This 20A 3P+N circuit breaker (MCB) protects the three phases of a circuit and switches the neutral with them. This makes it suitable for three-phase appliances that also use a neutral conductor, such as many sauna heaters and hobs. The C characteristic takes the starting current of motors and compressors into account.
Where do you use 20 A per phase?
- a three-phase sauna or heating system, if the manufacturer specifies 20 A per phase
- a hob connected to three phases plus neutral
- the supply to a small three-phase sub-board
On 2.5 mm², 20 A is the maximum permitted in homes under AREI (the Belgian electrical installation regulations). Please note: the fourth pole assumes a neutral conductor; in a three-phase network without neutral (3×230 V), this version serves no purpose.
Benefits
- supply can be connected at the top or the bottom
- IP20, IP40 with cover
- can be mounted in any position in the consumer unit
- all poles linked: a single action switches the entire circuit
Connection
The terminals are clearly numbered, with the neutral marked separately (N). This way, you cannot mix up the phases and the neutral. On both sides, each terminal combines a lift terminal and a cage terminal, for cable or busbar.
Good to know
A sauna, hob or heat pump is connected according to the wiring diagram and cable cross-section given in the manual. Leave this work to a qualified electrician and then schedule the mandatory inspection by an approved inspection body.
| Product code | BM417820 (Schrack BMS4 C 20/3N) |
|---|---|
| EAN | 9004840390872 |
| Rated current | 20 A |
| Tripping curve | C |
| Poles | 3P+N: 3 protected poles, switched neutral (not protected) |
| Breaking capacity | 4.5 kA (EN 60898-1), 6 kA (EN 60947-2) |
| Rated voltage | 230/400 V AC, 50/60 Hz |
| Width | 4 modules (approx. 70 mm) |
| Terminal capacity | 1 to 25 mm² |
| Power loss | 10.1 W |
| Max. back-up fuse | 80 A gG |
| Degree of protection | IP20, IP40 with cover |
| Ambient temperature | -5 °C to +40 °C (calibrated at 30 °C) |
| Standards | EN 60898-1, EN 60947-2 |
| Reference | 9004840390872 |
| Category | Circuit breakers and RCDs |
| Merk | Schrack |
| Weight | 0.46 kg |
Shipping with GLS
- We ship with GLS to your address in Belgium for €7.95; shipping is free when you spend €65 or more on standard items. To the Netherlands: €11.95, free from €75.
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