Quick Hits

📱 EPISODE — Article 335

Instrumentation Tray Cable: Type ITC

SLIDE 1 — What Is Type ITC Cable?
📊 LOW-VOLTAGE, LOW-CURRENT INDUSTRIAL CABLE

Type ITC cable is built for instrumentation and control circuits operating at 150 volts or less AND 5 amperes or less. This is niche territory — mainly industrial establishments with instrumentation systems.

📖 Fun fact: this used to be Article 727, but got relocated to Chapter 3 (Wiring Methods) during the 2023 NEC cycle since the committee felt it fit better as a wiring method article rather than where it sat before.

📋 Listing (335.2): Type ITC cable must be LISTED. Fire resistance is tested via UL 1685 (vertical-tray flame test) or CSA C22.2 No. 0.3 (char length under 4 ft 11 in.).

⚠️ Reminder (335.4): installing ITC cable ALSO requires compliance with other applicable NEC articles — this article doesn't stand alone.

SLIDE 2 — Uses Permitted (335.10)
✅ WHERE ITC CABLE CAN GO

Only in industrial establishments with qualified-persons-only maintenance/supervision:
✅ Cable trays
✅ Raceways
✅ Hazardous locations (per specific sections in 501, 502, 503, 504, 505)
✅ Enclosed in a metallic sheath/armor over the nonmetallic sheath — supported at max 6 ft intervals
✅ ITC-ER marked cable (no metallic sheath, but meets MC cable's crush/impact standards) — exposed installs need continuous support/protection, secured at max 6 ft intervals (with a 6 ft unsupported transition allowance between trays/equipment if not subject to damage)
✅ Aerial cable on a messenger
✅ Direct buried (if identified for the use)
✅ Under raised floors in process control/rack rooms (arranged to prevent damage)
✅ Under raised floors in IT equipment rooms per 645.6(E)(2)

SLIDE 3 — Uses NOT Permitted (335.12)
🚫 STRICT VOLTAGE/CURRENT & SEPARATION RULES

❌ NEVER on circuits over 150V or over 5A — that's the hard ceiling for this cable type

🔀 MIXING WITH OTHER CABLES
Installing ITC with other cable types is governed by THOSE cables' specific articles. If the governing article doesn't address installation WITH ITC cable, it's NOT PERMITTED.

🚫 ITC cannot be installed with power, lighting, non-power-limited Class 1 circuits, or other non-power-limited circuits — UNLESS:
1️⃣ Terminated within equipment/junction boxes with insulating barrier separation, OR
2️⃣ A metallic sheath/armor is applied over the ITC's nonmetallic sheath

SLIDE 4 — Ampacity, OCP, Construction + Exam Question
📊 AMPACITY & OVERCURRENT PROTECTION (335.80, 335.90)

🔹 Standard ampacity: 5 amperes
🔹 22 AWG conductors: 3 amperes
🔹 OCP: max 5A for 20 AWG and larger, max 3A for 22 AWG

🏗️ CONSTRUCTION (335.100)
Conductors: 22 AWG–12 AWG, copper or thermocouple alloy, insulation rated 300V, shielding permitted. Cable must resist fire spread; outer jacket must resist sunlight and moisture. If a metallic sheath/armor covers the nonmetallic sheath, an overall nonmetallic jacket ISN'T required.

📌 Marking (335.120): follows 310.8(A)(2)–(A)(5) — but voltage ratings are NOT marked on the cable (since it's capped at 150V by definition).

🧠 TEST YOURSELF

Q: Per 335.10 and 335.12, Type ITC cable is limited to circuits operating at what maximum voltage and current?

A) 300V and 10A
B) 150V and 5A
C) 600V and 20A
D) 50V and 1A

(Drop your answer 👇)

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