4
Section 2 — Installation
RTS “HS” Type Transfer Switch
Solderless, screw-type terminal lugs are standard.
The conductor size range is as follows:
Conductor sizes must be adequate to handle the max-
imum current to which they will be subjected; 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.
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 con-
ductors are used, apply corrosion inhibitor to con-
ductors. 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 mechanism terminals.
Use a torque wrench to tighten the conductors,
being sure not to overtighten, or damage to
the switch base could occur. If undertightened,
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 fol-
lows:
1. Connect UTILITY (NORMAL) power source cables
to switch terminals N1, N2, (N3).
2. Connect EMERGENCY (STANDBY) source power
cables to transfer switch terminals E1, E2, (E3).
3. Connect customer LOAD leads to switch termi-
nals T1, T2, (T3).
4. Connect neutral conductors of UTILITY,
EMERGENCY and customer LOAD to the neutral
block.
Conductors must be properly supported, of approved
insulative qualities, 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 100-400 amp circuits.
2.5
CONNECTING START CIRCUIT
WIRES
Control system interconnections consist of UTILITY
1 and 2, and leads 23 and 194. Control system
interconnection leads must be run in a conduit that
is separate from the AC power lead. Recommended
wire gauge sizes for this wiring depends on the length
of the wire, as recommended below:
2.6 AUXILIARY CONTACTS
If desired, there are Auxiliary Contacts on the transfer
switch to operate customer accessories, remote advi-
sory lights, or remote annunciator devices. A suitable
power source must be connected to the COMMON (C)
terminal. See Figure 2.3.
Contact operation is shown in the following chart:
NOTE:
Auxiliary Contacts are rated 10 amps at 125 or
250 volts AC. DO NOT EXCEED THE RATED
VOLTAGE AND CURRENT OF THE CONTACTS.
Figure 2.3 – Auxiliary Contacts
S
ide views shown in Utility position
MAXIMUM WIRE LENGTH
RECOMMENDED WIRE
SIZE
460 feet (140m)
No. 18 AWG.
461 to 730 feet (223m)
No. 16 AWG.
731 to 1,160 feet (354m)
No. 14 AWG.
1,161 to 1,850 feet (565m)
No. 12 AWG.
Switch Position
Utility
Standby
Common to Normally Open
Open
Clo
s
ed
Common to Normally Clo
s
ed Clo
s
ed Open
Switch Rating
Wire Range
400A
(1) #4-600 MCM or
(2) 1/0-250 MCM
