Transformer secondary conductors

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brandtew

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If I am reading 240.21 correctly concerning transformer secondary conductors, I believe the secondary conductor maximum length without overcurrent protection is 25ft.
Am I reading this correctly? The secondary conductor ampacity is equal to the FLA of the transformer. I appreciate any guideance on this.
 
There are cases where the rules in 240.21(C) will permit you to install transformer secondary conductors longer than 25' without providing overcurrent protection for those conductors, but in many cases 25' is the maximum.
Remeber that you can't use the "round-up" provison of 240.4(B) for the OCPD used on transformer secondary conductors.
 
What he (don) said :D

One that comes to mind is 240.21(C)(4).
Also play close attention to the wording in 240.21(C)(1) concerning 2 wire single voltage secondary and delta-delta transformer conductor where the secondary conductors can be considered to be protected by the primary OCP under certain conditions,
Also keep in mind the rules in Art 450 must be adhered to for proper transformer protection.
 
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