Installation
2.3
CONNECTING POWER SOURCE AND
LOAD LINES
M ake sure to turn OFF both the UTILITY
(NORMAL) and EMERGENCY (STANDBY)
power supplies before trying to connect power
source and load lines to the transfer switch.
Supply voltages are extremely high and dan-
gerous. Contact with such high voltage power
supply lines will result in an extremely hazard-
ous, possibly lethal, electrical shock.
Wiring diagrams and electrical schematics are provided in this
manual. Power source and load connections are made at a transfer
mechanism, inside the switch enclosure.
2.4.1
3-POLE MECHANISM
These switches (Figure 2.1) are used with a three phase system,
when the three phase NEUTRAL line is to be connected to a
NEUTRAL lug and is not to be switched.
Figure 2.1 — Typical 3-Pole Transfer Mechanism
(800 Amp Shown)
Solderless, screw-type terminal lugs are standard.
The conductor size range is as follows:
Switch Rating
600A
800A
Conductor sizes must be adequate to handle the maximum current to
which they will be subjected to, based on the 75°C column of tables,
charts, etc. used to size conductors. The installation must comply fully
with all applicable codes, standards and regulations.
4
Wire Range
2 x 1/0-500 MCM per pole
4 x 4/0-500 MCM per pole
Before connecting wiring cables to terminals, remove any surface
oxides from the cable ends with a wire brush. All power cables should
enter the switch next to transfer mechanism terminals. If ALUMINUM
conductors are used, apply corrosion inhibitor to conductors. Tighten
terminal lugs to the torque values as noted on the decal located on the
inside of the door. After tightening terminal lugs, carefully wipe away
any excess corrosion inhibitor.
All power cables should enter the switch next to the transfer mecha-
nism terminals.
Use a torque wrench to tighten the conductors,
being sure not to over tighten, or damage to
the switch base could occur. If not tightened
enough, a loose connection would result,
causing excess heat which could damage the
switch base.
Connect power source load conductors to clearly marked transfer
mechanism terminal lugs as follows:
1.
Connect UTILITY (NORMAL) power source cables to switch
terminals N1, N2.
2.
Connect EMERGENCY (STANDBY) source power cables to
transfer switch terminals E1, E2.
3.
Connect customer LOAD leads to switch terminals T1, T2.
Conductors must be properly supported, of approved insulative quali-
ties, protected by approved conduit, and of the correct wire gauge size
in accordance with applicable codes.
Be sure to maintain proper electrical clearance between live metal
parts and grounded metal. Allow at least 1/2 inch for all circuits.
2.4
CONNECTING START CIRCUIT WIRES
Control system interconnections may consist of N1, N2, and T1, and
leads 0, 23 and 194. Reference instruction manual of specific engine
generator for wiring connection details. Recommended wire gauge
sizes for this wiring depends on the length of the wire, as recom-
mended in the following chart:
MAXIMUM WIRE LENGTH
1-115 ft (1-35m)
116-185 ft (36-56m)
186-295 ft (57-89m)
296-460 ft (90-140m)
Exceptions: If the insulation rating on all wiring is rated for 600V,
and the application meets code, it is acceptable to include generator
control and power wiring in one conduit.
RECOMMENDED WIRE SIZE
No. 18 AWG.
No. 16 AWG.
No. 14 AWG.
No. 12 AWG.