XFMR Secondary Protection

[anbm]

Which NEC section requires transformer secondary protection and the protection must be within 10 feet from the transformer?
I typically see elec. panel downstream of a xfmr located next to it...

 

[ron]

You might be thinking of 240.21(C)(2).

 

[don_resqcapt19]

You have to remember that there are two sets of rules. The ones in Article 450 apply only to the protection of the transformer itself and the ones in 240.21(C) apply to the protection of the conductors that are connected to the secondary terminals of the transformer.