Transformer feeding MLO panelboard
- Thread starter trallio
- Start date
- Status
Johnhall30
Senior Member
- Location
- New Orleans, LA
- Occupation
- Engineer
You have to provide secondary protection for the transformer. You have to use a main breaker within 10' of the transformer.
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Only if the panelboard has 6 or fewer breakers. You need to protect the secondary windings of the transformer, the secondary conductors from the transformer to the panel, and the panel itself, against overcurrent. A main breaker on the panel can do all three jobs. A fused disconnect or enclosed breaker within 10 feet of the transformer can also do all three jobs. An MLO panel with no more than 6 breakers can do all three jobs, if the ratings of all breakers add up to no more than would be required from a single OCPD. But an MLO panel with more than 6 breakers is not permitted to perform the three jobs.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
A panelboard would require a single OCPD ahead of it. 408.36
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
You used to be able to, but not any more. This is not service entrance equipment.
As infinity said - 408.36 requires panelboards to have a main device somewhere.
- Status