100A or 200A, for a Smokies cabin?

About a third of the cabins in the Sevierville and Pigeon Forge rental market are still on 100A service. Most of them work fine, until they do not. The transition point is not age. It is load. Here is how we actually size a panel for a cabin, and the four scenarios that almost always push us to recommend the upgrade.

What a 100A service actually gives you

A 100A residential service delivers about 24,000 watts of continuous capacity (240V x 100A). That sounds like a lot, but the way the National Electrical Code calculates “service load” pulls in everything connected to the panel, with weighting for the largest loads. A typical 3 bedroom Smokies cabin from the late 1990s runs:

• HVAC (heat pump or central AC plus electric resistance backup) at 7,000 to 12,000 watts
• Water heater (electric) at 4,500 watts
• Range (electric) at 8,000 watts (rated load, not constant)
• Dryer at 5,500 watts
• Hot tub at 6,000 to 9,000 watts (240V dedicated)
• Lighting and small-appliance loads at 3,000 to 5,000 watts

Add it up and the connected load is well over 30,000 watts. The reason a 100A service still works is that not every load runs simultaneously. NEC calculations use a diversity factor that assumes the dryer and the range and the hot tub heater are not all on at once.

On a typical cabin used by an owner-occupant, that math works. On a fully-rented cabin with eight guests doing laundry, cooking dinner, and running the hot tub at 9pm in July, it does not. The main breaker trips. The guest calls the owner. The owner calls us.

The four scenarios that push us toward 200A

Scenario 1: You are putting in a hot tub OR a second HVAC zone

Either one of these alone can push a 100A service over the diversity limit during peak demand. Both together almost always trip the main breaker during high-occupancy weekends. We size to 200A as a default whenever a cabin owner adds either.

Scenario 2: You are adding an EV charger

A 50A Level 2 charger is not a small load. Plug it in alongside an existing cabin load and you are routinely over capacity on a 100A panel. The math for this is in our EV charger cost breakdown.

Scenario 3: The cabin is rented year-round

Owner-occupied use rarely stresses a 100A service because owners control the load (you do not run the dryer and the hot tub simultaneously on purpose). Guests do not have that discipline. If you are renting full-time and the cabin sleeps 6 or more, 200A is the right starting point for new builds and the right upgrade for existing properties.

Scenario 4: You want a backup generator

A whole-home automatic transfer switch sized to a 100A service limits the generator you can install. Most cabin owners want a Generac 18kW to 24kW so they can keep the hot tub and the heat pumps running during an outage. That requires 200A. See our breakdown of how we size whole-home generators for Smokies cabins.

When 100A actually still works

Plenty of cabins do not need 200A. If the cabin is:

• Owner-occupied or used by family only, not rented out
• Two bedrooms or fewer
• On gas heat and gas water heating
• Without a hot tub or with only a small plug-in spa (120V, not 240V)
• Without an EV in the future plan

…then a 100A service is fine and an upgrade is wasted money. We tell people this all the time. We are not in the business of selling upgrades nobody needs.

The real cost of waiting

The argument against a proactive upgrade is “if it works, do not fix it.” The counter-argument is what happens when it stops working: usually during peak rental week, usually after hours, usually with paying guests in the cabin. Same-day emergency electrical service in the Smokies during summer runs roughly 50% higher than scheduled work, and the calendar pressure removes negotiating room on parts and labor.

If your cabin is in the “marginal 100A” zone (3 bedrooms or more, hot tub, electric heat, heavy rental calendar), the smart move is to schedule the upgrade in shoulder season (October through March) when we have capacity and you have low occupancy. The work takes one day. The savings on the timing alone usually offset 20 to 30 percent of the project cost.

The cheapest panel upgrade is the one done in February, not the one done at 11pm on a Saturday in July with eight guests waiting on power.

How to know which one is right for your cabin

We do a free load calculation on every quote. We measure your actual usage with a clamp meter over a 48-hour window when possible, look at the cabin’s appliance lineup, factor in your rental calendar, and tell you whether 100A is still right or whether the upgrade pencils out.

For a free walk-through, send us a message or call (865) 256-0876. You can also see panel upgrade jobs we have done across the corridor in our project gallery, and check our hours and reviews on Google.

Volt Pro Services works with cabin owners and property managers across Sevierville, Pigeon Forge, Gatlinburg, and Wears Valley. We understand the rental calendar and we schedule around it.