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Thread: single phase transformer

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    single phase transformer

    I have 277V to 120V, 2kVA, single phase transformer. I have provided the grounding electrode conductor to grounding electrodes however, I am wondering if it requires neutral to ground i.e. system bonding jumper NEC 2014 250.30?

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    Based on 250.21(B) I would say "yes" but more detail might be warranted.
    At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

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    Quote Originally Posted by augie47 View Post
    Based on 250.21(B) I would say "yes" but more detail might be warranted.
    250.21(b) is ground detectors???

    Sent from my SM-G935U using Tapatalk

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    Quote Originally Posted by hhsting View Post
    250.21(b) is ground detectors???

    Sent from my SM-G935U using Tapatalk
    opps 250.20(B) (either ignorance or a typo )
    At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

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    Quote Originally Posted by augie47 View Post
    Based on 250.21(B) I would say "yes" but more detail might be warranted.
    Its step down transformer 277V To 120V Hammond power C1F1C003WES 3KVA 1PH Transformer.
    Last edited by hhsting; 01-11-19 at 05:49 PM.

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    I can not think of a reason for there not to be a bonding jumper looking at 450.6 & 250.20
    At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

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    Quote Originally Posted by hhsting View Post
    I have 277V to 120V, 2kVA, single phase transformer. I have provided the grounding electrode conductor to grounding electrodes however, I am wondering if it requires neutral to ground i.e. system bonding jumper NEC 2014 250.30?
    Yes, you will need to make this a grounded system. If it is straight 120 volt ground one end of the secondary winding. You will have the full 3 KVA output at 120 volt. If this is a 120/240 unit you could ground the mid point but you will only get 1/2 the output on each leg.
    One advantage if it is straight 120 volt or (you connect it that way) is you could possibly omit secondary protection.

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