277-120 Transformer

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hotneutral

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I installed power for a gate camera and tapped off of the power for the motor because there was nothing else available anywhere close and the camera draws almost nothing. I come to find out the the gate motor is fed from a transformer taking 277 from the property lighting panel to 120. I have 125 hot to neutral at the camera receptacle but the transformer seems to have a floating ground because I have ~70V H-G and ~50V N-G at the receptacle. Do I need to bond neutral and ground at the transformer?
 
hotneutral said:
I installed power for a gate camera and tapped off of the power for the motor because there was nothing else available anywhere close and the camera draws almost nothing. I come to find out the the gate motor is fed from a transformer taking 277 from the property lighting panel to 120. I have 125 hot to neutral at the camera receptacle but the transformer seems to have a floating ground because I have ~70V H-G and ~50V N-G at the receptacle. Do I need to bond neutral and ground at the transformer?
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Do you have a picture of the transformer name plate? What kind of transformer is it?

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hotneutral said:
I installed power for a gate camera and tapped off of the power for the motor because there was nothing else available anywhere close and the camera draws almost nothing. I come to find out the the gate motor is fed from a transformer taking 277 from the property lighting panel to 120. I have 125 hot to neutral at the camera receptacle but the transformer seems to have a floating ground because I have ~70V H-G and ~50V N-G at the receptacle. Do I need to bond neutral and ground at the transformer?
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I'd say bond the 120v neutral side of the transformer to the case

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Connect an equipment ground from X4 to the equipment ground for the case and the camera receptacle. Your neutral will be on X4 also

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hotneutral said:
I installed power for a gate camera and tapped off of the power for the motor because there was nothing else available anywhere close and the camera draws almost nothing. I come to find out the the gate motor is fed from a transformer taking 277 from the property lighting panel to 120. I have 125 hot to neutral at the camera receptacle but the transformer seems to have a floating ground because I have ~70V H-G and ~50V N-G at the receptacle. Do I need to bond neutral and ground at the transformer?
Click to expand...
Also I'd like to add. Is the original feeder to the gate sized large enough to handle the load of both the motor and camera? I'd read article 240.21 in the 2020 NEC to make sure your taps are legal. You probably need an over current protective device on the secondary side of the transformer. Read article 225 as well

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the transformer picture is not clear cant see the specifications on the nameplate
 
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I’m in Florida so we’re still on 2014 here. All site lighting was 480 originally but had neutrals available. When the metal halides were replaced 277 leds were installed as the replacement and there were circuits left. The ”electricians“ who did the work for the gates stole some circuits from the lighting panel and used them to feed their transformers.

Transformer is wired straight 120. I don’t think this transformer is listed for a split phase secondary. Gate motor pulls substantially less than half circuit ampacity. I can’t remember the exact rating of the motor.
 

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Electricheaven said:
Also I'd like to add. Is the original feeder to the gate sized large enough to handle the load of both the motor and camera? I'd read article 240.21 in the 2020 NEC to make sure your taps are legal. You probably need an over current protective device on the secondary side of the transformer. Read article 225 as well

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There is no issue with load. The transformer is more than capable of handling both the gate motor and the camera. I did not know about the transformer until after I investigated the floating ground and I haven’t looked into the code requirements of to rectify that yet.
 
hotneutral said:
There is no issue with load. The transformer is more than capable of handling both the gate motor and the camera. I did not know about the transformer until after I investigated the floating ground and I haven’t looked into the code requirements of to rectify that yet.
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I'd add a circuit breaker on the secondary side

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I don’t believe the transformer needs any overcurrent protection other than the breaker protecting the branch circuit on the primary. If the transformer were rated for 120/240 wouldn’t that be included in the wiring diagram on the name plate?
 
hotneutral said:
I don’t believe the transformer needs any overcurrent protection other than the breaker protecting the branch circuit on the primary. If the transformer were rated for 120/240 wouldn’t that be included in the wiring diagram on the name plate?
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It is rated for 120/240. To get your 120/240 connect wires X2 and X3 and X2 becomes your neutral and you ground that

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hotneutral said:
I don’t believe the transformer needs any overcurrent protection other than the breaker protecting the branch circuit on the primary. If the transformer were rated for 120/240 wouldn’t that be included in the wiring diagram on the name plate?
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You can smoke that transformer if there is a big enough load on that transformer. The highest amperage is 8 amps on the primary side side and whats the circuit breaker rating for the feeder you're tapping off of

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20A. And you’re right the transformer needs primary and secondary protection. The existing load will not be an issue but it still needs to be protected under 450.3 based on the transformers current ratings. Thanks for all the replies.
 
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