Metal Box and Doorbell Trans. Question

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  #1  
Old 12-01-13, 07:34 PM
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Metal Box and Doorbell Trans. Question

Hi-
I mounted a new doorbell transformer today. Its a Heath Zenith brand. It has a plastic screw/locknut that mounts to a 1/2" knockout. I mounted it to a blank 4" cover with the knockout hole in center.

However, I have all metal conduit which serves as my ground. Was this the wrong transformer (ie plastic mount) for this application? I fear its against code to have this plastic locknut business inside a metal box.

The old transformer didnt have a ground wire, new one did which I made a connection with the box.

But I wonder, if instead I had just capped the green, would I still have been grounded?

If a portion of the metal of the transformer was in contact with the cover its mounted on then I should be grounded? Unless of course I bought the wrong tranny, perhaps for a plastic box or something?


Heath Zenith Wired Door Chime Transformer-121AC-A at The Home Depot

How can I test this for ground without having to take the box apart?
 
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  #2  
Old 12-01-13, 10:48 PM
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Welcome to the forums.

The old transformer didn't have a ground wire, new one did which I made a connection with the box.
That's all you need to do. It doesn't matter that the transformer had a plastic connection.... it is grounded thru the green wire. So a ground screw in the back of the metal junction box is ideal.
 
  #3  
Old 12-02-13, 04:18 AM
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Hi thanks for your reply.

Are you sure the transformer isnt for a plastic box since it has a plastic lock nut and a ground wire?

I just want to make sure its code compliant to have plastic inside a metal box.

Is it OK to have the transformer on the load side of a gfci?
 

Last edited by ardmi; 12-02-13 at 04:42 AM.
  #4  
Old 12-02-13, 07:03 AM
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It is fine on a metal box. I'd put it on the line side so a tripped GFCI wouldn't interfere with operation but if only GFCI protected circuit available that is fine. No code question either way.
 
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