Harsco Industrial SC-2000 Installation & Owner's Manual page 14

3.4.2 Three Phase Power Supply Connection (SC-3000 & SC-4000 Only)
Main Power Connection Box
Check the rating nameplate of the SC-3000 or SC-4000 boiler to determine the required electrical service:

208-240VAC, three phase, 60 hertz

440-480VAC, three phase, 60 hertz
The incoming three phase power for the SC-3000 & SC-4000 boilers is connected to the over-current safety
device (rated for 20 Amps) and the Ground terminal located in the main power connection box. Figure 3.4.2
shows the Low Voltage (TB1) and High Voltage (TB2) terminal blocks, plus the Main Power Connection Box
on the SC-3000 & SC-4000 with the front door hidden for clarity:

Terminal 1 = HOT L1

Terminal 3 = HOT L2

Terminal 5 = HOT L3

Terminal G = GROUND
The Main Power Connection Box features a Control Transformer which steps down two hot leads from the
incoming three-phase power in order to supply 110-120VAC single phase power to the boiler's control system.
Be aware that SC-3000 & SC-4000 boilers ordered in the 240V configuration, are pre-wired from the factory for
operation with 240 VAC three phase incoming power.
If 208 VAC three phase power is supplied to the boiler, the internal control transformer must be re-wired for
operation at this lower voltage. The wire in terminal X3 on the load side of the internal control transformer must
be moved to terminal X4. This supplies the 120 VAC power to the controls from the 208 VAC main voltage.
Refer to Section
6.1.4
NOTE: The hot lead terminals can
accommodate maximum 12AWG
wire. The ground terminal can
accommodate maximum 8 AWG
wire.
CAUTION: Do not over‐tighten the
hot lead terminal screws. Maximum
tightening torque = 13 in‐lbs!
Low Voltage (TB1) Terminal Block
High Voltage (TB2) Terminal Block
Main Power Connection Box
Harsco Industrial, Patterson-Kelley Technical Service 1.877.728.5351
for proper wiring and configuration of the internal control transformer.
Control Transformer
Figure 3.4.2
14
Gas Fired Boiler