705.11(B), (C), and (F) Conductors and Connections.
Code Change Summary: Several changes occurred in 705.11 including the proximity of the required overcurrent protection for a line side connection.
In the 2023 NEC®, the language in 705.11(B) was revised and formatted into a list while retaining the previous text requiring service conductors connected to a power production source service disconnecting means to be sized in accordance with 705.28 and to not be smaller than 6 AWG copper or 4 AWG aluminum or copper-clad aluminum.
Another change occurred with the relocation of the previous language in 705.11(D) referencing line side conductor splices. These rules are now located in 705.11(C) and list item 1 requires any splices or taps made to service conductors to be done in accordance with 230.33 or 230.46.
Section 230.46 requires product listing for power distribution blocks, pressure connectors, or other devices used to make splices and taps. Power distribution blocks installed on service conductors shall be marked “suitable for use on the line side of the service equipment” or equivalent. Pressure connectors and devices for splices and taps installed on service conductors shall be marked “suitable for use on the line side of the service equipment” or equivalent.
Since the 2020 NEC®, product safety standards have been changing with new testing methods that address free-floating wire splices such as insulation piercing taps which are not secured to the enclosure. These devices move with the spliced conductors during a high-level fault condition and prior to the 2020 NEC®, were not required to be tested in the same way as typical power distribution blocks which bolt to the enclosure.
Splicing devices suitable on the line side of service equipment must be able to withstand opposing forces that can occur during a fault condition when the service conductor is likely to whip or move.
In the 2020 NEC®, Section 705.11(C) required overcurrent protection within a specified maximum distance from where power source output circuit conductors made a line side connection to a service inside a building.
In the 2023 NEC®, Section 705.11(C) was revised, and the previous maximum distances required in (C) were eliminated as the language was moved to new section 705.11(F).
Now, instead of overcurrent protection being required within a specified maximum conductor length from where power source output circuit conductors make their connection to a service inside a building, 2023 NEC® Section 705(F) sends the code reader to Part VII of Article 230 for that information. The rules in Part VII of Article 230 do not differentiate between interior service conductors or exterior service conductors; they are the same.
Section 230.91 is in Part VII of Article 230 and requires a service overcurrent device to be an integral part of a service disconnecting means or it shall be located immediately adjacent thereto. If fuses are used as the service overcurrent device, the disconnecting means shall be located ahead of the supply side of the fuses.
Additionally, the previous requirements on ground-fault protection from 2020 Section 705.11(E) have been simplified and incorporated into 2023 NEC® 705.11(F). Now, the rating of the overcurrent protection device of the power production source service disconnect shall be used to determine if ground-fault protection of equipment is required in accordance with 230.95.
Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2023 NEC® edition of NFPA 70.
2020 Code Language:
705.11(B) Conductors. The power source output circuit conductors from the service conductors point of connection to the first overcurrent protection device shall be sized in accordance with 705.28 and in no case sized smaller than 6 AWG copper or 4 AWG aluminum. These conductors shall be installed in accordance with 230.30 or 230.43.
705.11(C) Overcurrent Protection. Where the power source output circuit conductors make their connection to the service outside of a building, they shall be protected by overcurrent devices in a readily accessible location outside the building or at the first readily accessible location where the power source conductors enter the building. Where the power source output circuit conductors make their connection to the service inside a building, they shall be protected with one of the following methods:
(1) With an overcurrent device located within 10 feet of conductor length in dwelling units and 16.5 feet in other than dwelling units from the point of connection to the service
(2) In other than a dwelling unit, with an overcurrent device located within 71 feet of conductor length from the point of connection to the service, provided that cable limiters installed in all ungrounded conductors are located within 16.5 feet of conductor length from the point of connection to the service
2023 Code Language:
705.11(B) Conductors. Service conductors connected to power production sources shall comply with the following:
(1) The ampacity of the service conductors connected to the power production source service disconnecting means shall not be less than the sum of the power production source maximum circuit current in 705.28(A).
(2) The service conductors connected to the power production source service disconnecting means shall be sized in accordance with 705.28 and not be smaller than 6 AWG copper or 4 AWG aluminum or copper-clad aluminum.
(3) The ampacity of any other service conductors to which the power production sources are connected shall not be less than that required in 705.11(B).
705.11(C) Connections. Connections to service conductors or equipment shall comply with 705.11(C)(1) through (C)(3).
N (1) Splices or Taps. Service conductor splices and taps shall be made in accordance with 230.33 or 230.46 and comply with all applicable enclosure fill requirements.
N (2) Existing Equipment. Any modifications to existing equipment shall be made in accordance with the manufacturer’s instructions, or the modification must be field evaluated for the application and be field labeled.
N (3) Utility-Controlled Equipment. For meter socket enclosures or other equipment under the exclusive control of the electric utility, only connections approved by the electric utility shall be permitted.
705.11(F) Overcurrent Protection. The power production source service conductors shall be protected from overcurrent in accordance with Part VII of Article 230. The rating of the overcurrent protection device of the power production source service disconnecting means shall be used to determine if ground-fault protection of equipment is required in accordance with 230.95.