On this page
The honest answer: not uncovered
A running generator produces electricity at its outlets and inside its windings, and rain falling on those live components creates a path for current. The two real hazards are electrocution to anyone touching a wet, energized unit and internal damage: water entering the alternator can short and ruin the windings, turning a temporary problem into a dead generator.
So running a portable generator bare in the rain is genuinely dangerous and can destroy the machine. But the answer is not to shut off power in a storm either, since storms are exactly when you need it. The answer is to cover it correctly while keeping it ventilated.
Canopy and tent solutions
A purpose-built running cover, the GenTent class of product, is a frame and canopy that mounts to the generator and sheds rain and snow while leaving all four sides open for airflow and heat dissipation. These are designed to be on while the unit runs, unlike a storage cover, which must never be on a running generator.
What you must not do is improvise an enclosure. A tarp draped tight, a closed shed, or a box traps exhaust and heat: trapped carbon monoxide kills, and trapped heat can ignite. The rule is a roof over the top with open sides, never a sealed space around a running engine.
- ·Use a running-rated canopy with open sides
- ·Never put a storage cover on a running generator
- ·Never run it in a closed shed, garage, or tarped box
Clearances from the house
The dominant danger with portable generators is carbon monoxide, an invisible, odorless gas that has killed people running units too close to or inside their homes. Keep the generator at least 20 feet from the house with the exhaust directed away from doors, windows, and vents, and never run one in a garage even with the door open.
That 20-foot clearance shapes where the canopy and the generator sit during a storm: far enough out that exhaust disperses, on stable footing, away from anything the rain could float against it. A standby unit, by contrast, is fixed outside at a code clearance from openings and is built for this, which is one of the trade-offs in choosing a standby versus a portable generator.
Grounding requirements
Whether a portable generator needs a separate ground rod depends on how it is wired. Most modern portable generators are bonded-neutral and, when powering equipment through their own outlets with cords, are treated as a separate system that the manufacturer typically does not require a driven ground rod for. The frame still bonds to neutral internally.
The picture changes when the generator feeds the house through a transfer switch. In many transfer-switch setups the house grounding electrode system serves the generator and the generator neutral must not be re-bonded, which can mean using a switch that does not transfer the neutral or a generator configured as a non-bonded neutral. Because the correct grounding depends on the transfer switch type and local code, a licensed electrician sets this up when the transfer switch is installed. The details of how transfer switch wiring connects explain why neutral bonding matters, and the cost to hook a generator up to a house covers what that install runs. Standby units are grounded as part of their permitted installation.
- ·Cord-and-plug use: bonded-neutral portables usually need no separate ground rod
- ·Transfer-switch use: grounding and neutral bonding depend on the switch type and local code, which factor into transfer switch installation pricing
- ·Standby units are grounded as part of the permitted install
Rather talk it through with a pro?
Calls are answered around the clock and routed to a licensed electrical pro serving your area.