Quick Hits

EPISODE 5 — 265.5(C)(2)

DC Polarity Identification

SLIDE 1 — DC SYSTEMS

265.5(C)(2)

Now we're dealing with branch circuits supplied from DC systems over 1500 volts.

The NEC gets very specific about identifying polarity.

For ungrounded conductors:

4 AWG or larger → identify by polarity

6 AWG or smaller → identify by polarity using the specified methods

SLIDE 2 — POSITIVE POLARITY

For qualifying conductors 6 AWG or smaller, positive polarity can be identified using methods such as:

🔴 Continuous red finish

🔴 Red stripe

🔴 + / POSITIVE / POS markings

🔴 Approved permanent marking methods

The marking requirements are intended to make polarity identifiable throughout the installation.

SLIDE 3 — NEGATIVE POLARITY

Negative polarity has its own identification requirements.

Common permitted methods include:

⚫ Continuous black finish

⚫ Black stripe

⚫ – / NEGATIVE / NEG markings

⚫ Approved permanent marking methods

STUDY TIP:

Don't turn this into:

“Red always means positive.”

Learn the actual identification requirements and conditions.

SLIDE 4 — REVIEW ⚡

A qualifying DC branch circuit has an ungrounded conductor 6 AWG or smaller serving positive polarity.

Which marking could be used?

A. +
B. POS
C. POSITIVE
D. All of the above

ANSWER: D

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