Short answer: the NB1L, NB2LE and NXBLE-63 are all 1P+N residual current circuit breakers with overcurrent protection to IEC/EN 61009-1, all 6 kA, all with 30, 100 and 300 mA sensitivities in Type AC and Type A. Pick between them on three things, not on the residual current rating: current range (NXBLE-63 goes to 63 A, NB1L to 40 A with a 63 A frame, NB2LE to 40 A), certificate file (NB2LE has the widest published set, including UKCA, EAC and KC), and pole options (NB2LE is 1P+N only, the other two add 2P, 3P+N and 4P).
This comparison is written for the buyer who has to put one line on a purchase order and defend it later. We are an independent trading company — not a manufacturer, and not an appointed distributor of any brand — so every rating below is quoted from the published data for that series, and every certificate claim is tied to an exact ordering code.
What an RCBO is doing in the circuit
An RCBO combines the two protections a final circuit needs: overcurrent, like an MCB, and residual current, like an RCCB. The alternative is an MCB plus an RCCB upstream, which protects a group but does not say which circuit tripped. An RCBO per circuit costs more per way and takes the same 18 mm as a 1P+N MCB, but a trip is localised and the rest of the board stays live.
The overcurrent part carries the circuit’s load current continuously; the residual part only acts on a fault. So the current rating and the certificate file for that exact rating dominate the decision, while sensitivity is the easy part: 30 mA for socket outlets, 100 or 300 mA for fire protection of a distribution circuit.
The three series side by side
| Attribute | NB1L | NB2LE | NXBLE-63 |
|---|---|---|---|
| Standard | IEC/EN 61009-1 | IEC/EN 61009-1 | IEC/EN 61009-1 |
| Rated voltage | 240/415 V AC | 230/240 V AC | 230/400 V AC, 50/60 Hz |
| Rated current | 1–40 A in 1P+N; 63 A frame available | 6–40 A (40 A frame) | 6–63 A |
| Tripping curve | B, C | B, C | B, C |
| Residual sensitivity | 30 / 100 / 300 mA | 30 / 100 / 300 mA | 30 / 100 / 300 mA |
| Residual type | Type AC and Type A | Type AC and Type A | Type AC and Type A |
| Breaking capacity Icn | 6 kA (10 kA on high-breaking variants) | 6 kA; residual making/breaking IΔm 3 kA | 6 kA |
| Poles | 1P+N, 2P, 3P+N, 4P | 1P+N | 1P+N, 2P, 3P+N, 4P |
| Electrical life | Not published as a single figure — ask per code | 4,000 operations | Not published as a single figure — ask per code |
| Published certificate file | CB, VDE, KEMA, CE-LVD | CE, CB, KEMA, UKCA, EAC, KC, UA-TR | Certificate set varies by market — ask per code |
| Distinguishing feature | Widest pole range of the three | Widest certificate set; 3 kA residual making capacity published | Highest current rating and a self-test variant |
Two entries in that table need care. First, the 63 A frame in the NB1L line does not mean every NB1L code is available at 63 A — the 1P+N device is documented to 40 A, and the larger frame is a separate part of the range, so the exact code decides. Second, NXBLE-63 has a self-test derivative, the NXBLE-63ZB, which tests the residual current circuit on a schedule instead of relying on the user pressing the test button; that is a real difference for installations where a monthly manual test never happens.
Current range: the decision that is easiest to get wrong
A 32 A RCBO on a 32 A circuit is not automatically correct: the rating has to sit above the design current and below the cable’s capacity, and coordinate with the upstream device so a fault trips the RCBO rather than the board. On a 63 A submain neither NB1L nor NB2LE reaches the load — only NXBLE-63 does, which eliminates two series before any other consideration.
At the other end, below 6 A the NB2LE and NXBLE-63 ranges do not start, while NB1L documents codes down to 1 A. In practice that matters for control circuits and small single-phase loads where 6 A is already generous, though most of those circuits are better served by a 6 A device anyway.
Certificates: the part that decides the destination
The NB2LE has the widest published set of the three: CE, CB, KEMA, UKCA, EAC, KC and the Turkish UA-TR file. If the destination is the UK, Korea, Russia or a customs-union country, that file is the reason to pick this series, and it is also the reason not to assume the same file covers a different current rating — a certificate is issued against ratings and a frame, and a 40 A code is not covered by a 16 A certificate.
The NB1L publishes CB, VDE, KEMA and CE-LVD documents. For a European consultant who expects a VDE file, that is the easiest conversation of the three. The NXBLE-63’s certificate set varies by market and has to be asked for code by code rather than assumed, which is why we do not print a blanket claim for it.
None of these is a substitute for a national approval where one exists. A CE declaration is a self-declaration against the applicable directives; a CB report is a test report that national schemes can accept as an input; neither is a licence to sell in a market that runs its own registration. The same device may be perfectly legal in one country and require a separate registration in the next.
Type AC or Type A: the choice that follows the load
Type AC responds to alternating residual current only. Type A additionally responds to pulsating direct residual current, which is what you get downstream of most single-phase electronic loads: LED drivers, computer power supplies, variable-speed drives on single-phase input, and EV chargers. For a modern socket circuit, Type A is the defensible choice; Type AC survives mainly in cost-driven specifications and in replacements of existing stock.
Type B, which also covers smooth direct residual current, is a different device class and is required where the load can produce smooth DC — three-phase drives, some EV chargers and certain photovoltaic inverters. None of the three series above is a Type B device, and no amount of careful ordering turns one into one.
| Circuit | Series that fits | Why |
|---|---|---|
| Domestic socket circuits, 16–32 A | NB2LE or NXBLE-63, Type A, 30 mA | Standard 1P+N application; NB2LE if a UKCA/EAC/KC file is needed |
| Submain to a flat or small unit, 40–63 A | NXBLE-63, Type A | Only this series reaches 63 A |
| Three-phase final circuit with neutral | NB1L or NXBLE-63, 3P+N | NB2LE is 1P+N only |
| Unattended installation, no monthly test discipline | NXBLE-63ZB | Self-test derivative checks the residual circuit automatically |
| Single-phase EV charger | Type A RCBO plus a Type B RCD if the charger declares DC leakage | Follow the charger’s installation instructions; some units include DC fault detection internally |
What the ordering code has to contain
Series, current, curve, residual sensitivity, residual type, pole configuration and the certificate file required for the destination. Written as a string — NB2LE, 20 A, C curve, 30 mA, Type A, 1P+N — that is a device a factory can pick. Written as “20 A RCBO”, it is a coin toss between three series with different certificate files and different pole options.
For a replacement, send the front label and the side marking: the residual type is often printed only on the side.
FAQ
Is an RCBO the same as an MCB plus an RCCB?
Functionally yes, physically no. An RCBO puts both protections in one 18 mm device and protects one circuit; an MCB plus an RCCB protects a group of circuits and a trip takes out the whole group. The RCBO also gives you a localised indication of which circuit tripped.
Can I use a 30 mA RCBO as the main switch of a board?
It is a poor choice even where it is permitted. A 30 mA device at the incomer trips the entire installation on one faulty appliance, and its rated current has to carry the whole board’s load. Use an isolator or a main breaker at the incomer and RCBOs on the final circuits.
Which series has the best certificate coverage?
The NB2LE publishes the widest set of the three — CE, CB, KEMA, UKCA, EAC, KC and UA-TR — but coverage is per rating and per frame, so the exact code decides. NB1L publishes CB, VDE, KEMA and CE-LVD; the NXBLE-63 certificate set has to be confirmed code by code.
Do these devices work at 60 Hz?
Yes. The residual current sensing is not frequency-selective in the way a coil is, and these series are rated 50/60 Hz where the marking says so. What does change with 60 Hz markets is the certificate and the voltage marking, not the residual function.
What is the difference between Icn and IΔm?
Icn is the short-circuit breaking capacity of the overcurrent part — 6 kA on all three series. IΔm is the residual making and breaking capacity, published as 3 kA for the NB2LE and 6 kA for the NB1L; it describes the device’s ability to break a residual fault current, not a short circuit.
Related: RCCB and RCBO range · MCB vs RCCB vs RCBO · RCCB Type AC vs Type A · Type B RCD for EV chargers · 6 kA vs 10 kA breaking capacity · Which certificate does my country require? · Markets we serve · Request a quotation