Model SI-50 and SI-100 Smart Interrupter by Radiodetection

50 and 100 Amp Models. Solid State with GPS, High Current Switching capability, Compact Size.


  • 50A and 100A versions.
  • Easy to use.
  • Extremely compact and lightweight, fits in tight areas, no orientation requirements.
  • On/Off ranges between 0 to 100 seconds.
  • Reverse Polarity Protection.
  • 300-hour battery life from two D cell batteries, or can run continuously from CP supply.
  • Fully microprocessor controlled, automatically stores the last ten used setups and stores up to 10 Waveforms.
  • Master/Slave synchronization as standard.
  • Radiodetection patented GPS synchronization is standard. Permits synchronization of any number of interrupters remote from each other. Permits 24-hour timer operation.
  • Advanced power electronics mean cool running even at high ambient temperatures.
  • Can generate 4 Hz & 8 Hz for compatibility with Radiodetection's Precision Pipe Locator.
  • Software upgrades via RS-232 socket.
  • Over voltage, current and heat protection.
  • User replaceable leads.
  • Can be used as a conventional 50A or 100A interrupter as well a generating unique signatures for the Radiodetection Stray Current Mapper (SCM) System. 

Ordering Information

Smart Interrupter - 50 amp (GPS) - Includes Bag: Part No: 10/SN2181-50-G-GB
Smart Interrupter - 100amp (GPS) - Includes Bag. : Part No: 10/SN2181-100-G-GB

Technical Specifications

Current Output

50A / 100V peak continuous or 100A / 100V peak continuous High Current Option.

Connection Outputs

2 cables (CP supply, CP switched, (with auxiliary Ground Terminal).

Switching Patterns

On/Off Time 0-100 s (0.1 sec increments up to 10 secs). Unit saves history of last ten patterns. Last pattern used selected at power on. SCM and Precision Pipe Locator signals.


Method 1: Master/Slave (unit to unit via initial hardwired connection): 100 ms in 12-hour period.
Method 2: GPS synchronization (requires GPS option) ± 4ms

24-Hour Timer

Programmable On/Off timer repeats every 24 hours (requires GPS option).


Controls keyboard inputs, LCD functions, non-volatile storage, RS232 communications and FET switching.

User Interface

2-line by 16-character LCD with alphanumeric and special character display. Automatic backlight.


User input via 9-key membrane keypad.

Software Upgrades

Via RS-232 interface.


2 x 1.5V D cells for 300 hours of operation at 20°C.

CP Power

Will run continuously from CP supply if above 5V.

Environmental Protection

IP65 rain and dust resistant.

Operating Temperature

13.8°F (-20°C) to 140°F (60°C)

Reverse Polarity

Protection for 10 minutes with audible warning.


Housing high impact structural foam plastic.


Size 12" x 6" x 3" (80 mm) (300 x 150 x 80 mm)


2.5kg (5.5 lbs)

EMC Compliance

Meets EC Directive 89/336/EEC and FCC Part CFR Part 15.

Radiodetection products are under continuous development and are subject to change without notice.