Technical Data
Parameter Specification / Typical Value
Product Series / System CM-MSS Modular Surge Protection System
Device Type Type 2 / Class II Surge Protection Device (SPD)
Application Class Class II (Per IEC 61643-11 / EN 61643-11)
Rated Voltage (Un) 230 V AC (50/60 Hz)
Max. Continuous Operating Voltage (Uc) 275 V AC (This is the maximum RMS voltage it can withstand continuously. Must be verified with the official datasheet).
Voltage Protection Level (Up) Typically ≤ 1.5 kV (at In). This is the residual voltage measured across its terminals during a surge, defining its protective capability. Confirm exact value from datasheet.)
Nominal Discharge Current (In) 20 kA (8/20 µs wave, per pole). The standard test current it can withstand for 15 surges.
Max. Discharge Current (Imax) 40 kA (8/20 µs wave, per pole, single shot). The maximum peak current it can withstand once.
System Compatibility TN-S, TN-C-S, TT
Response Time < 25 ns
Status Indication Visual indicator (e.g., color flag)
Auxiliary Contacts Yes, 1 Changeover (SPDT) remote signaling contact (Standard with "S" variant).
Thermal Protection Integrated thermal disconnector.
Mounting 35 mm symmetrical DIN rail (EN 60715)
Module Width 18 mm (1 module, for 1P+N or 1P version)
Standards Compliance IEC 61643-11, EN 61643-11
Short-Circuit Withstand Follows the declared Icp value when protected by the recommended upstream fuse/gBreaker (e.g., 63A gL/gG or 50A B-curve MCB).
The ABB CM-MSS.21S is a surge protection device (SPD), also known as a Type 2 / Class II surge arrester, from ABB's CM-MSS modular surge protection system. It is a critical component in safeguarding electrical installations and sensitive equipment against damaging transient overvoltages caused by indirect or remote lightning strikes and switching operations within the power network.