Mike Dolt Enterprises
Mike Dolt Enterprises
User: Indian_Rdr, Location: usa
Asked on: Thursday, May 27, 2021 at 12:05 pm EDT
Answered on: Thursday, June 20, 2024 at 10:49 am EDT
Question: Taking over a job and the service doesn't seem legal to me. What they have is a 400(320) meter base with a 400a non-fused disconnect fed with parallel 3/0s from meter to line side. From the load side of the disconnect, they did 2/0 cu to a 200a panel directly on the other side of the wall and another 200a panel about 100' across the building (same building) also fed with 2/0.If both panels were located in the same room, to my interpretation, it would be legal. The second panel being 100' away, does the tap rule come into play and need to have an OCPD?I also have an issue with the disconnect as they are disconnecting both grounded and ungrounded conductors with no means of bonding the neutral and EGC. Since it's the first means of disconnect, it must be bonded there right?
Tap Rule
Yes, the tap rule comes into play in this scenario. Since the second panel is more than 25 feet from the disconnect (per NEC 310.15(B)(5)), a tap is considered to exist. The tap rule requires an overcurrent protective device (OCPD) at the tap point.
Disconnecting Both Grounded and Ungrounded Conductors
According to NEC 250.24(A), the first means of disconnect for a service shall disconnect both the grounded and ungrounded conductors. However, this disconnect is also required to bond the neutral and equipment grounding conductor (EGC) together. This is not provided in the current setup.
Proposed Solution
To address these issues, the following changes should be made:1.
Install an OCPD at the Tap Point
Install a 200A circuit breaker or fusible switch at the point where the 2/0 cable for the second panel branches off from the disconnect.2.
Bond the Neutral and EGC
Install a bonding jumper between the neutral and EGC terminals on the load side of the disconnect. This will ensure that the neutral and EGC are bonded at the first means of disconnect, as required by NEC 250.24(A)(5).
3.
Consider Updating the Disconnect
The current disconnect may not comply with NEC requirements for a service disconnect. Consider replacing it with a disconnect that is rated for the service size and that provides the necessary bonding.
Note: It is important to consult with a licensed electrician to confirm the details of the proposed changes and ensure compliance with applicable electrical codes. Flag for review