I am doing electrical assessments for some old multi-family buildings, built in the early to mid 1900s. I'm a little confused by the electrical distribution in some of these buildings. The main electrical room will have a large switchboard with 3-phase switches. These switches have 200A fuses and are marked to feed 5-8 apartments. Inside the apartments, there will be a 208V single phase panel and a meter sitting outside each apartment. These panels do not have main breakers. There is no other intermediate fuse box or breaker panel between the main board and the apartment panels. Are the three phase circuits tapped at 2 of the wires at each apartment? Was this a pre-tap rule configuration?
Multi-Family Electrical Distribution
- Thread starter dwgrant
- Start date
- Location
- Illinois
- Occupation
- retired electrician
I don't think that installation was ever permitted by the code. The use of two ungrounded conductors and the grounded conductor from a 208Y/120 volt system to supply panels in individual apartments is common, but there needs to be an OCPD at the meter or in the apartment panel.
That's what I would expect as well. One apartment I saw had upgraded their panel and added an MCB. The rest do not have OCPDs between the three-phase switch and the single phase apartment panel. Could I be missing something here? The meters are mounted above the service entrance to the apartments and do not have a fuse or circuit breaker nearby.