Transformer as junction box

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dnem

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You always have the primary conductors and the secondary conductors but how about the presence of other conductors that are foreign to the function of the transformer ?

The installation that I'm looking at has 3 pieces of 277/480 house/landlord gear, the meterbase, a disconnect, and a step down transformer. . The contractor wants to feed elevator equipment from the house/landlord 277/480. . He doesn't have the room in either the meterbase or disconnect to bring in additional wires so he wants to attach his elevator panel supply conductors to the transformer primary terminals.

He could replace the disconnect with a panel, which would be the quality way to do it, but he wants to find out if the NEC would require him to do that.

Engineer says he'll draw up whatever he works out with me.

What do you think ?

I've found restrictions on "foreign" equipment in the transformer housing [450.8(C)], but even those are just restrictions and not exclusions.

David
 
Why does the electrician not want to install the panel? Is there a space restriction of some sort ? If not IMO,I would insist on the panel. Why would you take down the elevator to work on the load side of the transformer/load center? If I had to be called in to service an install like feeders tapped on the primary of a transformer I would have many questions as to why it was done like that. Just my 2 cents.
 
Sass5150 said:
Why does the electrician not want to install the panel? Is there a space restriction of some sort ?
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No space restrictions. . He's just looking at what's the cheapest route for him and I'm looking to just enforce code minumum.
 
I would say no, just based on the lugs. The lugs in the tranformer are not designed for this purpose. Changing out lugs is not as simple as just removing the existing lugs and adding a different lug... I would request a letter from the manufacturer for that scenario.
In that same request to the manufacturer, I would forward the info of what the contractor wants to do and see what the response of the manufacturer is.
 
Pierre C Belarge said:
I would say no, just based on the lugs. The lugs in the tranformer are not designed for this purpose. Changing out lugs is not as simple as just removing the existing lugs and adding a different lug... I would request a letter from the manufacturer for that scenario.
In that same request to the manufacturer, I would forward the info of what the contractor wants to do and see what the response of the manufacturer is.
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Pierre,
Most transformers above 15kVA are supplied without lugs. While manufacturers may offer lug kits for sales they are not reqired and the installer is free to use other components.
 
So the disconnect is providing overcurrent protection for the transformer and the elevator controller?
 
RB1 said:
So the disconnect is providing overcurrent protection for the transformer and the elevator controller?
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The disconnect is providing overcurrent protection for the transformer and the elevator controller supply wiring. . I'm assuming that the elevator equipment is multiple circuits from an elevator panel. . The contractor is looking for a place to get power for his elevator panel. . The metered 277/480 landlord power can only be found in 3 locations, the meterbase load lugs, the landlord 277/480 disconnect, and the primary lugs of the 277/480 transformer that supplies 120/208 to the house panel.

David
 
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