DMG_1
Member
- Location
- Boston, MA, USA
Gentlemen, a few questions regarding Short Circuit Study and Transformers. I am using Cooper fuses in my example:
1. When plotting a TCC to show primary side transformer protection I would assume that the ELSP (current limiting for internal transformer faults) and Bay-O-Net (overload / secondary faults) would need to both be shown to provide evidence that a transformer is completely protected. Is that correct?
2. If I was just plotting a TCC to show transformer primary side coordination with upstream devices I would think that only the Bay-O-Net fuse would be required. The ELSP will only melt on an internal transformer fault.
3. I have seen many transformer nameplates. For internal fusing they usually show an ELSP and Bay-O-Net in series or an isolation link in series with a Bay-O-Net. If I see only one fuse on the nameplate can I assume that this would be a Bay-O-Net fuse to protect the transformer in accordance with NEC Table 450.3(A)?
Thanks.
1. When plotting a TCC to show primary side transformer protection I would assume that the ELSP (current limiting for internal transformer faults) and Bay-O-Net (overload / secondary faults) would need to both be shown to provide evidence that a transformer is completely protected. Is that correct?
2. If I was just plotting a TCC to show transformer primary side coordination with upstream devices I would think that only the Bay-O-Net fuse would be required. The ELSP will only melt on an internal transformer fault.
3. I have seen many transformer nameplates. For internal fusing they usually show an ELSP and Bay-O-Net in series or an isolation link in series with a Bay-O-Net. If I see only one fuse on the nameplate can I assume that this would be a Bay-O-Net fuse to protect the transformer in accordance with NEC Table 450.3(A)?
Thanks.