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Restricted Service RatesAuthor: E.E. Kimberly Because of the high peak demand on the systems of some power utilities and a substantial margin of unused capacity provided for emergency service, a restricted service is sometimes offered. The use of such service is permitted at certain hours only, when the generatingstation load is normally low. An attractive rate is possible for such service, because of the curtailed investment required. Ideal loads for restricted service are water pumping, water heating, and other uses of electricity which are not necessarily synchronized with peak load operations. SAMPLE RATE STRUCTURES Schedule A Alternating and Direct Electric Current Power Service. The Service furnished under this schedule is Alternating Electric Current, Single or Three Phase, 60 cycles, 120240 or 220440 volts, and Direct Electric Current at 120240 volts. A minimum monthly charge of $1.25 per kw or fraction thereof, of maximum demand, plus the following kwhr charges for energy consumed.
Schedule B Character of Service: 115230460 volts alternating current. Lighting will be included and will be billed at the power rate where the normal monthly power bill amounts to not less than $125.00 per month, provided the lighting demand is not more than 25% of the power demand. 115230 volts direct current. AH direct current power service shall be supplied under this schedule and the lighting will be billed at the power rate under the following conditions: A  where the normal monthly demand is 150 kilowatts or more. B  where the normal monthly power bill is not less than $125.00 and the lighting demand is not more than 25% of the power demand. Minimum charge: Two dollars and fifty cents ($2.50) net per month on all installations up to and including 5 hp of connected load. Above 5 hp of connected load, fifty cents ($0.50) net per horsepower per month. Demand: In determining the maximum demand of an installation under power schedule B, the following rules shall apply: If an installation is less than 5 hp, its demand will be arbitrarily fixed at o hp. In installations of 5 hp to 25 hp, inclusive, the connected load in horsepower will be multiplied by 0.6 and the product will be considered the maximum demand in kilowatts. In installations of 25 hp to 50 hp, inclusive, the connected load in horsepower will be multiplied by 0.55 and the product will be considered the maximum demand in kilowatts. In installations of 51 hp to 200 hp, inclusive, the connected load in horsepower will be multiplied by 0.5 and the product will be considered the maximum demand in kilowatts. In installations of 201 hp and above, the connected load in horsepower will be multiplied by 0.45 and the product will be considered the maximum demand in kilowatts.
The company reserves the right to make tests at any time on the premises of any customer, and may, at its option, fix the demand by test, and the demand so fixed shall remain in force until the company makes other tests to determine the maximum demand. In fixing the demand of any installation, if there is a considerable portion of the load which is not used during the company's load peak, and if the customer will agree not to use this portion of the load during such hours as the company may specify, then the company may take this feature into consideration in fixing the maximum demand. Discounts: Quantity discounts in accordance with the following schedule are applicable to Power Rate B and are determined by the gross bill, viz:
Schedule C Rate: The consumer's monthly bill shall be the sum of the demand charge and the energy charge. Demand Charge: First 10 kw of billing demand at $30.00 per kw per year payable at the rate of $2.50 per month. Next 30 kw of billing demand at $25.00 per kw per year payable at the rate of $2.10 per month. Next 160 kw of billing demand at $21.60 per kw per year payable at the rate of $1.80 per month. Next 200 kw of billing demand at $19.20 per kw per year payable at the rate of $1.60 per month. All over 400 kw of billing demand at $18.00 per kw per year payable at the rate of $1.50 per month.
Energy Charge: Energy used each month will be billed at the following rates: All kwhrs in first quantity block at  38 mills per kwhr. All kwhrs in second quantity block at  19 mills per kwhr. All kwhrs in third quantity block at  16 mills per kwhr. All kwhrs in excess of the sum of the three quantity blocks at 13 mills per kwhr. Energy Blocks First Quantity Block: The kilowatthours in the first quantity block shall be as follows: For corrected demands of: From 5 kw to 25 kw  350 kwhr. From 25 kw to 100 kw  350 kwhr plus 6 kwhr for each kw of demand in excess of 25 kw. From 100 kw to 400 kw  800 kwhr plus 4 kwhr for each kw of demand in excess of 100 kw. From 400 kw to 1600 kw  2000 kwhr plus 3 kwhr for each kw of demand in excess of 400 kw. From 1600 kw to 5600 kw  5600 kwhr plus 2§ kwhr for each kw of demand in excess of 1600 kw. Over 5600 kw  15,600 kwhr plus 2 kwhr for each kw of demand in excess of 5600 kw. Second Quantity Block: The kilowatthours in the second quantity block shall be four times the kilowatthours in the first quantity block. Third Quantity Block: The kilowatthours in the third quantity block shall be four times the kilowatthours in the second quantity block. Measured Demand: The measured demand shall be the average kilowatt capacity used by the consumer during the fifteenminute period of maximum consumption during the month. Power Factor: The company reserves the right to test or meter the power factor of the consumer's load and, if greater than 85% lagging, then the measured monthly demand shall be decreased for billing in the ratio that 85% bears to the actual power factor (in per cent) as determined. The correction for all leading power factors shall be the same as for 100% power factor. If the power factor of the consumer's load is less than 75% lagging, then the measured monthly demand shall be increased for billing in the ratio that 75% bears to the actual power factor (in per cent) as determined. Corrected Demand: The measured demand in kilowatts corrected for power factor shall be the corrected demand. In no event, however, shall the corrected demand be less than 5 kw. Billing Demand: The billing demand shall be the corrected demand in kilowatts of the current month, but not less than 50% of the highest billing demand of the preceding months. Minimum Charge: The minimum bill in any month shall be a sum equivalent to the charge for 50% of the highest billing demand of the preceding eleven months. Character of Service: This rate is available only to consumers having demands of 5 kilowatts or over.
Example 241.  A consumer uses 6400 kwhr of energy in a month. The maximum demand as measured is 50.6 kw. Calculate the power bill under Schedule A.
Solution.  The total energy charge is found as follows: 2500x0.025 = $ 62.50 2500x0.0225= 56.25 1400x0.020 = 28.00 Total = $146.75 Demand charge = 50.6 kw at $I.25 = $63.75 Total bill = $146.75 + $63.75 = $210.50 If the bill is paid when due, the charge is $210.50x0.95 = $199.97


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