ivsenroute
Senior Member
- Location
- Florida
This time I am just going to post the answer and explanation.
10. The minimum size for the grounded service conductor is __________ .
A) not smaller than the required ungrounded service conductor and not smaller than the load served as calculated by Article 220
B) not larger than required for the load served by grounded service conductor
C) not larger than the required conductor to the supplemental grounding electrode
D) not smaller than the required grounding electrode conductor, or 12.5% of the ungrounded conductors.
D is correct.
Correct! The answer comes from the 2005 NEC Section 230.22 AND 230.42(C) Minimum Size and rating, Grounded Conductors. Article 230.22 provides instruction for determining the minimum neutral load and gives us permission so size the neutral (grounded service conductor) conductor based solely on the calculated load. That being said, choice ?A? cannot be correct because it does not take Article 230.22 into account. Choice ?B? is not always correct because we have conditions when the conductor brought to the service is required to be larger than the load served. There are cases when the grounded service conductor brought to the service must also be larger than the supplemental grounding electrode conductor. The minimum size of the grounded service conductor can never be less than the load served as calculated in article 220. There is a requirement that the grounded service conductor not be smaller than the required grounding electrode conductor which is stated in choice ?D?. This information is detailed in Article 230.42(C), which states: The grounded conductor shall not be less than the minimum size as required by 250.24(C)1. A review of Article 250.24(C) will reveal Article 250.24(C)(1) which states in part: This conductor (grounded service conductor) shall be routed with the phase conductors and shall not be smaller than the required grounding electrode conductor specified in Table 250.66. For larger ungrounded conductors the (1100 kcmil copper or 1750 kcmil aluminum) The grounded conductor would be required to be a minimum of 12.5% of the ungrounded conductors.
10. The minimum size for the grounded service conductor is __________ .
A) not smaller than the required ungrounded service conductor and not smaller than the load served as calculated by Article 220
B) not larger than required for the load served by grounded service conductor
C) not larger than the required conductor to the supplemental grounding electrode
D) not smaller than the required grounding electrode conductor, or 12.5% of the ungrounded conductors.
D is correct.
Correct! The answer comes from the 2005 NEC Section 230.22 AND 230.42(C) Minimum Size and rating, Grounded Conductors. Article 230.22 provides instruction for determining the minimum neutral load and gives us permission so size the neutral (grounded service conductor) conductor based solely on the calculated load. That being said, choice ?A? cannot be correct because it does not take Article 230.22 into account. Choice ?B? is not always correct because we have conditions when the conductor brought to the service is required to be larger than the load served. There are cases when the grounded service conductor brought to the service must also be larger than the supplemental grounding electrode conductor. The minimum size of the grounded service conductor can never be less than the load served as calculated in article 220. There is a requirement that the grounded service conductor not be smaller than the required grounding electrode conductor which is stated in choice ?D?. This information is detailed in Article 230.42(C), which states: The grounded conductor shall not be less than the minimum size as required by 250.24(C)1. A review of Article 250.24(C) will reveal Article 250.24(C)(1) which states in part: This conductor (grounded service conductor) shall be routed with the phase conductors and shall not be smaller than the required grounding electrode conductor specified in Table 250.66. For larger ungrounded conductors the (1100 kcmil copper or 1750 kcmil aluminum) The grounded conductor would be required to be a minimum of 12.5% of the ungrounded conductors.
