Step and Touch Instrument
Video Overview
SNT Kit
The SNT Kit contains everything you need to monitor step and touch potential, including:
- SNT instrument
- user guide
- carrying case
- battery charging adapters
- ground rod
- magnetic and clamp probe end
User Guide
The Step and Touch (SNT) instrument monitors and alarms "Step and Touch" potential caused by ground potential rise. When used properly, the SNT can enhance the safety of transmission line crews.
Alarm Ranges
The SNT provides audible and visual alarm warnings if the probe voltage is in a dangerous range. Each voltage range has a distinct pattern of bright flashing LEDs and audible 80 dB(A) alert. (The SNT also detects and warns of Lost Probe Connection and Low Battery).
| Range | Instrument Actions |
|---|---|
| 0 - 100V |  |
| 101 - 499V |   |
| 500V+ |   |
Utility Tested & Field Proven
An innovation by Bonneville Power Administration engineers, the SNT Instrument has been helping ensure the safety of BPA line crews since 2003.
Starting in 2011, the SNT is available to other customers from the long-time manufacturer of the SNT instrument, Delta Computer Systems, Inc.
Specifications
| Full Scale Voltage 50 Hz to 60 Hz | 999 Vrms sine wave with < 5% Total Harmonic Distortion |
| Absolute Max Probe Voltage | 5000 Vrms |
| Step Voltage Response | 95% rise time < 1 second. During probe check, step response may be up to 4.5 seconds. |
| Accuracy | 1% typical for 500 V (3.5% from -30°C to +50°C) |
| Probe Impedance | 20 MΩ |
| Voltages Displayed | 10 to 999 Vrms |
| Standard Alarm Voltage Ranges (others can be programmed by the factory as an option) | 0 to 100 — Green LEDs slow flash 101 to 499 — Yellow LEDs flash, beeps every second 500 plus — Red LEDs flash rapidly, beeps rapidly |
| Audio Alert | 90 dB at 2 feet |
| Displays | Voltage Display 3 digit voltage using bright seven segment displays Threshold Warning Three high intensity Green LEDs Five high intensity Yellow LEDs Eight high intensity Red LEDs Check Probe & Battery Low Blue LEDs |
| Probe Connection Check | Performed every 60 seconds. Duration is 3.5 seconds, during which time the probe voltage is not sampled. |
| Battery Life | 60 hours typical. Low battery is indicated by LED, very low battery activates fault mode (flashing LEDs and audible alert). |
| Battery Type | Ni-MH, 500 charge cycles typical |
| Ingress Protection | Designed for IP64 |
| Instrument Weight | 907 grams (2 pounds) |
| Kit Weight | 10K grams (22 pounds) includes instrument and case |
| Case Size (H × W × L) | 19.1 cm × 39.6 cm × 50.2 cm (7.5 in × 15.6 in × 19.75 in) |