Inflatable cord amp budget
Budget how many identical inflatable blowers fit on a cord/circuit from watts each versus 80% circuit headroom.
load_A = (blowers × W) ÷ 120; remaining_A = circuit_A × 0.8 − other_A − load_A
When to use
Use this when planning several matching blowers on one outdoor circuit or heavy-duty cord. Enter blower count, nameplate watts each, breaker size, and other loads already on that circuit.
Continuous-load planning uses 80% of breaker amps (15A → 12A; 20A → 16A).
Identical or average-watt blowers on this cord/circuit.
From the nameplate; if only amps, W ≈ A × 120.
Usually 15 or 20.
Porch lights, controllers, etc. already drawing.
Worked example
Example defaults — 4 blowers × 120 W; 15A breaker; 1A other.
Load: (4 × 120) ÷ 120 = 4 A. Budget: 15 × 0.8 − 1 − 4 = 7 A remaining → OK.
If remaining goes negative, reduce blowers or move some to another circuit.
Second example: one input changed
From the defaults (Blower count = 4; Watts per blower = 120; Breaker size (amps) = 15; Other loads on circuit (amps) = 1), the calculator shows:
Blower load: 4.00 A (4 × 120 W ÷ 120)
80% budget: 12.00 A on a 15 A breaker
Remaining headroom: 7.00 A (OK)
Planning aid only — follow nameplate and outdoor cord ratings.
Now raise Blower count from 4 to 6 and keep the other entries. The result becomes:
Blower load: 6.00 A (6 × 120 W ÷ 120)
Remaining headroom: 5.00 A (OK)
Comparing the two runs tells you how sensitive the answer is to that one measurement. If a small change in it swings the result a lot, measure it twice.
Limits / assumptions
Assumptions: 120 V nominal; identical watts; continuous-load 80% rule.
See also: Inflatable amp draw and GFI circuit headroom.
Not a substitute: cord gauge vs length, outdoor GFCI protection, or manufacturer daisy-chain limits.
Use outdoor-rated cords sized for the total load. Prefer GFCI protection outdoors. Do not bury non-rated cords or exceed the cord’s amp rating.
FAQ
Only amps on the label?
Multiply nameplate amps × 120 to estimate watts, or enter W = A × 120.
Mixed blower sizes?
Sum watts manually or run separate groups; this tool assumes matching watts.
Cord length?
Long thin cords drop voltage — pick gauge with the extension-cord gauge tool.
Why 80%?
Continuous holiday loads are commonly planned at 80% of breaker rating to reduce nuisance trips and heat.