Testing & TroubleshootingQuestion 494 of 521
A terminal on a device is marked 'CU' only. What does this mean for terminations?
a.It may be used with copper or aluminum interchangeably
b.It is listed for copper conductors only; aluminum must not be landed on it
c.It requires antioxidant paste with any conductor
d.It is rated for control wiring only
Explanation
A 'CU'-only marking means the terminal is tested and listed for copper conductors exclusively; landing aluminum can cause overheating and failure from oxidation and dissimilar-metal effects. Only terminals marked 'CU-AL' or 'AL-CU' accept aluminum. The marking is about conductor material, not paste (c) or a voltage/control limit (d).
Law Reference: 2023 NEC §110.14Practice all 521 questions free — no signup required.
Related questions on this topic
- Three resistors of 10 ohms, 20 ohms, and 30 ohms are wired in series. What is the total resistance the ohmmeter should read across the string?
- Two 20 ohm resistors are connected in parallel. What total resistance will an ohmmeter read?
- The 2023 NEC added a requirement on how terminations must be tightened when the manufacturer provides a torque value. What does it require?
- A newly connected three-phase motor runs backward. What is the standard corrective action?
- A receptacle reads 120 V hot-to-neutral but 0 V hot-to-ground. Neutral-to-ground also reads 0 V and the ground pin has no continuity to the panel. What is the fault?
- Testing a suspected conductor with an ohmmeter, you read 'OL' (over-limit / infinite). What does this indicate about the conductor?
Last reviewed: · editorial process
PrepPass Editorial Team · Verified against California CSLB C-10 Electrical Trade Examination · How we review