Surge-Trap SPD Type 1 XT Installation Instructions - Mersen

INSTALLATION INSTRUCTIONS
Surge-Trap ® Type 1 XT Series SPD
The STXT Series is a high quality, high energy surge
suppressor designed to protect equipment from
damaging transient overvoltages. The STXT Series
is parallel connected device intended for service
entrance, panelboard or equipment specific protection.
Proper installation is important for maximize product
performance. These installation instructions do not
replace national or local electrical codes requirements.
WARNING – Risk of Electric Shock
• Qualified licensed electricians should install or service
all SPDs
• SPDs should never be installed or serviced when
energized or during electrical storms
• Use appropriate safety precautions including Personal
Protection Equipment
• Failure to follow instructions can result in death, serious
injury, and/or equipment damage
• For outdoor applications, customer must seal conduit
nipple using watertight fittings to ensure watertight
connection
• Read this manual in its entirety prior to installing
Compliance:
UL 1449 Third Edition and 2008/2011 NEC ® Article 285
generated changes regarding SPDs installation. The STXP
Series SPD fully complies with latest regulatory changes.
There is new emphasis on installation location and are
identified as Types 1, 2, 3 or 4 locations, outlined below.
Type 1:
Type 2:
Installation on the line side or load side of the
service disconnect overcurrent device, and
may be used in Type 2 or Type 4 installations.
Examples: Surge arresters, lightning arrestors,
meter hubs, metering cabinets, ran out of breaker
positions, etc.
Downstream of service disconnect; probably will
connect via breaker. Examples: Switchboards,
power panels, panelboards, equipment, motors,
pumps, etc.
The STXT Series is a Type 1 SPD and suitable for use in
all locations. Type 1 SPDs are evaluated more rigorously
by UL for 2008/2011 NEC Article 285 compliance. Type
1 SPDs have been evaluated for line side applications
without need for supplemental overcurrent protection. Type
1 SPDs include internal overcurrent protection. There are
practical maintenance reasons for installing on load side
of the main overcurrent device (i.e. Type 2 installation).
When connected on load side of main disconnect, its
recommend connecting a 50A - 30A circuit breaker to
protect the recommended 8 AWG conductors. The circuit
breaker serves as a disconnect switch and provides NEC
imposed short circuit protection to the conductors in Type 2
or 4 applications.
2008/2011 NEC Art 285 & UL 1449-3
SPD Types: Type 1, 2, 3, & 4
Based on Location within electrical distribution system
(also coincides with ANSI/IEEE C62.41.2 - 2002
Categories C, B &A)
Type 3:
Type 4:
Plug-in SPD
Usually treated as a UL Recognized component
in a larger UL Listed finished product. Examples:
UL 508 control panels, medical equipment, wind
turbines, signage, conveyers, elevators, etc.
DIN-rail mounting may be handy.

Specifications
Temperature Operating
Temperature Storage
Wire Size & Installation
Torque
Appropriate Circuit
Breaker based on
conductor size
NEMA 250 Enclosure
Rating
-40 o C (-40 o F) to 60 o C
(+140 o F)
-55 o C (-67 o F) to 65 o C
(+149 o F)
8 AWG; 18 inch-pounds
30A (SPD includes internal
OCP)
Type 4X with appropriate
sealing
Device Operation:
SPDs sense overvoltage conditions and create a momentary
short circuit to redirect harmful surge energy to earth ground,
resetting automatically waiting for the next surge. Operation
is similar to a pressure relief valve on a water heater: pressure
builds, valve opens to relieve pressure, resets when pressure
drops. SPDs are capable of repeating this function thousands
of times before needing replacement.
Voltage Rating & Application:
Before installing your STXP, verify by nameplate voltage or
model number that it has the same voltage rating as the
power distribution system. DO NOT INSTALL ANY LOWER
VOLTAGE RATED PRODUCT. See attached Data Sheet or
call Mersen Technical Services at (978) 465-4853 for help.
The system configuration is defined by the secondary
windings of the transformer supplying the service entrance
main or load. This includes whether or not the transformer
windings are referenced to earth via a grounding conductor.
The system configuration is not based on any specific load
or equipment connection. SPDs should be installed per
the distribution system, not per a load or motor’s wiring
connection. For example: A 480V three phase motor
appears to be connected in 480V Delta. In reality, the
distribution system is configured as a 480Y/277V grounded
Wye, with or without a neutral pulled to the motor or MCC.
The system is a 480Y/277V Wye, even though the load
is connected as a Delta. A grounded Wye has a defined
reference to ground (i.e., neutral is bonded to ground). In
contrast, some Delta systems are ungrounded, which have
no reference to ground.
WARNING SPDs on Ungrounded Systems:
Caution – Ungrounded systems are inherently unstable
and can produce excessively high line-to-ground voltages
during certain fault conditions. During these fault conditions,
any electrical equipment including SPDs, may be subjected
to voltages which exceed their designed ratings. This
information is being provided to the user so that an informed
decision can be made before installing any electrical
equipment on an ungrounded power system.
STXT Series SPDs have high a SCCR (short circuit
current ratings) capacity including the lead conductors.
Supplemental overcurrent protection is not required to
protect your STXT SPD. However, NEC ® convention
requires that connecting conductors have overcurrent
protection in Type 2 or 4 applications. Follow applicable
codes. Your STXT device features internal overcurrent and
over-temperature protection that will disconnect effected
surge suppression components at end of life. Power to the
load is maintained but unprotected and the STXT should
be replaced as soon as possible. The STXT SPD is factory
sealed and contains no serviceable parts.
Service Clearance:
Service clearance is needed at the front of the XT Series
unit only, 36 inches minimum is the required distance for
clearance pursuant to the NEC.
Cascade Surge Protection:
For optimum surge protection, cascade or staged surge
suppression should be implemented at the service entrance
and downstream locations as appropriate. Known or
expected surge sources, as well as sensitive loads, should
also have localized surge suppression. For interconnected
electronic loads (data cabling), SPDs should also be utilized
to protect the devices on either end of the interconnecting
data cables.
System Grounding:
Equipment grounding conductor must be used on all electrical
circuits connected to the SPD. For best performance,
use single point ground system where service entrance
grounding electrode system is connected and bonded to all
other available electrodes, building steel, metal water pipes,
driven rods, etc. For sensitive electronics and computer
systems, we recommend that the ground impedance
measurement be as low as possible. When metallic raceway
is used as an additional grounding conductor, an insulated
grounding conductor should be run inside the raceway and
sized per the NEC. Adequate electrical continuity must be
maintained at all raceway connections. Do not use isolating
bushings to interrupt a metallic raceway run.
A separate isolated ground for the SPD is NOT
recommended. Proper equipment connections to grounding
system and ground grid continuity should be verified via
inspections and testing on a regular basis as part of a
comprehensive electrical maintenance program. On 4-Wire
Power Systems, neutral to ground bonding (Main Bonding
Jumper) must be installed per the NEC. Failure to do so
WILL damage SPDs.
2

INSTALLATION:
Plan your installation and accomplish the following:
• Meet all National and Local codes (NEC ® Article 285
and UL 1449 address SPDs).
• Confirm System voltage to SPD voltage (120V SPD will
fail instantly on 240V, 277V, etc.).
• Mount STXP as close to panel or equipment as possible,
keeping leads as short as possible.
• Ensure leads are as short and straight as possible,
including neutral and ground. If using a breaker, use a
breaker position closest to SPD and panel’s neutral &
ground.
• If using a breaker, recommended breaker size is 50A -
30A due to recommended 8 AWG conductors.
• Make sure system is grounded per NEC and clear of
faults before energizing SPD.
• Never Hi-Pot test any SPD. Product will fail prematurely.
1. Use voltmeter to check voltages and ensure correct
SPD. See Data Sheet for specs & wire-outs.
2. Determine mounting method (See Figure 2) – weather
resistant equipment may be required.
3. If SPD has optional Dry Contact, pre-plan its installation.
4. Remove power from panel/source. Confirm panel and
all sources are de-energized.
5. Identify breaker location and SPD location. Position
SPD such that front panel is visible.
6. Mount SPD – weather resistant applications require
additional sealing, o-rings, etc. (not included).
• Remove an appropriately sized knockout from panel.
• Connect conductors as appropriate – short and
straight as possible (Hi-Legs are Phase B).
7. Label or mark conductors as appropriate (neutral:
white, ground: green, energized: black, hi-leg: orange).
8. Make sure system is bonded per NEC and is clear of
hazards or faults before energizing (N-G bonding not
per NEC will fail SPDs: #1 cause of SPD failures).
9. Energize and confirm proper operation of green
indicators and/or options.
Connecting Optional Form C Dry Contact & Audible Alarm:
Three (3) 3’ (~1m) 18 AWG wires are included through the
nipple with this option. (These are smaller than the 10 AWG
SPD conductors.) Gray is Common, Blue is Normally Open
and Blue is Normally Closed. (We generally recommend
the Normally Closed configuration because it detects
disconnected or failed wiring whereas normally open does
not.) If the dry contacts are not utilized, insulate lead ends,
coil and secure. Audible alarm will still function correctly.
The contact is rated 250V, 5A. Higher energy applications
require supplemental relaying. This option monitors
suppression element condition and is not intended for use
as phase loss or phase detection monitoring.
NORMAL OPERATION:
Phase indicator LEDs (Green)
Each STXT phase is equipped with Green LED. Should loss
of surge protection occur on each phase, the Green LED
will extinguish and the Red Service LED will flash. Every
suppression component is monitored. Note -Green LED’s
will go out due to loss of power or severe under voltage.
Service LED (Red) Flashes due to problem. Red Service
LED is slaved to Green LEDs and will illuminate when any
Green LED extinguishes.
Audible Alarm Option
If equipped with optional Dry Contact and Audible Alarm,
these options are slaved via logic to the Green LEDs. In
the event of a problem, the dry contacts will change state
and the audible alarm will sound. The audible alarm may be
silenced by de-energizing the SPD.
Dry Contact Option
One set of Form C dry contacts are included with the
Dry Contact option. Dry Contacts change state during
inoperative conditions, including loss of power. Any status
change can be monitored elsewhere via Dry Contacts.
Note – Dry contacts are rated at max 5A at 240V AC or DC.
Figure 3
Dry Contacts
Figure 2
Mounting & Dimensions
3
Remote Monitor Accessory Option
Remote Monitor is available for remote annunciation.
It requires a standalone 120V power source (wall plug
transformer) and uses one set of Form C dry contacts.
The Remote Monitor can be configured to monitor several
Mersen SPDs simultaneously. Installation is detailed in a
separate document. Contact factory as appropriate.

Figure 4
Flush Mount “/FM”
(Preferred Installation)
Maintenance:
SPDs require minimal maintenance. Periodic inspection of
diagnostic indicator is suggested to ensure proper operation.
Supplemental Instructions for
Deep Wall Mounting (Walls over 4” thick)
Using the Enclosed Mounting Feet
Troubleshooting & Service:
Please contact Mersen Technical Services for any service
related issues.
Figure 5
Conduit Installation
CORRECT INSTALLATION
Threaded 6 Full Turns
INCORRECT INSTALLATIONS
Step 1
Prepare Wall and SPD
Step 2
Insert into Wall
POOR ENGAGEMENT
Conduit needs to be
threaded in farther
OVERTIGHTENED
Stresses box, ONLY
6 full turns required
Figure 6
Typical Panel Installation
To Protected Loads
Step 3
Mount the SPD
Step 4
Mount the Lid
• Use closest breaker to
SPD
• Locate SPD close
to intended breaker
• Keep Leads Short as
Possible
• Avoid Sharp Bends
Wall Cutout
Front View
6 3/4”
Tall
• Rotate XT
such that LED
indicator is
most visible
6 1/16”
Wide
• Outdoor installation
requires appropriate
weather sealing at
nipple (o-ring, sealing
condulet, etc.)
4

Figure 7
Electrical Drawings for Customer Connections
SPLIT
2 Hots, 1 Neu, 1 Grnd
WYE
3 Hots, 1 Neu, 1 Grnd
Figure 5
HI-LEG DELTA (B High)
3 Hots, (B HIGH),
1 Neu, 1 Grnd
DELTA & HRG WYE
3 Hots, 1 Grnd
SINGLE POLE
1 Hot, 1 Neu, 1 Grnd
CORNER GROUND
DELTA (B grounded)
2 Hots, 1 Grnd
5

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