This is the part for a sub-feed or final circuit where you need both overcurrent and earth-fault protection in one DIN-rail unit — saves a module slot compared to separate MCB and RCCB. The D curve handles motor inrush and transformer loads without nuisance tripping; the 300 mA Type A residual detects pulsating DC fault currents common on variable-speed drives and electronic loads.
Siemens 5SU1644-8RC63 RCBO 63A 4-pole D curve Type A 300mA
MPN5SU1644-8RC63
Siemens SENTRON 5SU1644-8RC63, RCBO (residual current circuit breaker with overcurrent protection), 63 A, 4-pole, 7 modules, D characteristic, Type A, 300 mA residual current.
Source DocumentedChannel stated on listing & quote
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Worldwide DispatchDHL/FedEx — transit quoted per order
Independent China distributor & sourcing agent· Listing updated Sep 2026
Product details
Frequently asked questions
What does the D characteristic mean on this RCBO?
The D tripping characteristic means the magnetic trip operates at 10 to 20 times the rated current (63 A), so it's sized for loads with high inrush — motors, transformers, welding equipment — without nuisance tripping on startup.
What is the 5SU1644-8RC63 used for?
It's a combined overcurrent and residual-current device (RCBO) for 4-pole circuits up to 63 A, providing D-curve overcurrent protection and Type A 300 mA earth-fault protection in a single 7-module DIN-rail unit.
Where can I buy the 5SU1644-8RC63?
This part is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time.
MPN
5SU1644-8RC63