Good morning! This sounds like a challenging but potentially rewarding project. Let's break down your questions and concerns.

Lighting



48V and Existing Wiring



Absolutely not. Even if technically, the wire gauge might seem sufficient for a 48V low-voltage lighting system (and that's a big "if" requiring careful calculation based on amperage and distance to avoid voltage drop), reusing the existing NM cable is a violation of the National Electrical Code (NEC) and just generally bad practice. Here's why: NEC Article 300.3(C) Integrity of Conductors

Conductors must be suitable for the voltage and conditions. Existing NM cable is designed and rated for 120V/240V systems. Running low voltage through it changes the intended use and creates potential future confusion.

NEC 300.3(A) Single Raceway or Cable

All conductors of a circuit, including the neutral and any equipment grounding conductor, must be run together in the same raceway or cable. You can't pick and choose which wires you use.

Insulation Degradation

The insulation on the existing NM cable is likely old, brittle, and possibly damaged by the way it's been stapled in the chinking. This greatly increases the risk of short circuits, especially if you try to manipulate it.

Future Misuse

Someone (yourself or a future homeowner) might see the existing wiring and incorrectly assume it's 120V, leading to a dangerous situation.

Safety

Just plain unsafe! The existing wiring is already identified as a problem, and reusing it won't solve anything, only potentially create new issues.

Recommendation

This isn't worth digging into. You need to run new, properly sized and rated low-voltage wiring specifically designed for low-voltage lighting applications. Use appropriate Class 2 wiring methods.

Receptacles



Floor Boxes

Using floor boxes from the crawlspace makes a lot of sense for access and minimizing cutting into the logs. Consider the following:

Location

Carefully plan the placement of floor boxes to avoid areas with heavy foot traffic or furniture placement.

Moisture

Ensure the crawlspace is dry and sealed to prevent moisture from entering the floor boxes. Consider using boxes with a high degree of ingress protection (IP rating).

Boxes

Use floor boxes specifically designed for the type of flooring (wood, etc.) and that meet NEC requirements for floor box applications (e.g., tamper resistance if required).

Tamper Resistant

Make sure any floor boxes installed are tamper resistant, especially if small children are going to be present.

Cutting Receptacles into Logs

This is where things get tricky and require careful consideration.

Log Structure

You MUST consult with a structural engineer or experienced log home builder before cutting into the logs for any electrical work. Cutting into the logs could compromise the structural integrity of the cabin. They can advise on appropriate methods and limitations.

Settling

Log homes settle over time. Any wiring installed directly into the logs must accommodate this movement. The best bet is to not run any wires in the log, but instead the chinking between the logs.

Tools

If you must cut into the logs (again, after professional consultation):

Chainsaw

A chainsaw is sometimes used for the rough cut to create the space for the electrical box. However, chainsaw use is highly dependent on how precisely it is used.

Reciprocating Saw

Can be used to finish the rough in opening, although the space can be difficult to work within.

Oscillating Multi-Tool

A tool with a narrow blade can be used to cut in the wiring channel behind the box, as well as cut out the opening for the electrical box to sit within.

Drill/Auger Bit

For drilling pilot holes and running wires through the logs (again, only with expert advice).

Chisels

For fine-tuning the opening and creating a flush surface.

Wire Management

Use flexible conduit (like ENT, smurf tube, or flexible metal conduit (FMC)) from the box to the crawlspace. The conduit will allow the wiring to move without putting stress on the connections. Make sure the wire and conduit are properly secured.

Sealing

Carefully seal any gaps around the box and conduit to prevent air infiltration, moisture, and insect entry.

Wiremold (or Equivalent)

This is a great alternative to consider! Surface-mounted raceway systems are easier to install, don't require cutting into the logs, and can be painted to match the log color. It's often the preferred method in log homes. Run a dedicated circuit and avoid tapping existing circuits where possible.

Recommendation

The best advice is to minimize cutting into the logs. If you must, get professional structural advice first. Consider Wiremold as a cleaner, safer, and less intrusive option.

Ballpark Pricing and T&M



T&M is Smart

Given the unknowns in an old log cabin, T&M is the most sensible approach.

Detailed Estimate

Even for a T&M job, provide a detailed estimate outlining the scope of work, materials needed, and your hourly rate. This helps the owner understand the potential cost.

Contingency

Build in a generous contingency (15-20%) to cover unforeseen issues that are common in old homes.

Material Sourcing

Consider material sourcing logistics. Will you be providing the materials or will the owner? Clarify who is responsible for any returns.

Important Considerations for Log Cabins



Chinking

Be extremely careful when working around chinking. It can be fragile and easily damaged. Repairing it can be costly. If possible, avoid disturbing the chinking altogether.

Insulation

Older log cabins may have little to no insulation. This can affect wiring runs and the placement of electrical boxes.

Grounding

Ensure proper grounding throughout the cabin. Log homes can be particularly susceptible to lightning strikes.

Fire Safety

Pay close attention to fire-stopping around wiring penetrations. Log homes can burn quickly, so preventing fire spread is crucial.

Local Codes

Check with your local building department for any specific codes or requirements for log homes in your area.

Permits

Make sure you pull the necessary permits for the electrical work.

Safety First

Wear appropriate PPE, including eye protection, gloves, and a dust mask.

In Summary



Absolutely no to reusing the existing NM cable for low-voltage lighting. Floor boxes are a good option for receptacle placement. Minimize cutting into the logs. Get professional advice first. Consider Wiremold. Go with T&M and provide a detailed estimate with a contingency.* Pay close attention to safety, codes, and the unique challenges of log homes.

This project will require careful planning, execution, and communication with the homeowner. Good luck! Flag for review