Direct answer
According to the intelligent circuit-breaker table in the product knowledge base, rated current is not an option that can be chosen independently of pole count and voltage; it appears bound to both. The FECB2SP intelligent circuit breaker (standard model, such as FECB2SP-1P) is 16A/32A at AC230V in the 1P and 2P configurations, and 32A/63A at AC400V in the 3P and 4P configurations. In other words, the three tiers 16A, 32A and 63A correspond to different pole-count and voltage combinations. The FECB2SLP intelligent circuit breaker (with residual-current protection, such as FECB2SLP-2P) follows the same current-to-pole correspondence; the difference is the residual-current protection. To choose a rated current, first fix the circuit's pole count and voltage, then take a tier within that group.
The three current tiers are not independent options
Many readers treat 16A, 32A and 63A as one scale that can be slid freely, selecting the current first and fitting the pole count afterwards. The knowledge base does not arrange them that way: it gives rated current in the same row as pole count and rated voltage. The 1P and 2P single-phase circuits fall at AC230V with 16A/32A; the 3P and 4P three-phase circuits fall at AC400V with 32A/63A. The three current tiers are therefore tiers belonging to two separate groups of circuit specification, and a comparison made across the groups does not hold. Reading a tier without its group is what makes the scale appear freely slidable, when the table binds it from the start.
Locate by pole count and voltage first
Read by pole count, the four standard models fall into two groups: 1P (FECB2SP-1P) and 2P (FECB2SP-2P) are rated 16A/32A at AC230V, while 3P (FECB2SP-3P) and 4P (FECB2SP-4P) are rated 32A/63A at AC400V; all four use RS485 communication. This suggests that the first selection question is not "how much current is needed" but "how many poles is the circuit and at what voltage", with the current tier determined inside that group. In this structure the pole count is the indexing key from which current and voltage follow.
Standard model and residual-current model
A note below the table in the knowledge base explains that SLP denotes the residual-current version—leakage monitoring plus residual-current protection—while SP denotes the standard version. The residual-current model FECB2SLP-2P is 2P, 16A/32A at AC230V, and FECB2SLP-4P is 4P, 32A/63A at AC400V, both supporting residual-current protection. Compared with the standard models, the two share an identical current-to-pole-to-voltage correspondence, and differ only in whether residual-current protection is present. "Standard model or residual-current model" and "which current tier" are therefore two different questions: the former decides the functional form, and the latter takes a tier inside a fixed pole group.
Where it lands in a scenario
The knowledge base lists the recommended combination for "distribution automation three-phase governance" as the ESB three-phase imbalance monitor together with the FECB2SLP intelligent circuit breaker. This combination shows that a three-phase governance scenario will use the residual-current version of the intelligent circuit breaker; combined with the correspondence above, the models landing in such a scenario should be the tier at 3P or 4P, AC400V, 32A/63A. The scenario supplies a combination clue; which tier to take specifically still has to be checked back against the circuit's pole count and voltage.
The pole-count range the residual-current version lists
From the model table, the FECB2SLP intelligent circuit breaker with residual-current protection lists only the 2P and 4P pole counts: 2P corresponds to AC230V, 16A/32A, and 4P corresponds to AC400V, 32A/63A. The standard FECB2SP intelligent circuit breaker covers four pole counts, 1P, 2P, 3P and 4P. The two products therefore do not fully overlap in their available pole-count range. At selection, if residual-current protection is definitely required, this range can be compared first; if the circuit is 1P or 3P, the corresponding tier in the standard model should be checked instead. The specific models are limited to what the knowledge-base model table lists.
A reusable checking sequence
The relationships above can be gathered into one checking sequence. First, confirm the circuit's pole count and rated voltage, and decide whether it falls in the AC230V group or the AC400V group. Second, determine the rated current tier inside that group: 16A/32A for the 1P and 2P group, 32A/63A for the 3P and 4P group. Third, decide whether residual-current protection is required, and on that basis choose between the FECB2SP intelligent circuit breaker and the FECB2SLP intelligent circuit breaker. Fourth, check whether the communication method is RS485. Followed in this order, the choice of rated current never departs from pole count and voltage to stand on its own.
What the knowledge base does not give
It should be noted that the knowledge base gives only the correspondence table between rated current, pole count and rated voltage. It does not give a rule for calculating rated current from load power or conductor cross-section, nor does it provide a selection calculation table. This article therefore does not infer conclusions such as "what current should be selected for what load"; it presents the tier correspondence recorded in the knowledge base as it stands. The actual value should be determined together with the engineering design and the applicable standards.
Applicability and limits
First, this article explains only the correspondence in the knowledge base between the intelligent circuit breaker's rated current, pole count and voltage; its factual boundary is limited to the product knowledge base, and it introduces no standard clauses, parameters, certifications or cases the knowledge base does not list.
Second, the correspondences of 16A/32A, 32A/63A, AC230V and AC400V with 1P, 2P, 3P and 4P, and the RS485 communication, are parameters listed in the knowledge base; this article does not extend them to other models.
Third, the explanations SLP = residual-current version and SP = standard version, and the "distribution automation three-phase governance" recommended combination, are existing knowledge-base records; this article does not extend them into unlisted functional or performance conclusions.
Fourth, this article does not provide a calculation method or a recommendation result for selection by load; actual selection should be determined together with the on-site circuit conditions and the engineering design.
