Section 407-321-4 - LOAD PROFILESA. Load Profiles for Customer Groups. 1. Each transmission and distribution utility shall develop a set of load profiles for each of the three customer profile groups defined in Section 4.A.2. Each customer profile group's load profile set will contain 24-hour profiles that may be used to represent each day of a year. Each daily profile will represent an average per-customer load, at the point of retail delivery. Each profile will represent a 24-hour day that may be identified through some indicator such as month, day of the week, weather condition, or any other indicator that significantly affects load. Profiles may be created by combining the metered loads from more than one day. Each customer profile group will be used to represent those customers not telemetered.2. The three customer profile groups shall be:a. Residential. This profile group shall contain all customers defined as residential by the terms and conditions of the transmission and distribution utility. The profile group shall exclude customers with deemed load profiles and customers who are telemetered.b. Small Non-Residential. This profile group shall contain all non-residential customers that meet the availability criteria to take service under a core customer class of the transmission and distribution utility that does not include a demand charge. The profile group shall exclude customers with deemed load profiles and customers who are telemetered.c. Medium Non-Residential. This profile group shall contain all non-residential customers that do not meet the criteria for a small non-residential customer and that meet the availability criteria to take service under a core customer class of the transmission and distribution utility that includes a demand charge and in which a customer's maximum demand shall not exceed 500 kW, or the kW breakpoint that is closest to but does not exceed 500 kW. The profile group shall exclude customers with deemed load profiles and customers who are telemetered.3. Deemed load profiles are permissible but not required for customers whose loads are easily estimated through engineering characteristics.B. Profiling Methodology 1. For each transmission and distribution utility, samples in each customer profile group will be designed to produce the following accuracy:a. a 90% confidence level with plus or minus 10% error margin in hourly load at the time of the transmission and distribution utility's summer peak for utilities operating in the ISO-NE control area; or a 90% confidence level with plus or minus 10% error margin in hourly load at the time of the transmission and distribution utility's winter peak for utilities operating in the Maritimes control area .b. to the extent that it is practicable, a high level of accuracy in the peak hours of all months in the year should be achieved, while maintaining the provisions in Section B.1.a; andc. to the extent that it is practicable, a high level of accuracy in all hours of the year should be achieved, while maintaining the provisions in Section B.1.a.2. Transmission and distribution utilities shall re-sample each customer profile group no less frequently than every two years. This provision will be waived if the transmission and distribution utility demonstrates to the Commission that the current sample represents the customer profile group with reasonable accuracy.3. Transmission and distribution utilities shall use either simple random sampling or stratified random sampling to select samples of each customer profile group.4. Transmission and distribution utilities shall use either ratio analysis or mean-per-unit analysis to create load profiles from the samples of each customer profile group.65- 407 C.M.R. ch. 321, § 4