ebj at transformer

[RY_Guthrie]

I have a 45 kva/480-208/120 dry type transformer feeding a panel for temp power. I bonded the secondary neutral to ground do I need to also bound the neutral to ground at the first means of disconnect? wouldnt this be considered a parrallel path? My supervisor and I have a friendly wager on this. thanks

 

[raider1]

Welcome to the forum.

You will install a system bonding jumper at only ONE location. If you install a system bonding jumper at both the transformer and at the first disconnecting means then you will have issues with objectionable current (Neutral current). This will create a parallel path for neutral current to flow. (See 250.30 for the requirements for grounding and bonding of separately derived systems)

Chris

 

[brian john]

Bond as noted, but you can bond at either location, any ONE of the two you noted.