Electrical Load Calculator

Reptile fire safety and electrical circuit loading

We developed this electrical planner out of concern about fires in the reptile community. It is part of our ongoing fire-safety project, which we are working on with an electrician. Our goal is to help reptile keepers understand the loading of electrical circuits and recognize potential overloads.

Use the planner to add up equipment loads, assign them to circuits, and compare the full connected load with each breaker rating and your chosen planning limit. It also estimates energy use, operating cost, and equipment heat output.

How do you use the electrical load calculator?

1. Choose your electrical standard and enter your electricity rate per kWh from your bill. Check the circuit voltage, breaker rating, and planning limit.
2. In Load library, choose a preset or create a custom load using the actual equipment rating. Add it to the facility plan, or include it in an enclosure and rack configuration.
3. Set the quantity, average-operation schedule, and assigned circuit for each placed load. Review the electrical and heat summary as you make changes.

How are energy cost and circuit load calculated?

Daily energy in kWh = watts × quantity × equivalent full-power hours per day ÷ 1,000. Energy cost = kWh × your electricity rate. Monthly estimates use an average month of 365.25 ÷ 12 days. The full connected load is used for breaker comparison; reducing average operating time changes energy and heat estimates, not the connected load.

Worked example: a 100-watt lamp

Start with an otherwise empty United States plan and a 120 V circuit. Add one Halogen lamp — 100 W preset, leave average operation at 50%, and enter an example electricity rate of $0.15/kWh. Here, 50% represents the equivalent of 12 full-power hours per day.

The result is 1.2 kWh per day, about 36.5 kWh per average month, and $5.48 per month. Connected current is about 0.83 A. The heat estimate is 341 BTU/h at full power and 171 BTU/h averaged over the day. These are example inputs, not a recommended heating schedule.

What assumptions should you check?

Presets and operating percentages are starting points. Actual equipment ratings and operation determine the estimate. The planning limit is a chosen margin, not an electrical-code approval. Heat output uses 3.412 BTU/h per watt and excludes air conditioners from the heat total; it does not predict enclosure temperature or required cooling capacity.