WFCO EM-15 Administrator Guide
SAFETY INFORMATION ........................................................................................................... 3
EM-15 / EM-20 OPERATION
Introduction ................................................................................................................................... 3
Product Description ....................................................................................................................... 3
Modes of Operation ..................................................................................................................... 4
EM-15 Power Relay Mode ....................................................................................................... 4
EM-20 Power Relay Mode w/ Short Delay ............................................................................5
EM-20 Power Relay Mode w/ Long Delay ............................................................................ 5
EM-20 Logic Relay Mode w/ Short Delay ............................................................................. 5
EM-20 Logic Relay Mode w/ Long Delay ............................................................................ 6
EM-20 Remote Control ................................................................................................................ 6
EM-20 Remote Panel Functions .................................................................................................. 7
EM-15 / EM-20 INSTALLATION
Mounting the Enclosure ................................................................................................................ 7
Mounting to a Wall or Floor ........................................................................................................ 8
Mounting to a WF-89xxPEC ...................................................................................................... 8
Mounting to a WF-85xx ............................................................................................................... 8
Mounting the EM-20 Remote Control ....................................................................................... 9
EM-15 / EM-20 WIRING
System Wiring Diagram ..............................................................................................................10
Internal EM-15 / EM-20 Wiring ............................................................................................... 11
Wiring Instructions ..................................................................................................................... 12
Air Conditioner Logic Wiring for the EM-20 ......................................................................... 12
EM-15 / EM-20 TROUBLESHOOTING .......................................................................13
SPECIFICATIONS ............................................................................................................. 14
APPENDIX A ........................................................................................................................ 15
Timing Diagram Example ........................................................................................................... 15
GENERAL COMPLIANCE INFORMATION ............................................................ 16
TABLE OF CONTENTS
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3
!WARNING!
Risk of Electrical Shock. Disconnect or isolate all power supplies before making electrical
connections. More than one disconnection or isolation may be required to completely
de-energize equipment. Contact with components carrying hazardous voltage can cause
electric shock and may result in severe personal injury or death.
!IMPORTANT!
All wiring must conform to local, national, and regional regulations. Use copper conductors
only for all wire connections. Do not exceed the electrical ratings for the EM-15 / EM-20 or the
equipment connected to it.
!CAUTION!
is product should be installed by an experienced technician. CAUTION and care must be
taken when servicing this equipment. To prevent severe shock or electrocution, consult your
servicing dealer.
!WARNING!
is unit employs components that can produce arcs or sparks. To prevent re or explosion, do
not install in compartments containing batteries or ammable materials (LP gas). is product
is NOT ignition protected.
EM-15 / EM-20 OPERATION
Introduction
e EM-15 / EM-20 is a cost-ecient, energy management branch circuit expander. is
product is designed to share the power from a single branch circuit between two mid-to-large
power loads that normally require their own breaker. Potential applications include microwaves,
replaces, hairdryers, water heaters, or even two air conditioners. RVs with two or more air
conditioners frequently require 50A AC service; however, the EM-20 can be employed to
manage two air conditioners in an RV with 30A service.
All WFCO products are designed to better meet the needs of RV owners while also making
the job simpler for the installer. e EM-20 oers three exible mounting options, as well as, a
number of unique features – like four basic power modes and a remote panel for manual energy
management – making it easy for RV owners to assign energy to the circuit they need at any
particular time. e EM-15 also oers three exible mounting options, and can quickly be
utilized wherever there is a need for energy management on a 15A branch circuit.
Product Description
e EM-15 / EM-20 is an Energy Management Switch designed to be used in recreational
vehicles to share the power from a single 15A / 20A branch circuit between two mid- to large-
loads. e device applies power to both loads until the total loaded current exceeds
approximately 13.5A / 18A. It then cuts the power to the secondary load to prevent the 15A /
20A circuit breaker from tripping while maintaining the primary load. e secondary load will
be restored automatically when the total loaded current drops below a preset level (~5A).
e EM-15 / EM-20 default primary (priority) branch is Circuit A. e secondary load (which
may be shut o) shall be wired to Circuit B.
Modes of Operation
EM-15 Power Relay Mode:
e EM-15 has a single mode of operation for the following application: sharing the
power between two appliances on a 15A breaker (for example: a microwave and a replace
or water heater).
is mode of operation functions as follows: Power is applied to the EM-15. Aer a short
delay of approximately 4 seconds, power will be supplied to both the primary and sec-
ondary circuits. e EM-15 constantly monitors current levels, and will shut down the
secondary circuit once levels reach approximately 13.5A. Once the current levels have
dropped below approximately 5A, power will return to the secondary circuit.
EM-20 Modes:
e EM-20 has 4 basic modes of operation.
1. Power Relay Mode w/ Short Delay
2. Power Relay Mode w/ Long Delay
3. Logic Relay Mode w/ Short Delay
4. Logic Relay Mode w/ Long Delay
e mode can be switched using the red & white switch located inside the EM-20. If the
mode is changed it will require the power to be cycled OFF then ON before the EM-20
will recognize the new mode. e EM-20 implements these modes through 4 dierent
internal relays (2 high current power relays and 2 low current logic relays).
Power Relay vs Logic Relay:
In Power Relay Mode, when faced with an over current condition, the power for the entire
secondary circuit shuts OFF.
In Logic Relay Mode, when faced with an over current condition, the power for the
secondary circuit always remains ON, while a “logic relay” switches states.
Logic Relay Mode expects the load to manage its’ own power. is is a very important
distinction! Logic Relay Mode shall NOT be used unless the load is designed to be used
with an energy management system, and has inputs which expect a simple, low power
relay switch closure.
Long Delay:
When an air conditioner is in operation, its compressor circulates refrigerant under high
pressure. Once OFF, it will take 2-3 minutes for this high pressure to equalize. For this
reason, the EM-20 adds an o-time delay of approximately 3 minutes. is delay will
prevent “short cycling” the compressor and will also be observable during the initial
power ON sequence of the EM-20.
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5
EM-20 Power Relay Mode w/ Short Delay:
is mode shall be used when two appliances (without compressors) are sharing the same
circuit breaker (for example: a microwave and a replace or water heater).
Power is applied to the EM-20. Aer a short delay of approximately 4 seconds, power will be
supplied to both the primary and secondary circuits. e EM-20 constantly monitors current
levels, and will shut down the secondary circuit once levels reach approximately 18A. Once the
current levels have dropped below approximately 5A, power will return to the secondary circuit.
EM-20 Power Relay Mode w/ Long Delay:
is mode shall be used when attempting to combine two loads with compressors that are not
set up to use logic relays.
Power is applied to the EM-20. Aer a delay of approximately 3 minutes, power will be supplied
to both the primary and secondary circuits. e EM-20 constantly monitors current levels, and
will shut down the secondary circuit once levels reach approximately 18A. e “OFF time delay
timer” is then triggered. Once the timer has expired, and the current levels have dropped below
approximately 5A, power will return to the secondary circuit.
EM-20 Logic Relay Mode w/ Short Delay:
is mode shall be used when attempting to combine two air conditioners on one 20A breaker.
ese air conditioners shall be equipped with energy management system inputs and have the
ability to use logic relays for compressor control. THIS MODE SHALL ONLY BE SELECTED
IF THE AIR CONDITIONER CONTROL CIRCUITRY PROVIDES THE NECESSARY OFF-
TIME DELAY ITSELF TO PREVENT SHORT CYCLING THE COMPRESSOR.
Power is applied to the EM-20. Aer a short delay of approximately 4 seconds, power will be
supplied to both the primary and secondary circuits. Both power relays will continue to stay on
for as long as there is power applied to the EM-20. e control is performed through the logic
relays. e EM-20 constantly monitors current levels, shutting down (energizing) the secondary
logic relay when levels reach approximately 18A. Once the current levels have dropped below
approximately 5A, the secondary logic relay will be de-energized.
EM-20 Logic Relay Mode w/ Long Delay:
is mode shall be used when attempting to combine two air conditioners on one 20A
breaker. ese air conditioners shall be equipped with energy management system inputs
and have the ability to use logic relays for compressor control. THIS MODE SHALL BE
SELECTED IF THE AIR CONDITIONER CONTROL CIRCUITRY DOES NOT PRO-
VIDE THE NECESSARY OFF-TIME DELAY ITSELF TO PREVENT SHORT CYCLING
THE COMPRESSOR.
Power is applied to the EM-20, aer a short delay of approximately 4 seconds, power will
be supplied to both the primary and secondary circuits (also triggering the “OFF time
delay timer” of approximately 3 minutes) and the logic relays will be energized. Both
power relays will continue to stay on for as long as there is power applied to the EM-20.
e control is performed through the logic relays. Once the “OFF time delay timer” has
expired the EM-20 de-energizes the logic relays, and will constantly monitor current
levels, shutting down (energizing) the secondary logic relay when levels reach
approximately 18A. e “o time delay timer” is then triggered. Once the timer has
expired, and the current levels have dropped below approximately 5A, the secondary logic
relay will be de-energized.
EM-20 Logic Relay Operation Detail:
e EM-20 logic relays provide dry relay contacts (simple low current switch closure) and
operate as follows: Under normal operation with both circuits ON, the logic relays will be
de-energized (relay common connected to the normally closed contacts). When the total
current exceeds the upper trip limit, the logic relay for the secondary channel is energized
(relay common connected to the normally open contacts).
For wiring air conditioners with energy management logic capabilities please refer to the
Air Conditioner Logic Wiring section.
EM-20 Remote Control
e EM-20 remote control allows the user to easily specify which circuit should always
remain ON, in the event that appliances on both branches require too much power. e
LEDs indicate which branch will be Primary, allowing the other branch to be shut OFF.
Pushing the button (until a so click is felt) will change the preference. e LED for the
circuit indicating the primary branch will change immediately as soon as the button is
pressed.e background relay activation will occur aer a short delay of approximately 4
seconds.
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EM-20 Remote Panel Functions
Function: Set Circuit Priority
EM-15 / EM-20 INSTALLATION
Mounting the Enclosure
e EM-15 / EM-20 has primarily been designed for three dierent mounting congura-
tions. A simple rotation of the mounting bracket facilitates the dierent congurations.
1. Wall/Floor Mounting.
2. Back of WFCO WF-89xxPEC Power Centers.
3. Back of WFCO WF-85xx Power Centers.
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Circuit A LED is Illuminated
OR
NO Remote Installed
Circuit B LED is Illuminated
Circuit A is always available Circuit B is always available
Circuit B drops out on over-current
condition
Circuit A drops out on over-current
condition
Mounting to a Wall or Floor
Bracket Position:
Mounting to a WF-89xxPEC
Bracket Position:
e brackets will slide into the slots on the back of the power center, with the screws in the
top of the power center going through the bracket to hold it in place.
Mounting to a WF-85xx
Bracket Position:
No bracket is necessary. e mounting holes for the bracket on the EM-15 / EM-20 have
corresponding holes on the back of the 85xx series power centers. Remove the brackets
and use the bracket screws to mount the EM-15 / EM-20 directly to the back of the power
center.
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Mounting the EM-20 Remote Control
e remote-control panel should be mounted in an easily accessible location. e supplied
remote cable shall be routed from the remote location to the EM-20.
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EM-15 / EM-20 WIRING
System Wiring Diagram
For 20A applications, use 12AWG copper conductors only. For 15A applications, use
14AWG copper conductors only.
Internal EM-15 / EM-20 Wiring
For 20A applications, use 12AWG copper conductors only. For 15A applications, use
14AWG copper conductors only.
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Wiring Instructions
For 20A applications, use 12AWG copper conductors only. For 15A applications, use 14AWG
copper conductors only. All wiring shall meet local codes/standards and be performed by
qualied personnel.
• If the remote panel is NOT used or NOT available, the priority circuit shall be connected
to circuit A.
• Remove the lid and put it in a temporary safe place.
• Feed Romex cable from the 15A (for EM-15) or 20A (for EM-20) circuit breaker into the
centrally-located cable clamp.
o Connect Black wire to TB1 (AC Input / Line).
o Connect White wire to TB4 (Neutral).
o Connect Ground wire to TB7 (FG).
o Fasten all terminals down (suggested torque 7 in-lbs).
o Secure the AC Power wire with the two-screw clamp connector.
• Feed 2 Romex cables from the Circuit A and Circuit B into the cable clamp near the end.
o Connect the Circuit A Black wire to TB2 (Circuit A).
o Connect the Circuit A White wire to TB5 (Neutral).
o Connect the Circuit A Ground wire to TB8 (FG).
o Connect the Circuit B Black wire to TB3 (Circuit B).
o Connect the Circuit B White wire to TB6 (Neutral).
o Connect the Circuit B Ground wire to TB9 (FG)
o Fasten all terminals down (suggested torque 7 in-lbs).
o Secure the wires for Circuit A and Circuit B in the two-screw clamp connector.
• Put lid back on the EM-15 / EM-20.
• For the Remote: Mount the Remote Control in a convenient location. Route and connect
the remote cable into the 6-pin phone connector on both the EM-20 and the remote.
Air Conditioner Logic Wiring for the EM-20
is section shall be used if you have two air conditioners designed to be used with an energy
management system. For best operation, make sure the air conditioner fan is set to auto.
EM-20 Molex
5569 Pin #
EM-20 Molex 5569
Wire Color
Description Air Conditioner
Connections
1BLK AC1-NC
2WHT AC1-COM AC1-Load Shed
3BLU AC1-NO AC1-Load Shed
4RED AC2-NC
5ORG AC2-COM AC2-Load Shed
6YEL AC2-NO AC2-Load Shed
e EM-20 logic relays provide dry relay contacts and operate as follows: Under normal
operation with both circuits ON, the logic relays will be de-energized (relay common
connected to the normally closed contacts). When the total current exceeds the upper trip
limit, the logic relay for the secondary channel is energized (relay common connected to the
normally open contacts).
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Symptom Potential Reason Action to Perform
No power on both circuits. 1. No power to EM-##
2. EM-## is in “OFF-time
delay”
1. Verify that the RV has
power & reset the EM-##
breaker
2. Power the EM-## for 5
minutes & verify operation
No power on one circuit
(the other circuit is OK).
1. Load may not be turned
ON
2. EM-## may have turned
o 1 circuit because of
current draw
3. EM-## may be in “OFF-
time delay”
1. Turn ON both loads
2. Turn OFF power to the
operating circuit appliance,
wait 5 minutes & verify
operation of the other
circuit appliance
3. Power the EM-## for 5
minutes & verify operation
Both circuits are on at the
same time.
1. Total current draw may
be below the trip point
2. EM-## may be in the
wrong mode
1. Turn both appliances
on high & verify that the
circuit breaker doesn’t trip
2. Refer to qualied service
technician for mode
verication
No LED lights on the
remote.
1. No power to EM-##
2. Bad connection on the
remote cable
3. Defective remote
1. Verify that the RV has
power & reset EM-##
breaker
2. Replace remote cable
3. Replace remote
Switch doesn’t work on the
remote.
1. EM-## may be in “OFF-
time delay”
2. Defective remote
1. Power the EM-## for 5
minutes & verify operation
2. Replace remote
Refer to the Troubleshooting Chart on the next page.
e air conditioner logic wiring chart assumes the air conditioner expects a relay contact
closure when the compressor should be o. Please refer to the air conditioner
manufacturers manual for more information.
EM-15 / EM-20 TROUBLESHOOTING
Troubleshooting Chart
Specications
Model: EM-15 & EM-20
Power: 120V / 60Hz
Power Relay: 2; Contact Rating: 30A / 250VAC; Coil Rating: 12VDC
Logic Control Relay
(EM-20 ONLY):
2; SPDT Contact Rating: 3A / 250VAC; Coil Rating: 12VDC
Delay Time: 3 minute resume delay time for air conditioner protection (EM-20
ONLY); N/A for general appliances
Enclosure: Fire-retardant reinforced plastic
Dimensions: 128 x 112 x 73 mm / 5.04 x 4.41 x 2.9 in (L x W x H)
Weight: 0.55 kgs / 1.21 lbs
Mounting: Wall/Floor mounting or mount directly to the back of WFCO
Power Centers (8900 or 8500 Series)
Remote Switch
(EM-20 ONLY):
12 long wire and RJ11 connector; 1 switch to set circuit
priority; 2 LEDs to indicate which circuit is priority
AC Connections: 9P terminal block for 12 AWG / 14 AWG wire; Suggested 7 in-lb
torque
Safety: CETL / UL 916 + CSA C22.2 NO. 205
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Timing Diagram Example
APPENDIX A
GENERAL COMPLIANCE INFORMATION
AGENCY Listings
UL:
e EM-15 / EM-20 Series units are ETL listed for the United States and Canada.
FCC Compliance Class B:
NOTE: is equipment has been tested and found to comply with the limits for a Class B
digital device, pursuant to Part 15 of the FCC Rules. ese limits are designed to provide
reasonable protection against harmful interference when the equipment is operated in a
commercial environment. is equipment generates, uses, and can radiate radio
frequency energy, and if not installed and used in accordance with the instruction manual,
may cause harmful interference to radio communications. Operation of this equipment
in a residential area is likely to cause harmful interference in which case the user will be
required to correct the interference at his own expense.
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