Power - At the Table
We now reach the power strips. Given our 20A circuit with 4A per player, there should only be five power outlets available for players to plug their own surge protectors into. Since inexpensive outlet strips are sized for 15A and overloaded extension cords can heat up and catch fire, you'll want to use two extension cords and power strips per 20A circuit instead of a single cord and strip.
Typically, you will want to run heavy-duty 12-16 gauge extension cords from the outlets on the table box down to the table location for the systems the circuit will power. Don't skimp on cheap extension cords! I've found that single outlet cords intended for outdoor use are rugged, properly sized and work well. Plan on buying at least some 50 foot (or longer) extensions, since your power is feeding from one end of the table and you'll need about 36 feet of cord to reach the farthest table location.
Figure 12: Table power outlet plan
(click image to enlarge)
Figure 12 shows the power strip arrangement that I've found works well with my perferred 12 table / 24 player cluster. You can see that it uses two flavors of power strips - one with three outlets and the other with two. Note in Figure 12 that the three outlet and two outlet strips are alternated so that their nearest neighbor is always the other flavor (except for one position at the bottom right position).
Figure 13: Taped up and ready for action!
Don't worry about finding outlet strips with these exact numbers of outlets, since Figure 13 shows my low-tech solution for making them. It's important to not skip this step of blocking outlets since if there's an open outlet, it will get something plugged into it! An overloaded cord can overheat and catch fire, so block those spare outlets!
A final note is that you can use less expensive power strips without circuit breakers and preferably without power switches (if there's no switch it can't be accidentally shut off). Surge protection is ok if you want to spring for it, since it might provide an extra level of protection in an overload situation.
Attendee Surge Protector
At the very end of the power distribution is each gamer's personal power distribution. All attendees should supply his or her own power strip (preferably with surge protection) for their computer and monitor. This is very important since with my power distribution scheme only a single outlet is available for each attendee.
As you can see, building a power grid is definitely not a chore to be taken lightly, considering the amount of power you will be dealing with. I would go as far to say that you shouldn't even consider attempting anything without the assistance of a certified electrician. All of the equipment listed above should be rented from a company specializing in large event setups, or built by an insured contractor.
But no matter what, if something goes wrong with the power setup at your event, liability waivers may get you out of small incidents where one or two people's computers get fried. But gross negligence will place you in serious hot water!