Class 2 transformer in j box

Lou44

Member
Location
North Carolina
Occupation
Electrician
Was wanting to get an opinion if this met article 725.136(D).

Found a class 2 transformer in a 4 gang box with switches and lighting power circuits. It is grounded and separated from the power and switches by more than a .25” as the code requires and the class 2 cable is only in the box to connect to the transformer but I’m still skeptical. The transformer is thermally protected and seems to be completely fine where it is.

Obviously this is not ideal or good electrical work in my opinion but I’m curious if it would meet this section of the code. I’ve seen these transformers installed like this before and cannot figure out how they pass inspection.
 

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
Sounds pretty oddball a photo of the install would help, but we do it in control boxes all the time, I dont see a violation.
 

Lou44

Member
Location
North Carolina
Occupation
Electrician
51523330953_7ee2c2cca4_s.jpg
Everything is spaced out really well I think it meets code but I just want as many opinions as I can get
 

mikeames

Senior Member
Location
Germantown MD
Occupation
Teacher - Master Electrician - 2017 NEC
Is it me or in the image the size of a postage stamp? I tried to open it up separately.
 

Lou44

Member
Location
North Carolina
Occupation
Electrician
Sorry I’ll try and upload a better image. Still haven’t quite figured out how to upload these yet.

The class 2 cable is on the left in the image.
 

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Lou44

Member
Location
North Carolina
Occupation
Electrician
That’s what I’m saying but no one has been able to show me where it is stated in the article above that this isn’t allowed. The class 2 cable is 600V rated and it’s separated by more than a .25”. The only thing I can figure would be it’s cross sectional area being overfilled. Which is pretty obvious.

The owner told me it was installed about 9 months ago. So I figured on leaving it alone it’s grounded and thermally protected. So it’s clearly not overheated at any point.
 
Location
Tulsa
Occupation
Electrician
Ok, thought about it a minute.
First thought would be cubic inch violation.
It's rated in cubic inch. There is cubic inch for wire and device. Now what about a transformer?
Thinking out load, Would this violate the cross section area for an enclosure. Going to read up on that as well. Would that apply to this box.
Now I do know old work Carlon boxes are not hr rated. Would this apply?
Break out book tommorow.
 
Location
Tulsa
Occupation
Electrician
Let's look at box first. What is the listed cubic inch.
Next, do I count one 12-2g nm cable one device and three (6) #16 or 18
One class two grounded transformer.

A quick read of 314.24 may or may not define the answer.
Key words ( to be mounted properly and without likely hood of damage to conductors within the box).
So a look at the transformer mounting spec would be warrented. Maybe an AHJ item.
Based on the 1/2" nipple I would say no without an attachment plate. My opinion.

Table 314.16 B
#12- 2.25
#16- 1.75
#18- 1.50

314.16 (4)
Double volume for yoke or equipment based on largest conductor.

So how do we account for the transformer, equipment?
 
Location
Tulsa
Occupation
Electrician
Well as long as you have the cubic inch accounted for I see nothing in 725 to say no. You have separation.
450 says go to 725.

I'll read some other articles.
So far so good.
Been reading 2014 NEC
 
Location
Tulsa
Occupation
Electrician
It says "in". I see feet ( in pics I posted) so that can be secured to enclosure. So the way I see it. Make sure cubic inch is good install per mfg, maintain separation, use proper class two conductors.
Good to go even though I don't like it.
 

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GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Is the transformer being held in place only by the electrical tape? That does not seem appropriate.
Without a rigid mounting, it seems quite possible for the metal of the transformer case to touch one of the terminals of the adjacent switch. A positive barrier might mitigate that.
 

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
I wonder if thats a remodel box, could you replace the box with a set of metal gang boxes and use a K/O to hang the transformer off the side of the box in the wall? Might not have clearance.
 
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