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    maverick44's Avatar
    maverick44 Posts: 1, Reputation: 1
    New Member

    Dec 2, 2009, 07:01 AM
    What's the difference between a 120 volt and 120/208 volt system?
    We offer our unit in a 120 or 277 volt version. A customer just told me he is using a "120/208" system. What does that mean and will our 120 volt rated product work with it?
    KISS's Avatar
    KISS Posts: 12,510, Reputation: 839
    Uber Member

    Dec 2, 2009, 08:02 AM

    208 is usually 3 phase. It's stepped down to 120 for the 120 common single phase products to work. Single phase 208 is usually available too It's just never stepped down to a 120 3 phase panel. No point.

    277 comes from a 480 three phase system. 277 is usually reserved for lighting and has a separate panel. 277 is single phase too.

    There is a chance, that your customer has a higher voltage such as 480, but doesn't know. There would be a panel dedicated to lighting at 277 V if he did. The 480 would typically be used to run the HVAC systems.

    Yes, your product would work on single phase 120 on a 120/208 V system. The customer probably has 120 single phase, 208 single phase and 208 three phase, but may not.

    Sometimes, some commercial establishments like apartments would be furnished 3 phase power to the building, but metered single phase to each apartment.

    What's the power requirement of your product in Watts?
    tkrussell's Avatar
    tkrussell Posts: 9,657, Reputation: 724
    Uber Member

    Dec 2, 2009, 11:28 AM
    Review the attached diagram and see how 120 volts is dereived from a 120/208 Volt WYE system.

    You 120 Volt unit will work fine, your customer basically told you he has a three phase 4 wire system.
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