Eaton MTL TP48-N-NDI Surge Protector SPD 20kA 35V for 2/3/4-Wire Transmitters with 316 Stainless Steel Housing
The MTL TP48-N-NDI is a field-mounted surge protection device (SPD) from Eaton's Crouse-Hinds MTL Series, designed specifically to protect 2, 3, and 4-wire process transmitters from damaging transient overvoltages and lightning-induced surges. This rugged, pipe-style surge protector screws directly into the spare conduit entry of field instruments, providing high-level protection without any additional wiring or enclosure modifications.
The TP48-N-NDI features hybrid surge protection circuitry combining high-energy solid-state components with a gas discharge tube, capable of safely diverting up to 20kA of surge current away from sensitive instrumentation. The device resets automatically after each surge event, ensuring continuous protection without manual intervention.
- Universal Transmitter Protection - Protects 2, 3, and 4-wire transmitters in a single device
- Easy Direct Mounting - Screws directly into spare conduit entry; no additional wiring or modifications required
- Hazardous Area Certified - ATEX, FM, and IECEx certified for Intrinsically Safe (IS) and Explosion-proof (Ex d) applications
- Zero Loop Resistance - Parallel connection design introduces no resistance into the measurement loop
- High Surge Rating - 20kA maximum surge current (8/20µs waveform)
- Rugged Construction - 316 stainless steel housing rated IP66 for harsh environments
- Auto-Resetting - Self-resets after each surge event; no maintenance required
- 10-Year Product Warranty - Backed by Eaton MTL's industry-leading warranty
| Parameter | Value |
|---|---|
| Model | TP48-N-NDI |
| Nominal Voltage (Un) | 35V DC |
| Max Continuous Operating Voltage (Uc) | 58V |
| Max Surge Current (Imax) | 20kA (8/20µs) |
| Nominal Discharge Current (Isn) | 3kA (8/20µs) |
| Impulse Current (Iimp) | 2.5kA (10/350µs) |
| Voltage Protection Level (Up) | <76V @ 1kV/µs |
| Residual Voltage @ Isn | 95V (L-G 500V) |
| Bandwidth (fG) | 1MHz |
| Capacitance (C) | 100pF |
| Leakage Current | <10µA @ max working voltage |
| Housing Material | 316 Stainless Steel |
| Thread Type | 1/2″ NPT |
| Ingress Protection | IP66 |
| Operating Temperature | -40°C to +60°C (working) / -40°C to +85°C (storage) |
| Weight | 175g (6.2oz.) |
| Certifications | ATEX, FM, IECEx, CENELEC |
| Warranty | 10 years |
The MTL TP48-N-NDI is ideal for protecting field-mounted process transmitters in:
- Oil & Gas Facilities - Offshore platforms, refineries, pipelines
- Chemical Processing Plants - Hazardous area instrumentation
- Power Generation - Power plants, substations
- Pharmaceutical Manufacturing - Critical process control
- Water/Wastewater Treatment - Remote field instruments
- Petrochemical Installations - Zone 1 and Zone 2 hazardous areas
| Wire Configuration | Protection Provided |
|---|---|
| 2-Wire (Loop-powered) | +ve, -ve |
| 3-Wire | +ve, -ve, signal |
| 4-Wire | +ve, -ve, signal +ve, signal -ve |
- Screw the TP48-N-NDI into the spare conduit entry of the field transmitter (1/2″ NPT thread)
- Connect the flying leads to the transmitter's terminal block (+ve, -ve, and signal as required)
- Connect the earth lead to the internal grounding stud
- Operation - The parallel connection introduces zero resistance into the loop while safely diverting surge currents to ground
The Crouse-Hinds series MTL TP48 surge protection device safeguards field-mounted process transmitters where it matters, right at the unit. After a simple installation (the TP48 screws into an unused conduit entry, with no additional modification), it provides high-level protection against surges and transients while normal operation remains unaffected.
The TP48 resets itself automatically after each operation. The device is available with screw threads to suit different transmitters, with explosion-proof and intrinsically safe options for hazardous areas.
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