Siemens Surge Protective Device TPS3 12 - Manual (Page 9)

Terminals
Terminals will accept 14 - 2 AWG conductor and are provided for line
(phase), neutral (if used), and equipment safety ground connections.
8 AWG is the minimum recommended wire size because UL testing
and evaluation was performed using 8 AWG.
Wire Size and Installation Torque
This is a parallel-connected SPD; it is not series-connected. The size of
the SPD wiring is independent of the ampere rating of the protected
circuit. Recommended wire is 6 AWG for phase, neutral and ground
connections. Torque connections to 18 inch-pounds. Conductor
length should be as short as possible.
If other wire sizes are used, all conductors must be the same gauge.
Note that larger conductor might appear to be beneficial. However,
large conductor tends to have the same inductance as smaller
conductor, thus netting limited improvement in exchange for being
more difficult to work with.
Terminals accept 14 - 2 AWG conductor with 6 AWG being preferred.
Coordinate conductor size and overcurrent protection per applicable
codes.
If equipped, Disconnect Switch will accept 6 AWG to 1/0 AWG, with
6 AWG preferred. Torque connections to 18 inch-pounds. Do Not
over-torque connections on Disconnect Switch as they will fail upon
overtightening and will not be covered by warranty.
System Grounding
An equipment grounding conductor must be used on all electrical
circuits connected to the SPD.
For the best performance, use a single point ground system where
the service entrance grounding electrode system is connected to and
bonded to building steel, metallic piping, driven rods, etc. (NEC and
IEEE Std 142-2007 are appropriate standards).
For sensitive electronics and computer systems, ground impedance
should 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 may isolate the SPD from the
rest of the electrical system, thus decreasing performance. Ensure
grounding system meets NEC. Proper equipment connections to
grounding system and ground grid continuity should be verified via
inspections and tested 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.
NEMA 3R Drain Holes for Standard Steel Enclosure
In order to maintain a UL 3R rating, two 0.25” (6mm) holes must be
drilled in opposite corners of the bottom surface of the enclosure. Take
care to not damage internal SPD components. Remove any drilling
remnants. (Do not perform on other enclosures or ratings.)
Figure 3: NEMA 3R Drain Holes
Module Rotation Feature
Installation lead wire length must be minimized because longer
leads hurt performance. Lead length may be reduced by rotating
the module inside the enclosure. SPD ships with terminals pointing
down. If installation lends itself toward other orientation, the module’s
aluminum backplane can be unscrewed and reoriented. For example,
if leads enter from top, rotate module assembly such that leads are
shortest. Be careful with ribbon cable connector and take care to
retighten screws & secure ribbon cable. Mounting screws are in four
corners. Rectangular enclosures may be rotated up or down only.
Figure 7: Rotating Module
Diagnostic Cable Connector
Mounting Screws
in Corners
6