11
ELECTRICAL
GENERAL
The installation must conform with these instructions and the local
code authority having jurisdiction and the requirements of the power
company. In the absence of local codes, the installation must comply
with the current editions of the National Electrical Code, NFPA 70 or
the Canadian Electrical Code CSA C22.1.
An electrical ground is required to reduce risk of electrical shock
or possible electrocution. The water heater should be connected
to a separate grounded branch circuit with over-current protection
and disconnect switch. The water heater should be grounded in
accordance with national and local codes.
Voltage applied to the heater should not vary more than +5% to -10%
of the model and rating plate marking for satisfactory operation.
DO NOT ENERGIZE THE BRANCH CIRCUIT FOR ANY REASON
BEFORE THE HEATER TANK IS FILLED WITH WATER. DOING
SO WILL CAUSE THE HEATING ELEMENTS TO BURN OUT AND
VOID WARRANTY.
The factory wiring is attached to a terminal block within the external
junction box unit. The branch circuit is connected to the terminal
block within this junction box. The water heater should be connected
to a separate, grounded, branch circuit with overcurrent protection
and disconnect switch. The water heater should be grounded in
accordance with national and local codes.
BRANCH CIRCUIT
The branch circuit wire size should be established through reference
to the current edition of National Electrical Code, NFPA 70 or the
Canadian Electrical Code CSA C22.1 or other locally approved
source in conjunction with the heater amperage rating. The branch
circuit should be sized at 125 percent of the heater rating and further
increase wire size as necessary to compensate for voltage drop in
long runs.
CALCULATING AMPERAGE/OVERCURRENT PROTECTION
The heaters come from the factory in two congurations:
1. Two wire C-2 circuit for single element heater equipped with a
high limit control, single phase power input.
2. Four wire A-8 circuit for dual element heater equipped with two
high limit controls, single phase or three phase power input.
The heater with dual elements is factory wired for connection to
a three wire, three-phase delta branch circuit, non-simultaneous
operation. In addition a ground conductor is required.
Element connection is for non-simultaneous operation. This means
only one element at a time operates. The wiring diagram, on page
12, shows the heater may be eld converted to simultaneous
element operation by moving the red wire on “J” terminal to L1. It is
then possible for both elements to operate at once as determined
by the thermostats. Regardless of element connection the heater
operates in an “unbalanced” fashion.
The heater may be eld converted to single-phase operation by moving
the wire on L3 of the terminal block to L2. L3 is not used, see page 12.
The heater, now in single-phase non-simultaneous operation, may
be eld-converted to single phase simultaneous operation by moving
the red wire on terminal “J” to L1, see page 12.
This is an example of calculating heater amperage for both types
of element operation. From this, the branch circuit conductor and
overcurrent protection sizing can be established.
The example is of a three-phase 240 volt unit with two, 6 kw
elements. The notations are for units eld c onver ted to single -phase.
Check the heater model and rating plate for actual specications
and substitute those values in the following.
TABLE 3
Non-simultaneous:
(as factory wired)
Simultaneous:
(Field conversion)
3000 ÷ 240 = 12.5 amps*
3000 ÷ 240 = 12.5 amps*
12.5 x 1.73 = 21.6 amps
*NOTE: as a single-phase non-
simultaneous unit.
*NOTE: as a single-phase
simultaneous unit the total is:
12.5 x 2 = 25 amps
The rating of the overcurrent protection should be computed on the
basis of 125 percent of the total connected load amperage. Where the
standard ratings and settings do not correspond with this computation,
the next higher standard rating or setting should be selected.
To Next Page
Loading...
Need help?
General
