1. 1 Air Conditioning Three Phase Power

2. 2 Most common in commercial and industrial buildings Three hot legs, one ground, and one neutral L1, L2, L3, N, and Ground Most common in commercial and industrial buildings Three hot legs, one ground, and one neutral L1, L2, L3, N, and Ground

3. 3 Two types of transformer hook ups Delta(OLD) Wye(NEW)

4. 4 208 Volt Three basic types of three phase power that you may encounter –208V-3 phase-60Hz (Wye) –240V-3 phase-60Hz (Delta) –480V-3 phase-60Hz (Wye) Three basic types of three phase power that you may encounter –208V-3 phase-60Hz (Wye) –240V-3 phase-60Hz (Delta) –480V-3 phase-60Hz (Wye)

5. 5 208V-3 phase-60Hz (Wye) Common in newer commercial buildings that require three phase power for large equipment, but also need many 120 volt circuits.

6. 6 Power Configuration –208V 3 Phase –208V Single Phase –120V Single Phase For single phase power use 2 leads –2 Hot legs (208V) –One hot leg and neutral (120V) Power Configuration –208V 3 Phase –208V Single Phase –120V Single Phase For single phase power use 2 leads –2 Hot legs (208V) –One hot leg and neutral (120V)

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8. 8 480V-3 phase-60Hz (Wye) Common in industrial buildings where high voltage is desirable, large amounts of fluorescent lighting (277V) are needed, and minimal 120 volt circuits are needed.

9. 9 Examples of equipment used in HVAC: –Evaporator fans –Compressor –Condenser fans (277V) Examples of equipment used in HVAC: –Evaporator fans –Compressor –Condenser fans (277V)

10. 10 Power Configurations –480V three Phase –277V single Phase * Separate transformer in building needed to supply 120 volt power. Power Configurations –480V three Phase –277V single Phase * Separate transformer in building needed to supply 120 volt power.

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13. 13 240V-3 phase-60Hz (Delta) Found in older commercial and industrial buildings Contains one high leg or wild leg The wild leg should always be phase B in the panel Center leg or wild leg should be orange Do a safety check first Found in older commercial and industrial buildings Contains one high leg or wild leg The wild leg should always be phase B in the panel Center leg or wild leg should be orange Do a safety check first

14. 14 Care must be taken between wild leg and neutral –Wild leg to neutral is 180V-200V –Not usable voltage –Should be identified orange. Always check with your volt meter when working on any three phase system Each leg to neutral or ground Care must be taken between wild leg and neutral –Wild leg to neutral is 180V-200V –Not usable voltage –Should be identified orange. Always check with your volt meter when working on any three phase system Each leg to neutral or ground

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