Selec RSS-TD1A125ZP DC Input AC Output Solid State Relay 25A
Selec RSS-TD1A125ZP Solid State Relay – 25A, 24–330VAC, DC Control, Zero-Cross
25A panel-mount solid-state relay with 24–330VAC load voltage, 4–32VDC control input, zero-cross switching, LED status indication, and IP20 protective housing for reliable heater & industrial load switching.
The Selec RSS-TD1A125ZP is a compact 25A solid-state relay designed to switch AC loads using a 4–32V DC control signal. Featuring zero-cross switching, LED indication, high surge immunity, and IP20 touch-safe housing, it is ideal for heaters, ovens, packaging machinery, and industrial automation panels.
KEY FEATURES
Rated load current: 25A
Load voltage range: 24–330 VAC
Control input: 4–32 VDC
Zero-cross switching (ZP = Zero-cross Resistive type)
High surge withstand capability
LED ON indicator
IP20 protective cover
Fast response time
Reverse voltage protection
TECHNICAL SPECIFICATIONS
Input Specifications
| Parameter | Value |
|---|---|
| Control Voltage | 4–32 VDC |
| Control Current | 4–15 mA |
| Pickup Voltage | 3 VDC |
| Dropout Voltage | 1 VDC |
| Reverse Voltage Protection | Yes (40V max) |
| LED Indicator | Yes (input ON) |
| Input Impedance | 2 kΩ |
| Response Time | ON/OFF: ½ cycle + 1 sec |
Output Specifications – 125ZP
| Parameter | Value |
|---|---|
| Rated Load Current | 25A |
| Load Voltage Range | 24–330 VAC |
| Minimum Load Current | 50 mA |
| Transient Voltage | 800 Vpk |
| Off-State Leakage | 10 mA |
| On-State Voltage Drop | 1.5V |
| dv/dt | 1000 V/µsec |
| 1-second Surge Current | ~150 Apk (series value) |
| 1-cycle Surge Current | ~400 Arms |
Mechanical & Environmental
| Parameter | Value |
|---|---|
| Dimensions | 44.5 × 57.5 × 27.3 mm |
| Weight | ~87 g |
| Mounting | Panel mount |
| Housing | Glass-filled polyester |
| Baseplate | Aluminium |
| Operating Temp | −30°C to +80°C |
| Storage Temp | −30°C to +100°C |
| Humidity | 93% RH non-condensing |
| Dielectric Strength | 4000 Vrms (Input–Output–Ground) |
Terminal Wiring & Torque
| Terminal | Wire Size | Torque |
|---|---|---|
| Input M4 | 0.75–2.5 mm² | 1.2 N·m |
| Output M5 | 1.5–10 mm² | 2.0 N·m |
The wiring diagram shows:
DC control on ± terminals
AC load connected in series with AC supply
APPLICATIONS
Industrial heater switching
Temperature controllers with SSR output
Plastic moulding & extrusion heaters
Packaging machinery
HVAC heating loads
Solenoid, valve & resistive loads
Small motors (soft-switching)
WHAT’S IN THE BOX
RSS-TD1A125ZP SSR
IP20 protective cover
Mounting screws
User leaflet
FAQS
Q1. What is the load current of RSS-TD1A125ZP?
Rated 25A.
Q2. What control voltage does it need?
4–32V DC.
Q3. Is it a zero-cross SSR?
Yes, the “ZP” suffix = the zero-cross resistive version.
Q4. What load voltage range is supported?
24–330 VAC.
Q5. Is a heat sink required?
Recommended for sustained currents >15A.
Q6. Can it be used for inductive loads?
The ZP version is for resistive loads; inductive loads require the L suffix model.