ProTec T2 DCB & DCU Series
The Raycap ProTec T2 DCB and DCU series are DIN rail-mounted pluggable Class II surge protective devices (SPDs) developed for industrial DC systems. DCB is for bipolar, DCU for unipolar DC networks. They offer up to 40 kA discharge capacity, 30 kA short-circuit withstand capability, and a < 25 ns response time; compliant with IEC 61643-41 and UL 1449 5th Edition.
DC power distribution is becoming increasingly common in industrial facilities. When equipment such as robot arms, motor drives, and controllers are directly supplied via a DC busbar, the AC/DC conversion stage is eliminated, and efficiency increases. The ProTec T2 DCB and DCU series are specifically developed for the protection of these DC busbar architectures and other DC applications.
The series consists of two branches:
- ProTec T2 DCB 3Y — for Bipolar DC systems. Used in bipolar earthed networks and TN-C, TN-C-S, and TN-S systems. Protection mode: (+)-PE/M/G, (-)-PE/M/G, (+)-(-). 250 V, 500 V, and 750 V versions are available.
- ProTec T2 DCU 3Y — for Unipolar DC systems. Used in unipolar earthed/unearthed networks and TN, TT, and IT systems. Protection mode: (+)-PE/G, (-)-PE/G, (+)-(-). 500 V, 1000 V, and 1500 V versions are available.
Both series are classified as Class II / DC SPD Type 1. Discharge capacity is In 20 kA, Imax 40 kA (8/20 µs); total discharge current is 55–70 kA depending on the model. Response time is < 25 ns — a critical value against fast-rising DC pulses.
The most critical safety element in DC circuits is short-circuit withstand capability; in DC, arcs do not self-extinguish. The series offers 30 kA (L/R < 3 ms) DC short-circuit withstand capability (SCCR 100 kA according to UL) and features a thermal disconnector (TD) in each pole. The end-of-life varistor is safely disconnected from the circuit, eliminating fire risk.
The pluggable module design simplifies maintenance: the protection module is replaced without removing the base unit and wiring — reducing plant downtime. The green flag / not green indicator on the front panel facilitates status checks; fault information can be transmitted to PLC/SCADA via the optional remote signaling contact (-R).
The products comply with IEC 61643-41:2025 and UL 1449 5th Edition, Annex SB standards. They are suitable for harsh industrial environments with a wide operating temperature range of -40 °C … +85 °C. The DCB series also has defined temporary overvoltage (TOV) withstand values for TN and TT systems.
- Designed for industrial DC busbar and DC power systems
- Class II — DC SPD Type 1
- DCB: bipolar systems | DCU: unipolar systems
- Maximum discharge current (Imax) up to 40 kA
- Total discharge current (ITotal) up to 70 kA
- 30 kA (L/R < 3 ms) DC short-circuit withstand capability — SCCR 100 kA according to UL
- Fast response time: < 25 ns
- Pluggable module — easy maintenance, short downtime
- Thermal disconnector (TD) protection in each pole
- Fault indicator: green flag / not green
- Optional remote signaling contacts (-R version)
- IEC 61643-41:2025 and UL 1449 5th Edition Annex SB compliance
- Defined TOV (temporary overvoltage) withstand values for DCB
- Wide operating temperature: -40 °C … +85 °C
- 35 mm DIN rail mounting (EN 60715)
- Housing: UL 94 V-0 flame retardant thermoplastic
- Protection class: IP 20 (embedded)
- Overvoltage category: III
ProTec T2 DCB 3Y — Bipolar (IEC values)
| 250 | 500 | 750 | |
|---|---|---|---|
| Rated DC system voltage (+)/(-)-PE/M Un | 250 V | 500 V | 750 V |
| Uc (+)-(-) | 500 V | 1000 V | 1500 V |
| Uc (+)/(-)-PE/M | 250 V | 500 V | 750 V |
| In (8/20 µs) | 20 kA | 20 kA | 20 kA |
| Imax | 40 kA | 40 kA | 40 kA |
| ITotal (8/20 µs) | 70 kA | 70 kA | 55 kA |
| Protection level Up | 2400 V | 3150 V | 3700 V |
| Response time tA | < 25 ns | < 25 ns | < 25 ns |
| ISCCR (DC) | 30 kA | 30 kA | 30 kA |
| Iimp (10/350 µs) | 5 kA | 5 kA | 2.8 kA |
| ITotal (10/350 µs) | 10 kA | 10 kA | 3 kA |
| UL: Vdcmcov | 500 V | 1000 V | 1500 V |
| UL: VPR | 1800 V | 2500 V | 3000 V |
| UL: SCCR | 100 kA | 100 kA | 100 kA |
ProTec T2 DCU 3Y — Unipolar (IEC values)
| 500 | 1000 | 1500 | |
|---|---|---|---|
| Rated DC system voltage (+)-(-) Un | 500 V | 1000 V | 1500 V |
| Uc | 500 V | 1000 V | 1500 V |
| In (8/20 µs) | 20 kA | 20 kA | 20 kA |
| Imax | 40 kA | 40 kA | 40 kA |
| ITotal (8/20 µs) | 70 kA | 70 kA | 55 kA |
| Protection level Up | 2400 V | 3150 V | 3700 V |
| Response time tA | < 25 ns | < 25 ns | < 25 ns |
| ISCCR (DC) | 30 kA | 30 kA | 30 kA |
| Iimp (10/350 µs) | 5 kA | 5 kA | 2.8 kA |
| ITotal (10/350 µs) | 10 kA | 10 kA | 3 kA |
| UL: Vdcmcov | 500 V | 1000 V | 1500 V |
| UL: VPR | 1800 V | 2500 V | 3000 V |
| UL: SCCR | 100 kA | 100 kA | 100 kA |
Mechanical & Environmental (both series)
- Operating temperature: -40 °C … +85 °C | Humidity: 5–95% | Pollution degree: 2
- Altitude: up to 2000 m
- Terminal tightening torque: 4.5 Nm
- Conductor cross-section (max.): 35 mm² (solid/stranded) / 25 mm² (flexible), Cu only
- Overcurrent protection (max.): 200 A gBat
- DIN 43880 size: 3 TE / 54 mm — Weight: 350–385 g
- Remote contact capacity: AC 125 V/1 A; DC 48 V/0.5 A, 24 V/0.5 A, 12 V/0.5 A
- Spare module (spare plug): 1 TE / 18 mm, 61–73 g
Ordering codes — DCB (Bipolar)
| Product | 250 | 500 | 750 |
|---|---|---|---|
| ProTec T2-xxxDCB-3Y | 59.A955 | 59.A957 | 59.A959 |
| ProTec T2-xxxDCB-3Y-R (with remote contact) | 59.A956 | 59.A958 | 59.A960 |
The ProTec T2 DCB and DCU series are used in industrial and infrastructure applications where DC power is utilized:
- Industrial DC busbar systems — efficient architectures eliminating AC/DC conversion
- Robot arms and automation equipment — production lines powered by DC busbars
- Motor drives — DC link and drive supply lines
- Controllers and control panels — control panel supply lines
- Electric vehicle (EV) fast charging stations — DC charging infrastructure
- Battery energy storage systems (BESS) — DC side protection
- Safety lighting systems — DC supply lines
- Bipolar earthed DC networks — DCB series (TN-C, TN-C-S, TN-S)
- Unipolar earthed/unearthed DC networks — DCU series (TN, TT, IT)
- Data centers and DC distribution infrastructures — DC power backbones
- Harsh industrial environments — -40 °C … +85 °C operating range
- Continuous production facilities — short downtime maintenance with pluggable module
