Thursday, May 24, 2007

Electricity, The Real LAN Party Fuel

What makes a LAN Party happen? Electricity. If gamers can't power their rigs, they can't frag and when their not fraging, they're not having fun. This means that without it, your party is going to miserably fail.

At most LAN Parties getting enough electricity is a challenge and at our event it's no different. For a small event you may have to run extension cords from surrounding rooms to have enough electricity. Even if your location says it has enough power, you may still have to rent power converting equipment in order to use it. Another option for a large event is to rent a generator to provide the necessary power. If you're using local power, make sure you have access to the circuit breaker panel for the space so you can verify that you have enough electricity and reset any breakers if you do trip one at your event. For most small LAN Parties, the only equipment you have to buy are extension cords and power strips.

How much electricity do I need?
At a LAN Party, it is optimal to provide 3 to 4 amps (A) of electricity for each computer. Even though some desktops have 500 watt power supplies, they don't come close to using it. Most computers don't use as much electricity as they think. My very high end Desktop rig with a 650 watt power supply only draws 300 watts (or about 3A) so planning for 4A is more than enough. Use this numbers to calculate how many amps total you need power everyone's computers. Most household circuits are either 15A or 20A, so doing the math a 15A circuit can support about 4 desktops and a 20A circuit can support 5 or 6. At our event, since we have so many laptop users, we take this in to account when planning our power setup so we can minimize the number of extension cords we have to buy. An average laptop uses around 100 watts or about 1A of electricity so on our 20A circuits, we seat 2 laptops and 2 desktops to a power strip & extension cord to maximize the number of computers we can power. It would be better if we had only 6 computers (3 desktops & 3 laptops) on a circuit but in our location is short on electricty. You're probably going to have to run extension cords from other rooms in order to supply enough juice.

The Electrical Panel
The first step is to find out which outlets are on each circuit. This is really easy to do. Look around the space you are using and note where all of the outlets are. Plug a lamp into one of the outlets. Goto the electrical panel and look around to see if the circuit breakers are labeled and find the ones most likely to be for the outlets you noted. Flip the switches on the breakers, off and on, one by one until your lamp turns off. (see the diagram left for reference) Check the surrounding outlets and mark all of the outlets that no longer have electricity. All of these outlets are on the same circuit. Back at the panel, look and see how many amps the circuit breaker is rated and write this down. (see picture right) and turn the breaker back on. Continue this until you find all of the circuit breakers for all of the outlets you want to use.

The last thing you have to take into account is the total amount of electricity coming into your building. To find this, look for a number like 150A, 200A, 300A, etc stamped in white on the larger breaker at the top center of your electrical panel (the one for the panel in the picture above is in an adjacent box). This is the total amount of electricity you have to work with. Often the sum of the amps little breakers below the the large one will be greater because under normal conditions, none of the breakers work at their max. Add up the sum of the amps of the breakers you are going to be using. For example : LAN (3 x 15A) + LAN (2 x 20 A) + AC 50A etc for a grand total. If this value exceeds the total amount you are going to have, you are going to have to either reduce the number guest you invite, move to your party to a venue with more power or rent a generator. For reference, a 20A circuit can theoretically carry 2400 watts of electricity (calculated by using watts = amps*volts) but most will trip when they reach around 80% load (about 16A or 1920 watts). Proportionally, a 15A circuit can theoretically carry 1900 watts but typically can only carry 12A or 1440 watts.

Extension Cords
Almost always the outlets you want to use are out of reach of the power strips so you have to use extension cords to bridge the gab but you have to take into account is the number of amps that a power strip and extension cords can carry. 20 amp power cords and power strips are expensive so we split them over 2 separate power strips and extension cords carrying 10 amps each. As the length of the cords get longer, the less energy they can carry. A 25ft cords can handle about 14 amps but a 50ft cords may only handle 12 amps and as you can in the picture left, if you use even longer cord, the number of amps drops even more. So before you go out shopping get an idea of how long your extension cords need to be when you are out purchasing them. Usually you will need to buy 2 extension cords for every 5 computers your hosting.

Power Strips
On the tables, power strips divide the electricity from the extension cords giving every guest a single outlet that they can plug their own surge protector into. To prevent overloading, I assign each seat an outlet and tape over any extra. When you're shopping for power strips note that there is a difference between a power strip and a surge protector. A power strip doesn't provide any sort of protection from surges. Power strips are a cheaper alternative especially when guests will be bringing their own surge protectors. Make sure you tell your guests to bring a surge protector. Again, usually you will need to buy 2 for every 5 computers you're hosting.

Hooking It All Up
Only run as many extension cords as needed. If you have to run more then two cords on a single circuit, make sure you tape off all but the outlets you're going to use to make sure the circuit as a whole won't be overloaded. When running the cords, try to keep the runs as short as possible and leave any extra cord loose to prevent heat from building up and becoming a fire hazard. For safety, tape down all of the cables to the floor using blue tape because it is easy to remove after your party.

Prevent Overloads
Overloading is the most serous danger to a LAN Party as it not only could it cause a lot of cause a loss of power but it could also cause a fire. While you're at your electrical panel, turn off any circuits you're not using like your oven and cloths dryer so aunt Lulu can't crash your party by doing her laundry.
You should also set some rules beforehand like no UPS's (uninterrupted power supplies), speakers, mini fridges, microwaves and other nonessential items. UPS's while helpful, waste electricity and when you are on a tight electrical budget, these can tip the balance. After the event starts, periodically scan the tables for problems and if necessary, nicely explain why they have to disconnect their hairdryer from their surge protector.

Here is a quick review...

Circuit 1 is an example of what we use at our LAN-O-THON events. We have 2 desktops and 2 laptops on each of the 2 extension cords we have plugged into a 20 amp circuit.

Circuit 2 is an example of using more than 2 extension cords on a circuit but the circuit as a whole is not overload since it is only powering 12A worth of computers.

Circuit 3 is an example of the optimal setup for an event where guests bring mostly desktops. Five computers are divided over 2 extention cords pluged into a 20A circuit.

Circuit 4 is full of problems. With 7 computers on a 15A circuit it's at almost double its rated capacity and the circuit breaker is going to trip. Also having 16 amps on a single extension cord is a accident waiting to happen because when a cord is overload, it heats up and could start a fire. on a side note the extra outlets on the power strips aren't taped over, so someone could plug another computer in and make the situation even worse.

If Something Goes Wrong.
While loosing power is a major interruption to your event, it can and will happen and you better be prepared. If power does go out, first calm everyone down and announce you're going to try to fix it as quickly as possible and to stop the moaning, you can provide some sort of alternative like a poker game.

Anytime the power goes out, before anything else, unplug all of the computers that lost power. When the electricity comes back one you don't want a power surge to ruin any of your guests' computers.

If the entire building looses power, first check to see if the surrounding area's also lost power. If they did, the good news is that it is probably not your fault but the bad news is you're at the mercy of the power company. If your neighbors still have power, most likely you just blew your primary circuit breaker. Find your main circuit breaker box and see if the big main breaker at the top center of the box has tripped (usually a red, yellow or orange stripe will be visible on the breaker that wasn't before. You did look at the breaker box before your event right?). If it tripped, you don't have enough electricity coming into your building or house to power everything. You're going to have to unplug some things before flipping the breaker back on or it's just going to happen again.

Most commonly though, just a few computers will loose power.

First check to see if other computers on the same circuit are still on. If they are, check to see if the affect guests are all using the same power strip. If not, skip to my next idea. If they are, check to make sure the power strip is turned on and it's fuse didn't blow (may sound stupid but it happens). Then check the outlet that's suppose to be powering it. If it still has power flowing to it, check the extension cords to make sure they are all properly connected and if you still haven't found the problem, try swapping them to see if that solves the problem.

If the blackout is affecting multiple power strips and they are all on the same circuit, check the electrical panel for a tripped breaker (again look for a red, yellow or orange stripe that wasn't there before). If this is true, move some of the computers to a different circuit that's not being used and then flip the switch on the breaker to turn the power back on.

Anything not fixed by the above is harder to trace and could be a compound problem. Treat everything as if it wasn't related to any of the other power problems. Check the breaker box and if everything looks normal, continue to checking all of the power strips and extension cords.
Try connecting the extension cords to outlets on circuits you haven't tapped yet and see if that solves the problem. If you can't find the problem, you may have suck it up and end your event early and call a certified electrician out to fix the problem.

Have a question? Did I leave something out? That's what the comment box is for.

Continue on to The LAN in LAN Party


Anonymous said...

Hey, Is it okay to split a 20A load over two 33 ft. 16awg cables?


Anonymous said...

edit: It would really save me some money not having to use 14awg cables.

Croc said...

You should be good.