Huray a LANparty related post!

If you are looking to run a LAN at your house, an essential part of preparation is to make sure peoples PC's will have the power they need to run for a whole day of fragging goodness.

You should be aware that a computer power supply has a power rating in Watts (A Watt is simply the Voltage times the Ampage, or W=VA) which corresponds to its maximum draw, ie it doesn't draw 400W constantly, even though its rated at 400W. You will also notice that powerboards and so forth will have a rating of 2400W, meaning they are rated to deliver 2400W of power.

A typical circuit in your home is rated for 10Amps at 240VoltsAC which is 10*240 = 2400Watts.

Simple maths will tell you that 2400W circuit / 400w PSU gives you 6 computers if they are running at max load and not including the monitor. This is a reasonable maximum, however in my experience 10 computers per circuit is usually safe, as most PSU's arent running at full power. Even with 500W PSU's, im still comfortable with 10 computers if the wiring in your house is relatively new.

The catch is that electricians will wire the points in your house sometimes seemingly randomly, especially if points are added later on - they will just attach to the closest wiring in the wall, which could mean the point from another room.

So you will need to spend a few moments and map out what points are connected to what in your house. This will save you face if a circuit trips, and you wont be called a douche bag and taped to the toilet.

To work out which outlets (called General Purpose Outlets - GPO's in Australia) are connected to which circuit breaker, and what other devices are attached to the same circuit. You should first look in the distribution board of your house. In Australian homes, this will be on the side of your house or sometimes near the door. It will virtually never be inside unless you are in an appartment. If you arent sure, ask your parent or landlord.

If you are lucky, there will be a diagram showing which points are connected to which breaker. If so, great! make a copy of that information and skip the rest of this guide, otherwise its time for some detective work!

Start by making a drawing of your houses layout, and then putting the location of each outlet. Remember that outlets lurk behind things like your fridge, your microwave and your tv cabinet. Find yourself a small easily moved lamp which will be used later for testing.

Then head to your Distribution Board and turn off the breakers for the GPO in your house, this may not be practical if life critical devices are plugged in. Use common sense and dont unplug your grandmothers life support! But also keep in mind that you may reset clocks and other things, so don't forget to ask your parents first if you live with them.

If you aren't sure which are breakers, which are safety switches etc. You should get a friend or electrician who does!

Having off'd all the breakers, turn on just one.

Using the map of your house, head to each outlet and plug in your lamp. If it turns on, mark on your map that this outlet is connected to the circuit that is currently on, and what other appliances are plugged in. Then head back to the Distribution Board and turn on another Circuit Breaker, repeating the process over and over untill all outlets are mapped.

With all the outlets mapped, make a summary of what appliances are on each circuit.

Now with this information you can spread out your guests computers on to the different circuits, and if a circuit breaker does pop, you will have good information for where to move one of the computers too before you turn it back on again!

NB. Its handy to make a nice copy of this information and put it on your fridge for easy reference during your LAN. You may even consider sticking another copy on the map in the cupboard that holds your Distribution Board.