EWS Installation Instructions:

The Cascade EWS is a multi-function electrical power monitoring system including:
a Monitor Panel with indicators,
three types of sensor inputs, and
a local alarm and four remote alarm outputs.

Click below for shortcuts to these sections:
Installing the EWS-MP Monitor Panel
Installing the EWS-PS Power Supply
Installing an EWS-CT Current Transformer
Installing an EWS-TS Temperature Sensor
Installing an EWS-SW Switch Sensor
Installing an EWS-RA Remote Alarm
Connection to Building / Plant Monitoring System
Installing an EWS-DL Data Logger
Configuration Options for Installers

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Installing the EWS-MP Monitor Panel:

The monitor panel is enclosed in a 5" x 10" x 1" aluminum case which needs to be attached to the wall. The monitor should be in a visible location that is accessible by staff on site so they can easily acknowledge an alarm.

If the alarm outputs are to be connected to an existing security alarm system, then choose a location near the security system alarm panel.

If the alarm outputs are to be connected to a telephone dialer for calling out alarms if the facility is not staffed, then choose a location near the telephone patch panel.

If the EWS system is for local alarms only, then the MP should be in easy view and access by staff. Near the electrical breaker panel is often a convenient place.

The EWS needs a source of 12 Volts direct current that can be derived from the Class 2 power supply of an existing security alarm system or from an optional Class 2 power adaptor from a normal wall receptacle. It would be best to have a 120V power outlet close to the monitor panel.

The MP should not be mounted in an area that is subject to large temperature swings during the day or even seasonally. It helps to reduce temperature variations if a plywood backing panel is attached to the wall for mounting the MP. (The analog current signal compression circuitry is temperature compensated for about +- 10C from the temperature at the time of calibration but it is always best to minimize the temperature variation.)

The MP should be kept away from cool areas that could cause condensation on the circuitry. Even though the circuit board is coated to minimize the possibility of corrosion, leakage currents on the circuit board surface could cause the signals to drift and cause false alarms.

There is a key-hole in the back of the MP that can go over the head of a screw in the mounting backing panel and two screw holes in the wire-way next to the terminal strips. (The terminal access cover is removed by loosening the two cover screws. The inside of the access cover has detailed connection labeling. The access cover is designed to slip back onto the cover screws to assist with connection of the sensor and alarm wires.

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Supply Power to the Monitor

The monitor system is CSA / NRTL approved as a Class 2 device when it is:

  1. powered from a Class 2 power supply, and
  2. is only connected to specified Class 2 sensors, and
  3. is only connected to Class 2 alarm output devices.

The monitor can be powered by an (optional) EWS-PS Power supply which is a Class 2 power adaptor with rated output at 12Vdc and 500ma. The polarity of the power input to the EWS-MP does not matter, in fact it can operate from an AC (50hz or 60hz) source as well. The range of input voltage is from 10Vdc to 24Vdc or 9Vac to 18Vac.

If the EWS is to be powered from a security system monitor panel then connect the battery backed (sensor power) to the appropriate inputs on the EWS-MP. For your information, the table below shows the supply current required for an EWS with a full complement of sensors and accessories at various supply voltages:


(Volts dc)















When power is applied to the EWS-MP, verify that the power indicator comes ON. You can leave the power connected during installation to make verification of the wiring to the sensors easier. Damage to the monitor system is not likely through any combination of incorrect wiring the sensor inputs. However, damage may occur if an external source of power is accidentally applied to the inputs. The input connections are protected against accidental Electro-Static Discharge (ESD) from an installer. However, it is always a good plan to connect the aluminum chassis of the Monitor Panel to Earth Ground and have the installer touch the chassis with a finger before trying to make connection to the terminals.

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Installing an EWS-CT three phase Current Transformer:

The EWS-CT is CSA / NRTL approved as an interface device between Class 1 and Class 2 circuits when the primary supply voltage is not more than 600 Vac. When the EWS-CT is installed through a knock-out hole in an electrical enclosure, the Class 2 circuitry is completely outside of the enclosure. Except when mechanical or environmental protection is required, the Class 2 wiring can be exposed.

The EWS-CT is a Current Transformer that provides one milliamp of output current for every amp of load current. A current transformer expects to have a low resistance load (burden) connected across the output leads. If you were to measure the output voltage between wires on the sensor with an AC voltmeter, the readings would be relatively meaningless. If the current was measured with an AC milliamp meter, then the load current would be approximately 1000 times what the meter says.

The EWS-CT is to be installed in the electrical enclosure at the source of power for the electrical load to be monitored. If there is a disconnect or circuit breaker supplying power to the load, then make sure that the EWS-CT is on the load side just ahead of the load. If more than one electrical load is run from the main circuit, it is best to monitor each load separately. For example, if there is a compressor and a condenser fan, then each load should be monitored separately.

The EWS-CT can measure all 3 circuits of a 3-phase load or three independent single phase loads. (You will have to set a configuration switch on the EWS-MP for that channel to tell the monitor if it is a single or 3 phase load input.)

Secure the current transformer into a knock-out in the wall of the electrical enclosure with the transformer on the inside and the Class 2 wiring outside. Orient the transformer so that the load wires will fit through easily without stress. The sensor hole diameter is adequate for the wiring to most loads up to about 60 amps.

Disconnect the power wires going to the load and re-route each load wire through one of the holes in the current transformer module. The order of the primary load wires through the EWS-CT sensing holes is not important for the correct functioning of the monitor. In some cases, it is useful to record which phase wire is on which channel so they are labeled on the CT for your convenience.

Route the sensor wires to the EWS-MP, splice on extra 4 conductor telephone wire if required. The output signals from the EWS-CT is a current source but the resistance in the wires between the sensor and the panel should be not more than 10 ohms. For most installations, four conductor telephone wire is adequate. 

The table below shows the maximum length of extension wire for various wire gauges.  

Meters Feet Wire Gauge
100 300 22
150 500 20
225 750 18 *
375 1250 16 *
600 2000 14 *

*  Note that the terminal strip connectors on the Monitor Panel are designed for 20 Awg maximum.  If you try to insert larger wires, you risk damaging the connector. If you use extension wires larger than 20 Awg, you will need to splice back to 22 Awg near the monitor panel.

Note: If the wiring is in a high electrical noise environment, then shielded wire may be required to prevent electrical noise from causing false alarms.

When the wire is connected to the EWS-MP, strip about 1/4 inch (3mm) and insert the wire into the appropriate terminal by depressing the lever to open the contact clamp. The maximum wire size rating of the connector terminals on the EWS-MP is 20 Awg.  If you have used heavier wire extensions because of long distances from the sensor to the monitor panel, then it is best to splice back to a smaller wire gauge before making connection to the monitor panel.

The polarity of the wiring connections is important. The wire labeled COMMON on the EWS-CT must go to the COM terminal of the connector. If this is not done, then the currents from the three loads will be combined and a circuit breaker trip or abnormal operating currents may not be detectible.

If the EWS-CT is used to monitor a 3 phase load, then make sure that the DIP Switch 3 is OFF. If it is monitoring one or more single phase loads, then set the DIP switch 3 to ON.

When the DIP Switch 3 is OFF, any current measured on any of the 3 circuits will be used to determine if the circuit breaker is OK. All three currents must be less than the threshold to indicate a breaker trip.

When the DIP Switch 3 in ON, each channel must have a minimum current or a breaker trip will be reported. Any one of the channels will generate a breaker trip alarm, you will not know which phase input caused the alarm so you will have to check all three circuits.

Note: It is not normal to have multiple branch circuits operating from different circuit breakers in one electrical enclosure. If you are monitoring 3 single phase loads supplied by the same circuit breaker, you can treat the load as a 3 phase load.

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Installing an EWS-TS Temperature Sensor

The EWS-TS is an integrated circuit type temperature sensor that provides an output voltage that is 10 millivolts per degree K when provided with a suitable bias current. The polarity of the sensor connection is important. If the sensor is connected backwards (or if the wires to the sensor are shorted together) then the EWS-MP will register a fault during calibration. If no temperature sensor is connected then during calibration the EWS-MP will ignore that sensor input thereafter.

The table below summarizes the voltage on the sensor at various temperatures when measured across the sensor connection terminals at the terminal strip of the EWS-MP. This information might be helpful for an installation and service technician.

Deg C

Deg F

Sensor Voltage





































The analog input range of a temperature input on the EWS-MP is 2.50V +/- 0.8V. If there is no sensor connected the input voltage is 5 Volts. If the sensor voltage is above 3.3V during calibration, then the EWS-MP will think that there is no sensor connected and that channel will be ignored. If the temperature during calibration is within the range from -50C to +55C then the system will alarm if the sensor input voltage goes outside of the valid range. This provides a failsafe alarm in case of sensor wiring shorts or open circuits.

If the sensor is connected backward, the voltage across the sensor will be about 1 volt and the EWS-MP will register a wiring or sensor fault.

Locate the EWS-TS sensor in the area to be monitored for temperature. (It is not important for the temperature sensor to actually be measuring a temperature related to the load current on that channel.) Try to attach the sensor to an object that has a lot of thermal mass so that air currents will not significantly affect the sensor temperature. Keep the sensor out of an area that may be heated by lights or sunlight. Keep the sensor out of the draft of circulation fans if the fans cycle ON and OFF. If the sensor is in a freezer with a defrost cycle, the sensor must not be affected by the defrost cycle temperature changes or a temperature alarm could be generated every defrost cycle.

The sensor is encapsulated to protect against moisture and condensation but it is not intended for emersion.

Route the wiring to the EWS-MP. The sensor and wiring is Class 2 so the wiring can be exposed unless it needs mechanical or environmental protection. If wiring extension is required, then a single pair (or one pair of a 4 conductor) telephone wire is usually suitable. The current to the EWS-TS is about 1 milliamp at 25 C and 10 ohms of round-trip resistance in the wires will make a 2 degree error in temperature. Since the absolute calibration of the temperature sensor is not critical to the operation of the EWS-MP, a series resistance of 20 ohms can easily be tolerated. Use the wire table given for the EWS-CT as a guide for making extensions to temperature sensors.

The temperature signal can be subject to extreme Radio Frequency and electrical noise so it may be required to use shielded extension cable in noisy electrical environments to avoid false temperature alarms.

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Install an EWS-SW Switch Sensor:

The Switch sensor input on the EWS-MP provides an alarm if the sensor circuit is open continuously for more than 5 minutes. A series connection of many Normally Closed switch contacts can be connected to this input. If any one of the series connected switches opens, then the 5 minute timer will start counting down.

The EWS-SW is a magnetically operated switch contact that is closed when the magnet is in proximity to the sensor. When the magnet moves away from the sensor, the internal contact opens.

The polarity of connection of switch contacts to this monitoring circuit is not important. There is a current supplied from the EWS-MP to operate this switch sensor circuit. When the circuit is closed, there is about 5 milliamps of current flowing. When the circuit is open, a voltage of +5Vdc can be measured across the terminals on the EWS-MP.

A break in the wiring loop will appear to the EWS-MP to be the same as an open switch contact.

There is a wide variety of switch type sensors used in the security monitoring industry as well as pressure limit switches, temperature limit switches, float switches and flow switches that could be used as input devices on this monitoring circuit. You could use a single independently powered electronic switch (if it is a Class 2 device) with an open collector NPN switch to common as an input device. Using multiple transistor output sensors is not likely to work properly.

The loop resistance must be less than 100 ohms when all of the switch sensors are closed. The total length of wire in the loop for various wire gauges shown for the EWS-CT can be 10 times as long for each gauge when used on this switch input.  In extremely noisy electrical environments, it may be necessary to use shielded wire to minimize false alarming.

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Install an EWS-RA Remote Alarm:

If the EWS-MP is mounted in a remote location that is not easily accessible by staff, or if it is in an acoustically noisy area, then an EWS-RA Remote Alarm may be useful. The EWS-RA operates on 10 - 24 Volt dc power supplied from the EWS-MP.

This remote alarm is connected to the designated terminals on the EWS-MP. Polarity of connection to the alarm is important, follow the polarity markings on the label and the alarm.

If it is desired to use a different remote alarm with its own power source, then a pilot relay must be used. The coil voltage for an auxiliary relay (not supplied) should match the supply voltage used for the EWS-MP (ie: 12Vdc or 24Vdc ). The pilot relay coil current must be not more than 100 milliamps or damage to the EWS-MP drive circuit could result. The energy stored in a relay coil is commutated by a diode on the EWS-MP so an external snubber is not required.

If the remote alarm is a long way from the EWS-MP use extension wire of appropriate gauge according to length as specified in the table for the EWS-CT.

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Connection to a Building / Plant Monitoring System:

The four types of alarms are available as independent outputs for connection to a building / plant monitoring system. These can also be used as inputs to process control PLCs. Each output is optically isolated from each other and from the EWS circuits.

Many security monitor systems have inputs from sensors that can be distributed throughout a facility such as motion sensors, smoke detectors, water sensors etc. The optically isolated outputs from the EWS-MP can be used as similar inputs for the security monitor system.

Some security monitor systems require that each input loop be isolated and this can be accomplished easily with the alarm outputs.

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Install an EWS-DL Data Logger:

In some cases, particularly if alarms are being generated and it is not obvious what is causing them, a service technician would like to know details about the current being used by individual loads. There are about 60 internal values used by the EWS-MP to determine if an alarm should be generated. The EWS-DL Data Logger is an option that will collect all of the internal data values every minute for up to 4 days. After 4 days, the oldest data will be over-written so that the most current 4 days of data is retained.

After the EWS-DL has collected data, the data can be retrieved to a Personal Computer using the serial port. If you have the EWS-DV Data Viewer software installed on your computer, you can follow the menu instructions for getting data from the logger memory.

The EWS-DL is designed to be connected to and disconnected from the EWS-MP while the EWS-MP is in service. Do not disconnect power from the EWS-MP when connecting or disconnecting the data logger or the 24 hour time base clock will reset. This will not hurt anything except that the alarm functions based on the 24 hour time base will start again from that time onward.

Use the cable provided to connect the EWS-DL to the  EWS-MP. (A regular phone extension cable will not work.)  Auxiliary power is not required when the EWS-DL is connected to the EWS-MP as it receives power from the EWS-MP.  The external power adapter is to be used when downloading the data into a Personal Computer when the EWS-DL is not connected to the EWS-MP.  

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EWS-DV Data Viewer Software

The Data viewer software allows a facilities manager or service technician to see the load currents and temperatures of all of the sensors for the most recent 4 days in a convenient graphical format.


Configuration Options for Installers:

There are 4 input channels called A, B, C, and D on the label. Each input channel has 3 current sensing inputs and one temperature sensor input. There is a configuration DIP switch associated with each channel that the installer can use to configure the operation of that channel.

The current inputs can be combined as a 3 phase current sensing input or as 3 independent single phase current sensing circuits. The purpose of each DIP switch setting is described below:

DS1 DS2  
OFF OFF temperature range alarms at +/-12C
ON OFF temperature range alarms at +/-6C
OFF ON temperature range alarms at +/-4C
ON ON temperature range alarms at +/-2C


ON = consider the current input device as single phase

OFF = consider the current input device as three phase

DS4 DS5  
OFF OFF average current alarm disabled
ON OFF average current range alarms at +/-48% *
OFF ON average current range alarms at +/-32% *
ON ON average current range alarms at +/-16% *


ON = enable duty cycle alarm

OFF = disable duty cycle alarm

*(Since the current signals are compressed to provide a very wide range of currents, the % values given on the label are not really a % of linear current.)

There is an 8 position general configuration DIP switch that is used to configure other aspects of the monitor system as described below:


 Currently Unused


ON = enable peak current detection alarm (all channels)

OFF = disable peak current detection alarm (all channels)


 Currently Unused


Currently Unused


Currently Unused


ON = 1hr delay on dial out

OFF = 5min delay on dial out


ON = 24hr re-alarm enable 

OFF = 24hr re-alarm disable


ON = enable local audio alarm

OFF = disable local audio alarm

The four alarm outputs for connection to a separate alarm call-out system are isolated from each other and from circuit common. Some alarm systems expect a normally closed isolated loop for each switch input. If the alarm system expects normally closed contacts to a common, then the alarm outputs can be jumpered with a common ground or common high. The output switching ratings of these alarm outputs are noted on the label as +24 Volt max. and 50 mA max.

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