⚡ QUESTION OF THE WEEK (2026) ⚡
#QuestionOfTheWeek2026:
An electrician is installing a 120/208V, 3-phase, 4-wire separately derived system (transformer secondary). The derived ungrounded conductors consist of two (2) parallel runs of 3/0 AWG copper conductors per phase, routed in separate raceways into a single main secondary disconnect enclosure.
Using the 2026 NEC, determine the minimum size copper System Bonding Jumper (SBJ) required inside the secondary disconnect enclosure.
🔎 Study Challenge: Don't just calculate it — find the information you need in the NEC first. Look for:
- The section governing separately derived system bonding jumpers.
- The rule for determining total equivalent circular mil area when ungrounded conductors are installed in parallel sets.
- The applicable Table used to size main and system bonding jumpers.
💬 Comment your answer and identify the NEC section(s) or table(s) you used.
⚡ 2026 NEC FastTraxTube.com
⚡ Study Credit: TRADEHOG.NET
⚠️ Educational question. Verify applicable requirements using the NEC edition and local amendments.
