Natfuelbilll
Senior Member
Please discuss use of 240.21(C)(4) for a transformer located indoors feeding a outdoor switch.
Can the AHJ approve the installation?
Can the AHJ approve the installation?
240.21(C)(4) Indoor Transformer
- Thread starter Natfuelbilll
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Carultch
Senior Member
- Location
- Massachusetts
If the transformer is inside, part 4 of 240.21(C) does not apply. 240.21(C) applies to the conductors that are outside, originating from a transformer that is outside. When the transformer is inside, inevitably there will be a length of its secondary conductors that are also inside.
Vice-versa, the NEC makes an exception, allowing the OCPD/disconnect to be indoors immediately nearby the location where the secondary conductors enter the building. But it doesn't make an exception for indoor transformers feeding an outdoor switch, to allow you to have unlimited length of the conductors.
Vice-versa, the NEC makes an exception, allowing the OCPD/disconnect to be indoors immediately nearby the location where the secondary conductors enter the building. But it doesn't make an exception for indoor transformers feeding an outdoor switch, to allow you to have unlimited length of the conductors.
Natfuelbilll
Senior Member
Can a AHJ approve/sign off the indoor transformer installation?
- Location
- Illinois
- Occupation
- retired electrician
Not really. 90.4 permits the AHJ to waive specific requirements of the code, but only where " it is assured that equivalent objectives can be achieved by establishing and maintaining effective safety". Not sure that there is any way to do that given what the rule in 240.21(C)(4) permits and the fact that there are rules in 240.21(C) the do apply where the transformer is inside.
In addition, granting a special permission for something that the code clearly prohibits exposes the AHJ and his or her employer to legal liability, and you are not likely to to find an AHJ that would be willing to take that risk[/QUOTE]
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