Industrial Electrical Code Violations You May Be Overlooking

As an electrician, I am often called in to inspect and repair electrical systems in industrial settings. Over the years, I have seen many code violations that facility managers overlook or are simply unaware of. In this article, I will discuss some of the most common industrial electrical code violations and how to avoid them.

Improper Conductor Sizing

One of the most frequent violations I come across is undersized conductors. The National Electrical Code (NEC) includes specific guidelines for selecting the proper wire size based on expected load and ambient temperature. Undersized wiring can lead to excessive voltage drop, overheating, and potential fire hazards.

When sizing conductors, I always refer to NEC Articles 310 and 400. I ensure the conductors can handle the full ampacity of the circuit at expected temperatures. I also derate ampacity as needed for ambient temperatures above 30°C, more than three current-carrying conductors bundled together, and other stipulations in the code.

Tips for Avoiding Undersized Wiring

• Carefully calculate expected load and demand factors for each circuit. Do not guess or estimate low.
• Measure ambient temperatures where wiring will be routed. Adjust ampacity accordingly.
• When in doubt, go up a size. It is better to be oversized than undersized.
• Inspect existing wiring to ensure it meets code requirements for the connected load. Upgrade if necessary.

Lack of Overcurrent Protection

The NEC requires overcurrent protection for all conductor sizes. Overcurrent devices like circuit breakers and fuses open the circuit when excessive current flows. This protects the wiring from overheating and potential fires.

Common violations I see related to overcurrent protection include:

• Missing fuses or breakers altogether
• Overcurrent devices rated higher than the ampacity of the conductors
• Fuse and wire sizes that do not match NEC requirements

Complying with Overcurrent Protection Requirements

• Carefully select overcurrent devices that match conductor ampacity per NEC Articles 240 and 430
• Where the code allows higher device ratings, use the next higher standard rating only
• Label all enclosures with the maximum fuse or trip rating
• Never increase fuse sizes without evaluating if conductors can safely handle the potential current

Insufficient Conductor Insulation

Industrial facilities often have wiring exposed to physical damage, chemicals, moisture, and extreme temperatures. The NEC requires using insulation rated for the specific environment.

Some mistakes I frequently notice include:

• Using standard THHN wiring in wet or corrosive areas
• Exposed wiring not rated for temperatures exceeding 90°C
• Damaged insulation not promptly replaced
• Wiring not properly rated for its routing method (e.g. in conduit, direct burial)

Ensuring Proper Insulation Material and Protection

• Classify areas by potential environmental hazards to select suitable insulation
• Use wiring rated for wet locations in damp areas
• Protect wiring from physical damage using conduit or other rugged covers
• Inspect insulation regularly and replace any compromised wiring right away
• Follow NEC tables for insulation types permitted for each wiring method

Improper Conductor Terminations

Secure, robust connections are critical for safety and reliability. Unfortunately, I often find improper terminations in industrial settings due to rushed jobs or lack of expertise.

Some examples of faulty terminations:

• Wire strands not fully inserted into connectors
• Insulation pinched under screw terminals
• Wires connected to incorrect device terminals
• Loose connections prone to arcing
• Mismatched conductor and lug sizes

Best Practices for Reliable Terminations

• Use compatible lugs and connectors rated for the wire size
• Twist stranded conductors together before inserting into lugs
• Tighten connections to torque specifications, do not overtighten
• Ensure insulation is completely stripped so it does not get pinched
• Double-check wiring diagrams when landing conductors
• Inspect for loose connections using thermal imaging or vibration analysis

Inadequate Conduit and Box Fill

The NEC specifies the maximum percentage conduit and junction boxes can be filled with wiring. Exceeding these limits can damage insulation and generate excessive heat.

I regularly find boxes overfilled beyond code due to:

• Pulling more circuits into a box than planned
• Using smaller boxes than required by code
• Not considering fill requirements when splicing wires
• Changing wiring but not upsizing boxes

Avoiding Overfilled Raceways and Enclosures

• Calculate fill requirements for each section of conduit and box
• Use NEC Chapter 9 fill tables as permitted for each wiring method
• Upside conduit and boxes if adding or rerouting wires
• Do not bundle multiple circuits in the same raceway without checking fill
• Limit box fill to less than 40% where possible

By being aware of these common industrial electrical violations, facility managers can avoid potential safety hazards and code citations. Let me know if you have any other questions! I am always happy to do a thorough inspection and point out any issues.