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One laptop draws, on average, probably 50W (that's a rough estimate -- my MacBook actually draws 18W when I'm writing, or up to 45W if I'm doing CPU-intensive tasks). 200 * 50W is 10,000W. A small boardroom size projector draws 350-500W, call it 500 for safety. That's another 1000W, for 11,000W. A PA system is kind of a wild card, but at a maximum will draw maybe 1000W. Depends a lot on the amplifier, and what kind of sound you're putting through it.

In any case, that puts us at a nice round 12,000 watts. It's nice and round because, powering the whole thing with 120V (watts = volts * amps) means you're drawing 100A.

A typical home circuit supplies 15A. A heavy duty home circuit supplies 20A. I'm not sure how the Women's Building is wired, but you'll need at least 5 20A circuits to meet worst-case load. Most likely, you won't *need* this much power, but it'd suck to pop breakers, so it's worth having it handy.

If each laptop power strip has 8 utilized outlets, then you'll be running 400W (or 3.3A) per power strip. That'd allow you to put about 6 power strips on a 20A circuit.

Bottom line, you'll have to get together with the building's management and tell them you'll need about 100A of power that night. With any luck, they've got at least that much in a room designed to seat 200 people, but it'd be better to ask first. They may be able to run extension cords from other rooms or circuits.

A "circuit" in this case is a series of outlets which are hooked together, and run to a common breaker. There may be one circuit per outlet, or all the outlets might be on one circuit -- that's why you need the management's involvement.

Assuming the building is up to code (which it almost certainly is), there's no fire danger from what you're proposing. Make sure all power strips and extension cords are properly rated (ie, 3.5A or 400W for laptop power strips, and 500-1000W (up to about 10A) for projectors and sound system -- any but the lightest cords will work for laptop power, and you might need to be careful with the projectors and sound). The worst you should experience is a sudden outage if you exceed the breaker's rating for that circuit. If you use thin/cheap extension cords, there is a danger of the wire overheating, but probably only on the projectors or sound system.

Since I don't know that space at all, I can't comment on what kind of extension cords you might need, but it sounds like you'd do well to find a local electrician-wrimo who'd be willing to consult before the event. You're definitely talking about enough power to be concerned about doing it right.

Email me back with more specific questions, if you like. I'd be glad to help, even though I'm nowhere near SF.