# Doorbell transformer in attic



## jar546 (Jan 12, 2010)

Why was this failed?


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## Fortner (Jan 12, 2010)

Re: Doorbell transformer in attic

I don't see any box connectors for the NM. Was the metallic box bonded?  I believe you have to protect that doorbell transformer from damage also. Why is a GFI receptacle in the attic?


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## jar546 (Jan 12, 2010)

Re: Doorbell transformer in attic



			
				Fortner said:
			
		

> I don't see any box connectors for the NM. Was the metallic box bonded?  I believe you have to protect that doorbell transformer from damage also. Why is a GFI receptacle in the attic?


Plastic bushings for securing NM were properly installed.

Metal box was properly bonded with grounding conductor.

Not in an attic with storage space.

Don't know why he spent the money on a GFCI but that is not a problem

Hint, this is a commonly overlooked problem with these types of transformers............


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## JBI (Jan 12, 2010)

Re: Doorbell transformer in attic

Don't know why it failed, but the GFCI might be in case of humidity?


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## Pcinspector1 (Jan 12, 2010)

Re: Doorbell transformer in attic

Is that the rafter cross tie or top of the ceiling joist? Question would be about insulation covering the outlet if it's a ceiling joist.

I hope that GFI's not on the bathroom outlet circuit!


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## vegas paul (Jan 12, 2010)

Re: Doorbell transformer in attic

Guarding of energized parts?  NEC 450.8.  Need a case or enclosure for protection against insertion of foreign objects...


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## georgia plans exam (Jan 12, 2010)

Re: Doorbell transformer in attic

Would it have to do with the mixing of voltage ratings in the same enclosure???

GPE


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## Fortner (Jan 12, 2010)

Re: Doorbell transformer in attic

450.21 (A)


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## raider1 (Jan 12, 2010)

Re: Doorbell transformer in attic



			
				Fortner said:
			
		

> 450.21 (A)


Article 450 does not apply to Class 2 and 3 transformers.

Take a look at 450.1 exception No 4.

Chris


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## raider1 (Jan 12, 2010)

Re: Doorbell transformer in attic



			
				georgia plans exam said:
			
		

> Would it have to do with the mixing of voltage ratings in the same enclosure???GPE


There is no mixing of voltages in the same enclosure in this example.

The class 2 wiring is not in the 4 square box.

Chris


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## raider1 (Jan 12, 2010)

Re: Doorbell transformer in attic

The transformer would be marked "Not for installation in an attic" so 110.3(B) would be the applicable code section to fail this installation.

Chris


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## vegas paul (Jan 12, 2010)

Re: Doorbell transformer in attic

725.136 (A)


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## jar546 (Jan 12, 2010)

Re: Doorbell transformer in attic



			
				raider1 said:
			
		

> The transformer would be marked "Not for installation in an attic" so 110.3(B) would be the applicable code section to fail this installation.Chris


BINGO!!


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## raider1 (Jan 12, 2010)

Re: Doorbell transformer in attic



			
				vegas paul said:
			
		

> 725.136 (A)


The Class 2 conductors are not located in the same box with the power conductors.

The Class 2 transformer is installed on the exterior of the 4 square metal box and only the 120 volt connection wires are located in the box.

The class 2 wiring is connected to terminals on the outside of the transformer.

Chris


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