Short answer: the two Siemens families in this question map differently. 5SL6 is a residential modular MCB — IEC/EN 60898-1, 6 kA in the base line and 10 kA in the higher codes. Its closest CHINT equivalent is the NXB-63: Icn 6 kA, or 10 kA in the H version, In 1–63 A, B/C/D, 18 mm per pole. 3VA1 and 3VA2 are moulded-case breakers — roughly 100–630 A with Icu up to 150 kA by frame and class, with ETU electronic trip units. There the CHINT mapping is NXM (16–1600 A, up to 70 kA at 400 V) and NM8N (frames 125–1600 A), with the NERVAX NDM2 line as a further option in the 63–800 A band. This is a series-level comparison, not an approved substitution.
Why the two lines get different answers
A 5SL6 and a 3VA1 have almost nothing in common except the maker’s name on the front. The 5SL6 is a din-rail module: it protects a final circuit in a distribution board, and the decision variables are rated current, curve, pole count and module width. The 3VA is a switchboard device: it carries a feeder or a sub-main, and the decision variables are frame size, breaking class, trip unit and coordination with the devices above and below it.
So this page keeps the two apart. The modular section is a rating comparison. The moulded-case section is a comparison plus a warning about trip units and selectivity studies — the two things that decide whether a swap actually works in service.
Brand names and model numbers are the property of their respective owners and are referenced for comparison only. CHINT products are independently manufactured and independently certified; they are not authorised, sponsored or officially approved by Siemens.
5SL6: the modular MCB mapping
| Attribute | Siemens 5SL6 | CHINT NXB-63 | CHINT NB1-63 / NB1-63H |
|---|---|---|---|
| Device type | Residential / light-commercial modular MCB | Modular MCB | Modular MCB |
| Standard | IEC/EN 60898-1 | IEC/EN 60898-1 | IEC/EN 60898-1 (IEC 60947-2 version available) |
| Rated current | Up to 63 A | 1–63 A | 1–63 A |
| Curves | B, C, D | B, C, D | B, C, D |
| Breaking capacity | 6 kA base, 10 kA in higher codes | Icn 6 kA; 10 kA in the H version (2P 220–240 V, Ics 7.5 kA) | Icn 6 kA; 10 kA in NB1-63H |
| Module width | 18 mm per pole | 18 mm per pole | 18 mm per pole |
| Poles | 1P–4P and multi-pole variants | 1P–4P, 1P+N, 3P+N | 1P–4P, 1P+N, 3P+N |
The mapping holds at the 6 kA and 10 kA steps, which is where residential boards live. It does not extend beyond the 10 kA modular band: a higher kA requirement is a different device class, not a longer cross-reference row. The same rule protects you at the other end. If the specification or the utility asks for 6 kA, a 4.5 kA residential device does not answer it, however close the price looks.
Also note the frequency side, because Siemens sells into both 50 Hz and 60 Hz markets and so do we. A modular MCB rated 50/60 Hz covers both, but the rated voltage that goes with each grid is not the same everywhere, and the certificate that a 110–127 V market asks for is its own question. We cover that in how grid voltage decides the device.
3VA1 and 3VA2: the moulded-case mapping
| Attribute | Siemens 3VA1 / 3VA2 | CHINT NXM | CHINT NM8N | NERVAX NDM2 |
|---|---|---|---|---|
| Standard | IEC/EN 60947-2 | IEC/EN 60947-1/-2/-3 | IEC/EN 60947-1/-2/-3/-4-1 | IEC/EN 60947-2 |
| Current range | Roughly 100–630 A | In 16–1600 A, frames 125–1600 | Frames 125–1600 A | 63–800 A band |
| Breaking capacity | Up to 150 kA by frame and class | Up to 70 kA at 400 V AC; up to 50 kA at 690 V AC | Up to 100 kA at 440 V AC in the top class; AC 690 V down to 10 kA | Per frame and class, by code |
| Trip unit | Thermal-magnetic and ETU electronic trip units | Thermal-magnetic, instantaneous magnetic, electronic | Thermal-magnetic and electronic | Thermal-magnetic and electronic |
| Mounting | Fixed and plug-in options | Fixed and plug-in | Fixed and plug-in | Fixed and plug-in |
Two reading notes on that table. First, a Siemens class letter and a CHINT class letter are not the same number: each letter indexes a kA row in its own maker’s catalogue, at a stated voltage. Match the published values at the same voltage, code by code, or do not match them at all. Second, the NXM range reaches up to 1600 A, so it also covers the larger legacy frames where a 3VA-grade device is being replaced in a switchboard. Our MCCB selection guide shows how frame, class letter and pole count combine into one order code.
There is a commercial dimension to this one. Siemens has a strong installed base in parts of Latin America and the Middle East, where industrial tenders often name approved brands. If your project carries a named-brand clause or an approved-brands list, the substitution question is answered by the specifier, not by a cross-reference table. We are happy to supply the datasheet and certificate pack your engineer needs to make that case — but we will not tell you a brand is pre-approved when it is not.
The trip unit is where the equivalence ends
With thermal-magnetic devices, mapping is arithmetic: In and the fixed instantaneous value are published, and both sides can be listed. With an ETU-class electronic trip unit it is not.
The protection shape (long-time, short-time, instantaneous, ground) is comparable, so we can write “similar protection functions”. What does not travel is measurement accuracy, harmonic handling, energy metering and the communication interface. A Modbus or fieldbus register map is maker-specific; a controller that talks to one device does not automatically talk to another. And the plug-in base or racking of the outgoing device cannot be reused, because those interfaces are proprietary.
One more rule that saves projects: when the brand changes, the coordination study is new. Published cascade and selectivity tables are specific combinations from one maker. Reuse the old report at your own risk; we will flag it in the quotation rather than let it surface at commissioning.
A note on motor protection (3RV and 3RU range)
Motor protection often rides along with the same tender, so it is worth a paragraph. Siemens 3RU21 and 3RU11 thermal overload relays and 3RV20 motor-protection breakers map, at the standard steps, to the CHINT NR2 overload relay (setting range 0.1–150 A, trip class 10A) and the larger NXR platform used with NXC contactors, with the NS2-25 / NS2-32 motor-protection breaker (0.1–32 A, thermal-magnetic, adjustable) covering the manual-starter step.
Two cautions. Compare the trip class (Class 10 versus Class 20) before substituting, because it changes the starting duty the relay tolerates. And at the high end of the Siemens range there is no strong like-for-like domestic equivalent, so for that segment the honest answer is to keep the original brand or move to an engineered protection scheme. Our contactor and motor-control range lists what we can certify per code.
Certificates across the two families
Certificates follow ordering codes, not families and not brands. In the CHINT moulded-case range the publicly documented certificates include CB, CE and EAC attached to specific codes, and the modular range carries its own certificate set by series. If your market needs SAA (Australia), UL 489 (North America), SASO or G-Mark (Gulf) or a national registration, that is a separate question answered by the certificate file for the code you buy. We send it with the quotation. See how we verify genuine product and the full cross-reference page.
FAQ
Q: Is the CHINT NXB-63 a Siemens 5SL6 equivalent?
A: It is a comparable residential modular MCB at the 6 kA and 10 kA steps — In 1–63 A, B/C/D curves, 18 mm per pole. It is not an approved or official replacement and the accessories are not interchangeable. Confirm the exact code for the rating you need.
Q: What replaces a Siemens 3VA1 or 3VA2 moulded-case breaker?
A: The closest CHINT families are NXM (16–1600 A, up to 70 kA at 400 V) and NM8N (frames 125–1600 A), with NERVAX NDM2 in the 63–800 A band. Match frame, class letter and kA value at the same voltage, code by code.
Q: Can I reuse my existing plug-in base or racking?
A: No. Those interfaces are proprietary. Replace the device and its base together.
Q: Both are electronic trip units — are they interchangeable?
A: Only in terms of protection functions. Measurement accuracy, harmonics, metering and communication are not equivalent, and the coordination study must be re-run.
Q: Does a 4.5 kA device substitute for a 6 kA requirement?
A: No. Match the minimum breaking capacity the board or specification states. A lower kA device does not qualify.
Q: Do Siemens and CHINT certificates transfer?
A: No. Every certificate names an exact ordering code. Cross-reference the ratings, then check the certificate for the code you actually order.
Send the code, get the comparison
Tell us: the Siemens code you are replacing · modular or moulded-case · frame and class · the kA figure at your voltage · trip unit type · poles and mounting · quantity · destination and grid · the certificate your client needs. You get the candidate code, its datasheet page and the certificate that covers it, within 24 hours. Request a quotation.
Related: ABB, Schneider and Siemens cross-reference · MCB and DC breaker catalogue · MCCB and ACB range · Contactors and motor control · Choosing an MCCB · Grid voltage decides the device · Contact
Brand names and model numbers are the property of their respective owners and are referenced for comparison only. CHINT products are independently manufactured and independently certified; they are not authorised, sponsored or officially approved replacements. Cross-reference data is indicative — final selection must be verified against official datasheets by a qualified engineer. HAZAM is an independent trading company; we are not the manufacturer and we are not an appointed distributor. Certificates and ratings always refer to the exact ordering code.