Electrical
AmpDesk
For the motor, the run, and the house.
- Enter horsepower and voltage.
- See the table current, the wire, the breaker, and the overload.
- Check a long run, a house service, or a wire size on its own sheet.
Field calculators
Electrical and HVAC calculators for the job site.
For electricians, HVAC techs, and operators checking a number before they order the wire or the duct.
These are planning sheets. They are not a permit, and they do not replace the nameplate or the person on the job.
HVAC
AirDesk
For the room and the duct.
- Enter the room size and the climate zone.
- See a cooling screen and the supply air.
- Get a round duct, and a rectangle that matches it.
Where the numbers come from
Each sheet names its source. This is the short list.
- Motor currentNEC Tables 430.248 and 430.250
- Wire sizeNEC 430.22 and Table 310.16
- Breaker or fuseNEC 430.52
- OverloadNEC 430.32, set from the nameplate
- House serviceNEC Article 220
- Supply airBTU/h divided by 1.08 times the temperature rise
- Duct sizeEqual-friction method