EZ Meter A4231/3 User manual

Dual 3-Wire, Single Phase Meter (Model A4231/3)
EZ
METER
Watthour Meters
Product Selection Guide
User Manual
Installation Manual

CAUTIONS
Serious injury can result from electric shock.
Be sure to turn off the power before installing or
servicing any meter.
Fire can result from loose electrical
connections. Ensure that all connections are
secure.
A loose or improperly connected neutral can
damage equipment and cause fires. Most meters
that count faster than they should are connected
to a bad neutral.
Current transformers (CTs) should not be
placed over wires with current flowing through
them without connecting them to the meter or
twisting the two wires coming from the CTs
together. A very serious shock hazard exists if
the wires are just left loose.
These meters should only be installed by
experienced electricians. If you do not fully
understand these instructions, call Customer
Support at 1-805-688-9696 for clarification.
In most localities, a permit and inspection is
required to install the meters. In some localities,
it is illegal to use an unapproved meter for
revenue billing. Check with your local Weights
& Measures office or other regulatory agency.
Legends
These symbols appear on meter labels.
1Caution, risk of Danger
G Equipment protected throughout by double
insulation
HAlternating Current
Abbreviations & Glossary
Common abbreviations used in this manual
include:
AMR - Automatic Meter Reading System
CT - Current transformer
KWH - Kilowatthour
Element - An input for measuring power,
usually a current transformer (CT)
Contact Information
EZMeter Technologies
583 N Refugio Road
Santa Ynez CA 93460 USA
1-805-688-9696
www.ezmeter.com
[email protected]
Note: This manual applies to meters that have a letter (A-G) as the first character of the model
number. A separate manual is available for meters made prior to 2010 by Davidge Controls.
Rev.6/26/17
Copyright 2017 EZMeter Technologies
i

Contents
CAUTIONS..................................................................... i
Legends. ....................................................................... i
Abbreviations&Glossary.......................................................... i
SafetyCertification. ..........................................................Page 3
AccuracyCertification.........................................................Page 3
ANoteforCaliforniaUsers..................................................Page 3
LimitedWarranty.............................................................Page 4
ProductSelectionGuide. ......................................................Page 5
AutomaticMeterReading(AMR).............................................Page 5
Bi-directionalMeters.......................................................Page 6
Voltage..................................................................Page 6
Maximum Current and Current Transformers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 7
DisplayandResolution. ....................................................Page 7
Enclosures................................................................Page 8
ModelNumbers...........................................................Page 8
PartNumberSuffixesforOrdering...........................................Page 11
EZMeterCurrentTransformers.................................................Page 12
OperatingInstructions........................................................Page 13
Understanding the Meter Electronics Module Label. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 14
InstallationInstructions.......................................................Page 16
InstallingtheNEMA4XEnclosure...........................................Page 16
Installingtheflushmountenclosure. .........................................Page 16
Anoteondifferentmetertypes:..............................................Page 16
InstallingtheCTs.........................................................Page 16
ElectricalConnections.....................................................Page 18
SurgeProtection..........................................................Page 18
DisplayConnections. .....................................................Page 18
IsolatedOutputs..........................................................Page 19
RS-232andRS-485 Connections............................................Page 19
I2CPortConnection. .....................................................Page 20
WiringDiagrams.........................................................Page 21
TestingtheInstalledMeter. ...................................................Page 25
Page 1

TroubleShooting............................................................Page 26
Installing a Grid Connect NET485 (Ethernet-RS422/485 Adapter). . . . . . . . . . . . . . . . . . . . . Page 27
ConnectingDigiRadioModemstoEZMeters. ....................................Page 29
ConnectingSnapLinkRadiostoEZMeters. ...................................Page 31
RS........................................................................Page 32
PhantomNeutralInstallationGuide..............................................Page 36
ObviusAcquiSuiteConnections................................................Page 37
NextCenturyRadioModule. ..................................................Page 38
ModbusInterfaceDescription..................................................Page 39
Modbus Registers & Summed Accumulator Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 41
EZMeterPowerSuiteQuickStartGuide..........................................Page 47
Page 2

Safety Certification
Underwriter’s Laboratories (UL)
Most EZMeters have been tested by UL
to UL916 and carry the UL Recognized
Component mark for the United States
(UL916) and Canada (CAN/C22.2 No
1010.1-04). File number is E362606.
Accuracy Certification
All EZ Meters are guaranteed to meet
the latest ANSI C12.1 accuracy standard for
electric meters. This standard allows an
error of up to 1% when new and 2% when
field tested.
In California, Maryland and Canada,
meters are regulated by the government
when used for revenue billing. Contact the
local Weights and Measures office. Only
meters that have been Type Approved by the
California Division of Measurement
Standards may be used for revenue billing
within California (all EZ Meters exceed
California’s accuracy requirements, but all
are not type approved).
A Note for California Users
All meters used in California for which a
charge is made for power must have been
inspected by a Weights & Measures
inspector and placed in service by a
Licensed Service Agent or a Weights &
Measures official. The meter must be
reinspected by Weights and Measures every
ten years. It is a misdemeanor to fail to do
this. See the ezmeter.com website for more
on these requirements.
The only EZMeters that have been
certified for revenue billing in California are
the 200 amp versions of the 120 volt to
neutral meters when using the Model JD6W
current transformer. Approved California
meters are models
A31x3x/yzxx
where xmay be any digit, ymay be 0 or 3
and zmay be 0 or 1. 0 is assumed if xand y
are not present. The CTEP certificate
number is 5674(a)-14.
Page 3

Limited Warranty
EZMeter Technologies warrants its products, if used in accordance with all applicable instructions,
to be free from original defects in material and workmanship for a period of five years from the date
of manufacture. If the product should prove defective in material or workmanship within that
period, EZMeter Technologies will repair or replace the product, in its sole discretion. Service under
this Warranty can only be obtained by your delivering or shipping the product (with all shipping or
delivery charges prepaid) to: EZMeter Technologies, 583 Refugio Road, Santa Ynez, CA 93460.
EZMeter Technologies will pay return shipping charges. Call EZMeter Technologies at (805)
688-9696 for a Return Material Authorization (RMA) before sending any equipment back for repair.
THIS WARRANTY DOES NOT APPLY TO NORMAL WEAR OR DAMAGE RESULTING
FROM ACT OF GOD, ACCIDENT, MISUSE, ABUSE, OR NEGLECT. SELLER MAKES NO
EXPRESS WARRANTIES OTHER THAN THE WARRANTY EXPRESSLY SET FORTH
HEREIN, EXCEPT TO THE EXTENT PROHIBITED BY APPLICABLE LAW. ALL IMPLIED
WARRANTIES INCLUDING ALL WARRANTIES OF MERCHANTABILITY OR FITNESS
ARE LIMITED IN DURATION TO THE WARRANTY PERIOD SET FORTH ABOVE AND
THIS WARRANTY EXPRESSLY EXCLUDES ALL INCIDENTAL AND CONSEQUENTIAL
DAMAGES. (Some states do not allow limitation on how long an implied warranty lasts, and some
states do not allow the exclusion or limitation of incidental or consequential damages so the above
limitations or exclusions may not apply to you. This Warranty gives you specific legal rights, and
you may have other rights which vary from jurisdiction to jurisdiction).
Damage from lightning strikes, power surges, and improperly connecting the meter to the power
source are not covered by the warranty.
Page 4

Product Selection Guide
This chapter provides information to help you choose the best meter for your requirements.
Automatic Meter Reading (AMR). Every EZMeter is available with one of four Automatic Meter
Reading (AMR) capabilities: None, Pulse, EZ Plus, or ModBus.
No AMR requires someone to visit each meter periodically and manually write down the reading
from the display.
A Pulse meter generates an isolated pulse, usually every kwh, which is detected by some type of
data logger or pulse counting radio. EZ Meters are compatible with most type of pulse counting
systems including Oscar, Inovonics and Hexagram. These systems are usually installed at the site
and connected to a billing service via telephone modem or the internet. The pulse is generated by an
optocoupler and mimics a dry-contact closure, except that it is polarity sensitive. Standard pulse
duration is 50 milliseconds. Other pulse lengths are available. Contact the factory.
EZ Plus and Modbus are two separate software protocols used for addressing meters using a
serial interface. Either one is available with an RS-232 or RS-485 interface.
RS-232 is a very common interface that is intended for a single device within about 30 feet.
Because of the addressing scheme used in the EZ Plus and Modbus protocols, multiple meters can
be addressed, but no tests have been conducted to see how many will work. RS-232 meters are not
currently in production, but may be special ordered.
RS-485 is a protocol used commonly in building and industrial control systems. Up to 256
devices can be on one network, even more if repeaters or radio links are used. RS-485 is the most
commonly used serial interface for meter reading. USB to RS-485 adapters are available at low cost
from a number of vendors. TCP/IP to RS-485 adapters are also available allowing a network of
power meters to be connected to the internet. Most telephone modems have an RS-232 port which
requires an RS-232 to RS-485 adapter to connect the meter network to a phone line. Another option
for extending an RS-485 network is to use two radios, something frequently done to avoid trenching
between two buildings. More powerful radios have a range up to seven miles
The modular design of EZMeter communications allows other modules to be developed and
implemented fairly inexpensively. Expect a meter with a built-in radio shortly.
EZ Plus is a relatively easy to implement protocol that will provide all the information available
by Modbus. The free EZMeterReader billing program uses the EZ Plus protocol. The EZMeter
Power Suite package supports both EZ Plus and Modbus. Since it is a binary protocol, there is a
chance it could conflict with an ASCII protocol if sharing the same network. The network must be
1200, 4800, 9600 or 19,200 baud, 8 data bits, 1 stop bit, no parity.
Page 5

Modbus is an old protocol and the de facto standard for building and industrial automation. The
register map is available on page 39. Several third party software vendors offer software already
configured to the EZMeter register map. Meters can be ordered for either big (default) or little
endian and either signed (default) or unsigned integers.
Bi-directional Meters. All one, two and three element meters are available as bi-directional meters
that measure the number of kwh that flow in each direction. These meters are most often used in
conjunction with solar, wind or other alternative energy systems connected to the grid.
Voltage. Each EZMeter must be ordered to match the electric system where it will be installed. The
first character of the model number determines the voltage range the meter can handle.
Note: Each meter model is capable of handling a range of voltages. Select the meter with the
voltage range that includes the voltage you want to measure.
A. 100-130 volts to neutral, 200-260 volts line to line, single output:
Single element: 100-130 volts to neutral, single phase.
Two element: 100-130 volts to neutral, 200-260 volts line to line, single phase or two phases of
a three phase system.
Three element: 100-130 volts to neutral, four wire, three phase wye.
A. 100-130 volts to neutral, 200-260 volts line to line, dual output:
Two element: Two 100-130 volts to neutral, single phase services or
One bidirectional 100-130 volts to neutral, 200-260 volts line to line, single phase or two phases
of a three phase system.
Three element: One 100-130 volts to neutral, single phase plus one 100-130 volts to neutral,
200-260 volts line to line, single phase or two phase of three phase system, or one
bidirectional 100-130 volts to neutral, four wire, three phase wye.
Four Element: Two 100-130 volts to neutral, 200-260 volts line to line, single phase or two
phases of three phase system.
B. Three element only: 100-130 volts to neutral on two legs, 200-260 volts to neutral on the third
leg, 200-260 volts line to line, four wire, three phase delta. Can also be used in place of an A
single output meter with a slight loss of accuracy at the low end on L3.
C. 200-260 volts to neutral, 400-500 volts line to line
Single element: 200-260 volts line to neutral, single phase
Two element: 200-260 volts to neutral, 400-500 volts line to line, or two phases of three phase.
Three element: 200-260 volts to neutral, 400-500 volts line to line, three phase wye
D. 240-300 volts to neutral, 430-500 volts line to line
Single element: 240-300 volts line to neutral, single phase
Two element: 240-300 volts to neutral, 430-500 volts line to line, or two phases of three phase.
Three element: 240-300 volts to neutral, 430-500 volts line to line, three phase wye
When used with the EZMeter Technologies Phantom Neutral module, this meter will monitor
a three-wire, three phase delta service.
Page 6

E. Three element only: 240-300 volts to neutral on two legs, 430-500 volts to neutral on the third
leg, 430-500 volts line to line, four wire, three phase delta.
F. Dual Element only: 200-260 volts line to line, three wire, three phase delta
G. Dual Element only: 440-500 volts line to line, three wire, three phase delta
Maximum Current and Current Transformers. Each EZMeter is calibrated to work with a
specific model current transformer (CT) at any current up to the maximum rating for the meter.
Solid core CTs require that the power be turned off and the wire carrying the load to be measured
must be disconnected, run through the CT, and reconnected. Split core CTs come apart and can be
installed without disconnecting the wires.
Solid core CTs are available for current ranges up to100, 150, 200, 250 or 400 amps. Split core
CT ranges up to 60, 200, 400, 800, 1200 or1600 amps.
CTs can be installed in parallel. If want to measure several circuits in a breaker panel and the
circuits are on the same leg, but opposite sides of the breaker panel, you can use two CTs, one on
each side, so you don’t have to rewire the panel.
The wires on CTs can be extended a reasonable distance as long as the wire resistance does not
exceed one ohm.
Display and Resolution. Each EZMeter can be equipped with either an LCD display or an electro-
mechanical counter that displays accumulated kilowatt hours. Some considerations:
An electro-mechanical counter costs less than an LCD display, but there are a few trade-offs.
The standard counter is rated to work down to 10EC (14EF) and is not suitable for outdoor use in
cold climates. An extended temperature range counter rated down to -30E(-22EF) is available at
added cost. If the temperature drops below the counter’s operating range, the counts will be lost
forever unless you are using an automatic meter reading system. If you have a dual output meter,
the LCD display will actually cost less than two counters. Counters are recommended when a local
display is required, but the meters will be read by an AMR system. They are also recommended for
locations in bright sunlight where an LCD display is difficult to read.
LCD displays have several advantages. Single output meters display accumulated kwh on the
top line of the display while the bottom line cycles through volts, watts, amps, and power factor.
The dual output meters display accumulated kwh for the second channel on the bottom line. If
mounted in a location where the display stops working because of low temperature, the display will
return to normal operation with no loss of kwh when it warms up.
Counters for meters with 0.1 kwh resolution have a red number on the right side to indicate
tenths of kwh. The other numbers are all white. Counters for meters with 1.0 kwh or 0.01 kwh
resolution have all numbers the same color. The LCD displays have a resolution of 0.01 kwh.
Page 7

Enclosures. A variety of enclosures that hold different numbers of meters are available. Most are
NEMA4X rated plastic enclosures with the meters mounted on a plastic panel inside. Use of plastic
enclosures allows AMR radios to be mounted inside. Interior rated enclosures have a clear cover
while exterior rated ones have a solid cover. The LCD displays are available only on the solid door
version.
Available versions are:
5" x 6.9" x 3" enclosure holds one or two meters and one or two displays. An optional fixture
allows the enclosure to be flush mounted in a wall.
6" x 6" x 4" enclosure holds one or two meters and two displays.
12" x 7" x 5" enclosure holds up to four meters and displays. It can hold six meters if two are
mounted on the back of the enclosure with velcro.
13" x 13" x 6" enclosure holds up to eight meters and eight displays.
19" x 15" x 7" enclosure holds up to twelve meters and twelve displays.
Model Numbers. Each digit in a model number specifies a different feature or option. Use the
table below to determine the options in the electronics module of your meter.
First Character - Voltage (see detailed description on page 6)
A = 100-130 volts to neutral, 200-260 line to line
B = 100-130 volts to neutral on two legs, 200-260 volts line to neutral on third leg, 200-260
volts line to line, four wire, three phase delta
C = 200-260 volts to neutral, 400-500 volts line to line
D = 240-300 volts to neutral, 430-500 volts line to line
E = 240-300 volts to neutral on two legs, 400-500 volts to neutral on the third leg, 400-500 volts
line to line, four wire, three phase delta.
F = Dual Element only: 200-260 volts line to line, three wire, three phase delta
G = Dual Element only: 430-500 volts line to line, three wire, three phase delta
Second Character - Number of elements supported
1 = One element
2 = Two element
3 = Three element
4 = Four element (dual two element meter)
Third Character - Display option
0 = No counter driver (AMR only)
1 = One counter (standard meter)
2 = Two counters (dual 2-in-1 meter)
3 = 2 line LCD display (standard meter)
4 = 2 line LCD display (dual 2-in-1 meter)
Page 8

Fourth Character - Maximum rated current (Meter Class)
0 = 60 amps
1 = 100 amps
2 = 150 amps
3 = 200 amps
4 = 250 amps
5 = 400 amps
6 = 800 amps
7 = 1200 amps
8 = 1600 amps
9 = 2000 amps
Fifth Character - Automatic Meter Reading (AMR)
0 = No AMR or AMR through I2C port
1 = Isolated pulse output
2 = RS-485 EZ Plus protocol
3 = RS-485 Modbus protocol
4 = RS-232 EZ Plus protocol
5 = RS-232 Modbus protocol
6 = TinyMesh radio
7 = Next Century radio power/pulse interface
Valid meter model numbers contain at least five characters. The model number may contain up to
five additional characters. If none of the additional characters are present, the “0" value is implied.
Sixth Character - Always a slash / unless there are no additional characters.
Seventh Character - The CT Model.
Additional CT models may be added at any time. Presently the models are:
0 = 4720/4 - 400:1, 250 max amps, solid core, 1" ID (discontinued)
1 = JC16F - 400:1, 100 max amps, split core, 0.6" ID
2 = S0140 - 3000:1, 1600 max amps, split core, 1.25" ID (discontinued)
3 = JD6W - 2500:1, 400 max amps, solid core, 0.7" ID
4 = S0160 - 3300:1, 1600 max amps, split core, 2.0" ID
5 = KFC-203-FD - 2000:1, 400 max amps, split core, 1.2" ID
6 = JC36S3 - 3000:1, 800 max amps, split core, 1.4" ID (special order)
7 = WC3-200 - 400:1, 400 max amps, split core, .94" x .75" inside
8 = WC4-800 - 800:1, 800 max amps, split core, 1.7" x 1.3" inside (special order)
9 = WC5-1600 - 1600:1, 1600 max amps. Split core, 3.5" x 2.0" inside (special order)
A = XH-BCT-1000 - 1000:1, 250 max amps, solid core, 1.0" ID (special order)
B = XH-SCT-T24/200 - 2500:1, 260 max amps, split core, 0.93" x 0.99" inside
C = WC6-2000 - 2000:1, 2000 max amps, split core, 8.4" x 4.7" inside
D = JD7W - 417:1, 250 max amps, solid core, 0.7" ID
E = Eaton Model 417, equivalent to JD7W
Page 9

Eighth Character - Resolution
0 = Display: 1.0 kwh
Isolated: 1.0 kwh
1 = Display: 0.1 kwh
Isolated: 0.1 kwh
2 = Display: 0.01 kwh
Isolated: 0.01 kwh
3 = Display: 0.01 kwh
Isolated: 1.0 kwh
Ninth Character - Parity and Bidirectional
0 = No parity, standard meter
1 = No parity, bidirectional meter
2 = Even parity, standard meter
3 = Even parity, bidirectional meter
4 = Odd parity, standard meter
5 = Odd parity, bidirectional meter
Tenth Character - Baud Rate (Modbus Configuration) or Isolated Pulse Timing.
For Serial Port meters (modbus configuration, EZPlus where noted)
0 = 9600 Baud (little endian, unsigned integers and EZPlus)
1 = 19,200 Baud (little endian, unsigned integers and EZPlus)
2 = 9600 Baud (little endian, signed integers)
3 = 19,200 Baud (little endian, signed integers)
4 = 9600 Baud (big endian, unsigned integers)
5 = 19,200 Baud (big endian, unsigned integer)s
6 = 9600 Baud (big endian, signed integers)
7 = 19,200 Baud (big endian, signed integers)
8 = 4800 Baud (EZPlus only)
9 = 1200 Baud (EZPlus only)
For Isolated Pulse Meters
0 = 50 ms pulse, 150 ms recovery
A-Y = Pulse length is position of letter in alphabet time 129 ms, recovery time is 129 ms longer
than pulse length
Z = Custom pulse length
Page 10

Part Number Suffixes for Ordering. The part numbers above are printed on the meter cases and
enclosures. For ordering and invoicing, a part number suffix consisting of a hyphen (-) and two
digits may be appended to the part number. The first digit is the number of CTs that go with the
meter. The second digit represents the type of mechanical counter that goes with the meter. The
codes are
5 = Counter for 0.1 kwh resolution, one red wheel, standard temperature range (4921/1)
6 = Counter for 1.0 or 0.01 kwh resolution, all white wheels, standard temperature (4921/0)
7 = Only one type 5 counter for dual meter with 4 CTs.
8 = Only one type 6 counter for dual meter with 4 CTs
9 = LCD Counter and ribbon cable
In addition, California approved meters require special marking on the current transformers.
Append a letter “C” to the model number to be sure your meter will pass the state testing procedure.
Page 11

EZMeter Current Transformers. Each meter is manufactured to work with one model of current
transformer (CT). While it is true that a CT with the same turns ratio can be substituted for another
without causing a significant error, for best accuracy, use the CT specified on the meter label. The
meter has been calibrated to account for variations in how the CT responds to different phase
angles, a function of the core material rather than the turns ratio.
The seventh character of the meter model number specifies the CT that should be used. If there is
no character in the seventh position the 4720/4 CT should be used. See the table on page 10.
Page 12

Operating Instructions
After installation, the EZ Meter is simple to operate. You read the meter the same way you read
the odometer in a car. The label on the front of the meter indicates the resolution of the display,
either full kilowatt hours (kwh), tenths of kwh or hundredths of kwh The label on the outside of the
enclosure also states the resolution. The mechanical counters are available with all white digits or
all white except the right hand digit being red which indicates tenths of kwh. Normally, the display
reads in full kwh, except if the right most digit is a different color, it is reading in tenths. And except
if someone did not use the correct display with the meter module. Look at the label to be sure.
To charge a tenant for power used, subtract the meter reading at the beginning of the billing
cycle from the meter reading at the end of the cycle and multiply the difference by the rate per
kilowatt hour.
Whenever power is applied to the L1 terminal, the red LED on the electronics module should
light. The light will flash off then back on every time one of the legs measures 1/100 of a kwh (or
whatever quantity is indicated by the Kt value on the meter label (see below).
For meters made in 2015 and earlier: (see the date code on the label. 4Q15 = Oct-Dec 2015)
If the red LED flashes on and off every second, the meter is detecting a high
phase angle power factor is below .7) on one or more of the legs. This could
indicate a piece of equipment is not operating properly or it could mean that
the CTs and voltage references were not paired properly when using three
phase power. See the installation instructions for curing this condition. To
disable the high phase angle alarm (if you want to test the accuracy of the
meter at a high phase angle), install a jumper between the two pins on the
I2C connector closest to the display connector on the front row.
For meters made after 2015:
Beginning in January 2106, the low power factor warning is only active when reverse current is
detected. This means that if the CTs were installed correctly, the continuous flashing of the red LED
usually indicates that the voltage and current inputs to the meter were not properly matched during
installation and the meter is only recording half (or 2/3) the power being consumed. This only
occurs when the power is supplied from a three phase transformer.
Meters with electro-mechanical displays have a green LED that will flash briefly every time the
display counter advances.
Meters with an RS-485 interface have a bi-color LED that flashes red briefly every time the
meter senses traffic from the serial port. It flashes green when it responds to a request over the serial
port. Meters with an RS-232 interface, and the original RS-485 meters, have a yellow LED that
flashes when the meter responds. If the bi-color LED comes on bright red and stays on, it indicates
the serial connection was not properly installed or the isolated power has failed.
You can clean the outside of the meter enclosure with a general purpose cleanser such as 409 or
Fantastic if necessary. Do not use harsh bathroom cleaners or alcohol.
Page 13

If the meter appears to operate erratically, it is probably because it measures each phase
separately and flashes the red LED when each phase accumulates 1/100 kwh (or other resolution).
The resolution may be different for the red LED, the display and the isolated output. Check the
meter label where the resolution of each will be noted.
If you believe the meter is not measuring correctly, perform the test on page 25 and see the
troubleshooting suggestions on page 26.
Understanding the Meter Electronics Module Label
The center section on the meter label reveals a lot of data about the meter, but some of it is in
the language used by the metering standards.
Display Units - The resolution of the meter display. Either 1.0, 0.1 or 0.01 KWH. Multiply by the
value show on the display to get the total KWH the meter has recorded. Meters with 1.0 resolution
have all digits the same color and the display shows KWH with no conversion needed. Meters with
0.1 resolution are usually sold with the right hand digit being a different color and is read as if there
were a decimal point before the odd colored digit. Some older meters had the notation Kt: 1000
along with the display resolution. That confusing statement is no longer required by California
Measurement Standards.
Red LED (Kt) - The Red LED serves two functions. If it is flashing about once a second, it
indicates a low power factor on one or more legs. A slower flash indicates the meter has recorded
the amount of energy shown on the label, usually .01 KWH (10 WH) for most meters. It may be as
high as .5 KWH for high voltage, high current meters.
Depending on the type of meter, the next line will provide the isolated output resolution or the type
of serial communication and the default baud rate.
Oper. Temp: - The operating temperature range applies to the electronics module only. The low
temperature is usually lower than the low temperature for the electro-mechanical display.
Voltage - The range of voltages in which the meter will operate measured between line and neutral
(L/N). If there is no neutral, it is the voltage line to line (L/L). For four wire delta meters, the
voltage for the high leg is shown on the left for L3.
Max Amps (CL) - The maximum load (in amps) on each leg that the meter can handle. This is also
referred to as the meter class.
Test Amps (TA) - This is another term from the standards and is set by the manufacturer, usually at
15% of the class rating (maximum amperage).
Max current draw: All EZ Meters use 2 watts or less for operation of the meter.
Page 14

CT Ratio: The turns ratio of the current transformer that is intended for use with this meter.
Vertically printed next to the labeling of the CT terminals is the model number of the current
transformer the meter was calibrated against. Each model of CT has a slightly different phase angle
adjustment which is programmed into the meter during calibration. Using a current transformer
with a different model number, but the same turns ratio may cause an error of a few tenths of one
percent. Using a current transformer with a different turns ratio, or a current transformer with an
internal burden resistor, will cause a significant error.
Page 15

Installation Instructions
These instructions are for meters whose model number begins with a letter, not a number.
The EZ Meter consists of an electronics module, one or more current transformers (CTs), a
display of one or two electro-mechanical or LCD display counters, and an enclosure that holds from
one to 12 meters. If the meter will be mounted outside in direct sunlight, be sure to order a UV
resistant enclosure or paint the standard enclosure. The CTs and display may be mounted in the
same enclosure or mounted in a remote location. A common practice is to mount the CTs in a
breaker panel and mount everything else in a separate adjacent enclosure. A circuit breaker rated at
20 amps or less should be installed before the meter. Be sure no one will be able to turn off the
breaker and defeat the meter. If a fuse is used to protect the meter, it should be a delayed-action fuse
and the meter’s power supply will short hot to neutral for half a cycle (1/120 second) on power up.
Installing the NEMA4X Enclosure: Use the metal brackets provided to mount the enclosure in a
suitable location. Drill a hole anywhere in the side or back of the enclosure for a conduit to connect
to a breaker panel or disconnect box in compliance with local electrical codes. After the meter has
been installed and tested, secure the cover using the screw or small padlock provided. You should
also label each display counter with the unit name or number.
Installing the flush mount enclosure: This enclosure was designed to be recessed into a sheet
rock wall. Cut a 6” square opening in the sheet rock adjacent to a stud. Drill a hole in the back or
side of the enclosure for a conduit. Install the CTs and make the electrical connections as described
below before installing the enclosure in the wall. Fillister head screws with holes are provided so
that the cover may be secured with a seal if required.
A note on different meter types: All EZmeters come with a 12 pin connector for voltage and CT
inputs. There are three voltage inputs and three CT inputs (3&3) or two voltage inputs and four CT
inputs (2&4). The 3&3 configuration must be used whenever a three phase wye or delta load is
being measured. Either configuration can be used for measuring single phase loads, even if the load
uses one or two legs of a three phase service. The 2&4 configuration is most commonly used in
marinas and apartment buildings where two 3-wire 120/240V (or 120/208V) services are close
enough to each other to be monitored by one meter.
Installing the CTs: (See the appropriate Figure on pages 22 and 23.) If you are using solid core
CTs, you must turn off the power to begin your installation. Disconnect one end of the wire (or
wires) with the load to be measured and pass it through the center of the CT and reconnect the
wire(s) where it was attached before. Connect the two wires coming out of the CT to the appropriate
terminals on the electronics module. Begin connecting CTs to CT #1 and continue until all the CTs
for that meter are installed. The CT should be installed with the arrow facing the direction of current
flow or the label facing the source.
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You can install more than one CT on each leg if you need to. You might need to if you were
measuring several circuits in one breaker panel and the wires were not long enough for all to go
through one CT or if you wanted to measure power being used in two separate breaker panels. Just
be sure all the wires on each leg go through CTs that are connected to the same terminal on the
meter and that the direction marks on the CTs are aligned the same. Multiple CTs should be
connected in parallel.
If you run more than one wire through a CT, be sure that the current flow is the same direction
for all wires and that all the wires are the same leg (phase). That means there should be no voltage
variation between the wires (if you touched them together, they would not spark). Failure to do so
will cause the power flowing in one wire to be subtracted from the power flowing in the other wire
instead of being added to it.
The CT wires can be extended if needed. We have tested them at 500 feet and they can probably
be extended even further. If the line resistance is much over one ohm, accuracy of the meter will be
affected, especially at high phase angles. Be sure to install the CT wires in conduit. Connections
should either be soldered or made with gel filled wire nuts. Any resistance in the connection will
cause the meter to read lower than it should. The wire used should meet local codes for insulation.
Any size wire from 22 AWG to 12 AWG may be used. #18 is suggested.
You can install split core CTs without disconnecting the wire. If you have to install them
without turning off power, connect the wires to the meter before securing the two parts of the CT
over the wire carrying the load. Be sure to secure the two parts of the CT so it cannot come apart.
Note: Working in an electric panel that has power connected to it is an OSHA violation.
Do not mix CTs with different turns ratios on the same meter.
CTs Are Directional (or Not)
If the meter is otherwise installed correctly, it will accurately record all the power that flows
through the CTs. If you are working with three phase power, even if only one or two legs of it,
you should be sure the arrows or labels are facing in the right direction. The meter has a phase
angle warning that flashes the red LED every second if power factor is below 0.7 and polarity is
reversed. This will happen if the CTs are facing the proper direction, but the voltage and current
sources are not properly matched. (L1 voltage and L1 CT should be on the same phase, etc).
If you want the phase angle warning (red LED flashes) to work all the time, simply install the
CTs backwards. Doing so will cause Modbus and Plus meters to report watts as a negative
number. Rather than physically turning the Cts around if needed, just reverse the black and white
wires where they connect to the meter.
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Electrical Connections: You need to provide a voltage reference for each phase of the power you
are metering plus connect the neutral to the meter as well. The voltage ranges printed on the
electronics module label (before L1, etc) refer to the voltage between neutral and that terminal and
indicate what meter works with what electrical system. The voltage associated with the meter name
is the most commonly used voltage in the range. See the diagrams on pages 19 and 20 for specific
models. For meters that do not have a Neutral reference, the voltage ranges printed on the label are
line to line voltages.
You can use any size wire from 28 AWG to 12 AWG. Be sure insulation meets local codes.
Each phase should be protected by a circuit breaker or fuse of 20 amps or less. For safety, a switch
or circuit breaker must be installed between the meter and the mains power source. It shall be in
close proximity to the meter and within easy reach of the operator and shall be marked as the
disconnecting device for the equipment. If a fuse is used, it should be a slow-blow type. Connecting
the meter on the protected side of a GFCI may cause the GFCI to trip when power is applied to the
meter.
Surge Protection: Like computers, TVs and other electronic devices, EZMeters are subject to
damage from electrical surges. In fact they are particularly likely to be damaged because they are
typically installed as the first piece of electronics that the surge hits when it enters the submetered
electrical distribution system. Consider a whole-house surge protection device or other sacrificial
protection device.
Display Connections: (See Fig 1 and Fig 7) The electro-mechanical counter comes already
connected to the meter. If you purchased an OEM version of the product, connect as shown in the
WARNING
Hazardous voltages exist in CT wires when they are not connected to a meter and current is
flowing through wire passing through the CT. Wire nut the CT wires together if you must
remove the meter and leave the CTs in place. Failure to do so may damage the CT or shock
someone.
IMPORTANT
You must ensure that the leg connected to the AC L1 terminal is the same leg which passes
through CT L1, and the same for (AC L2 & CT L2) and (AC L3 & CT L3). This is especially
important when connected to three phase power because the meter will only record 50% of the
power used on legs that are not properly paired. After the installation is complete, turn on a 60
watt or greater load for each leg and observe the red LED. If it is flashing, you most likely did not
wire the meter properly (The flashing LED indicates a power factor of 0.7 or less - optimum
power factor is1.0).
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