 - 3.500 MKD (the device)
- 30 mA RCD, branded (Schneider/ABB/Legrand): 3.500 - 6.000 MKD
- Selective RCD (for protection by branch): 5.000 - 10.000 MKD
- Fitting into an existing board: 1.500 - 3.000 MKD
- Complete board replacement with an RCD: 15.000 - 35.000 MKD (for a flat)
If your board has no RCD, fitting a single protective device costs under 5.000 MKD in total. For that money you get protection that could literally save your life.
Does my house have an RCD?
It is easy to check. Go to the distribution board and look for:
- A device that is wider than a standard breaker (usually twice or three times as wide)
- With a test button (T or TEST) - usually yellow or blue
- Marked 30 mA or 0.03A
- Labelled FI or FID or RCD
Test it every month!
An RCD should be tested at least once a month. Press the “T” or “TEST” button - the board should trip immediately. If nothing happens, the RCD is not working and needs replacing straight away. This is standard practice that a lot of people forget.
RCD vs. circuit breaker - they are not the same!
This is a common confusion: people think that if they have circuit breakers they are “protected”. That is not correct.
- A circuit breaker protects the cables from overheating and short circuits
- An RCD (FID/FI) protects people from electric shock
You need both. A modern distribution board has circuit breakers + an RCD together.
Does your home have no RCD protection?
Elektro TR fits RCD protection within 1-2 hours. We come out anywhere in Skopje with the equipment needed, fit it into your existing board, and test it on the spot.
Call: 070 393 045Conclusion
RCD protection is not a luxury - it is basic safety that every home should have. For less than the price of an average electricity bill, you get a device that saves lives. If your old board has no RCD, do not put it off - the fix is simple, quick and cheap compared with the risk.