Guardian EXT-401 Installation & Operation Manual
Explosion Proof Telephone
Model EXT-401
Installation & Operation
Ph: 403.258.3100 \ email:info@guardiantelecom.com \ www.guardiantelecom.com
P002640 Rev. G 150109 1/9/2015 9:57 AM
Guardian Telecom Inc. Installation and Operation
Page 2
Table of Contents
Table of Figures
(1) EXT-401 Telephone
(1) Installation & Operation Manual
Model EXT-401
Package Contents ...........................................................................................2
Overview .........................................................................................................3
Features ..........................................................................................................3
Warnings .........................................................................................................5
General Requirements ....................................................................................5
EXT 401 Models ..............................................................................................6
Options ............................................................................................................6
Installing the EXT-401 .....................................................................................6
Wiring For Tip & Ring ......................................................................................8
Wiring For Peripheral Signaling Device ...........................................................9
Wiring of Tip & Ring with Optional Disconnect Switch ................................... 11
Installation of Peripheral Signaling Device with Power Disconnect Switch .... 12
Fuse Replacement ........................................................................................ 13
Replacement of Telephone Handset Assembly ............................................. 14
Replacement of ISH1125 Headset ................................................................ 15
Operating Instructions ................................................................................... 16
Engineering Specifications ............................................................................ 17
Replacement Parts ........................................................................................ 18
Warranty ........................................................................................................ 20
Disclaimer ..................................................................................................... 20
Warning ......................................................................................................... 20
Service Telephone Number ........................................................................... 20
Feedback ...................................................................................................... 20
Guardian Product Return ............................................................................... 21
APPENDIX A - Hazardous Location Classification ........................................ 22
APPENDIX B - Applications ........................................................................... 23
Figure 1 - Features ..........................................................................................4
Figure 2 - Dimensions .....................................................................................4
Figure 3 - Typical Installation ...........................................................................7
Figure 4 - Lower Junction Box Wiring ..............................................................8
Figure 5 - Upper Junction Box Wiring ..............................................................9
Figure 6 - Typical Installation With Disconnect Switches ............................... 10
Figure 7 - Optional Telephone Line Disconnect Switch Wiring ....................... 11
Figure 8 - Power Disconnect Switch Wiring ................................................... 12
Figure 9 - Fuse Replacement ........................................................................ 13
Figure 10 - Handset Replacement ................................................................. 14
Figure 11 - Headset Replacement ................................................................. 15
Figure 12 - Headset Hook Switch Operation .................................................. 16
Figure 13 - I.D. and Compliance .................................................................... 18
Package Contents
Guardian Telecom Inc. Installation and Operation
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Model EXT-401 Explosion Proof Telephone
This explosion proof telephone provides safe and reliable communication in hazardous locations, up
required. The signaling device may be actuated by an optional internal or external ring detect relay.
Enclosure
Internal Sealed Cavities
Keypad
Circuitry Coating
Magnetic Reed Hook Switch
telephone cradle.
Tone (DTMF)/Pulse Operation
Factory set to operate to tone (DTMF) exchanges unless pulse specified.
Intrinsically Safe Handset Operation
Field Replaceable Handset and Headset
Field Replaceable Fuse
Hearing-Aid Compatibility
Receiver Volume Control
Model EXT-401
Overview
to and including Class I Division 1, (see Figure 13 - I.D. and Compliance). Only standard wiring and
fittings are required to connect the telephone to the system; no barrier is necessary. Since the heavy
duty cast aluminum enclosure is basically soundproof, an external device to signal incoming calls is
Features
• Cast copper free aluminum with powder coat finish.
• Completely seal the unit.
• Standard configuration with an additional row of buttons for Last Number Redial,
Link/Flash to access PABX features and Line Release to duplicate hanging up the
handset (Link and Redial buttons may be replaced by Volume Up and Volume Down).
• One inch diameter buttons for gloves-on operation.
• Circuit boards have a UV cured epoxy coating which provides protection from
corrosive agents such as H
S, SO2, and NH
2
and environments with high humidity.
3,
• No moving parts, activates when the handset is removed from or placed in the
•
• The output from the telephone to the handset passes through an intrinsically safe
barrier ensuring a high degree of safety.
• The handset cord is attached to the telephone by a connector for ease of
replacement.
• The cord is designed for industrial applications and is available in 10’ (3m), 20’ (6m)
coiled and 22" armored lengths. An optional headset is available.
• A fitting in the bottom of the enclosure provides access to the fuse.
• The handset is compatible with inductively coupled hearing-aid devices.
• Selected models provide 13.5dB of range.
Guardian Telecom Inc. Installation and Operation
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Model EXT-401
Figure 1 - Features
Figure 2 - Dimensions
Guardian Telecom Inc. Installation and Operation
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Model EXT-401
Warnings
• In no case should this telephone apparatus or wiring be installed in a location where
acetylene may be present in the atmosphere.
• Two back cover retaining bolts on the model EXT-401 are factory sealed. Damage to the
seals voids the warranty and safety approvals, and may compromise unit safety.
• It is the responsibility of the installer to advise a supervisor if any telephone equipment or
wiring in a hazardous location may not comply with regulations and standards applicable to
that location.
• Avoid creating a spark by striking tools or metal objects together, against concrete, stone, or
any similar substance.
• Test equipment capable of producing an electric spark must not be used in an explosive
atmosphere.
• All apparatus should be completely assembled and properly sealed before reconnecting
power.
General Requirements
• An EXT-401 telephone should only be installed with proper authorization. It is necessary for
the customer and the telephone company to have a definite agreement regarding the
location of the telephone unit, auxiliary apparatus, and protector (i.e. lightning arrestor at the
demarcation block).
NOTE:
• To maintain maximum protection, broken or worn parts must be replaced immediately. Any
abnormal conditions should be immediately corrected. Periodic inspections are
recommended.
• Unless otherwise specified, the customer must provide and install explosion-proof conduit
and fittings approved by the Canadian Standards Association (CSA) or listed by
Underwriters Laboratories (UL). The customer is also responsible for having the system
inspected and approved by the appropriate electrical inspector in accordance with local
legal requirements and National Electrical Code Standards.
• EXT-401 telephone sets and associated external bells and control relays are designed to
provide security against ignition of the surrounding atmosphere. All parts of the apparatus
which might produce an electrical spark are completely enclosed. All passages to the
outside are made such that any spark or flame will be cooled to a temperature below the
ignition threshold before reaching the outside atmosphere.
• If the handset or cord is damaged, it must be replaced with part 301SC or 301SCPB
handset assembly. Handsets and cords are not covered under warranty other than to be
free of defects at time of installation.
• If the telephone is found to be defective or in need of repair, it must be returned to the
manufacturer. No field repair is possible other than replacement of the handset and fuse.
• Telephones in good condition may be moved from one location to another.
Guardian Telecom Inc. Installation and Operation
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PAR T NO.
DESCRIPTION
No Volume Control – Has LINK & REDIAL Buttons
P4011
No enhancements
P1011
Backplate & CE20 Line Powered Ringer
P4021
Ring Detect Relay
P1021
Ring Detect Relay, Backplate & CE20 Line Powered Ringer
P4022
Ring Detect Relay & Headset
P4023
Headset
P4036
Ring Detect Relay, Headset, Backplate & CE20 Line Powered Ringer
P4038
Headset, Backplate & CE20 Line Powered Ringer
Volume Control Buttons Replace LINK & REDIAL
P4012
No enhancements
P4030
Backplate & CE20 Line Powered Ringer
P4031
Ring Detect Relay
P4032
Ring Detect Relay, Backplate & CE20 Line Powered Ringer
P4033
Headset
P4034
Headset, Backplate & CE20 Line Powered Ringer
P4035
Ring Detect Relay & Headset
P4037
Ring Detect Relay, Headset, Backplate & CE20 Line Powered Ringer
installation or electrical wiring.
Installation.
peripheral equipment.
Model EXT-401
EXT 401 Models
Options
20C - Twenty foot handset cord.
22AC - 22" armored cord.
HS - Headset with thirty foot cord.
Installing the EXT-401
• Declassify the hazardous location before proceeding with any
• Follow all appropriate electrical codes and use only approved electrical
fittings for the installation.
• Choose a wall location that is free of obstructions and permits space for ½”
NPT conduit runs
• Ensure mounting can support 16.5lbs. (7.5kg), plus the weight of any
• Ensure that none of the electrical connection circuits are live.
• Use the template provided to locate and drill holes for mounting screws.
Use ¼” bolts or screws to mount the unit.
• Secure the unit to the wall:
• Attach lower conduit nipples to the telephone and ensure a minimum five
thread engagement.
• Mount an approved explosion proof junction box within 45.7 cm (18") of the
telephone’s lower sealing cavity and bring telephone wires into this box.
Fittings compatible with 1/2 inch NPT nipples, conduit, or 1/2 inch
explosion-proof flexible couplings not exceeding 45.7 mm (18 inches) may
be fitted directly.
Caution: Installation or
electrical wiring in a
hazardous location
could result in serious
injury to personnel or
damage to property.
Figure 3 - Typical
See:
See: Figure 2 -
Dimensions.
Tip: Use ¼” bolts or
screws to secure the unit
to the wall.
Guardian Telecom Inc. Installation and Operation
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Model EXT-401
Figure 3 - Typical Installation
Note: Models without volume control are not approved by the FCC and Industry Canada; they
must therefore not be connected directly to a Central Office line.
Guardian Telecom Inc. Installation and Operation
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dialing was specified. Switching in the field is not possible.
green wires and attach these wires to the ground screw in the junction box.
Model EXT-401
Wiring For Tip & Ring
• After mounting the telephone follow these steps.
NOTE: The ExT-401 is factory set for tone (DTMF) dialing unless pulse
• Run tip, ring and ground wires from the local exchange into the lower junction
box. The tip and ring wires must not be connected to the local exchange until
installation is completed. A sealing fitting must be installed within 45.7 cm
(18") on the exchange side of the lower junction box.
• Attach the tip and ring wires to the orange and blue wires from telephone
using twist on wire connectors. Attach #10 ring lugs to the end of the three
• Check the wiring and close the junction box.
TO 401
GROUND
GREEN
TIP & RING
BLUE & ORANGE
( NOT POLARITY SENSITIVE)
See: Figure 4 - Lower
Junction Box Wiring
Figure 4 - Lower Junction Box Wiring
FROM EXCHANGE
TIP
RING
GROUND
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