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ELECTRICAL SERVICE:
The MODEL 1 Water Heater is considered a
non-continuous heating appliance according to the
Definitions in the National Electric Code. An appliance load
that is not continuous for three hours or more is
considered non-continuous. Therefore, the MODEL 1
Water Heater, when used for standard domestic hot water
applications, is considered a non-continuous heating
appliance. Due to the diversity of water heating in a home,
the load (A) contribution of the MODEL 1 Water Heater to
the overall service load of the home or building can be
calculated using the optional methods of National
Electrical Code, sections NEC 220-82 or 220-83.
For new dwellings, the service load should be calculated
using NEC 220-82. For existing dwellings, the service load
should be calculated using NEC 220-83. By both calculation
methods, the MODEL 1 Water Heater load is generally
added to the service load at 40% of its maximum
nameplate rating. For instance, the maximum current (A)
rating of the MODEL 1 Water Heater is 48 A and 40% of this
rating is about 20 A. The 20 A is typically the load added to
the overall service load of the dwelling when using the
optional calculation methods as described in NEC 220-82
and 220-83, not the maximum current rating, 48 A. (Note
that a conventional electric water heater rated at 30 A load
will be rated at 30 A as is it considered a continuous
device.)
So, two MODEL 1 Water Heaters will only add 10 A to
the existing service load since 30 A was already
available for the existing 30 A tank. As a result, one or
more MODEL 1 Water Heaters will fit in most homes
that have a 150 or 200 A whole-house electrical service,
or can be installed using one or more subpanels with a
breaker that is sized accordingly.
POWER/VOLTAGE MODULATION:
During operation, the MODEL 1 Water Heater is
designed to use only the power necessary to heat the
water for various combinations of temperature rise and
flow rate.
DISCONNECTS AND SUBPANELS:
Electrical disconnect devices do not contain circuit
breakers and are not required by the National Electrical
Code (NEC) for residential appliances such as the
MODEL 1 Water Heater or any appliance rated less than
300 V. However, disconnects may be required by the
NEC for motor loads and for appliances with multiple
circuits in commercial applications.
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