Executive Summary This report contains an analysis and description of the existing electrical distribution of the including the distribution type, emergency power, uninterruptible power system, over current protection, equipment layout, and lighting system characteristics. A calculation of the building design load was also performed per NEC 2002 in order to compare the electrical distribution equipment ratings. Mechanical, receptacle, lighting, and other relevant equipments were factored in using the appropriate procedures and demand factors set by the NEC. The calculated design load in kva was then compared to the capacity of the existing substation transformers to ensure that it is greater than the design load. The main distribution panel, in this case, the (2) main switchgears and the feeders leaving it were also checked for size to assure proper ampere ratings to supply other distribution panels, which it feeds. This report concludes that all distribution equipments were properly sized: substation transformers, switchgears, and feeders leaving the switchgears. Further comparison of the design loads with the actual yearly energy usage also reaffirms that the electrical distribution was properly sized and that the design loads were indeed very conservative. In actuality, the (2) substation transformers that have a total capacity of 5000 kva are only being utilized at 3,000 kva for the peak demand load of the building. Analysis of the generator concludes that it no longer performs its original design intent. The paralleling generators were designed so that in the event that one fails, the other will be capable of carrying the load of the entire building. The actual energy usage data reports an increasing trend in building load consumption which may be due to an increase in occupancy in the building. Therefore, one 2,000 kva generator can no longer support 3,000 kva of the actual building energy usage. 1
Distribution Type and Building Utilization Voltages A radial system is used to distribute incoming power from the utility. The system is not reliable from the primary utility feed standpoint; thus, as explained further in the report, redundancy was heavily invested throughout the rest of the electrical distribution. A single incoming feed from the utility, PSE&G enters through the self-contained pre-packaged transformer substation owned by CNBC located adjacent to the exterior generator housing. Because CNBC has ownership of the service transformers, they are able to obtain a lower primary high voltage rate. Another benefit of owning the service transformers is that CNBC was able to obtain a larger transformer than the utility could supply. The available short circuit current from the utility, PSE&G is 10,500 AIC (substation transformer primary). The single utility feed with a voltage of 13.2 kv is stepped down by (2) Y-Y 2500kVA dry-type transformers in the substation unit to the building utilization voltage of 480/277V, 3-phase, 4- wire + ground, where the 3-phase line to line short circuit current is 49,775 AIC. The (2) 480/277V feeds from the transformers are then delivered to (2) 4000A, 3-phase, 4-wire + ground switchboards located in the in the basement of the CNBC building. The majority of the lighting operates at 277V and primary mechanical equipments have an operating voltage of 460V. Voltage is stepped down to 208/120V for general power use and some lighting loads. Distribution panels vary in sizes from 800A to 1600A, while the branch panels serving loads are all rated for 225A for both 480/277V and 208/120V. Dry-type delta-wye transformers are used to step down the voltage. K-rated transformers are use where computer and other technical loads are served. 150kVA PDUs are also used to step down voltage in order to serve computer loads. The PDU panels have an incoming feed of 480V, which its integral transformer steps down to 208/120V to serve the computer loads accordingly. This was done to save on cost of not having to supply a high voltage panel, a K-rated transformer, and a low voltage panel. In order to address the harmonics problem that is ensued by the computer loads, harmonics neutralizers are used in conjunction with the PDU panels to filter out the 3 rd harmonic. Please see the power riser diagram in Appendix A for a more detailed visual representation of the entire electrical distribution system. Emergency Power The entire building (power, lighting, mechanical, etc.) is backed by (2) factory packaged generator set with a continuous standby rating of 2,000 kw, 2,500 kva, 0.8 power factor, 480Y/277V, 3-phase, 4-wire, 60 Hz. The generator set is operated in conjunction with the generator control switchgear as an automatically started parallel generating plant. Each of the 2
generators has a 4000AF/trip insulated case circuit breaker for over current protection of the feeders to the paralleling switchgear. The generator switchboard is 480/277V, 6,000A, 3-phase, 4-wire, from which feeds the (12) 3-pole bypass isolation type automatic transfer switches (ATS) in the building. Each of the 2,000 kw generators was designed to be capable of carrying the full load of the building. The generators also have the ability to shed load in order to avoid an overload condition. The automatic transfer switches are programmed to drop-off from the generator in a predetermined sequence once the generators have reached a pre-assigned load. Although costly, having two generators where each can carry the building s entire load is one of the redundancies built into the power distribution system what the owner was willing to pay to ensure continuous broadcasting. Uninterruptible Power System It is very crucial that power shall be maintained in the studios at all times. To further secure the continuous power supply for the broadcasting studios a power-tied redundant uninterruptible power system was applied. The system is composed of (2) 1000kVA, 900kW uninterruptible power system (UPS-A and UPS-B) backed up with least 13 minutes of power for 800kW from 4 battery packs (2 storage batteries for each). The two units operate in parallel and simultaneously while sharing the load. Each of the 1000kVA UPS is capable of carrying the combined loads from the individual UPS. This is done so that if a malfunction on one of the modules occurs, that module can be disconnected while the other operating module shall continue to carry the two loads. The power-tie control regulates which circuit breakers are open or closed to deliver power from the (2) critical panel boards from either UPS-A or UPS-B, the maintenance by-pass, or the SCC input. Overcurrent Protection Thermal magnetic, quick-make, quick-break circuit breakers are used throughout the entire distribution system, with the exception of fuses for disconnects of mechanical equipment and fuses in the utility side of the transformer substation. All circuit breakers for 480/277V have a short circuit current rating of 10,000A symmetrical, and circuit breakers for 208/120V have a short circuit current rating of 14,000A symmetrical. All of the high voltage distribution panels (480/277V) and other high voltage panels they serve have main lugs only, therefore, those panels can only be shut off from circuit breaker in the distribution panel from which it was served. Low voltage panels (208/120V) immediately after step-down transformers have main circuit breakers to serve as the over current protection on the transformer secondary side. Fuses are of UL class K for 0-600A and UL class L for over 600A. 3
Equipment layout The generators and the substation are located outside of the CNBC Headquarters. The generators and the substation come in a prepackaged housing and are not exposed to the elements. The (2) switchboards for normal power, the generator paralleling switchgear, main distribution panels, ATS switches, and UPS-A, UPS-B with their 4 battery packs are located in the building s basement level. Equipments for branch circuit distribution are located among (3) electrical/mechanical closets in each floor: NW, SW, SE closets. The motor control center is located in the roof penthouse of the building. PDUs are located in the computer equipment room, which they serve. Electrical panels serving the studio and the kitchen are located within the corresponding spaces. Motor Power Distribution All roof top base building mechanical units are served by (2) 1600A, 480V, 3-phase, 4- wire motor control center panels. Mechanical equipment at the branch distribution level have fused disconnect switches for 3-phase motors, and junction boxes for 1-phase motors. The entire mechanical system of the building also has low voltage wiring to the building management system. The building management system is used to monitor all HVAC units and control their schedules of operation. Lighting System and Lighting Equipment Characteristics A great majority of the lighting system is rated for 277V operation. General space lighting utilizes fluorescent lamps. However, multi-story spaces such as the Business News room and the East Lobby uses metal halide lamps. Specialty low voltage lighting 120/12V and incandescent lighting is used in large conference rooms, the cafeteria, production control rooms, and other high-end spaces. Exterior façade and plaza lighting are all 277V luminaries with metal halide lamps. See the table below for characteristics of lamps and corresponding ballasts utilized. No specific ballasts were specified for each lamp. However, electronic fluorescent ballasts were called for in the specification as UL Class P with minimum power factor of 0.9, minimum ballast factor of 0.95, and less than 20% total harmonic distortion. 4
Lamp Lamp Voltage Ballast BF PF Input Amps Watts Watts F54T5HO/830 54 277 Electronic 0.95 0.9 60 0.24 CF26DD/E/830 26 120 Electronic 0.95 0.9 29 0.27 50MR16IR/WFL40 50 120/12 120/12V XFMR N/A 0.9 55 5.1 F28T5/830 28 277 Electronic 0.95 0.9 31 0.13 F54T5/830 54 277 Electronic 0.95 0.9 60 0.24 (2) F32T8/830 32 277 Electronic 0.95 0.9 38 0.16 F32T8/830 32 277 Electronic 0.95 0.9 35 0.16 CF32TT/E/830 32 120 Electronic 0.95 0.9 35 0.36 CF32DT/E/830 32 277 Electronic 0.95 0.9 35 0.16 CF42DT/E/830 42 277 Electronic 0.95 0.9 46 0.19 75PAR16/NFL 75 120 N/A N/A N/A N/A 0.63 50PAR20/NFL 50 120 NA N/A N/A N/A 0.42 20MR16/NSP10 20 120/12 120/12V XFMR N/A 0.9 22 2 75MR16/SP 75 120/12 120/12V XFMR N/A 0.9 83 7.6 BC60BT15/HAL/W 60 120 N/A N/A N/A N/A 0.5 F40T8/5000K 40 277 Electronic 0.95 0.9 44 0.18 F32T8/850 32 277 Electronic 0.95 0.9 35 0.16 42MR16/NSP15 42 120/12 120/12V XFMR N/A 0.9 46 4.3 BC150BT15/HAL/W 150 120 N/A N/A N/A N/A 1.3 150PAR38/NFL25 150 120 N/A N/A N/A N/A 1.3 100AR111/8/SP 100 120/12 120/12V XFMR N/A 0.9 110 10.20 Q50T3/12V/CL 50 120/12 120/12V XFMR N/A 0.9 55 5.1 75PAR30/H/SP10 75 120 N/A N/A N/A N/A 0.63 35MH/PAR30L 35 277 AUTO-REG N/A 0.9 38 0.16 CDM70MH/PAR30L 70 277 AUTO-REG N/A 0.9 77 0.32 CDM150MH/T6/830 150 277 AUTO-REG N/A 0.9 165 0.67 400W MH ED-17 400 277 AUTO-REG N/A 0.9 440 1.8 100W MH ED-17 100 277 AUTO-REG N/A 0.9 110 0.44 Power Factor Correction There are no capacitor banks used for power factor correction. In order to maintain a good power factor throughout the building, a high power factor at the equipment level is specified. 5
Important Design Requirements Because this is a broadcasting facility, the reliability of the power distribution system is critical. CNBC cannot afford a power outage in the entire building, especially for the broadcasting studios. Therefore, the power distribution has to be configured so that there is no single point of failures, and if failure does occur, it is a malfunction of the equipment itself and not within the power distribution system. NEC Building Design Loads Total Connected Mechanical Load: 3748.2kVA See mechanical load tables below for 3-phase and 1-phase mechanical load calculations and notes. Note: Full load currents were used to estimate this value; therefore it is a very conservative estimate because it was assumed that these motors are all operating simultaneously at full load. Moreover, the excess in mechanical load reflects all of the anticipated cooling due to the heat from the tenant installed broadcasting studio fixtures which were not part of the base building lighting system) Total General Lighting Load by Occupancy: 498.75 kva See lighting load tables below for general lighting load calculations and area distribution and notes. Total Demand Receptacle Load: 530.2 kva See receptacle load tables below for receptacle connected and demand load calculations and notes. Total Design Load for Entire Building: 4777.2 kva Note: Although this estimate comes very close to the incoming utility feed available at 5,000kVA, this estimate is once again very conservative due to the assumption that all the mechanical equipments and motors are simultaneously in operation at full load. Furthermore, the peak kw usage for the year according to the electrical utility load data in the section to follow indicates a maximum usage of only 3,000kW for the year. 6
3-Phase Mechanical Loads Designation Mechanical Unit Type Phase Voltage HP kw Amps/FLA Connected kva AHU-NW-G-1 Air Handling Unit 3 460 30-40 31.9 AHU-NW-G-2 Air Handling Unit 3 460 30-40 31.9 AHU-NW-1-1 Air Handling Unit 3 460 30-40 31.9 AHU-NW-1-2 Air Handling Unit 3 460 30-40 31.9 AHU-NW-2-1 Air Handling Unit 3 460 30-40 31.9 AHU-NW-2-2 Air Handling Unit 3 460 30-40 31.9 AHU-SW-G-1 Air Handling Unit 3 460 30-40 31.9 AHU-SW-G-2 Air Handling Unit 3 460 30-40 31.9 AHU-SW-1-1 Air Handling Unit 3 460 30-40 31.9 AHU-SW-1-2 Air Handling Unit 3 460 30-40 31.9 AHU-SW-2-1 Air Handling Unit 3 460 30-40 31.9 AHU-SW-2-2 Air Handling Unit 3 460 30-40 31.9 AHU-SE-G-1 Air Handling Unit 3 460 30-40 31.9 AHU-SE-G-2 Air Handling Unit 3 460 30-40 31.9 AHU-SE-1-1 Air Handling Unit 3 460 30-40 31.9 AHU-SE-1-2 Air Handling Unit 3 460 30-40 31.9 AHU-SE-2-1 Air Handling Unit 3 460 30-40 31.9 AHU-SE-2-2 Air Handling Unit 3 460 30-40 31.9 TX-SE Toilet Exhaust Fan 3 460 0.5-1.1 0.9 TX-SW Toilet Exhaust Fan 3 460 1-2.1 1.7 TX-NW Toilet Exhaust Fan 3 460 0.5-1.1 0.9 TX-S Toilet Exhaust Fan 3 460 0.5-1.1 0.9 GX-SE General Exhaust Fan 3 460 0.5-1.1 0.9 GX-SW General Exhaust Fan 3 460 1-2.1 1.7 GX-NW General Exhaust Fan 3 460 0.5-1.1 0.9 KX-1 Kitchen Exhaust Fan 3 460 10-14 11.2 SP-NW Spill Exhaust Fan 3 460 7.5-11 8.8 EF-B-1 General Exhaust Fan 3 460 0.5-1.1 0.9 EF-PH-1 Garage Exhaust Fan 3 460 7.5-11 8.8 EF-PH-2 Garage Exhaust Fan 3 460 5-7.6 6.1 EDH-B-1 Electric Duct Heater 3 460-25 34.5 27.5 PCWP-1 Primary Pump 3 460 50-65 51.8 PCWP-2 Primary Pump 3 460 50-65 51.8 PCWP-3 Primary Pump 3 460 50-65 51.8 SCWP-1 Secondary Pump 3 460 60-77 61.3 SCWP-2 Secondary Pump 3 460 60-77 61.3 SCWP-3 Secondary Pump 3 460 60-77 61.3 PCHP-1 Chilled Water Pump 3 460 100-124 98.8 PCHP-2 Chilled Water Pump 3 460 100-124 98.8 PCHP-3 Chilled Water Pump 3 460 100-124 98.8 7
Designation Mechanical Unit Type Phase Voltage HP kw Amps/FLA Connected kva GWP-1 Hot Water Pump 3 460 3-5 3.8 CT-1 Cooling Tower Cell 1 3 460 40-52 41.4 CT-1 Cooling Tower Cell 2 3 460 40-52 41.4 CT-1 Cooling Tower Cell 3 3 460 40-52 41.4 CH-2 Electric Chiller 3 460-272 375.5 299.2 CH-3 Electric Chiller 3 460-272 375.5 299.2 CH-4 Electric Chiller 3 460-272 375.5 299.2 EB-1 Electric Boiler 3 460-120 165.7 132.0 UH-G-1 Electric Unit Heater 3 460-10 13.8 11.0 UH-G-2 Electric Unit Heater 3 460-10 13.8 11.0 UH-G-3 Electric Unit Heater 3 460-10 13.8 11.0 UH-G-4 Electric Unit Heater 3 460-10 13.8 11.0 UH-G-5 Electric Unit Heater 3 460-10 13.8 11.0 UH-G-6 Electric Unit Heater 3 460-25 34.5 27.5 UH-G-7 Electric Unit Heater 3 460-25 34.5 27.5 UH-B-15 Electric Unit Heater 3 460-3.3 4.6 3.6 UH-B-16 Electric Unit Heater 3 460-3.3 4.6 3.6 UH-B-17 Electric Unit Heater 3 460-3.3 4.6 3.6 UH-B-18 Electric Unit Heater 3 460-3.3 4.6 3.6 UH-B-19 Electric Unit Heater 3 460-3.3 4.6 3.6 UH-B-20 Electric Unit Heater 3 460-3.3 4.6 3.6 UH-B-21 Electric Unit Heater 3 460-3.3 4.6 3.6 CH-B-1 Electric Unit Heater 3 460-3 4.1 3.3 CH-B-2 Electric Unit Heater 3 460-3 4.1 3.3 CH-G-3 Electric Unit Heater 3 460-5 6.9 5.5 CH-G-4 Electric Unit Heater 3 460-5 6.9 5.5 UH-PH-1 Electric Unit Heater 3 460-10 13.8 11.0 UH-PH-2 Electric Unit Heater 3 460-10 13.8 11.0 UH-PH-3 Electric Unit Heater 3 460-10 13.8 11.0 UH-PH-4 Electric Unit Heater 3 460-10 13.8 11.0 UH-PH-5 Electric Unit Heater 3 460-10 13.8 11.0 UH-PH-6 Electric Unit Heater 3 460-10 13.8 11.0 UH-PH-7 Electric Unit Heater 3 460-10 13.8 11.0 HV-1 Heating/Ventilating Unit 3 460 15-21 16.7 HV-2 Heating/Ventilating Unit 3 460 7.5-11 8.8 HV-2A Heating/Ventilating Unit 3 460 7.5-11 8.8 HV-3 Heating/Ventilating Unit 3 460 15-21 16.7 KMU-1 Heating/Ventilating Unit 3 460 10-14 11.2 AHU-G-1 Air Handling Unit 3 460 7.5-11 8.8 AHU-2-1 Air Handling Unit 3 460 40-52 41.4 AHU-2-2 Air Handling Unit 3 460 40-52 41.4 8
Designation Mechanical Unit Type Phase Voltage HP kw Amps/FLA Connected kva AHU-2-3 Air Handling Unit 3 460 40-52 41.4 AHU-2-4 Air Handling Unit 3 460 40-52 41.4 AHU-2-5 Air Handling Unit 3 460 20-27 21.5 AHU-2-6 Air Handling Unit 3 460 20-27 21.5 AHU-2-7 Air Handling Unit 3 460 30-40 31.9 CAC-B-1 Chilled Water AHU 3 460 7.5-11 8.8 CAC-B-3 Chilled Water AHU 3 460 7.5-11 8.8 CAC-G-1 Chilled Water AHU 3 460-38.8 53.6 42.7 CAC-G-2 Chilled Water AHU 3 460 10-14 11.2 CAC-G-4 Chilled Water AHU 3 460-38.8 53.6 42.7 CAC-G-6 Chilled Water AHU 3 460-38.8 53.6 42.7 CAC-G-7 Chilled Water AHU 3 460 10-14 11.2 CAC-G-8 Chilled Water AHU 3 460-38.8 53.6 42.7 CAC-G-10 Chilled Water AHU 3 460 10-14 11.2 CAC-G-11 Chilled Water AHU 3 460-38.8 51.6 41.1 CAC-G-12 Chilled Water AHU 3 460-38.8 51.6 41.1 CAC-G-14 Chilled Water AHU 3 460-38.8 51.6 41.1 CAC-G-15 Chilled Water AHU 3 460-21.3 28.4 22.6 CAC-G-17 Chilled Water AHU 3 460-21.3 28.4 22.6 FP-VAV-A/5 Fan Powered VAV Box 3 460-5 6.7 5.3 FP-VAV-A/6 Fan Powered VAV Box 3 460-6 8.0 6.4 FP-VAV-A/8 Fan Powered VAV Box 3 460-8 10.6 8.5 FP-VAV-B/5 Fan Powered VAV Box 3 460-5 6.7 5.3 FP-VAV-B/6 Fan Powered VAV Box 3 460-6 8.0 6.4 FP-VAV-B/8 Fan Powered VAV Box 3 460-8 10.6 8.5 FP-VAV-B/10 Fan Powered VAV Box 3 460-10 13.3 10.6 FP-VAV-C/5 Fan Powered VAV Box 3 460-5 6.7 5.3 FP-VAV-C/6 Fan Powered VAV Box 3 460-6 8.0 6.4 FP-VAV-C/8 Fan Powered VAV Box 3 460-8 10.6 8.5 FP-VAV-C/10 Fan Powered VAV Box 3 460-10 13.3 10.6 FP-VAV-C/12 Fan Powered VAV Box 3 460-12 16.0 12.7 FP-VAV-D/8 Fan Powered VAV Box 3 460-8 10.6 8.5 FP-VAV-D/10 Fan Powered VAV Box 3 460-10 13.3 10.6 FP-VAV-D/12 Fan Powered VAV Box 3 460-12 16.0 12.7 UH-B-1 Electric Unit Heater 3 460-3.3 4.4 3.5 UH-B-2 Electric Unit Heater 3 460-3.3 4.4 3.5 UH-B-3 Electric Unit Heater 3 460-3.3 4.4 3.5 UH-B-4 Electric Unit Heater 3 460-3.3 4.4 3.5 UH-B-5 Electric Unit Heater 3 460-3.3 4.4 3.5 UH-B-6 Electric Unit Heater 3 460-3.3 4.4 3.5 UH-B-7 Electric Unit Heater 3 460-3.3 4.4 3.5 9
Designation Mechanical Unit Type Phase Voltage HP kw Amps/FLA Connected kva UH-B-8 Electric Unit Heater 3 460-3.3 4.4 3.5 UH-B-9 Electric Unit Heater 3 460-3.3 4.4 3.5 UH-B-10 Electric Unit Heater 3 460-3.3 4.4 3.5 UH-B-11 Electric Unit Heater 3 460-3.3 4.4 3.5 UH-B-12 Electric Unit Heater 3 460-3.3 4.4 3.5 UH-B-13 Electric Unit Heater 3 460-3.3 4.4 3.5 UH-B-14 Electric Unit Heater 3 460-3.3 4.4 3.5 CH-G-1 Electric Unit Heater 3 460-15 20.0 15.9 CH-G-2 Electric Unit Heater 3 460-15 20.0 15.9 Total Connected kva 3576.9 Mechanical Unit Connected Demand Designation Type Phase Voltage HP Amps/FLA kva kva ELEV-1 Elevator Motor 3 460 30 40.0 31.9 27.1 ELEV-2 Elevator Motor 3 460 30 40.0 31.9 27.1 ELEV-3 Elevator Motor 3 460 60 77.0 61.3 52.1 ELEV-4 Elevator Motor 3 460 60 77.0 61.3 52.1 Total Demand kva 158.5 1-Phase Mechanical Loads Designation Mechanical Unit Type Phase Voltage HP kw Amps/FLA kva FCU-B-1 Fan Coil Unit 1 265 0.5 0.4 1.4 0.4 FCU-B-2 Fan Coil Unit 1 265 0.25 0.2 0.7 0.2 FCU-G-1 Fan Coil Unit 1 265 0.5 0.4 1.4 0.4 FCU-G-2 Fan Coil Unit 1 265 0.5 0.4 1.4 0.4 FCU-G-1-1 Fan Coil Unit 1 265 0.5 0.4 1.4 0.4 FCU-G-1-2 Fan Coil Unit 1 265 0.25 0.2 0.7 0.2 FCU-G-3 Fan Coil Unit 1 265 0.25 0.2 0.7 0.2 FCU-G-4 Fan Coil Unit 1 265 0.25 0.2 0.7 0.2 FCU-1-1 Fan Coil Unit 1 265 0.25 0.2 0.7 0.2 FCU-1-2 Fan Coil Unit 1 265 0.25 0.2 0.7 0.2 FCU-1-3 Fan Coil Unit 1 265 0.25 0.2 0.7 0.2 FCU-2-1 Fan Coil Unit 1 265 1.5 1.1 4.2 1.1 FCU-2-2 Fan Coil Unit 1 265 1.5 1.1 4.2 1.1 TX-G-1 Exhaust Fan 1 115-0.11 1.1 0.1 TX-1-1 Exhaust Fan 1 115-0.11 1.1 0.1 TX-1-2 Exhaust Fan 1 115-0.11 1.1 0.1 10
Designation Mechanical Unit Type Phase Voltage HP kw Amps/FLA kva EF-G-1 Exhaust Fan 1 115-0.46 4.4 0.5 EF-1-1 Exhaust Fan 1 115-0.74 7.0 0.8 OAF-G-1 Outside Air Fan 1 115 0.25-5.8 0.7 OAF-2-1 Outside Air Fan 1 115 3-34.0 3.9 TX-R-1 Exhaust Fan 1 115 0.75-13.8 1.6 Total Connected kva 12.9 Mechanical Load Notes: 1. Full Load Current for 3-phase motors were taken from NEC 2002 Table 430-150. Full Load Currents for 1-phase motors were taken from NEC 2002 Table 430-148. 2. CAC units in kw have electric reheat and infrared humidifiers. Power for which are already taken into account in the total kw as per the mechanical equipment schedules. 3. Units that were on stand-by were omitted from the load calculations because of extended inactivity. 4. 85% demand for elevators taken from NEC 2002 Table 620.14. General Lighting Loads by Occupancy Building Floor SF Unit Load kva Cellar Loading Dock/Storage 7,000 0.5 3.5 Mech/Elec. Room 7,200 0.25 1.8 Ground Loading Dock/Storage 4,000 0.5 2 Food Service/Seating 12,000 2 24 Office 33,000 3.5 115.5 Technical Production 11,300 3.5 39.55 Broadcast Studio 15,000 3.5 52.5 Computer Equip. Room 12,000 0.5 6 Common Space 25,200 0.5 12.6 Mech/Elec Room 2,500 0.25 0.625 1 st Office 56,300 3.5 197.05 Gym 5,800 1 5.8 Common Space 16,900 0.5 8.45 Mech/Elec Room 2,500 0.25 0.625 2 nd Mechanical Floor 115,000 0.25 28.75 Total kva: 498.75 11
Lighting Load Note: 1. Unit Loads obtained from NEC 2002 Table 220.3(A) General Lighting Loads by Occupancy Receptacle Demand Load # Duplex kva kva Building Floor Receptacles/Equipment Connected Demand Ground General Receptacles 1420 255.6 132.8 Equipment Racks 356 213.6 111.8 IT Racks 19 9.5 10 IT Servers 106 106.0 58 Kitchen Equipment 61 91.5 59.475 1 st General Receptacles 1701 306.2 158.09 Total kva: 982.4 530.2 Receptacle Demand Load Notes: 1. kva for duplex receptacles was taken as 0.180kVA per NEC 2002 code. Demand was taken as 100% of the first 10kVA and 50% of the remainder. 2. kva for racks and kitchen equipment were taken from electrical schedules in the construction documents. Actual equipment loads were used to represent receptacles serving the racks in the computer equipment room and business equipment room as well as appliance load for kitchen equipments. Demand of 65% for more than 6 kitchen equipments taken from table 220.20 Demand Factors for Kitchen Equipment Other Than Dwelling Unit(s). 12
Feeder Sizing Check Switchboard A Equipment Served EDP (via ATS2) Equipment Current Rating Feeder Size Feeder Capacity 1200A* see Note 2 (2) 4#500MCM 860A Sized Appropriately? NO* see Note2 DP-ELEC-A (via ATS3) 2000A (6) 4#400MCM 2010A YES DP-MECH-A (via ATS5) 2000A (6) 4#400MCM 2010A YES STUDIO LIGHTING A (via ATS7) 1200A (4) 3#350MCM 1240A YES UPS-INPUT A (via ATS11) 1600A (4) 3#500MCM 1520A YES* see Note 3 SPARE (for ATS9) 800A (3) 3#500MCM 1140A YES Switchboard B Equipment Served Equipment Current Rating Feeder Size Feeder Capacity Sized Appropriately? FIRE PUMP (via ATS1) 477A (2) 3#500MCM 760A YES DP-ELEC-B (via ATS4) 2000A (6) 4#400MCM 2010A YES DP-MECH-B (via ATS6) 2000A (6) 4#400MCM 2010A YES STUDIO LIGHTING B (via ATS8) 1200A (4) 3#350MCM 1240A YES UPS-INPUT B (via ATS12) 1600A (4) 3#500MCM 1520A YES* see Note 3 SPARE (for ATS10) 800A (3) 3#500MCM 1140A YES Feeder Sizing Check Notes: 1. Feeder ampacities checked in accordance to NEC 2002 Article 215.2 (A)(1) for feeders supplied by less than 600V. 2. Panel EDP is rated at 1200A. However it is fed from Switchboard A with an 800A circuit breaker. If inspected for feeder capacity based on an 800A rating on the circuit breaker in Switchboard A, the feeder is sized appropriately. This discrepancy may have been resolved at later issued drawings. The panelboard however contains loads with more than 800A and therefore, the conclusion that it is undersized still remains. 13
3. The feeders for the distribution panel UPS-INPUT A and UPS B appear to be undersized by 80A. However, this panelboard contains (3) 800A circuit breakers for the UPS input, Maintenance Bypass input, and SCC input. Only one of these inputs is utilized at a time. Therefore, a feeder with an ampere rating of 1520A is more than sufficient to supply an 800A current. Service Transformers Capacity Check The two transformers in the substation are rated at 2,500 kva. Total Transformer kva Capacity: 2 x 2,500 kva x 0.8 = 4000 kva (The 0.8 multiplier is a result of a design practice where transformers should ideally be operated at 80% of its rated capacity.) The total design load for the entire building is 4882.55 kva. It appears that the transformers are undersized. However, upon inspection of the peak kw usage for the year according to the electrical utility load data in the section to follow, there is a maximum usage of only 3,000kW for the year. In addition, the estimated design load is also very conservative because it assumed that all mechanical/hvac units are operating simultaneously at full load. Switchboard Capacity Check Ampere rating needed to carry 2,500 kva (for one service transformer rating) Needed Switchboard Ampere rating: 2,500 kva/(1.732*0.48v) = 3,007 A The two main switchboards are each rated at 4,000A. The switchboard is sized properly. Emergency Generator Capacity Check The generator set was designed so that in a situation where one fails, the other should be able to carry the full load of the building. Upon comparison with the total design load, one 2000 kva generator is not able to carry 4,882.55 kva. Moreover, in comparison with the annual building energy consumption data, one generator is still about 1000 kva below the peak building load consumption. It appears that as the year progresses, energy consumption in the building is also increasing. In the beginning of the year, data shows that the peak building demand load was at 2,179 kva and has increased to 2,964 kva by the end of the year of the data collected. Thus, the 2,000 kva generator that was once designed to be able to carry 100% of the building load no longer fulfills that function. 14
Utility Rate Structure 15
Electric Utility Load Data 16