Storage-Type Water Heaters

Storage-type water heaters will provide the largest volume of uniform temperature hot water per kilowatt of heating element. Storage-type water heaters can also be controlled for off-peak use in an energy management system and for use with possible future load shedding rates. A well insulated storage-type water heater will provide efficiency, uniform water temperature, control and the lowest cost electrical supply requirements for both the Company and the Customer.

Each storage-type water heater for use on single-phase services shall have a maximum heating element size of 5,500 watts. The water heater may have both lower and upper heating elements, but they shall be interlocked to prevent simultaneous operation. Storage-type water heaters rated 10 kW or less can be operated on any three-phase service. Larger storage-type, three-phase water heaters can be operated at many service locations. Customers desiring to use a larger storage-type water heater can request approval from the Company.

Instantaneous-Type Water Heaters

Instantaneous-type water heaters usually require a much larger heating element size than a storage-type delivering the same volume of water. The size of the heating element and the frequency of operation can cause excessive voltage fluctuations to the Customer and adjacent Customers. The Company may also have to provide larger supply facilities for an instantaneous-type water heater than would normally be required for a storage-type. Excess costs for larger supply facilities shall be paid by the Customer.

Each instantaneous-type water heater for use on a single-phase service shall have a maximum heating element size of 5,500 watts*. Individual 120 volt units may be utilized on 15 and 20 ampere branch circuits when in compliance with Article 210-23 (a) of the National Electrical Code. Instantaneous-type water heaters rated 10 kW or less can be operated on any three-phase service. Larger instantaneous-type three-phase water heaters can be operated at many locations. A Customer desiring to use a larger instantaneous water heater shall request approval from the Division Office. Costs for Company facilities in excess of normal requirements will be paid by the Customer.

* One 5,500 watt instantaneous-type water heater will not provide a sufficient amount of hot water for most premises requirements.

The operation of some equipment, such as computers, video, x-ray and other electronic voltage sensitive equipment may be affected by slight voltage fluctuations. In some cases the Customer may have to install Power Conditioning or Uninterruptible Power Supply (UPS) equipment to achieve satisfactory operation. In other cases, the Company, at the Customer's expense, may have to install special facilities. Since special consideration may be necessary for satisfactory operation, the Division Office should be consulted before such equipment is installed.

SNOW MELTING EQUIPMENT

Where equipment is installed for melting snow by means of electric resistance heaters in driveways, sidewalks, or similar areas, the Division Office shall be advised so that adequate transformer capacity may be installed. Costs for Company facilities in excess of normal requirements will be paid by the Customer.