Connecting Electrical Supplies; Accessing The Terminal Blocks - Navien NCB-20LHWE Installation & Operation Manual

8. Connecting Electrical Supplies

WARNING
Improperly connecting the electrical supplies can result
in electrical shock and electrocution. Follow all applicable
electrical codes of the local authority having jurisdiction.
Connecting the electrical components should be performed
only by a licensed professional.
DANGER
You must ensure that the boiler is disconnected from the
electrical supply before carrying out any servicing inside
the boiler and, particularly, on the electric terminal strips.
If the electrical supply is connected electrical
contact could occur, causing serious damage due to
electrocution.
CAUTION
Label all wires before disconnecting them when you work
on the controls. Wiring errors can cause improper and
dangerous operation. Verify proper operation after servicing.
The boiler electrical connections must be made by su ciently
quali ed sta in strict compliance with the sections below and
with any electrical safety regulations applicable at the time of
installation.
The NCB LHWE boiler has an electrical protection
Note
degree of IPX5D. The electrical connection must
be made via a bipolar switch located on the same
premises as the boiler. The switch must have a
minimum pole separation of 3 mm.

8.1 Accessing the Terminal Blocks

The terminal blocks 1 and 2 of the NCB LHWE boiler are located
inside the boiler. The terminal block 1 is located to the right of
the panel and the terminal block 2 is located below the front
panel.
To access the terminal blocks 1 and 2, follow the steps below
carefully:
1. Turn o the power supply to the boiler.
2. Remove the boiler's front cover by loosening the four screws
securing it to the case.
Before connecting the cables to the corresponding
Note
connector terminals, it is essential to thread them
through the cable glands located on the underside
of the boiler.
While threading the cables and making the
connections, take special care that no pieces
of cable fall onto the electrical connections or
electronic cards.
Make sure you have tightened the cables
su ciently. It is essential for the boiler to be
grounded.
3. Refer to the following illustration and remove the x screws
to access the terminal blocks.
Terminal
block 2
Terminal
block 1
Connecting Electrical Supplies 35