Electrical Essentials corrected calculation slides only

Transcription

1 Electrical Essentials corrected calculation slides only IAEI Southern Nevada Chapter/Educode 2015

2 Electrical Theory 1 Feeders and OCP 5 NEC Structure 2 Service and Grounding 6 Print Reading 3 Fault Current Calcs 7 Load Calculations 4 Plans Check/Inspections 8

3 Load Calculations Calculate each type of occupancy 1 Office Calculate loads for three office spaces 2 Residential Calculate loads for four apartments 3 Retail/ business Calculate loads for four businesses 4 House panel Calculate loads on house panel (common areas)

4 Office 1 Square Footage (general lighting) 2800 sq x 3.5 = 9800 VA x 1.25= 12,250 VA Receptacle Loads (larger of (K)(1) or (2)) 8 x 180 VA = 1440 VA < 2800 sq x 1 VA/sq = 2800 VA Equipment - Instant water heater = 1600 VA Heating and Cooling VA/ton = 8000 VA VA/ton = 6000 VA 25% of largest motor= 2000 VA Total load 32,650 VA Divide by Voltage 32,650 VA/208 V = 157 A Three Phase divisor 157 A/1.73 = 91 A

5 Office 2 Square Footage (general lighting) 1800 sq x 3.5 = 6300 VA x 1.25= 7875 VA Receptacle Loads (larger of (K)(1) or (2)) 7 x 180 VA = 1260 VA < 1800 sq x 1 VA/sq = 1800 VA Equipment - Instant water heater = 1600 VA Heating and Cooling VA/ton = 9000 VA 25% of largest motor= 2250 VA Total load 22,525 VA Divide by voltage 22,525/208 V = 108 A Three Phase divisor 108 A/1.73 = 63 A

6 Office 3 Square Footage (general lighting) 1400 sq x 3.5 = 4900 VA x 1.25= 6125 VA Receptacle Loads (larger of (K)(1) or (2)) 4 x 180 VA = 720 VA < 1400 sq x 1 VA/sq = 1400 VA Equipment - Instant water heater = 1600 VA Heating and Cooling VA/ton = 7000 VA 25% of largest motor= 1750 VA Total load 17,875 VA Divide by voltage 17875/208 V = 86 A Three Phase divisor 86/1.73 = 50 A

7 Load Calculations Calculate each type of occupancy 1 Office Calculate loads for three office spaces 2 Residential Calculate loads for four apartments 3 Retail/ business Calculate loads for four businesses 4 House panel Calculate loads on house panel (common areas)

8 Units 1 and 4 Square footage for general lighting 1400 sq x 3 VA = 4200 VA Kitchen small appliance loads 1500 x 2 = 3000 VA Laundry load 1500 VA Sum = 8700 VA Demand applied First 3000 VA + (.35 x 5700) VA = 4995 VA General lighting = 4995 VA

9 Units 1 and 4 continued Fixed in place appliances Dishwasher 1800 VA Disposal 600 VA Microwave 1200 VA Trash compactor 1500 VA Sum = 5100 VA Demand x.75 = 3825 VA The following are gas: water heater, dryer, heating and cooking A/C load 3.5 ton unit at 2000 VA/ton 7000 VA

10 Units 1 and 4 completion General Lighting = 4995 VA Appliances = 3825 VA Heating cooling = 7000 VA 25% of largest motor load = 1750 VA Sum = 17,570 VA 17,570 VA/208 V = 85 A Three phase divisor 85 A/1.73 = 49 A

11 Units 2 and 3 Square footage for general lighting 1550 sq x 3 VA = 4650 VA Kitchen small appliance loads 1500 VA x 2 = 3000 VA Laundry load 1500 VA Sum = 9150 VA Demand applied First 3000 VA + (.35 x 6150) VA = 5153 VA General lighting = 5153 VA

12 Units 2 and 3 continued Fixed in place appliances Dishwasher 1800 VA Disposal 600 VA Microwave 1200 VA Trash compactor 1500 VA Sum = 5100 VA Demand x.75 = 3825 VA The following are gas: water heater, dryer, heating and cooking A/C load 4 ton unit at 2000 VA/ton 8000 VA

13 Units 2 and 3 completion General Lighting = 5153 VA Appliances = 3825 VA Heating cooling = 8000 VA 25% of largest motor load = 2000 VA Sum = 18,978 VA 18,978 VA/208 = 91 A Three phase divisor 91/1.73 = 53 A

14 Load Calculations Calculate each type of occupancy 1 Office Calculate loads for three office spaces 2 Residential Calculate loads for four apartments 3 Retail/ business Calculate loads for four businesses 4 House panel Calculate loads on house panel (common areas)

15 Diner Loads General Lighting 1600 Sq x 2 VA = 3200 VA x 1.25 = 4000 VA Show Window 12 x 200 VA/ = 2400 VA Sign 1200 VA x 1.25 = 1500 VA General purpose receptacles 5 x 180 VA = 900 VA Total lighting and receptacles = 8800 VA Heating and cooking units are gas

16 Diner - Kitchen Equipment Dishwasher = V, 3 phase 22 A x 208 V = 4576 VA x 1.73 = 7916 VA Disposal V, 1 phase 12 A x 208 V = 2496 VA Refrigerator V 15 A x 120 V = 1800 VA Freezer V 18 A x 120 V = 2160 Microwave V 14 A x 120 V = 1680 VA Food Strip Heaters V 12 A x 120 V = 1440 VA x 2 = 2880 VA Total Equipment 18,932 VA x.65 = 12,306 VA

17 Diner - Mechanical Equipment 4 ton A/C unit 2000 VA/ton x 4 = 8000 VA Exhaust Fan 1/2 hp, 120 V at 9.8 A 9.8 A x 120 V = 1176 VA x 1.25 = 1470 VA Makeup air unit 1/2 hp, 120 V at 9.8 A 9.8 A x 120 V = 1176 VA x 1.25 = 1470 VA Plus 25% of largest motor load = 2000 V Total Mechanical equipment = 12,940 VA

18 Diner - Totals Lighting and Receptacles = 8800 VA Equipment = 12,306 VA Mechanical = 12,940 VA Total = 34,046 VA 34,046/208 V = 164 A 164 A/1.73 = 95 A

19 Coffee House General lighting 1500 Sq x 3 VA = 4500 VA x 1.25 = 5625 VA 4 receptacles 4 X 180 VA = 720 VA 24 track lighting at 150 VA/2 12 x 150 VA = 1800 VA x 1.25 = 2250 VA Sign 1200 VA x 1.25 = 1500 VA Show Window VA/ x 12 = 2400 VA Total lighting and receptacles = 12,495 VA Water heater and space heating is gas

20 Coffee House - Equipment 2 Espresso 25 A, 208 V, 3 phase 25 x 208 = 5200 x 1.73 = 8996 x 2 = 17,992 VA 2 Coffee 16 A, 208 V, 3 phase 16 A x 208 A = 3328 VA x 1.73 = 5757 VA x 2 = 11,514 VA 2 12 A, 120 V 12 A x 120 V = 1440 VA x 2 = 2880 VA Total equipment = 32,386 VA Mechanical Equipment 4 ton 2000 VA/ton 4 x 2000 = 8000 VA 25% or largest motor load = 2000 VA Total mechanical equipment = 10,000 VA

21 Coffee House - Totals Lighting and Receptacles = 12,495 VA Equipment = 32,386 VA Mechanical = 10,000 VA Total = 54,881 VA 54,881 VA/208 V = 264 A 264 A/1.73 = 153 A

22 Fitness Center General lighting 1500 Sq x 3 VA = 4500 VA x 1.25 = 5625 VA 5 receptacles 5 x 180 VA = 900 VA Sign 1200 VA x 1.25 = 1500 VA Show Window 12 x 200 VA/ 12 x 200 = 2400 VA

23 Fitness Center continued Instant water heater = 1600 VA 4 Ton A/C 4 x 2000 = 8000 VA 25% of largest motor load = 2000 VA Total = 22,025 VA 22,025/208 = 106 A 106/1.73 = 61 A

24 Jewelry Store General Lighting 1600 Sq x 3 VA = 4800 VA x 1.25 = 6000 VA 5 receptacles 5 x 180 VA = 900 VA 88 track lighting 88 /2 = 44 x 150 = 6600 x 1.25= 8250 VA Sign 1200 VA x 1.25 = 1500 VA Show Window x 200 VA = 2400 VA

25 Jewelry continued Instant water heater = 1600 VA A/C 4 ton 4 x 2000 = 8000 VA 25% of largest motor load = 2000 VA Total = 30,650 VA 30,650/208 = 147 A 147/1.73 = 85 A

26 Load Calculations Calculate each type of occupancy 1 Office Calculate loads for three office spaces 2 Residential Calculate loads for four apartments 3 Retail/ business Calculate loads for four businesses 4 House panel Calculate loads on house panel (common areas)

27 House Panel Lighting: 7 A3 Fixtures 7 x 90 VA = 630 VA 4 BB1 Fixtures 4 x 50 VA = 200 VA 2 F2 Fixtures 2 x 60 VA = 120 VA 2 AA1 Fixtures 2 x 60 VA = 120 VA Lighting Subtotal = 1070 x 1.25 = 1338 VA

28 House panel - Equipment and Receptacles Receptacles 6 6 x 180 VA = 1080 VA A/C unit 2 x 2000 = 4000 VA Elevator 5 hp 16.7 A x 208 = 3474 VA* 25% of largest load = 1000 VA Equipment and receptacle subtotal = 9554 VA Total house panel 1338 VA VA = 10,892 VA 10,892/208 = 52 A 53/1.73 = 30 A *This value is from the 3 Phase Table

29 Electrical Theory 1 Feeders and OCP 5 NEC Structure 2 Service and Grounding 6 Print Reading 3 Fault Current Calcs 7 Load Calculations 4 Plans Check/Inspections 8

30 What size Panels and Feeders are the minimum for each occupancy? According to our calculated loads what size could we use as a minimum? Office A Office 2-70 A Office 3-50 A Residence 1 & 4-50 A Residence 2 & 3-60 A Diner A Coffee House A Fitness - 70 A Jewelry - 90 A House - 30A

31 A good designer doesn t usually size the equipment for the minimum. This just isn t good for the customer, since we all know that, sooner or later, the tenant will want to add another piece of equipment or add load to the electrical system.

32 What size Panels and Feeders would be a good design for each occupancy? Office A Office A Office A Residence 1 & A Residence 2 & A Diner A Coffee House A Fitness A Jewelry A House - 100A

33 Using THHN/THHW cu wire, what size conductors would we use according to Table (B)(16) for the: 200 A Feeders = 3/0 AWG cu 150 A feeders = 1/0 AWG cu 100 A feeders = 3 AWG cu (however 3 AWG frequently isn t stocked so 2 AWG is used) What about (B)(7) for residential feeder sizing?

34 Dwelling Services and Feeders This language changed in the 2014 NEC (B)(7) 120/240-Volt, Single-Phase Dwelling Services and Feeders. For one-family dwellings and the individual dwelling units of two-family and multifamily dwellings, service and feeder conductors supplied by a single-phase, 120/240volt system shall be permitted be sized in accordance with (B)(7)(1) through (4).

35 Electrical Theory 1 Feeders and OCP 5 NEC Structure 2 Service and Grounding 6 Print Reading 3 Fault Current Calcs 7 Load Calculations 4 Plans Check/Inspections 8

36 Calculate the Service Size

37 Residential 5900 ft x 3 VA = 17,700 VA Small Appliance Circuits 4 x 3000 VA = 12,000 VA Laundry 4 x 1500 = 6000 Total Residential general lighting 35,700 VA First 3000 at 100% Remainder at 35% 3000 VA + 12,495 VA = 15,495 VA

38 Residential appliances (Look back at each unit total) Each unit had 4 items that totaled 5100 VA, therefore: 4 x 5100 VA = 20,400 VA Demand factor 20,400 x 75% = 15,300 VA Residential totals: 15, ,300 Total: 30,795 VA

39 Sums 1) Residential = 30,795 VA 2) 3) 4) 5)

40 Office general lighting and receptacles Receptacles are taken as the larger of 180 VA each or 1 VA per sq ; since 1 VA/sq is the larger value the combined lighting and receptacle load can be calculated as: 6000 sq x (3.5 VA + 1 VA) = 27,000 VA Continuous loads? Yes: 27,000 x 125% = 33,750 VA (At the engineer s discretion, the lighting could have been taken as continuous and the receptacles as non-continuous; often, you will see them calculated as one value.)

41 Sums 1) Residential = 30,795 VA 2) Office lighting and receptacles = 33,750 VA 3) 4) 5)

42 Diner/Coffee House General lighting (1600 Sq x 2) + (1500 Sq x 3) = 7700 VA Continuous: 7700 x 125% = 9625 VA Receptacles 9 x 180 VA = 1620 VA Diner Kitchen Equipment = 12,306 VA Coffee House Appliances = 32,386 Restaurant/Coffee House totals , ,386 = 55,937 VA

43 Sums 1) Residential = 30,795 VA 2) Office lighting and Receptacles = 33,750 VA 3) Diner/Coffee lighting and appliances = 55,937 VA 4) 5)

44 Fitness and Jewelry General lighting 3100 Sq x 3 VA = 9300 VA Continuous load 9300 x 125% = 11,625 VA Receptacles 10 x 180 = 1800 VA Track lighting 136 / 2 = 68 x 150 = 10,200 VA 10,200 VA x 125% = 12,750 VA

45 Fitness and Jewelry Continued Show windows 48 x 200 VA = 9600 VA House panel lighting and receptacles 1338 VA VA = 2418 VA Signs 4 x 1200 = 4800 x 1.25 = 6000 VA Store and misc lighting 11, = 44,193 VA

46 1) 2) 3) 4) 5) Sums Residential sub total = 30,795 VA Office lighting and Receptacles = 33,750 VA Diner/Coffee lighting and appliances = 55,937 VA Fitness/jewelry and misc lighting/recpt = 44,193 VA

47 Building Mechanical Equipment A/C equipment 1-2 ton unit 1-3 ton unit ton units 7-4 ton units ton unit Total tonnage = 48 tons 48 x 2000 = 96,000 VA Exhaust fan and makeup unit = 2940 VA 5 hp elevator = 3470 VA 25% of largest = 2250 VA Mechanical totals 96, = 104,660 VA

48 1) 2) 3) 4) 5) Sums - final Residential sub total = 30,795 VA Office lighting and Receptacles = 33,750 VA Restaurant lighting and appliances = 55,937 VA Stores and misc lighting = 44,193 VA Mechanical Equipment = 104,660 VA Building total = 269,335 VA Divide by Voltage 269,335 / 208 V = 1295 A three phase divisor 1295 / 1.73 = 748 A Therefore, an 800 amp Service is required.

49 Service Entrance Conductors (assuming customer owned service and using the same conductor types as used for the sub-feeders) 2 Parallel runs of 500 kcmil cu 380 A x 2 = 760 A

50 Sizing Equipment Grounds and Grounding Electrode Conducts Grounding Electrode Conductor to concrete encased electrode Table Total service conductor size = 1000 kcmil 2/0 AWG cu *Read (B) Size for concrete encased electrode 4 AWG cu

51 Metal Water Piping system bonding (A)(1) refers us to Table What size do we use for the Water Piping Bond conductor? 2/0 AWG cu Structural Steel? 2/0 AWG cu

52 Size the sub-feeder equipment grounding conductors Article Table A feeder would require 8 AWG cu conductor 150 A feeder would require 6 AWG cu conductor 200 A feeder would require 6 AWG cu conductor

53 Contact Us Christel Hunter Hunter Howard Herndon IAEI Southern Nevada Chapter