ELECTRIC SPACE HEATING REQUIREMENTS INCLUDING HEAT PUMPS AND AIR CONDITIONERS

Electric space heating and central air conditioning require special Company attention because the supply facilities may have to be increased. The air conditioner or heat pump compressor motors must also meet the motor starting current limitations. To ensure that the Company can be ready to supply electric service for heating or cooling when required, the Customer should apply for service or notify the Company as soon as the load is determined.

When electric furnaces, boilers, heat pumps or duct heaters are installed, resistance units rated larger than 48 amperes shall be subdivided and staged. Each resistance unit shall not exceed 48 amperes. A 20 second time interval shall be maintained between the switching of each stage. The time intervals shall be maintained while increasing or decreasing the load. Separate thermostatically controlled space heating units rated 48 amperes or less need not be staged.

The motor starting limits will allow the installation of single-phase heat pumps and air conditioners rated up to five tons. Some 4 and 5 ton units may require the installation of a control to prevent the compressor and outdoor fan from starting together to keep within the 150 ampere locked-rotor limitation. The heating contractor may choose to install more than one smaller heat pump or air conditioner in larger installations instead of one large unit.

ELECTRIC WATER HEATER REQUIREMENTS

Electric water heaters are classified as either "Storage-Type" with a storage tank capacity of at least 5 gallons or "Instantaneous-Type" with virtually no storage capacity. All water heaters shall conform to Article 422-14 of the National Electrical Code and be approved by the inspection authority having jurisdiction. Each water heater shall be specifically equipped with an approved pressure-temperature relief valve and a temperature limiting means, in addition to the control thermostat, which will disconnect all ungrounded conductors at a maximum available temperature setting of not more than 190oF.

All bathtubs, showers, sinks and washtubs supplied by an electric water heater shall have their metallic parts, metallic water pipes, and metallic drain pipes connected to them, bonded together.