00‐02‐0251 06‐24‐2010 Section 70 EG21 and EGS21 Series Electric Gage and Swichgage® Installation for Pressure, Temperature, Fuel Level, Voltmeter and Ammeter Wire/Connector Assembly NOTE: EG21 Series gage and EGS21 Series Swichgage movement and illumination require 12VDC to
function. For 24 or 32 volt systems, voltage converters are built into the electrical wire/connector
assembly and supplied with instrument.
Listed below are replacement part numbers for all wire/connector assemblies. Voltage converter included for 24 and 32 volt. Specify part
number when ordering.
12 VDC
24 VDC
32 VDC
EG21P / T / F
05004506
05006166
05006167
EGS21P / T / F
05004507
05006168
05006169
EG21AM
05004505
05006170
05006171
EGS21AM
05004504
05006172
⎯
EG21VM
05004508
05004508
⎯
EGS21VM
05004504
05004504
⎯
Gage Installation Sharper Accuracy. Higher Durability. Advanced Technology. The EG21 Series Electric Gage and the EGS21 Series Swichgage instrument take the electric gage to new heights with proven state-of-theart technology and reliability.
• EG Air Core movement design
• Exceeds the rigid SAE J1810 standard
• Technological improvements in
lighting, accuracy in reading and
wiring installation
• Corrosion-resistant materials
• Assurance of highest reliability and
service
• Soft, non-glare dial and pointer illumination by
“cold light” LED
• Environmentally sealed design
• Desirable for marine and other environmentally
sensitive applications
Electric Swichgage instrument The EGS21 Series Swichgage instrument has all of the features of the EG21 Series Gage plus an adjustable set point PowerHall® Effect
switch output for operating alarms or equipment shutdown. The trip point is adjustable over 90% of the scale and has a set point indicator
visible from the gage face. Now you can have both, the ease of electric gage installation and the reliable switching of Murphy’s famous
Swichgage instrument.
Dimensions In order to consistently bring you the highest quality, full featured products, we reserve the right to change our specifications and designs at any time.
MURPHY, the Murphy logo, and Swichgage® are registered and/or common law trademarks of Murphy Industries, Inc. This document, including textual
matter and illustrations, is copyright protected by Murphy Industries, Inc., with all rights reserved. (c) 2008 Murphy Industries, Inc.
Specifications Power input, all models and sender: 12 VDC or 24 VDC.
Case: Polyester (PBT), impact and weather resistant with screw-on mounting clamp.
Bezel: Polished 316 stainless steel standard; available in black, SAE style optional.
Lens: Clear Polycarbonate and UV stabilized.
Air Core Movement: Silicon dampened pointer.
Dial: Black with white markings; back-lite (marking becomes red when illuminated); dual scale with mirror band to reduce parallax reading
errors.
Swichgage Instrument Sensor: PowerHall® Effect; outputs ground signal (sinking output) rated: 300 mA continuous (EGS21 models).
Pressure, Fuel, Volts set on decreasing scale. Temperature and Amps set on increasing scale. Output saturation voltage (voltage drop
across switch): 1.3-2.3 Volts @ 25⁰C (may require some conditioning to work with logic inputs).
Swichgage instrument Set Point Indicator: Visible on mirror band (scale); adjustable from the back of the unit (1/16 in. hex type wrench).
Wiring: Plug connector with wire leads, 18 AWG (1.0 mm2 ), 8 in. (203 mm) long.
Operating Temperature: -40 to 185⁰F (‐40 to +85⁰C). Storage Temperature: -77 to 185⁰ F (-60 to +85⁰C).
Over voltage (Gage Movement): Withstands 200% of nominal system voltage for 5 min. Meets SAE J1810.
Reversed Polarity (Gage Movement): Withstands reversed battery terminal polarity indefinitely within operating temperatures.
Environment and Test: Meets SAE J1810 standards
Sender Installation CAUTION: Do not use sender body to tighten. If sealant tape or pipe dope is used on
the pressure sender, be sure that the tape or dope does not plug the sender’s orifice.
CAUTION: Extreme caution must be used in handling or working on or around the fuel
tank. It must be worked on only in a WELL VENTILATED area. Keep all flame and hot
materials away from it. Do not smoke while working on or around the tank. Avoid
sliding or dragging the tank, or other actions which may cause a spark.
NOTE: When installing the fuel sender in a non-metallic tank using a single wire sender, another wire
must be added from one of the sender mounting bolts to the battery ground (negative post). See 1 in
the ‘Tank Installation’ illustration above.
Basic Wiring WARNING: Disconnect battery negative cable before wiring or service.
*Yellow wire is optional for gage illumination and does not need to be connected for gage to operate. Sender Wiring Swichgage Wiring WARNING: DISCONNECT BATTERY NEGATIVE CABLE BEFORE WIRING OR SERVICE.
CAUTION: Connecting full Battery potential to the brown wire can damage the
Swichgage. Shutdown circuit is rated for 300 mA continuous, 900 mA inrush. Circuit
sinks to battery negative at set point.
CAUTION: Devices containing solid state components can be damaged or caused to
malfunction when used in systems which incorporate inductive loads (e.g. relays,
solenoids, etc.) that can generate voltage spikes.
To reduce the potential for this type of damage, install a flyback or clamping diode
across all inductive loads (see wiring diagram below).
Use Murphy diode package 65-00-0343 or equivalent. A typical diode is 1N4005 which
is readily available from commercial sources. Failures of this type are not covered by
our Limited Warranty.
Warranty - A limited warranty on materials and workmanship is given with this FW Murphy product. A copy of the warranty
may be viewed or printed by going to www.fwmurphy.com/support/warranty.htm
NOTE: Do not connect 117PH
or power on TL7 to brown wire.
Only use 518(A)PH or 760
Tattletale indicators. Pilot a
relay with a flyback diode
across the coil for loads pulling
more current than rated.
In 2008, surge absorber harnesses were shipped with the EGS21 family of Swichgage Instruments. These surge absorbers are now
built into the EGS21’s with Date Code E-5 (May 2009) or later. The external surge absorber harness is no longer needed. It will not
cause any problems if it is used with the new EGS21’s.
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