Transformer xo to ground

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Gerry789

New User
Location
Az
Occupation
Electrician
hello i just had a quick question I have a transformer that has parallel secondaries that feed a 400 amp panel when you have to bond x0 to ground do you have to run 2 bond jumpers the same size as the wire to withstand the 400 amps from x0 to ground?
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Welcome to the forum.

Do you mean electrode conductors from X-0 to building steel, or the grounding conductors from the transformer to the panel?

See whether your question is being asked and answered here:
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
You would potentially have these three items on the secondary side, the SSBJ , SBJ and GEC. Since you asked specifically about bonding the X0 I would guess that you're referring to the SBJ (system bonding jumper). For parallel secondary conductors you add them together and look for the appropriate SBJ in T250.102(C)(1). If the total is greater than 1100 kcmil then you use the 12.5% rule to size the SBJ.
 
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