EZ Meter A4231/3 User Manual
EZ
METER
Watthour Meters
Product Selection Guide
User Manual
Installation Manual
Dual 3-Wire, Single Phase Meter (Model A4231/3)
CAUTIONS
Legends
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.
These symbols appear on meter labels.
1 Caution, risk of Danger
Equipment protected throughout by double
G
insulation
H Alternating 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
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
EZMeter Technologies
583 N Refugio Road
Santa Ynez CA 93460 USA
1-805-688-9696
& Measures office or other regulatory agency.
www.ezmeter.com
salesinfo@ezmeter.com
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
Safety Certification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 3
Accuracy Certification.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 3
A Note for California Users.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 3
Limited Warranty.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 4
Product Selection Guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 5
Automatic Meter Reading (AMR).. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 5
Bi-directional Meters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 6
Voltage.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 6
Maximum Current and Current Transformers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 7
Display and Resolution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 7
Enclosures... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 8
Model Numbers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 8
Part Number Suffixes for Ordering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 11
EZMeter Current Transformers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 12
Operating Instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 13
Understanding the Meter Electronics Module Label. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 14
Installation Instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 16
Installing the NEMA4X Enclosure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 16
Installing the flush mount enclosure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 16
A note on different meter types:.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 16
Installing the CTs.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 16
Electrical Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 18
Surge Protection.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 18
Display Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 18
Isolated Outputs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 19
RS-232 and RS-485 Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 19
I2C Port Connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 20
Wiring Diagrams. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 21
Testing the Installed Meter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 25
Page 1
Trouble Shooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 26
Installing a Grid Connect NET485 (Ethernet-RS422/485 Adapter). . . . . . . . . . . . . . . . . . . . . Page 27
Connecting Digi Radio Modems to EZMeters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 29
Connecting Snap Link Radios to EZMeters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 31
RS.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 32
Phantom Neutral Installation Guide.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 36
Obvius AcquiSuite Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 37
Next Century Radio Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 38
Modbus Interface Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 39
Modbus Registers & Summed Accumulator Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 41
EZMeter Power Suite Quick Start Guide.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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
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.
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).
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 x may be any digit, y may be 0 or 3
and z may be 0 or 1. 0 is assumed if x and 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 electromechanical 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.
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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.
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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.
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