www.mgispeedware.com — A Division of Medusa Group Inc.
Installation Manual
Switch Control Panels (SCP)
Version 1.0 • November 2017
SCP Installation Manual
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Table of Contents
1. Introduction ................................................................................................. 3
2. Specifications............................................................................................... 4
3. General Installation .................................................................................. 6
4. Wire Gauge Selection – Table 1 ........................................................... 8
5. DIYS – Wire Terminals ............................................................................ 10
6. DIYS – Race Level Rockers .................................................................... 11
7. DIYS – Pro-Street Rockers ..................................................................... 12
8. DIYS – Off-Road Metal Toggle Switches .......................................... 13
9. DIYS – Off-Road LED Toggle Switches ............................................. 13
10. DIYS – Classic Car Duckbill Toggle Switches .............................. 14
11. DIYS – Classic Car Surface Mount Rockers .................................. 15
12. DIYS – Momentary Pushbutton Connections ............................. 15
13. DIYS – Ignition Key Switch Connections ...................................... 16
14. DIYS – Additional Notes ....................................................................... 17
15. Warranty ..................................................................................................... 19
16. Automotive Specs Sheet ...................................................................... 21
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MGI highly recommends reading this Installation Manual in its entirety
before proceeding with purchase and installation of any SCP.
1 Introduction
This installation manual contains general specifications for all Switch Control Panels (SCPs) as
well as individual installation instructions. This manual is intended to be used in conjunction
with the SCP Electrical Drawing. In addition to the information in this manual, other helpful
resources can be found online at:
www.mgispeedware.com/guides-documentation
Nomenclature applied throughout this document
MGI – Medusa Group Inc.
NEC – National Electrical Code
SAE – Society of Automotive Engineers
SCP – Switch Control Panel
RCP – Relay Control Panel
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2 Specifications
2.1 Each MGI SCP is provided as a components kit. Optional factory assembly is available
prior to checkout at additional cost.
2.2 SCPs are available with the following switch types:
2.2.1 Race Level horizontal rocker switches (illuminated LED – 20A).
2.2.2 Race Level vertical rocker switches (illuminated LED – 20A).
2.2.3 Pro-Street rocker switches (illuminated LED – 15A).
2.2.4 Classic Car duckbill toggle switches (illuminated neon – 15A).
2.2.5 Classic Car automotive type, surface-mount rocker switches (illuminated LED –
15A).
2.2.6 Off-Road bat-handle toggle switches (non-illuminated – 20A).
2.2.7 Off-Road bat-handle toggle switches (illuminated green tip LED – 20A).
2.3 Although aluminum enclosures are available for each SCP, weatherproof enclosures are
only available for Race Level horizontal SCPs and Off-Road non-illuminated SCPs.
2.4 Classic Car and Off-Road SCPs come with optional branch breakers and momentary LED
pushbutton or ignition key switch. All SCPs come with main feeder conductor and a
main fuse.
2.5 Unless otherwise selected using MGI’s online Fuse Size Calculator prior to checkout,
SCPs are provided as standard with the following main feeder conductor and main fuse:
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2.5.1 Loads connected to an SCP are all expected to be operated as non-continuous
use (defined by the NEC as having less than 3 hours of continuous use).
Accordingly (and with a slight additional amperage capacity over that required
by the NEC), the red main feeder conductor is sized to carry a minimum of:
(125% 𝑥 𝑙𝑎𝑟𝑔𝑒𝑠𝑡 𝑖𝑛𝑑𝑖𝑣𝑖𝑑𝑢𝑎𝑙 𝑙𝑜𝑎𝑑 𝑎𝑚𝑝𝑒𝑟𝑎𝑔𝑒)
+
(𝑇𝑜𝑡𝑎𝑙 𝑎𝑚𝑝𝑒𝑟𝑎𝑔𝑒 𝑜𝑓 𝑎𝑙𝑙 𝑜𝑡ℎ𝑒𝑟 𝑖𝑛𝑑𝑖𝑣𝑖𝑑𝑢𝑎𝑙 𝑙𝑜𝑎𝑑𝑠 𝑡ℎ𝑎𝑡 𝑎𝑟𝑒 𝑐𝑜𝑛𝑛𝑒𝑐𝑡𝑒𝑑 𝑡𝑜 𝑡ℎ𝑒 𝑆𝐶𝑃)
2.5.2 SCP main fuse sizes are provided by MGI as general application only and are
sized as follows:
Caution! Always follow the manufacturer’s fuse size requirement (or any other requirements) for your specific
load over that of the general recommendations in this manual.
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3 General Installation
3.1 Install the SCP in a clean and dry environment.
3.2 Connect one end of the red main feeder conductor to the car starter’s battery power
terminal. Install the supplied main fuse and holder (shown as F10 in SCP Electrical
Drawing) in the main feeder conductor between the starter and the MGI Switch Control
Panel.
3.3 SCPs are provided with GXL #14 AWG wire for the output of each switch (with the
exception of output wire for an SW-PB101 pushbutton switch, which is GXL #16 AWG). It
is also the user’s responsibility to install proper output (branch) fuses/breakers as may
be required by the NEC and SAE for individual loads.
3.4 Always use a switching relay for any electric motor, spotlight, or high-current resistive
loads (amplifiers, etc.). Switching relays are also necessary on the output of an MGI SW-
PB101 pushbutton switch. Please see MGI’s RL-5B-40/40 or RL-5B-50/80 relays.
3.5 SCPs are supplied with 5 feet of wire loom to be installed around the conductors
between the SCP and an MGI RCP. SCP enclosures and RCP kits are supplied complete
with a strain-relief connector that easily encompasses the wire loom encased
conductors between the SCP enclosure and RCP.
3.6 If your SCP installation does NOT include the installation of an RCP, install the output
conductors from the SCP to each of your branch circuits – providing each branch circuit
meets the use criteria for a switch without switching relay, and providing each individual
load’s rated amperage is within the switch’s rated load capacity listed in Article 2.2 of
this installation manual.
3.7 Alternatively, install the conductors between any SCP and RCP per the appropriate RCP
Electrical Drawing. When an SCP is connected to an RCP (with the SCP’s input connected
to RCP Terminal #11), your loads cannot be connected directly to an SCP switch output
because the RCP Terminal #11 is fed with a #16 AWG and fused at 5A. RCP Terminal #11
is a control circuit only.
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3.7.1 Where you want to operate some loads directly from the output of an SCP
switch, and other loads from an RCP (Eg: Connecting an SCP8 to an RCP6), then
the input power to the SCP must be taken from the RCP input red battery
terminal (not from RCP terminal #11). The main feeder conductor and main fuse
must be properly sized for the entire load.
3.8 All SCP installations should be completed minimally per the current and wire sizing
specifications outlined in the Wire Gauge Selection – Table 1 outlined below, and per
SAE electrical codes for low voltage circuits under 32v.
3.9 Where an SCP is connected to an RCP, the main fuse supplied with the SCP kit should
not be used provided that all SCP circuits are used to switch or control an RCP relay.
3.10 To change the main fuse (shown as F10 in SCP Electrical Drawing), gently squeeze the
fuse holder cover using the thumb and forefinger of both hands, with thumb/forefingers
placed on the sides of the cover – about 1” from each end of the cover – and lift
carefully. After changing the fuse, the fuse cover should be replaced using the same
thumb/forefinger aforementioned technique. Failure to follow these instructions can
result in damage to the plastic fuse cover mounting tabs.
3.11 Some MGI SCPs are supplied with factory-installed LEDs. These 3mm LEDs are very
bright. For more subtle LED light (50% less candlepower), add a separately purchased
EP-R101 damper resistor kit.
3.11.1 A single EP-R101 damper resistor can be used with an SCP where 4 to 8 LEDs are
already installed. Simply disconnect the 3mm LED (black wire with ring terminal)
from its ground terminal and add the damper resistor in series between the
disconnected LED ring terminal and ground.
3.11.2 Insulate the resistor and/or black wire ring terminals as may be required.
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4 Wire Gauge Selection — Table 1
NEC Recommended AWG/Ampacity Chart for Copper GXL or SGX Automotive Primary Wire
(Rated -51C to +125C, applied in a “Free Air” 12vDC circuit)
Table 1: Found online at www.mgispeedware.com/guides-documentation/wire-size-chart/
4.1 This printable table is a “captured” photo of the online interactive chart with
calculations set for a) single load branch conductors, b) 20°C ambient air temperature,
and c) 3% voltage drop based on a 13.8vDC nominal voltage.
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4.1.1 Use the interactive version of Table 1 on MGI’s website located under Guides
and Documentation to properly determine the size of your branch and feeder
conductors.
4.2 While this table outlines specifics for single copper conductors in Free Air per the NEC,
your automotive electrical installation does not necessarily conform to a “Free Air”
definition. Granted, your conductors are not installed in a heat encompassing shield
such as metal conduit or PVC tube either. Your conductors may be held firmly inside
(breathable) wire loom or sleeving, and may be tie-wrapped or secured with a multitude
of other conductors.
4.2.1 MGI can, however, appropriately suggest that you increase the Ambient Air
Temperature correction factor to allow for any heat restraints outlined in Article
4.2.
4.3 Maximum Voltage Drop – NEC standards allow for a maximum 3% voltage drop in
feeder conductors, and a maximum 5% voltage drop in branch conductors.
4.4 Branch conductor – Branch conductors are sized to carry 100% of load rated amperage
per the NEC minimal requirement for non-continuous use (defined by the NEC as having
less than 3 hours of continual use).
4.5 Feeder conductor – Feeder conductors are sized slightly larger than the NEC minimal
requirement for non-continuous use. Feeder conductors are sized to carry a minimum of
125% of the largest load’s rated amperage + the total amperage of all other individual
loads that are connected to the Feeder conductor.
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5 DIYS (Do It Your Self) — Wire Terminals
Instructions For LED Red wires to Parallel Connect Onto Other Wire Terminals
0.225 (Strip)
0.35 (Strip)
For Red Ring Terminal
The leading edge of the LED copper should enter the Red Ring Terminal about 1/8"
before the leading edge of the # 14 AWG (GXL)copper does. This will ensure that
the small LED Red wire is firmly connected within the Red Ring Terminal.
GXL # 14 AWG
LED Red wire # 26 AWG
0.330" (Strip)
0.455 (Strip)
For (Blue or Red)Female Disconnect
The leading edge of the LED copper should enter the Female Disconnect about 1/8"
before the leading edge of the # 14 AWG (GXL)copper does. This will ensure that
the small LED Red wire is firmly connected within the Female Disconnect.
GXL # 14 AWG
LED Red wire # 26 AWG
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6 DIYS — Race Level Rocker
Race Level Rocker Connection Schemes
32
712vDC LOAD
Switch LED Has
Polarity.
N/A
12vDC LOAD 1
Switch LED Has
Polarity.
32
7
1
LOAD 2
Note 1: Switch closes (2 to 1)or(2 to 3) - not both at the same time. If
the user needs to have LOAD 1 turned on in(2 to 1)position, and Both
LOAD 1 and LOAD 2 turned on in(2 to 3)position, then add a (load
current)sized diode between terminal 1 and terminal 3.
Race Level Rocker
Race Level Rocker
32
712vDC LOAD
Switch LED Has
Polarity.
N/A
Race Level Rocker
Race Level Rocker Switch Connection Scheme
12vDC LOAD 1
Switch LED Has
Polarity.
N/A
32
7
1
LOAD 2
Note 1: Switch closes (2 to 1) or (2 to 3)- not both at the same time. If the
user needs to have LOAD 1 turned on in (2 to 1)position, and Both LOAD 1
and LOAD 2 turned on in (2 to 3) position, then add a (load current)sized
diode between terminal 1 and terminal 3.
Race Level Rocker
Switch Models #: SW-ROC-RL101/X
Switch Models #: SW-ROC-RL102/R
Switch Models #: SW-ROC-RL103/X
Switch Models #: SW-ROC-RL104/B
Suffix (X)= Any letter.
Suffix (X)= Any letter.
Alternate Connection
Alternate Connection
Alternate Connection
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7 DIYS — Pro-Street Rocker
Pro-Street Level Rocker Connection Schemes
Switch Relative Position
from terminal side.
Switch Relative Position
from terminal side.
Pro-Street Level Rocker Switch Connection Scheme
Switch Models #: SW-ROC-PS30X/X
Suffix (X)= Any letter.
Switch Model #: SW-ROC-PS301/R
LOAD
12vDC LOAD12vDCSwitch is
Non-illuminated.
(OR)
Pro-Street Rocker
Switch Relative Position
from terminal side.
Switch Model #: SW-ROC-PSBLK
Alternate Connection
Alternate Connection
Alternate Connection
LOAD
12vDC LOAD12vDCSwitch LED Has
NO Polarity.
(OR)
Pro-Street Rocker
LOAD
12vDC LOAD12vDCSwitch LED Has
NO Polarity.
(OR)
Pro-Street Rocker
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8 DIYS — Classic Car Duckbill Toggle
Classic Car Duck Bill Toggle Switch Connection Scheme
9 DIYS — Off-Road LED Toggle
Metal Bat Handle Toggle Switch c/w Green Tip LED, Switch Connection Scheme
LOAD
12vDC
Classic Car Duck Bill Toggle Switch
Switch Relative Position from terminal side.
Classic Car Duck Bill Toggle Switch Connection Scheme
Switch Models #: SW-TOG-DB114/X
Suffix (X)= Any letter.
Paper Label This Side
Switch LED Has
Polarity.
N/A
Alternate Connection
13
12vDC LOAD
Switch LED Has
Polarity.
N/A
Metal Bat Handle Toggle c/w Green Tip LED
Metal Bat Handle Toggle Switch c/w Green Tip LED Switch Connection Scheme
Switch Model #: SW-TOG-LBH113
Switch Relative Position
from terminal side.
Alternate Connection
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10 DIYS — Off-Road Metal Toggle
Off-Road Metal Bat Handle Toggle Switch Connection Schemes
LOAD 1321
LOAD 2
Note 1: Switch closes (2 to 1) or (2 to 3) - not both at the same time. If the user
needs to have LOAD 1 turned on in (2 to 1) position, and Both LOAD 1 and LOAD
2 turned on in (2 to 3) position, then add a (load current) sized diode between
terminal 1 and terminal 3.
Off-Road Metal Bat Handle Toggle Switch Switch Model #: SW-TOG-BH104
12vDC LOAD 1654
LOAD 2
Note 1: Switch closes (2 to 1) + (5 to 4)or (2 to 3) + (5 - 6) - not both at the same
time. Terminals (1 and 4), (2 and 5), (3 and 6)are all indepenent from each other.
Off-Road Metal Bat Handle Toggle Switch Switch Model #: SW-TOG-BH105
32112vDC LOAD 1
654
LOAD 2
Note 1: Switch closes (2 to 1) + (5 to 4)or (2 to 3) + (5 - 6) - not both at the same
time. Terminals (1 and 4), (2 and 5), (3 and 6)are all indepenent from each other.
Off-Road Metal Bat Handle Toggle Switch Switch Model #: SW-TOG-BH106
321
12vDC
LOAD 1654
Note 1: Switch closes (2 to 1) + (5 to 4)or (2 to 3) + (5 - 6) - not both at the same
time. Terminals (1 and 4), (2 and 5), (3 and 6)are all indepenent from each other.
Off-Road Metal Bat Handle Toggle Switch Switch Model #: SW-TOG-BH105
321
654
321BLACK
REDJumpers
Switch (External) View Switch (Internal) View
Reversing a 12vDC PM Motor
12vDC
PM Motor
LOAD
12vDC
Off-Road Metal Bat Handle Toggle Switch
Switch Relative Position
from terminal side.
Off-Road Metal Bat Handle Toggle Switch Connection Schemes
Switch Model #: SW-TOG-BH101
LOAD
12vDC
Off-Road Metal Bat Handle Toggle Switch
Switch Relative Position
from terminal side.
Switch Model #: SW-TOG-BH102
Switch has No polarity. Switch has No polarity.
1 3 1 3
12vDC LOAD 1321
LOAD 2
Note 1: Switch closes (2 to 1) or (2 to 3) - not both at the same time. If the user
needs to have LOAD 1 turned on in (2 to 1) position, and Both LOAD 1 and LOAD
2 turned on in (2 to 3) position, then add a (load current) sized diode between
terminal 1 and terminal 3.
Off-Road Metal Bat Handle Toggle Switch Switch Model #: SW-TOG-BH103
12vDC
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11 DIYS — Classic Car Surface Mount Rocker
Classic Car Automotive Surface Mount Rocker Switch Connection Scheme
12 DIYS — Momentary Pushbutton
Momentary Pushbutton Switch Connection Scheme
LOAD
12vDC
Classic Car Automotive Surface Mount Rocker
Switch Relative Position
from terminal side.
Classic Car Automotive Surface Mount Rocker Switch Connection Scheme
Switch Models #: SW-ROC-SM20X/X
Suffix (X)= Any letter.
Switch Paper Label
Switch LED Has
Polarity.
N/A
Alternate Connection
12vDC
Momentary Pushbutton Switch
Momentary Illuminated LED RING Pushbutton Switch
Relative Position from terminal side.
Momentary Pushbutton Switch Connection Scheme
Switch Model #: SW-KEY101
C
NO
NC
LOAD
SOLENOID
OR RELAY
Fuse as may be required.
Note: MGI (crimp) Female disconnects must have wire inserted into the
crimp connector as far as the wire can be inserted into the funel of the Female
disconnect part of the terminal (about 3/8"). This will keep the Female
Disconnect firmly attached to the pushbutton switch.
(3A Maximum Resistive Load)
# 16 AWG
# 16 AWG
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13 DIYS — Ignition Key Switch
Ignition Key Switch Connection Scheme
12vDC
Ignition Key Switch
Ignition Key Switch Relative
Position from terminal side.
Ignition Key Switch Connection Scheme
Switch Model #: SW-KEY101
BAT BATSTART SOLENOID
SSORANGE # 14 AWGST
IGN ACC
RED # 10 AWG
RED # 10 AWG
# 14 AWG LOADS WITHOUT AUTO RUNNING
- AUDIO
- INTERIOR LIGHTING
- EMERGENCY FLASHERS
- ETC.
LOADS WITH AUTO RUNNING
- IGNITION
- HEADLIGHTS
- AUDIO
- INTERIOR LIGHTING
- EMERGENCY FLASHERS
- FANS
- PUMPS
- ETC.
Fuse all circuits as may be required.
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14 DIYS Notes
14.1 When placing SCP description labels onto the SCP faceplate, put a piece of masking tape
along the top or bottom line where you want to place the labels. Then peel only a
corner off a label from the label sheet. Place a (clean) small flat screwdriver under the
peeled label corner and press slightly so that the label stays on the screwdriver. Then lift
off the label while it is still stuck on the screwdriver. This will allow you to better
position the label along the masking tape edge for that “straight” look – without leaving
fingerprints under the label.
14.2 ON/OFF toggle switch nameplates are supplied with metal bat-handle toggle switches
only. The nameplates can also be purchased separately for use with duckbill toggle
switches. The nameplates have a small male tab on the bottom of their center hole
which helps to keep the nameplates vertically aligned onto a metal toggle switch. When
using these nameplates with duckbill toggle switches, you must file off the small male
tab in the nameplate so that the nameplate can be mounted on the duckbill toggle.
Unlike metal bat-handle toggle switches, the duckbill toggle does not have a female tab
for aligning ON/OFF nameplates.
14.3 Use only BLUE female disconnect crimp terminals on any Classic Car automotive surface
mount switch (SW-ROC-SM20X/X) male spade terminal. While RED female disconnect
crimp terminals are generally the same physical [spade] size as are BLUE female
disconnect wire crimp terminals, the RED female disconnects supplied by MGI will NOT
fit the Classic Car automotive surface mount switch male spade terminals.
14.4 Crimp Terminals – Red crimp terminals are generally used for #18 - #16 AWG wire while
blue crimp terminals are generally used for #16 - #14 AWG, with Yellow crimp terminals
generally used for #12 - #10 AWG wire. Primary automotive wire such as GXL has a
smaller circumference than does TEW and other types of industrial wire. For this reason,
red crimp terminals supplied my MGI may better suit #18 - #14 AWG GXL wire. Always
use a crimp terminal that closely fits the wire you are using; doing so will help to ensure
proper crimping of terminal onto wire.
14.5 Non-illuminated metal bat-handle toggle switches have screw terminals.
14.6 When connecting a wire ring terminal under the switch screw terminal, it is important to
firmly hold BOTH the wire ring terminal and switch body so that tightening the switch
screw terminal does not twist that terminal loose from the switch body pin.
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14.7 Always place the wire ring terminal on the switch screw terminal as shown below so
that BOTH the wire ring terminal and switch body can be held firmly in the same hand
while tightening the switch screw with a Phillips screwdriver in the other hand:
YES
NO
Bat Handle Toggle Switch
wire Ring Terminal
wire Ring Terminal
Bat Handle Toggle Switch
Switch Body Pin Switch Body Pin
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15 Warranty
15.1 Medusa Group Inc. warrants each of its products to be free from defects in materials or
workmanship when operated under normal working conditions and in accordance with
manufacturer's installation and operating instructions, for a period of twelve months
from the date of purchase. This warranty shall be in lieu of any other warranty
expressed or implied, including but not limited to any implied warranty of
merchantability or fitness for a particular purpose.
15.2 MGI shall not be responsible for removal, installation, or any other incidental or
consequential damages arising from, or caused by the use of any of its products.
15.3 MGI’s liability under this warranty shall be solely limited to the replacement or repair of
its defective product within the warranty period, and shall not be liable under any
circumstances for any damages including but not limited to personal injury or labor
costs. Under no circumstances will MGI be responsible for any repairs made by anyone
other than the factory or authorized repair depot, unless such repairs have been
authorized in writing by MGI.
15.4 Remedy for warranty shall include one of the following:
Where the complete product is returned to MGI (15.4.1)
15.4.1 MGI will repair or replace, at its sole discretion, any component that has been
found to be defective by the manufacturer, and is within the warranty period,
provided that the complete product is shipped with factory authorization,
freight prepaid, to the nearest MGI factory outlet or authorized service facility.
Upon completion of warranty repairs, MGI, or its authorized service center will
return the product freight prepaid, using Standard Ground delivery service as
selected by MGI.
Where the product remains installed in the automobile, and where one or more components are determined to be faulty (15.4.2 – 15.4.3)
15.4.2 Where any component is determined by MGI to be faulty within the warranty period, and where such a component is provided for under the terms of warranty, the replacement component will be shipped freight prepaid, (component pre-billed to the client) using Standard Ground delivery services as selected by MGI.
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15.4.3 Any faulty or damaged component that has been replaced under the terms of
warranty must be returned to MGI within 15 days, freight prepaid, in order to validate the warranty. MGI will evaluate and will either approve or deny the warranty claim, and will credit the client’s payment method according to MGI’s ruling. Some exceptions may apply.
15.5 Where any warranty component is requested by the recipient with delivery service
other than Standard Ground, the product will be shipped freight collect only.
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16 Automotive Specs
Loads
Load Type (Eg: Water Pump, Fan 1, Fan 2), etc.
Connected to RCP (terminal #)
Load Amps
Fuse size
Load 1
Load 2
Load 3
Load 4
Load 5
Load 6
Load 7
Load 8
Load 9
Load 10
Load 11
Load 12
For technical help, contact MGI at [email protected]
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