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Free Electrical Panel Load Study - Do You Actually Need an Upgrade?

Walk Your Panel Breaker-by-Breaker with NEC Article 220 Demand Factors

Professional residential load calculation tool that walks you through every breaker in your panel. Uses NEC Article 220 demand factors to calculate your actual service demand - not just the scary connected load total. Find out whether your panel has room for an EV charger, heat pump, or workshop subpanel before paying for an electrician's visit.

Electricians sometimes recommend panel upgrades based on connected load alone. Connected load adds up every nameplate watt in your panel - a number that's always larger than reality because you'd never run your oven, dryer, water heater, and every light at full power simultaneously. NEC demand factors account for this, and this tool applies them automatically.

Pro Tip: Before you accept a $5,000+ panel upgrade quote, run your panel through this tool. Many homeowners on 100A service discover they have more capacity than they think once NEC demand factors are applied. The "Can I Add?" feature alone could save you thousands.

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How It Works

  1. Enter Panel Details

    Start with your main breaker size (typically 100A or 200A), service voltage (240V single-phase for most homes), total panel spaces, and your home's square footage. Square footage drives the NEC 220.12 general lighting demand calculation.

  2. Add Each Breaker

    Walk your panel door-to-door and add each breaker. Choose from 35+ common residential circuit presets (kitchen small appliance, bathroom GFCI, range, dryer, water heater, HVAC, EV charger, etc.) or create custom entries with nameplate wattage. Each preset includes correct breaker size, typical wattage, and NEC load category.

  3. Assign NEC Load Categories

    Each circuit gets assigned to its NEC Article 220 category: general lighting (220.12/220.42), small appliance (220.52), cooking equipment (220.55), dryer (220.54), fixed appliances (220.53), or HVAC (220.60). These categories determine which demand factors apply to reduce your calculated load.

  4. Review Demand Analysis

    See the full NEC 220 Standard Method calculation: connected load vs. calculated demand with every demand factor referenced by NEC section number. The analysis shows exactly how much each category was reduced and why your calculated demand is 40-60% lower than the raw connected load total.

  5. Check the Verdict

    The verdict panel shows your service utilization percentage, remaining capacity in amps, and a clear recommendation: your panel is fine, it's getting tight, or you should consider an upgrade. A visual gauge makes it easy to see where you stand at a glance.

  6. Test New Loads with "Can I Add?"

    Use the built-in load tester to see if specific new circuits fit your current service. Select from common additions like a 48A EV charger, 30A mini-split, 50A hot tub, or workshop subpanel. The tool recalculates demand with the new load and tells you whether it fits or triggers an upgrade recommendation.

Built For

  • Homeowners considering adding an EV charger or heat pump to an existing panel
  • DIYers planning a workshop subpanel or garage addition
  • Home buyers evaluating whether a 100A panel needs upgrading before purchase
  • Property managers documenting panel capacity for maintenance planning
  • Electricians providing quick preliminary load studies for residential customers
  • Anyone who was quoted a $5,000+ panel upgrade and wants to verify it's actually necessary

Features & Capabilities

NEC Article 220 Standard Method

Applies the correct demand factors from NEC Article 220 for every load category: general lighting and receptacles (220.12/220.42), small appliance and laundry circuits (220.52), cooking equipment (220.55 - Column A table method), clothes dryers (220.54), fixed appliances (220.53 - 75% factor for 4+ appliances), HVAC non-coincident loads (220.60), and motor loads (430). Every factor is referenced by NEC section number so you can verify the math.

35+ Breaker Presets

Common residential circuits pre-loaded with correct breaker sizes, typical nameplate wattages, and NEC load categories. Includes kitchen small appliance (20A), bathroom GFCI (20A), electric range (40-50A), clothes dryer (30A), water heater (30A), tankless water heater (60-100A), central AC (30-60A), heat pump (30-60A), EV charger (40-60A), well pump (20-30A), pool pump (20A), hot tub/spa (50A), and many more. Add custom entries for anything not in the presets.

Connected vs. Calculated Demand

The key insight most homeowners never see. Your connected load (every nameplate watt added together) is always dramatically higher than your calculated demand (what NEC says your service actually needs). This tool shows both numbers side by side with percentage breakdowns by category, so you can see exactly why a panel that looks "overloaded" on paper may have plenty of real-world capacity.

Can I Add a New Circuit?

The most practical feature for homeowners and electricians. Select a common new load - Level 2 EV charger (48A), mini-split heat pump (30A), hot tub (50A), workshop subpanel (60A), tankless water heater (100A) - and see instantly whether it fits your current service. Shows the updated utilization percentage and whether an upgrade would be needed.

Upgrade Recommendation

When your panel is genuinely at capacity, the tool recommends the correct service upgrade size (typically 100A to 200A, or 200A to 320/400A) and shows the projected utilization at the new service size. Saves you from paying for an upgrade you don't need, and confirms when you do.

Physical Space Tracking

Capacity isn't just about amps - you also need physical breaker spaces. The tool tracks how many pole spaces your breakers consume versus how many your panel has. A 200A panel with only 2 open spaces may need a larger enclosure even if the amperage is fine. Flags when you're running out of physical room.

Common Service Sizes & What They Support

Service Size Connected Load (typical) Calculated Demand (typical) Can Usually Handle
100A / 240V (24 kW) 30-50 kW 12-18 kW Gas heat, gas cooking, no EV - tight for modern homes
150A / 240V (36 kW) 40-65 kW 18-28 kW Electric dryer, AC, one EV charger - comfortable for most homes
200A / 240V (48 kW) 50-90 kW 22-38 kW All-electric home, EV charger, hot tub, workshop - current standard
320A / 240V (77 kW) 80-130 kW 35-55 kW Large home with multiple high-draw loads, dual EV chargers
400A / 240V (96 kW) 100-160 kW 45-70 kW Very large homes, in-law suites, pool heaters, commercial-grade equipment

Frequently Asked Questions

Connected load is every nameplate watt in your panel added together. Calculated demand applies NEC Article 220 demand factors that account for the fact you'd never run everything at full power simultaneously. For example, NEC 220.42 reduces general lighting load to 35% after the first 3,000 VA. Calculated demand is always lower than connected load - often 40-60% lower.
Because you don't run your furnace and air conditioner at the same time. NEC calls these "non-coincident loads" and only counts the larger one. This is one of the biggest demand reductions in a typical residential load study.
No. The tool works with nameplate wattage alone, which is the NEC standard method. Measured amps are optional and provide additional data for comparison, but the demand calculation uses nameplate ratings.
It depends on your existing loads. A typical Level 2 EV charger draws 7.7 kW (32A). Run your panel through this tool to find out. Many homes with 100A service can accommodate an EV charger if existing demand is modest, but some cannot. That's exactly what this tool determines.
This provides a reliable estimate using the same NEC Article 220 Standard Method that electricians use. However, a licensed electrician should verify the results before making service changes. Local codes may differ from NEC, and your AHJ (Authority Having Jurisdiction) has final say.
This tool recommends considering an upgrade when calculated demand exceeds 95% of service capacity. While NEC doesn't specify a fixed threshold, 95% leaves minimal headroom for future loads or temporary surges. Most electricians consider 80% a comfortable utilization level.
Warning signs of an overloaded panel include: breakers tripping frequently, warm or hot breaker handles, buzzing sounds from the panel, lights dimming when appliances start, and a main breaker that trips. However, these symptoms can also indicate other problems like loose connections or failing breakers. The only way to know if your panel is truly at capacity is to run a load calculation using NEC Article 220 demand factors - which is exactly what this tool does. Many panels that seem overloaded based on nameplate ratings actually have plenty of capacity when demand factors are properly applied.
A 100A to 200A service upgrade typically costs $2,500-$5,000 for the panel, breakers, meter socket, service entrance cable, and labor. If the utility needs to upgrade the service drop or transformer, add $500-$2,000. Permit and inspection fees add $100-$500 depending on your jurisdiction. Before committing to this expense, run your panel through this load study tool - many homeowners discover their 100A service has sufficient calculated demand for their needs, including adding an EV charger or heat pump, once NEC demand factors are applied.
Disclaimer: This tool provides an estimate based on NEC Article 220 Standard Method for residential load calculations. It is not a substitute for a professional load study performed by a licensed electrician. Local codes may differ from NEC. Always verify with your AHJ (Authority Having Jurisdiction) before making service changes.

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