which one to follow, NEC OR IEEE979 for speration distance of outdoor oil transformer?

[Leo Li]

Just check the Seperation distance between 13.2/480V outdoor oil transformer (assume oil tank is 10000L) and building non-fire wall or between two transformers, in IEEC- 979, it state as below:



So From building wall to transformer or between two transformer should be 25ft .

But if follow NEC 110.34(A) table it from wall to transformer to be 6ft (condition2 for beyween transformer and wall) and 9ft (condition 3 for between two transformer) wihch is much less than requirement above IEEE979.


Below is our project drawings. It meer NEC but not meet IEEE-979. so I am confused which one to be followed or my understanding is wrong?

Thanks !!!

 

[don_resqcapt19]

Those two documents address two totally different things. The NEC is only looking at having enough space to safely work on the equipment. The IEEE document is looking at fire issues. Those are not in the NEC, but may be in the building or fire code that applies to the installation.

 

[Leo Li]

Those two documents address two totally different things. The NEC is only looking at having enough space to safely work on the equipment. The IEEE document is looking at fire issues. Those are not in the NEC, but may be in the building or fire code that applies to the installation.

thanks!