Cordless tools removed one whole category of hazard from the jobsite. They also introduced a couple that did not exist before, and most people never got told about the second part.
The corded list, still relevant
Even a mostly cordless crew plugs something in every day.
Inspect the cord before use. Not a formal inspection, just look: nicks in the jacket, exposed conductors, a plug that has been pulled at an angle until the strain relief gave up. Damaged cords are the leading cause of tool-related electrical incidents, and they fail in the worst conditions, which is to say wet ones.
Use ground fault protection outdoors, in basements, near concrete, and anywhere damp. On construction sites it is required for receptacles that are not part of the permanent wiring. A GFCI does not prevent a fault; it disconnects fast enough that the fault does not stop your heart.
Size the extension cord for the run. This is the one people get wrong most often. A long light-gauge cord causes voltage drop, which makes the tool draw more current, which makes both the cord and the motor run hot. If a cord is warm to the touch during use, it is the wrong cord. Heavier gauge for longer runs and higher amperage tools, always.
Never carry or hoist a tool by the cord, and never yank the cord to unplug it. Those two habits produce most of the damaged plugs you will ever see.
What cordless changed
Take away the cord and you take away the visible reminder that the tool is live.
A corded saw with the plug in your hand is obviously safe to touch. A cordless saw sitting on a bench looks identical whether it is armed or not. That is the source of the most common cordless injury pattern: reaching into a blade or bit to clear something, or changing an accessory, with the pack still in.
The habit is absolute. Pack out before changing a blade, a bit, or a guard, before clearing a jam, and before any adjustment that puts your hand near the business end. It takes two seconds and it removes the entire category.
Trigger locks and belt hooks matter for the same reason. A tool clipped to a belt with the trigger exposed to a ladder rung has started on people. Look for the lock, use it, and be aware of what your tool is pressed against when you climb.
Batteries are the new hazard class
Lithium packs store a lot of energy in a small package. Handled normally that is fine. There are a few conditions that are not normal.
Retire any pack that is swollen, cracked, punctured, has been submerged, or that gets unusually hot during a normal charge. A pack in that condition is not a maintenance issue; it is a fire risk, and it belongs in a battery recycling program rather than in a drawer or the trash.
Charge on a hard, non-combustible surface with room around the charger. Not on a stack of rags, not in the truck under a tarp, not overnight in a place where nobody would notice for hours. Let a hot pack cool before charging.
Keep terminals clean. Metal debris across contacts is a short circuit waiting for the right moment, which is why loose packs rolling around a truck bed full of screws is a bad arrangement.
The habits worth building
- Battery out before any blade, bit, or guard comes off
- Look at the cord before plugging in
- GFCI outside and anywhere damp, no exceptions
- Heavier cord for longer runs
- Charge on a clear hard surface, never on a hot pack
- Retire damaged packs the day you notice
None of this is complicated and none of it slows a day down measurably. It is the difference between a career of ordinary Tuesdays and the one afternoon everybody remembers for the wrong reason.