JH1600: Single Trip Alarm
JH1600R: Single Trip Alarm with True RMS Response
JH1620: Dual Trip Alarm
JH1620R: Dual Trip Alarm with True RMS Response

  • Input Ranges from 50mV to 250Vrms, 1mA to 5A
  • Inputs to 600Vrms available on Special Order
  • True-RMS Option Available
  • Red/Green Alarm Status LEDs
  • Industry-Standard Pinouts (11-Pin Socket)
  • AC or DC Power Options

JH1600/JH1620/ JH1600R/JH1620R



The JH1600/1620 Series alarms monitor an AC voltage or current and provide relay contact HI/LO trip outputs. Fixed-range devices, their input ranges are preset per your order. True-RMS models accurately maintain their setpoints even with varying nonsinusoidal waveforms. Standard models are average-responding, calibrated for accurate RMS sine wave response.

The alarm trip points are adjustable anywhere within the input range. Deadbands also are fully adjustable, from 0.25% to 100% of span. A slide switch, accessible through the top of the enclosure, selects HI or LO trip operation (on dual alarms, HI/HI, HI/LO or LO/LO). Red/green LEDs indicate alarm status.

Alarm contacts are rated at 5 amps, 230Vac or 30Vdc. Model JH1600 provides a DPDT relay; Model JH1620, two SPDT relays. AC and DC power options are available.


Model Number:  Select from the list above. Add suffix –AC for AC power or –DC for DC power.
Input Range:  Specify any AC voltage or current range allowed by the "Input Capabilities" spec, below.
Trip Point:  If you would like the trip points to be factory set, please specify the following for each trip point. Specify HI or LO trip, specify the setpoint and specify the amount of deadband required (or specify "minimum deadband").
Relay Action:  Standard is Failsafe - the relay is energized under normal conditions and deenergizes upon alarm or upon loss of power. Thus, loss of power is seen as an alarm condition. Or specify Option R (Reverse Acting) – relay is normally not energized and energizes (pulls in) upon alarm trip. Failsafe is provided if not specified.
Power:  Specify 115Vac, 230Vac, 12Vdc or 24Vdc.
Urethane Coating:  

Specify Option "U"


These alarms plug into any standard 11-pin circular ("octal") relay socket. JH Technology offers a socket suitable for DIN-rail or surface mounting (see the Accessories page). Pin connections are:

Pin 1: Power (AC or, if DC power option, DC plus). 
Pin 2:
No connection. 
Pin 3:
Power (AC or, if DC power option, DC minus). 
Pin 4:
AC signal input. 
Pin 5:
AC signal input. 
Pin 6:
Setpoint 1 relay NO contact.* 
Pin 7:
Setpoint 1 relay moving contact.* 
Pin 8:
Setpoint 1 relay NC contact.* 
Pin 9:
Setpoint 2 relay NO contact.* 
Pin 10:
Setpoint 2 relay moving contact.* 
Pin 11:
Setpoint 2 relay NC contact.*

  • Notes: NO (normally open) and NC (normally closed) refer to the relay state when no power is applied. For Failsafe operation the NO contacts are closed under nonalarm conditions. The NC contacts close upon alarm and upon loss of power. The terms Setpoint 1 and Setpoint 2 refer to dual-trip alarms. For single-trip alarms, both sets of contacts respond to the one trip point.


When monitoring the output of a current transformer never use a current-input module. Unplugging the alarm will remove the transformer’s secondary load, resulting in potentially damaging or dangerous voltage spikes (up to several hundred volts).

Instead, use a voltage-input alarm with an appropriate precision external shunt resistor. For 0/5 amps we recommend specifying a 0/250mVac input range with a 0.05 ohm, 0.1% 3 watt external shunt. We offer Part No. R0.05/DS011, a precision shunt resistor assembly preassembled to socket DS011. The socket snaps onto DIN rail or may be surface mounted using screws.


Voltage Input Capabilities:  50mVac minimum span, +/-250Vac maximum input. Offset ranges are allowed. (Input Impedance: 200Kohms or greater.)
Current Input Capabilities:  1mAac minimum span, +/-5 Amps ac maximum input. (Warning – see application note above regarding current transformer inputs.) Offset ranges are allowed. (Input Resistance: Varies with input range. Contact factory for details.)
Input Frequency:  40 to 1,000 Hz for specified accuracy.
Relay Contacts:  Single Alarm, one DPDT relay. Dual Alarm, two SPDT relays. Contacts rated 5 Amps resistive, 115/230Vac or 30Vdc. 1/8 HP max inductive load at 115/230Vac. Refer to instructions for contact protection when switching inductive loads.
Setpoint Adjustment:  0% to 100% of range.
Deadband Adjustment:  0.25% to 100% of range.
Response Time:  under 200 milliseconds.
Isolation:  Input is isolated from power and from relay contacts. 1,500Vac rms (2,100V peak) breakdown.
Guaranteed Operating Temperature:  -10 to +60 deg. C (14 to 140 deg. F).
Temperature Stability:  +/-0.02% of span per deg. C, or better.
Power Requirements:  AC, 115 or 230Vrms, 50/60 Hz., 2.5V-A. DC, 12 or 24Vdc, 2.5W.