Mike Dolt Enterprises
Mike Dolt Enterprises
User: pms_electric, Location: Miami Fla.
Asked on: Monday, April 25, 2011 at 7:34 pm EDT
Answered on: Tuesday, May 14, 2024 at 4:37 am EDT
Question: I am doing a project where the run is 500ft (emt indoors). The print calls for #4's on a 20amp breaker. I know that this is correct for the voltage drop but is there any point at the end That I can drop down to land on recpts. , switches, motors. What are the rules for this?
NEC Article 300.11(E)Rule
Conductors larger than #10 AWG that enter a raceway, conduit, box, outlet, or other termination point shall be terminated or spliced using a listed connector, fitting, or device that is suitable for the size and type of conductor.
Interpretation
This rule applies to all conductors larger than #10 AWG, including #4's. Therefore, it is not permissible to reduce the conductor size from #4 to #12 AWG at the end of the run.
Reasons for Rule
Safety
Terminating large conductors with smaller connectors can create loose connections, overheating, and potential fire hazards.
Voltage Drop
Reducing the conductor size would increase the voltage drop, which could affect the performance of connected devices.
Code Compliance
The NEC requires all conductors to be sized appropriately for the load they will carry.
Alternatives
If reducing the conductor size is necessary, the following alternatives may be considered:
Use a junction box
Install a junction box near the end of the run and transition to #12 AWG conductors within the junction box. Make sure the junction box is rated for the size and number of conductors.*
Use a larger breaker
If the load on the circuit is less than 20 amps, it is possible to use a smaller breaker (e.g., 15 amp) and #12 AWG conductors throughout the run. This option requires recalculation of voltage drop.
Note: It is important to consult with a qualified electrician before making any changes to the electrical system to ensure safety and code compliance. Flag for review