Quick Hits

EPISODE 8 — Separately Derived Systems Pt.1 Grounded Systems 1kva (270.30(A))

Slide 1 — Hook "This is the biggest single section in the whole article. We're splitting it into two episodes — starting with GROUNDED separately derived systems."

Slide 2 — The big picture

• A separately derived system = a system with no direct electrical connection to another supply (like the secondary of a transformer, or a generator not solidly tied to utility power).

• Key rule: on the load side of the system bonding jumper, the grounded conductor can NEVER be reconnected to ground, to equipment grounding conductors, or to non-current-carrying metal parts — that would create a dangerous parallel path.

Slide 3 — System bonding jumper & grounding electrode

• The system bonding jumper connects at ONE point — either at the source, or at the first disconnect/OCPD — and stays inside that originating enclosure.

• It connects the grounded conductor to the supply-side bonding jumper and either the metal enclosure (if at the source) or the disconnect enclosure + EGCs (if at the first disconnect).

• The grounding electrode used is the building/structure's grounding electrode system (or, if the source is outdoors, an electrode at that outdoor location).

• Multiple separately derived systems can share ONE common grounding electrode conductor, with individual tap conductors run to each system.

Slide 4 — Quiz + CTA Q: "On the load side of a separately derived system's bonding jumper, can the grounded conductor be reconnected to ground?" A) Yes, anywhere convenient B) No — that would create a dangerous parallel path C) Only if a licensed engineer approves it D) Only for systems under 5000V

✅ Answer: B — 270.30(A) prohibits this reconnection on the load side.

CTA: Follow for more daily quick-hit study notes 📚⚡

← View Chapter 2 Home

← Back To Article 270 Home

← Back To Quick Hits Home