I have a job to wire up a step up transformer 208v to 400v for a utilized peice of equipment (spray booth). The drawings indicate that I need a 30 amp 3 phase, 4 wire circuit with disconnect switch and thats all. The customer will supply the transformer. My question is do I need over current protection on the secondary side or will the 30 amp 3 phase breaker be sufficent for the primary and secondary of the transformer.
Step up transformer 208v to 400v 3 phase
- Thread starter amge
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LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Deleted: Read the question wrong.
mcclary's electrical
Senior Member
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aww, come on Larry, no joke for us tonight?
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
- Location
- Illinois
- Occupation
- retired electrician
If this is a delta/delta transformer, then a properly sized primary OCPD can be used to protect the secondary conductors. 240.21(C)(1). If it is any other type of transformer one of the other rules in 240.21(C) will apply.
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