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Topic: 18 gauge wire part of light fixture

User: 82angelfan, Location: Hesperia, Ca

Asked on: Friday, July 18, 2025 at 12:15 pm EDT
Answered on: Friday, July 18, 2025 at 12:23 pm EDT

Question: Got called by Los Angeles Department of Building and Safety for 18/8 SO cord that is part of a UL listed light fixture (lighted mirror). He is giving codes for ampacities on breakers 20 amp 277V circuit. This is same SO cord that I have seen on pendant strip fixtures and pendant hung table lights. What information can I provide to convince the inspector that the installation is good? I showed him UL listing but he still didn't buy it.

Okay, this is a common issue, and it often boils down to understanding how UL listings and the NEC (National Electrical Code) interact, especially concerning flexible cords like SO cord. Here's a breakdown of how to approach this, and what information you can present to the inspector

Understanding the Inspector's Concern

The inspector is likely focused on these areas: Ampacity of the SO Cord

The NEC (specifically Article 400) dictates the allowable ampacity of flexible cords. He's concerned that 18/8 SO cord may not be rated for the potential current draw on a 20A, 277V circuit, even if the fixture itself draws much less.


Overcurrent Protection

He's worried about the potential for the SO cord to overheat and cause a fire if a fault occurs in the fixture or the cord itself because the circuit is rated at 20A.

Proper Application

Flexible cords have specific permitted uses in the NEC. He wants to ensure the application of the SO cord in your mirror lighting fixture aligns with those uses.

Your Argument: Focus on the UL Listing and Intended Use


The key is to demonstrate that the UL listing overrides the general ampacity rules for the SO cord
in this specific, UL-listed application. Here's what to emphasize:1. UL Listing is Paramount (within its scope)



The Core Argument

"This fixture is UL-listed as a complete assembly. The UL listing process specifically tests and approves the entire fixture, including the 18/8 SO cord, for use under the conditions specified in the listing. This means UL has determined that the 18/8 SO cord is adequate and safe for use with this fixture even connected to the 277v 20A circuit. It's been tested and approved as a whole unit."

UL's Role

Remind the inspector that UL (or other Nationally Recognized Testing Laboratory - NRTL) is a third-party organization that tests products to national safety standards. Their listing signifies compliance
with those standards for the intended use. The UL listing is the approval for the ENTIRE fixture.

"The Listing Covers It"

State clearly: "The UL listing for this mirror lighting fixture specifically includes the use of the 18/8 SO cord as part of the approved assembly. The UL testing considered the cord type, length, and application within the fixture."

Show the UL Listing Mark

Clearly show the inspector the UL listing mark on the fixture itself and provide the UL file number if possible.


UL White Book

You can also reference the UL White Book general information concerning how UL listings work with respect to appliances, fixtures and flexible cords.2.

Fixture's Actual Current Draw



Measure and Document

If possible,
measure the actual current draw of the fixture using an amp meter while it's operating under normal conditions. Document this measurement. A very low current draw dramatically strengthens your argument.

Nameplate Information

Point out the fixture's nameplate. It should state the voltage, wattage, and current draw of the fixture. The nameplate is a critical piece of information for the inspector.

Low Demand

Emphasize that the fixture is designed to use a very small amount of current, despite being connected to a 20A circuit.3.

Specific Use Case & NEC Exceptions



NEC 400.7(A)

This section of the NEC covers uses permitted for flexible cords and cables. It generally includes connection of portable luminaires and pendants. This might be a key section to argue since it covers the types of fixtures where SO cords are often used.

NEC 400.7(B)

This section of the NEC covers uses NOT permitted for flexible cords and cables. Make sure that the fixture is not used for any of these disallowed applications.


Fixture is not a Substitute for Fixed Wiring

Ensure the fixture is not being used in a manner that violates the spirit of the code. It's intended to be connected, not permanently wired as a replacement for a hard-wired connection.

Fixture is Listed for Specific Application

Show that the UL listing on the fixture matches its specific use as a lighting fixture.4.

Code References to Support Your Position



NEC 110.3(B) Examination, Identification, Installation, and Use of Equipment

"Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling." This is a KEY code section! The inspector must follow the UL listing.

NEC Article 100 - Definitions

Understand the definitions of "Listed" and "Labeled." This will help you explain the importance of the UL listing.5.

Documentation



UL Listing Information

If possible, get the specific UL listing information for the fixture, either online from UL's website or from the manufacturer. This provides concrete evidence of what the listing covers.

Manufacturer's Specifications

Get the manufacturer's specifications for the fixture, which should include the cord type and the intended use.


Photographs

Take photos of the fixture, the UL listing mark, the nameplate, and the SO cord.

Written Argument

Prepare a concise written summary of your argument, including the code sections you're referencing and the UL listing information. Give this to the inspector.

How to Communicate with the Inspector



Be Respectful and Professional

Even if you disagree, treat the inspector with respect. They are trying to ensure safety.

Be Knowledgeable

Demonstrate that you understand the NEC and the UL listing process.


Be Prepared

Have all your documentation ready to present.

Ask Clarifying Questions

Try to understand the inspector's specific concerns. Ask him, "What specific code violation do you believe exists, given the UL listing of this fixture?" Understanding their specific objection will help you address it directly.


Offer Solutions

If there is any room for compromise, offer it. For example, if the inspector is still concerned about the cord being exposed, perhaps you can offer to add a strain relief or protective sleeve.

Escalate if Necessary

If you cannot resolve the issue with the inspector, ask to speak to their supervisor.

Important Cautions



Don't Alter the Fixture

Do not modify the fixture in any way. This will void the UL listing.

Don't Misrepresent Information

Be honest and accurate in your presentation.


Document Everything

Keep records of all communication with the inspector, including dates, times, and what was discussed.

In summary, the key is to prove that the UL listing specifically addresses the 18/8 SO cord in the context of this specific fixture, and that the fixture is being used in accordance with its listing and the NEC.
Good luck! Flag for review

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