The answer in two lines
An RCCB (earth leakage breaker) disconnects the supply the moment it senses current leaking outside the circuit (for example through a person), so its main job is protection against electric shock. It is not a replacement for the ordinary breaker (MCB), which protects against overload and short circuit, and it must be installed with a breaker upstream. For a flat the usual choice is 30 mA sensitivity, 2-pole for single phase or 4-pole for three phase, with an amp rating suited to the load and its upstream breaker. Final selection by a qualified electrician or engineer.
"Do I need an RCCB? 2-pole or 4-pole? 25, 40 or 63 A?" These questions come up with every distribution board. In this guide from Tawredaat (توريدات), an electrical and finishing materials supplier in Cairo and Giza (see also our FAQ), we explain simply what it is, how it works, when it is fitted and how to choose. Every technical point names its source; anything without a public source is written as general guidance.
What is an RCCB and what is it for?
RCCB stands for Residual Current Circuit Breaker. The title of the international standard IEC 61008-1 describes it as a residual current breaker without integral overcurrent protection. According to Schneider's guide, it automatically disconnects the supply to prevent injury or death by electrocution when leakage occurs.
- ✔ It protects people: if someone touches a live part or a faulty appliance, current flows through the body; the RCCB senses the difference and trips.
- ✔ 30 mA sensitivity: Electrical Engineering Portal gives 30 mA as the typical domestic value, and Schneider Egypt's FAQ says IEC 60364 only asks for 30 mA for human protection.
- ⚠ It does not protect against overload or short circuit: that is the job of the MCB. A 30 mA RCCB does not replace it, so an overload breaker must come before it. See our apartment breaker guide.
How does it work?
Per Schneider's guide, a magnetic toroid surrounds all the live conductors, including the neutral. In a healthy circuit the incoming and outgoing currents cancel and there is no flux. With leakage the sum is not zero, a flux appears and induces a current in a secondary winding that drives the tripping mechanism. In other words: it compares the phase and neutral currents, and if they differ (some current is escaping to earth) it trips.
For AC type (stated on our listings), ETI explains it detects sinusoidal alternating residual current and trips between 50% and 100% of the rated residual current, so a 30 mA device trips between 15 and 30 mA (our arithmetic from ETI's percentages). Type A also senses pulsating DC; if you have many electronic loads, ask your engineer whether a higher type is needed.
When do you need an RCCB?
We could not verify a specific Egyptian clause, so the decision under the applicable Egyptian code belongs to a qualified engineer. From the international standards cited in Schneider's guide:
- ✔ Bathrooms: circuits supplying equipment in or passing through the bathroom, IEC 60364-7-701 clause 701.415 (30 mA protection).
- ✔ Sockets: socket-outlet circuits up to 32 A in any type of building, IEC 60364-4-41 clause 411.3.3 (30 mA additional protection). That covers kitchen and washing-machine sockets too.
- ✔ Places people touch: Schneider Egypt says 30 mA is mostly used for sockets and places with human access.
- ⚠ If a circuit needs different protection (special equipment), the sensitivity is decided by an engineer.
This also ties into the whole board layout; see our distribution board guide for ways and protection placement.
2-pole or 4-pole? And how do I choose 25, 40 or 63 A?
Poles depend on your supply: per VIOX, single-phase line and neutral (a normal flat) suits 2-pole, and three-phase with neutral suits 4-pole, confirmed against the product's own wiring diagram, not just the words "three phase". Amps: per Hager's sheet, the rating per pole must not be exceeded by the maximum demand of the protected circuits, and per Schneider the RCCB rating must be equal to or greater than the upstream breaker, because that upstream breaker protects it from overload.
| Type | Suits | Available ratings | Available at Tawredaat (Schneider Resi9, 30 mA) |
|---|---|---|---|
| 2-pole (2P) | Single phase + neutral (normal flat) | 25 A / 40 A / 63 A | 2P 25A / 2P 40A / 2P 63A |
| 4-pole (4P) | Three phase + neutral (villa/shop/office or a three-phase board) | 25 A / 40 A / 63 A | 4P 25A / 4P 40A / 4P 63A |
How to choose the amps (general guidance)
- ✔ Start from the upstream breaker: size the main breaker or the one feeding the RCCB, then pick an RCCB of the same value or higher (Schneider).
- ✔ Check the load: the maximum demand of the circuits after it must not exceed the pole rating (Hager). Breaker sizing is in our apartment breaker guide and on the appliance nameplate.
- ✔ Check the product sheet: our listing titles state 30 mA, and the 2P 40A and 4P 25A titles say AC Type; check the page for the other ratings.
- ⚠ No fixed number says "a flat takes 25 or 40 A"; the engineer decides after counting loads.
The final choice of amps, poles and wiring belongs to a qualified electrician or engineer after the loads are counted.
Common RCCB mistakes
- ⚠ Installing it without an overload breaker upstream. The RCCB has no integral overcurrent protection (IEC 61008-1, Schneider), so a breaker must come before it.
- ⚠ Wrong earth or neutral wiring. Per Hager, if it trips intermittently, will not reset or the test button does not work, check the insulation of neutral and earth. The wiring itself is for a qualified electrician.
- ⚠ Never pressing Test. The button simulates a leakage and checks the mechanism works (HSE Blog) but does not measure trip time. Sources differ on frequency (for example the US CPSC recommends monthly), so follow the manufacturer's instructions.
- ⚠ One RCCB for the whole flat. Any fault trips every circuit; splitting circuits or using an RCBO per circuit isolates faults better (see the board guide).
- ⚠ Installing it yourself. Design, wiring and final testing belong to a qualified electrician or engineer.
RCCBs available on Tawredaat
Currently available (checked today):
- ✔ Schneider Resi9 25A 2P RCCB 30mA: 2-pole, 25 A.
- ✔ Schneider Resi9 2P 40A 30mA AC Type: 2-pole, 40 A.
- ✔ Schneider Resi9 63A 2P RCCB 30mA: 2-pole, 63 A.
- ✔ Schneider Resi9 4P 25A 30mA AC Type: 4-pole, 25 A.
- ✔ Schneider Resi9 40A 4P 30mA RCCB: 4-pole, 40 A.
- ✔ Schneider Resi9 4P 63A 30mA RCCB: 4-pole, 63 A.
See more in the earth leakage circuit breakers collection and circuit breakers and panels.
Frequently asked questions
Does an RCCB protect against overload?
No. It has no integral overcurrent protection, so an ordinary breaker (MCB) must come before it. Its job is leakage and shock protection.
What does 30 mA mean?
It is the sensitivity: the device trips when leakage reaches a value near it (an AC type trips between 50% and 100% of rated residual current, per ETI).
2-pole or 4-pole?
2-pole for single phase with neutral, 4-pole for three phase with neutral, confirmed against the product wiring diagram (VIOX).
25, 40 or 63 A?
The RCCB rating should be equal to or above the upstream breaker and its rating must not be exceeded by the maximum demand. The engineer decides after counting loads.
Do I have to press the Test button?
It simulates a leakage and checks the mechanism, but does not measure trip time. Follow the manufacturer's test schedule.
Can I install the RCCB myself?
No. Design, wiring and testing belong to a qualified electrician or engineer.
Ready to choose your RCCB?
Browse the Schneider Resi9 2-pole and 4-pole RCCBs in stock. Delivery in Cairo and Giza only.
About Tawredaat: Tawredaat (توريدات) is an Egyptian supplier of electrical and finishing materials, serving homeowners, companies and contractors in Cairo and Giza. Questions? See our FAQ.
Sources
- Schneider Electric, Earth Fault Protection: How to design efficient earth fault protection with Residual Current Devices (RCD), guide CA908066E, 2022 (30 mA for sockets up to 32 A per IEC 60364-4-41 §411.3.3; bathrooms per IEC 60364-7-701 §701.415; toroid principle; RCCB has no integral overcurrent protection and is protected by the upstream breaker, rated equal to or above it) — download.se.com/doc/CA908066E/CA908066E (web).pdf
- Schneider Electric Egypt FAQ: In which applications should RCCB adjustment be 10 mA or 30 mA? (IEC 60364 only asks for 30 mA; 30 mA mostly for sockets and places with human access) — se.com/eg/en/faqs/FA177318
- Electrical Engineering Portal, How a residual current device (RCD) works (toroidal transformer, live/neutral imbalance, 30 mA domestic, not a replacement for the MCB) — electrical-engineering-portal.com/how-residual-current-device-rcd-works
- IEC 61008-1:2010, Residual current operated circuit-breakers without integral overcurrent protection for household and similar uses (RCCBs), Part 1: General rules (title) — genorma.com/en/standards/iec-61008-1-2010-ed3
- ETI, Difference between AC and A type RCDs (AC type detects sinusoidal alternating residual current and trips between 50% and 100% of rated residual current) — etigroup.eu/media-center/eti-blog/difference-between-ac-and-a-type-rcds
- VIOX, How to choose an RCCB (single-phase line and neutral = 2-pole; three-phase with neutral = 4-pole, to be confirmed against the product wiring diagram) — viox.com/how-to-choose-an-rccb/
- Hager, RCCB installation sheet ID1_ID_6C5115D (current rating per pole must not be exceeded by the maximum demand of the protected circuits; check neutral/earth if it trips or the test button will not work) — assets.hager.com/step-content/P/HA_22842067/Document/std.lang.all/ID1_ID_6C5115D.pdf
- HSE Blog, RCD testing (the push-button test simulates an earth fault and checks the mechanism, it does not measure trip time; test intervals differ by country, e.g. monthly GFCI test recommended by the US CPSC) — hseblog.com/rcd-testing/
- Tawredaat product listings (poles, amps, 30 mA and AC type are taken only from the listing titles/descriptions on tawredaat.com) — tawredaat.com/collections/earth-leakage-circuit-breakers
ملخص بالعربي: قاطع التسريب RCCB بيقارن تيار الفاز بالنيوترال ويفصل لو فيه تسريب، لحماية الأشخاص من الصعق. مفيهوش حماية زيادة حمل فلازم قاطع عادي قبله. حساسية 30 مللي أمبير للبرايز والحمامات (IEC 60364). 2 قطب لفاز واحد و4 قطب لـ3 فاز، و25 أو 40 أو 63 أمبير. التصميم النهائي لفني أو مهندس مؤهل. المتاح: Schneider Resi9 في القاهرة والجيزة.
