I was under the impression that you could only have 6 mains on a transformer. According to art 450.3(A) note #2 if I have no secondary overcurrent protection then I can have as many overcurrent devises as I want as long as they are not over 125% of the transformer rating. Is this true? Can I have a 40 circuit panel with no main on the load side of this same transformer. The line side of the transformer is protected with 125% of the rating of the transformer. This 40 circuit panel is a lighting panel. In the case of a motor control panel. Can I have a 10 circuit panel on the load side of a transformer with only the proper size overcurrent on the line side of the transformer?
Transformer Protection
- Thread starter rheydel1
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- Logan, Utah
408.36(B) requires the overcurrent protection for a panelboard to be located on the secondary side of the transformer.
Also keep in mind that 450.3 only addresses secondary protection of the transformer windings. 240.21(C) addresses overcurrent protection of transformer secondary conductors.
Chris
Also keep in mind that 450.3 only addresses secondary protection of the transformer windings. 240.21(C) addresses overcurrent protection of transformer secondary conductors.
Chris
jumper
Senior Member
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- 3 Hr 2 Min from Winged Horses
See 408.36(B)
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
Darn it, first chance I ever had to beat David on a transformer question and the headbanger beats me by 1 minute.
Keep in mind that article 450 deals with transformer protection only. Do not confuse panelboards and motor control centers since they are not covered by article 450.
In answer to the transformer protection only: if the installation you are describing in table 450.3(A) is a supervised location then it would be possible to have as many OCPD's on the load side of the transformer as you wish and the transformer is considered to be protected.
Pete
In answer to the transformer protection only: if the installation you are describing in table 450.3(A) is a supervised location then it would be possible to have as many OCPD's on the load side of the transformer as you wish and the transformer is considered to be protected.
Pete
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
- Location
- Logan, Utah
Darn it, first chance I ever had to beat David on a transformer question and the headbanger beats me by 1 minute.
Sorry Derek.
Chris
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
Sorry Derek.
Chris
I am just happy I got the right code reference. I never forgot that you taught me that is the most important part.
Always look it up before posting.
I will just go find a reason to to pick on Bob, that always makes me feel better.:lol:
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