Sections C405.6 and C405.7—Electrical energy consumption.
C405.6 Electrical transformers. Low-voltage dry-type distribution electric transformers shall meet the minimum efficiency requirements of Table C405.6 as tested and rated in accordance with the test procedure listed in DOE 10 C.F.R. 431. The efficiency shall be verified through certification under an approved certification program or, where no certification program exists, the equipment efficiency ratings shall be supported by data furnished by the transformer manufacturer.
EXCEPTION: | The following transformers are exempt: |
| 1. Transformers that meet the Energy Policy Act of 2005 exclusions based on the DOE 10 C.F.R. 431 definition of special purpose applications. |
| 2. Transformers that meet the Energy Policy Act of 2005 exclusions that are not to be used in general purpose applications based on information provided in DOE 10 C.F.R. 431. |
| 3. Transformers that meet the Energy Policy Act of 2005 exclusions with multiple voltage taps where the highest tap is not less than 20 percent more than the lowest tap. |
| 4. Drive transformers. |
| 5. Rectifier transformers. |
| 6. Auto-transformers. |
| 7. Uninterruptible power system transformers. |
| 8. Impedance transformers. |
| 9. Regulating transformers. |
| 10. Sealed and nonventilating transformers. |
| 11. Machine tool transformer. |
| 12. Welding transformer. |
| 13. Grounding transformer. |
| 14. Testing transformer. |
Table C405.6
Minimum Nominal Efficiency Levels For 10 C.F.R. 431 Low Voltage Dry-Type Distribution Transformers
Single Phase Transformers | Three Phase Transformers |
kVAa | Efficiency (%)b | kVAa | Efficiency (%)b |
15 | 97.70 | 15 | 97.89 |
25 | 98.00 | 30 | 98.23 |
37.5 | 98.20 | 45 | 98.40 |
50 | 98.30 | 75 | 98.60 |
75 | 98.50 | 112.5 | 98.74 |
100 | 98.60 | 150 | 98.83 |
167 | 98.70 | 225 | 98.94 |
250 | 98.80 | 300 | 99.02 |
333 | 98.90 | 500 | 99.14 |
| | 750 | 99.23 |
| | 1000 | 99.28 |
a | kiloVolt-Amp rating. |
b | Nominal efficiencies shall be established in accordance with the DOE 10 C.F.R. 431 test procedure for low voltage dry-type transformers. |
C405.7 Dwelling unit electrical energy consumption. Each dwelling unit located in a Group R-2 building shall have a separate electrical meter. A utility tenant meter meets this requirement. See Section C409 for additional requirements for energy metering and energy consumption management.
EXCEPTION: | Dwelling units in other than Group R-2 multi-family and live/work units are not required to provide a separate electrical metering at each dwelling unit where electrical usage is metered separately for each of the following building end uses: |
| 1. Dwelling units. |
| 2. Sleeping units. |
| 3. Commercial kitchens. |
| 4. Central laundries. |
C405.7.1 Electric receptacles at dwelling unit gas appliances. Where dwelling unit appliances are served by natural gas, an electrical receptacle or junction box and circuit shall be provided at each gas appliance with sufficient capacity to serve a future electric appliance in the same location. The receptacles and circuits shall be included in the electrical service load calculation and shall meet the requirements of items 1 through 3 below. The receptacle or junction box for each gas appliance shall be located within 12 inches of the appliance and without obstructions between the appliance and the outlet. An electric receptacle is not required for a decorative gas fireplace.
1. Each gas range, cooktop, or oven, or combination appliance, location shall be served by a dedicated 240/208-volt, 40-amp receptacle connected to the dwelling unit electric panel with a 3-conductor branch circuit complying with 210.19(A)(3) of the NEC as adopted by Washington state and a minimum included load of 9600 VA for 240-volt systems or 8000 VA for 208-volt systems.
2. Each gas clothes dryer location shall be served by a dedicated 240/208-volt, 30-amp receptacle connected to the dwelling unit electric panel with a 3-conductor branch circuit and a minimum included load of 5000 VA.
3. The location of each gas domestic water heater installed within a dwelling unit shall be served by a dedicated 240/208-volt, 30-amp junction box connected to the dwelling unit electrical panel with a 3-conductor branch circuit and a minimum included load of 4500 VA.
[Statutory Authority: RCW
19.27A.020,
19.27A.025,
19.27A.160 and chapters
19.27A and
19.27 RCW. WSR 22-14-091, 23-12-101, and 23-20-021, § 51-11C-40507, filed 7/1/22, 6/7/23, and 9/25/23, effective 3/15/24. Statutory Authority: RCW
19.27A.020,
19.27A.025,
19.27A.160 and chapter
19.27 RCW. WSR 19-24-040, § 51-11C-40507, filed 11/26/19, effective 7/1/20. Statutory Authority: RCW
19.27A.025,
19.27A.045,
19.27A.160, and
19.27.074. WSR 17-10-062, § 51-11C-40507, filed 5/2/17, effective 6/2/17; WSR 16-13-089, § 51-11C-40507, filed 6/15/16, effective 7/16/16. Statutory Authority: RCW
19.27A.025,
19.27A.160, and
19.27.074. WSR 16-03-072, § 51-11C-40507, filed 1/19/16, effective 7/1/16. Statutory Authority: RCW
19.27A.020,
19.27A.025 and chapters
19.27 and
34.05 RCW. WSR 13-04-056, § 51-11C-40507, filed 2/1/13, effective 7/1/13.]
