Okay, let's break down the situation and find the best approach to bond that isolated EMT section. You're right to be concerned; that isolated section is a potential hazard.

Understanding the Problem FMC as Grounding Path

Flexible Metal Conduit (FMC) cannot be relied upon as an equipment grounding conductor (EGC) in many situations. Its resistance is too high, and it's not considered an effective fault current path. This is why you correctly identified that your EMT section is isolated.

Hazard of Ungrounded Metal

An ungrounded metal conduit section can become energized if a fault occurs within the wiring inside. This poses a shock hazard to anyone touching the conduit.

Code Considerations (and "Common Sense") NEC 250.96(A)

This section requires metal raceways containing service conductors, grounding electrode conductors, and supply-side bonding jumpers to be bonded. While technically you might argue this doesn't apply exactly to your load-side raceway, the intent is very clear: metal raceways should be bonded to ensure a low-impedance fault current path.

NEC 250.4(A)(5)

This section emphasizes that electrical equipment and wiring must be installed in a manner that "establishes and maintains a low-impedance circuit" for fault current.

Safety First

You're right to prioritize safety. Code compliance should lead to safety, but sometimes a practical "common sense" solution, if it doesn't violate code and enhances safety, is the right choice.

Evaluating Your Options1. Water Meter Bonding Kit

This is not the correct approach. Water pipe grounding is for bonding the water system itself, not for bonding electrical raceways. Further, bonding the water pipe is not a substitute for grounding the electrical system and can, in fact, introduce dangerous ground loops or stray currents. It's a complete misapplication of the purpose.2.

Mid-Run 1900 Box with EGC Lug

This is a code-compliant solution, but you've correctly identified the drawbacks regarding future modifications. The fact that the wires are likely to be larger gauge makes it even more difficult, with the box fill limits.

Recommended Solutions

I would suggest the following, depending on the specific situation and accessibility. Both solutions aim to create a reliable, low-impedance bond to the equipment grounding conductor: Option 1: Jumper to Existing EMT Run (Preferred)



If an existing EMT run goes from the garage back to the panel

This is ideal and likely to be the most practical.

Use a Listed Grounding Bushing or Clamp

At each end of the isolated EMT section, install a listed grounding bushing or clamp.

Bonding Jumper

Run a properly sized grounding jumper (insulated, usually green) between each grounding bushing/clamp and the adjacent EMT run that is continuous to the panel. Use bonding jumpers that are sized according to NEC Table 250.122, based on the rating of the circuit.

Important

Tighten all connections securely. Use a wrench, not just a screwdriver.

Example

You have 1" EMT, so you'd use a 1" grounding bushing, run a jumper (likely #12 AWG copper for a 20A circuit, larger for larger circuits) to a similar grounding bushing on the adjacent EMT.

Why this is good

It's simple, effective, and code-compliant. It creates a continuous, low-impedance grounding path. It doesn't obstruct future wiring changes.

Option 2: Run a dedicated Grounding Conductor



Run a grounding conductor from the garage 1900 box back to the panel. Size the grounding conductor based on NEC Table 250.122, based on the overcurrent protection of the circuit. Bond the conduit at each end with a grounding bushing, and connect the grounding conductor to each grounding bushing. This is likely a more difficult option.Important Considerations



Proper Sizing

Always size grounding conductors according to the NEC tables. Under-sizing is a significant safety issue.

Listed Connectors

Only use listed grounding bushings, clamps, and connectors. "Homebrew" grounding solutions are not acceptable.

Tight Connections

Make sure all connections are clean, tight, and properly torqued.*

Inspect the other EMT runs

Be sure the other EMT runs back to the panel actually have grounding bushings or other grounding means at the panel (they most likely do.)

In Summary:

Prioritize Option 1 if you can easily bond to an existing, grounded EMT run. If not, Option 2 is a viable, code-compliant, but more labor-intensive solution. Avoid the water pipe grounding idea entirely. The goal is to create a reliable, low-impedance fault current path to protect people and equipment. Flag for review