Studio strobes are high-power devices, often outputting more than enough energy to seriously maim or kill. While some newer strobe kits allow for hot-swapping cables, for generations of strobe packs, this was a big no-no. (As in, a serious electrocution-inducing no-no.) Be sure to read and understand the requirements of your own strobes before you go plugging and unplugging them willy-nilly. Dump the power as needed (by firing the strobes at shutoff, prior to unplugging) in order to avoid the possibility of getting zapped, and definitely don't work near water. A puddle could be enough to send all that power through you or your subject, rather than through the lights themselves.
Also, be careful about flammable things around your lights. They get hot (most of them, anyway) and could ignite the wallboard or a drop ceiling, or even a gel placed too close to the light. Even if you're not worried about dramatic explosions, hot lights can cause burns, so wear gloves as needed and don't touch bulbs in general.
If you're using lights with built-in barn doors, be sure they're open before firing up the light or you could fire up much more, unintentionally. (Exploding lights are no fun, especially when they sling molten glass toward you or your subject.) When it comes time to plug in lights or strobes, work from the pack to the wall. Then when unplugging, work from the wall back to the light.
When it comes to cables, coil them loosely and follow their natural shape; don't bend them around your elbow. This will help them to not only uncoil naturally without tangling, but it will help them to lay flat and straight when unfurled across the floor. If you must join to cords together, don't just plug them in; wrap one around the other to create a loose knot that won't pull apart easily. And again, avoid running cables through moisture of any kind. When working on location, if you encounter a two-pronged ungrounded outlet, don't simply remove the ground plug from your extension cord. At minimum, use an adaptor, but better yet, you should employ a portable GFCI or power strip with a circuit breaker built-in. Lastly, since there are so many opportunities for fires in studios (caused by electricity, as well as heat) it's a good policy to keep a fire extinguisher on hand.
Make sure your cords and cables lay flat on the ground; don't allow them to curl around in looping coils, don't hide them in grout lines on a tile floor, and don't place them in high-traffic areas. Cables do a wonderful job of practically jumping up and grabbing the ankles of people walking by, so your job is to do everything in your power to make them obvious and visible and yet nowhere near leaving the surface of the floor. I prefer to run them in straight lines across the set as needed, and rather than taping the length of a cable I use gaff tape (preferably bright yellow) to tape them down with large Xs of tape. A photographer friend uses yellow "caution" flags and bright orange cones to steer subjects away from cables and stand legs as well. I like to run my cables under the legs of the stand on which the light is sitting. This way if someone does somehow catch and pull on the cable it will pull the stand from the bottom rather than the top. This can be the difference between a stand the slides an inch and a stand that tips over and deposits a hot, heavy and electrified light right on top of you, your assistant or your subject's head. I've also been known to use area rugs or doormats to cover cables that might otherwise create a trip hazard—such as the USB cable running from a tethered camera to a computer on a table or stand a few feet away.
When working with C-stands, tightening the arms isn't enough. You should tighten them so that the weight of the light (or flag, etc) is serving to tighten the grip of the clamp, rather than loosening it. This is easy enough to test as you're setting up a stand; pull down on the end of the arm once you've got it clamped tight to the stand, and if it loosens and gives, you're going in the wrong direction. Reverse it and the light's weight will actually serve to help stabilize the clamp.
C-stands are also terrific eye-pokers and finger-pinchers. Put a boom arm with a pointy end of a long steel arm anywhere near eye level and you're asking for trouble. When you're focused on your task at hand, you'd be amazed at how invisible these items can become. Mark their ends with bright yellow tape, or better yet cover them with something soft—like a tennis ball, which is also highly visible yellow. Watch your fingers, too. When taking the weight off of a C-stand or light stand, keep your fingers clear of pinch points and never loosen a stand with one hand without taking the weight of the stand with the other.
To keep C-stands from tipping over, position them with their largest leg pointing toward the weighty side of the setup. Meaning, if you've got a large flag on top of the stand pulling it to the right, position that large leg to the right as well. It's also helpful if that large leg—or on a regular light stand, any leg—is pointing directly at your subject. Because this way if the stand does somehow tip, it's likely going to go in any direction other than directly at your subject. Remember, you're responsible for their safety, too.
Sandbags are probably the best way to keep stands from tipping over. Along with gaffer's tape, perhaps no tool is more helpful in studio safety than the simple sandbag. They keep stands upright, counterbalance boom arms, and help light stands function when used outdoors, where even a little wind becomes a big challenge. Position sandbags so that not only is the weight on the stand, but in the most logical position to counterbalance the heavy weight of the light/flag/reflector on top of the stand. It's good policy to use a sandbag on every light stand, and for large or heavy setups multiple sandbags are essential—just like they are if you're working outside or on an uneven surface.
Got any safety suggestions of your own? Please share them in the comments below. Until then, stay safe while you make great pictures.