Okay, this is a complex situation with multiple points of concern. Let's break it down and address your questions.

Issues and Concerns



Unapproved Transition Method

The combination of Liquid Tite, GRC, a Sur-Loc adapter, and HDPE is highly suspect and likely

not a listed or approved method for transitioning between raceway types, especially underground. The purpose of using liquid tight conduit and direct burial pipe (HDPE)is defeated by this method of transition. Environmental Concerns (Water and Freeze/Thaw)

You've already identified this. Water pooling around the adapter and repeated freeze/thaw cycles are a serious problem. Water ingress is a major concern for electrical connections and can lead to corrosion, ground faults, and eventual failure.

Mechanical Stress

The expansion and contraction of materials due to temperature changes (especially pronounced in Alaska) will stress these connections. The differences in the coefficient of thermal expansion between the metal components, the HDPE, and the heat shrink will lead to stress points.

Ground Conditions

Trench excavation causing slight depressions is not good. Poor drainage allows for water to accumulate and exacerbate the corrosion/freeze-thaw issues.

Pull-Out Rating Doesn't Guarantee Suitability

While the Sur-Loc might have a 700lb pull-out rating in a controlled laboratory setting, that rating doesn't account for the combined effects of moisture, corrosion, freeze-thaw cycles, and the differing expansion rates of dissimilar materials.

Exposed Conductors

This is a serious safety hazard. Any exposed conductors underground pose a risk of electrocution or ground fault.

Potential for Corrosion

The mix of dissimilar metals (coated metal flex, GRC, likely steel components in the Sur-Loc adapter) buried underground, especially with moisture present, creates a perfect environment for galvanic corrosion.

Workmanship Concerns

While you say the workmanship seems good, the fundamental design/methodology is flawed. Good workmanship doesn't excuse using an unapproved or inappropriate method.

Accessibility

The adapter connections are buried, making inspection and maintenance difficult and requiring excavation for any repairs.

The Sur-Loc Adapter

You're right to be suspicious. While Sur-Loc adapters are designed for connecting HDPE, their suitability for direct burial, especially in conjunction with rigid metal conduit and flex, is questionable. They are generally intended for water or gas lines, not electrical. They are not typically designed for the stresses and environment encountered in underground electrical installations.

Code Violations (Likely)

Based on the information provided, this installation likely violates multiple sections of the NEC (National Electrical Code), especially concerning:

300.5 Underground Installations

This section addresses burial depths, protection of conductors, and suitability of raceways.

300.7 Raceways Exposed to Different Temperatures

This addresses the need to seal raceways to prevent condensation and air circulation where they pass from a warm to a cold location.

300.11 Securing and Supporting

While not directly applicable in this situation, it highlights the need for proper support of raceways.

300.12 Mechanical Continuity and Raceways and Cables

Raceways must be installed as a complete system.

300.15 Boxes and Fittings - Where Required

Fittings must be identified for the intended use.

300.19 Supporting Conductors in Vertical Raceways While not directly applicable, the same concerns for load and securing applies. 314 Boxes and Conduit Bodies

This covers the types of boxes and conduit bodies that can be used in wet locations.

350 Flexible Metal Conduit: (Liquid Tite)

Use and installation requirements.

Chapter 3 Wiring Methods and Materials

Appropriate wiring methods.

110.3 Examination, Identification, Installation, and Use of Equipment

All equipment must be suitable for the intended purpose and installed according to the manufacturer's instructions.

Recommended Repair and Mitigation



Document Everything

Take extensive photos and detailed notes of all the failed connections and the overall installation. This documentation will be crucial for presenting your findings.

Stopgap Measure (Temporary and with Caveats)

If immediate remediation isn't possible, carefully re-secure the exposed conductors and thoroughly seal the failed connection with a listed, direct-burial-rated, moisture-resistant sealant specifically designed for electrical applications. Do not use generic silicone caulk or similar products. This is only a temporary fix to mitigate immediate hazards and must be followed up with a proper repair. Be aware that this may not be effective long-term due to ongoing environmental stresses.

Permanent Repair (Recommended)

The only reliable solution is to:1.

Excavate and remove the entire problematic transition assembly.2. Use Listed and Approved Transitions

Replace the unapproved assembly with a listed and labeled direct burial splice kit or transition fitting suitable for the application. Look for a splice kit specifically designed for transitioning between metal conduit and HDPE. These kits should be designed for direct burial, watertight, and provide proper mechanical and electrical continuity.3.

Proper Burial Depth and Backfill

Ensure the new connections are buried at the correct depth according to the NEC and local codes. Use proper backfill material (sand or pea gravel) to protect the raceways and prevent future settling.4.

Consider Direct Burial Cable

Depending on the specific application and voltage, consider using direct burial-rated cable (e.g., USE-2) instead of conduit and individual conductors. This eliminates the need for transitions and reduces the risk of water ingress. However, verify if this is allowable by the system design and AHJ.5.

Implement Drainage

Improve drainage around the trench to prevent water pooling.

Consult with a Qualified Electrical Engineer

Given the complexity of the issue and the potential code violations, it's highly recommended to consult with a qualified electrical engineer who has experience with PV systems and underground installations. They can assess the entire system, identify all potential problems, and recommend the most appropriate and code-compliant solutions.

Involve the Authority Having Jurisdiction (AHJ)

Inform the local electrical inspector (AHJ) about your findings and the proposed repair plan. Get their approval before proceeding with any work. They may have specific requirements or preferences.

In Summary

This installation has significant flaws that are likely to lead to premature failure and pose safety hazards. A comprehensive repair is necessary using approved materials and methods, following the NEC, and under the guidance of a qualified professional. Don't cut corners on this – the long-term reliability and safety of the PV system depend on it. The transition between liquid tight and HDPE needs to be completely re-thought and implemented correctly.

Disclaimer: I am an AI chatbot and cannot provide professional engineering or electrical contracting advice. This information is for general guidance only. Always consult with qualified professionals before making any decisions about electrical installations. Flag for review