A portable generator can run essential equipment during an outage or
supply power at a remote worksite. It also produces carbon monoxide,
electric-shock and fire hazards when placed or connected incorrectly.
Select it from a measured load list, then plan fuel storage, weather
protection and safe connection before an emergency.
Safety comes before
generator size
Run a fuel-burning portable generator outdoors only. The US Consumer
Product Safety Commission and Centers for Disease Control and Prevention
advise keeping it at least 20 feet—about 6 metres—from the house, with
exhaust directed away from doors, windows and vents. Never operate one
inside a home, garage, basement, shed or enclosed porch, even with doors
open.
Install battery-powered carbon monoxide alarms on every level and
outside sleeping areas according to local guidance. A generator’s CO
shutoff feature is a useful additional safeguard, not permission to
reduce the separation distance or run it in a partly enclosed space.
Keep the machine dry without enclosing it. Follow the manufacturer’s
wet-weather instructions and use a purpose-designed open-sided cover if
permitted. Do not touch equipment with wet hands.
Calculate running and
starting watts
List only the appliances that must operate. Record each continuous
running wattage and the highest starting or surge requirement. Motors
and compressors can briefly require much more power when starting.
Suppose a refrigerator uses 700 running watts and 2,200 starting
watts, lights use 200 W, a furnace blower uses 600 running and 1,600
starting watts, and electronics use 300 W. If everything may run
together, continuous demand is 1,800 W. The worst startup event must be
added to the other running loads. Exact calculation depends on which
loads start together; use manufacturer data or a meter rather than
generic web estimates.
Choose margin above the calculated requirement. Operating permanently
at the nameplate maximum leaves no room for startup events, changing
loads or derating in heat and altitude.
Conventional versus
inverter generator
Conventional portable generators are often economical for high
output. Inverter generators electronically regulate their output and
commonly vary engine speed with load, which can reduce noise and fuel
use at partial load. They are popular for camping, electronics and
smaller backup loads, but high-capacity models cost more.
“Inverter” does not make exhaust safe, and marketing terms such as
clean power need a measurable specification. Check rated continuous
watts, surge capacity, total harmonic distortion where relevant, sound
measurement conditions and outlet types.
Gasoline, propane or dual
fuel
Gasoline is widely available and delivers strong output, but it
degrades in storage and is hazardous to store. Propane can store longer
in a suitable approved cylinder and burns without gasoline residue in
the carburetor, though generator output may be lower on propane.
Dual-fuel units provide flexibility. Some models also support natural
gas, usually with different output ratings and installation needs.
Store fuel only in approved containers and in quantities and
locations allowed by local fire rules. Let the generator cool before
refueling. Spilled fuel on a hot engine can ignite. Plan consumption
from the manufacturer’s load-specific runtime figures, not the no-load
or quarter-load figure alone.
Connect equipment without
backfeeding
For individual appliances, use outdoor-rated extension cords sized
for the current and distance, with intact grounding and connectors. Do
not overload a cord or place connections in water.
Never plug a generator into a wall outlet. This practice, called
backfeeding, can energize utility lines and kill workers or neighbors.
To power selected household circuits, have a qualified electrician
install a listed transfer switch or other code-compliant interlock and
inlet arrangement. Requirements vary by jurisdiction and electrical
service.
Features worth comparing
Compare rated watts rather than peak watts alone. Check outlet
formats, 120/240-volt capability where needed, runtime at several loads,
tank size, noise test distance, electric start, low-oil shutdown, CO
shutoff, wheel kit, warranty and local service. Confirm whether neutral
and grounding arrangements suit the intended transfer equipment; that is
an electrical-design question, not a guess from plug shape.
Before outage season, read the manual, test-start the generator
outdoors, inspect cords, replace stale fuel as directed and verify
alarms. Keep a written load sequence so large motors do not all start
simultaneously.
A safe generator setup is a system: correctly sized machine, adequate
fuel, outdoor placement, CO alarms, suitable cords or transfer equipment
and people who know the procedure. Buying only the engine leaves the
highest-risk decisions unresolved.
