Okay, this is a frustrating situation, and you're smart to consider all your options. Let's break down the considerations

1. Legality and Code Compliance:
NEC and Local Codes

This is the primary concern. The National Electrical Code (NEC) and your local electrical codes are the final authority. Many jurisdictions explicitly prohibit burying splices of heating cable in floors. Even if it's technically allowed, it could create significant problems if you ever sell the house.

Accessibility

In general, electrical splices need to be accessible. A buried splice is not accessible. The code exists to ensure the safe and easy repair of electrical connections.

Inspector

Even if the tile guys or the electrician say it's okay, it must be approved by your local electrical inspector. If it's not, you could fail inspection and be forced to redo it anyway.

Permit

Was a permit pulled for the floor heating installation? If so, an inspection is mandatory, and this will likely be flagged. If no permit was pulled, that's an issue that needs to be addressed before any work is done to fix it.

2. Liability



Homeowner Responsibility

Ultimately, you are responsible for the safety and code compliance of your home. Even if you hire a contractor, you can be held liable if they do something that violates code.

Disclosure

If you do bury a splice, you are obligated to disclose that to any future buyer. This could significantly impact the resale value and potentially open you up to legal action if there are problems later.

Contractor Responsibility

The tile guys are responsible for the damage they caused. Their insurance should cover the repair. Push them to involve their insurance company.

3. Splicing Considerations (Assuming hypothetically it was legal and code-compliant)



Kit Quality

Use only manufacturer-approved splice kits specifically designed for heating cable. Cheaping out here is a recipe for disaster.

Professional Installation

The splice must be done perfectly. Even a slight imperfection can lead to overheating, arcing, and fire. This is not a DIY job.

Moisture Resistance

The splice must be completely waterproof.

Mechanical Protection

The splice and the surrounding cable need to be protected from physical damage. The kits usually have provisions for this, but ensure it's robust.

Heat Dissipation

Splices can be hotspots. The kit must ensure proper heat dissipation to prevent overheating.

Ohms too low

With only 26 ohms to ground you've likely got a dead short which requires a high amount of current. Your breaker should have tripped.

4. Finding the Fault



Thermal Imaging

A thermal camera might be able to pinpoint the location of the short. This is worth exploring. The short will cause a huge amount of current and could show up as a hot spot.

Time Domain Reflectometry (TDR)

This is a specialized electrical testing technique that sends a signal down the cable and analyzes the reflections to locate the fault. A qualified electrician with TDR equipment can often pinpoint the location very accurately. This would be a good option before ripping up tile.

Sectioning and Testing

As a last resort, you could carefully cut the cable in strategic locations and test each section to isolate the fault. This is risky and may damage the cable further.

5. Recommendation


Contact the Tile Contractor's Insurance

This is the first step. Make a claim with their insurance company. Let them handle the repair.2.

Consult a Licensed Electrician

Get a written opinion from a qualified, licensed electrician who is familiar with floor heating systems and your local codes. Ask them if a splice is even legal in your area, and if so, what the code requirements are. Get everything in writing.3.

Contact Your Local Building Inspector

Ask the building inspector anonymously about the legality of splicing buried heating cable in your jurisdiction. Get their interpretation of the code.4.

Weigh the Risks vs. Benefits

Even if a splice is technically legal, carefully consider the long-term risks: Potential for future failure and costly repairs. Impact on resale value.* Liability concerns.5.

Repair vs Replace

If a splice is not code compliant and is potentially a liability, replacing the whole floor heat system is the best option. Get quotes to remove the old system and install a new one.

In short, burying a splice in a floor heating system is almost always a bad idea, even if the local code allows it, due to the inherent risks associated with such a fix. You're smart to be cautious. Focus on getting the tile contractor's insurance to cover the cost of a proper repair, which likely means replacing the damaged section of the heating cable. Flag for review