ptonsparky
Tom
- Occupation
- EC - retired
I have been asking for fault currents from the POCO for several years, more so since the latest code. Rarely do I find anything over 10K. About had heart failure when the POCO came back with 24,000 at the transformer on a service change we did a few weeks ago.
One service is 3 ph 4 wire 120/240v with a high leg, closed delta. The other is single phase derived from the same bank. Less expensive and easier to run the 2 - 200 amp services this way vs one 400. A spare raceway had been buried by yours truly several years ago, just in case.
Using MHs fault current spreadsheet, the single phase drops wll below the 10k when details of the secondary lateral are included.
Our choices do not include that for a high leg delta? Solution?
One service is 3 ph 4 wire 120/240v with a high leg, closed delta. The other is single phase derived from the same bank. Less expensive and easier to run the 2 - 200 amp services this way vs one 400. A spare raceway had been buried by yours truly several years ago, just in case.
Using MHs fault current spreadsheet, the single phase drops wll below the 10k when details of the secondary lateral are included.
Our choices do not include that for a high leg delta? Solution?