Quoted from Yelobird:

Yeah, your breaker is going to be a bigger problem then your volume.... 10 games on a single breaker will likely not work. I would try to keep people grouped on 3-4 machines to avoid a trip. No bigger downer then having in process group games shutting off mid play. Could do the extension cord but not a fan of that idea. Be best to herd the group to less games being played. Games that are not played but on draw minimal amps.

Quoted from Yelobird:

Hmmmm says the guy that does side jobs wiring basements...... lol JK!! The thread below covers many of these questions in detail but it does depend on the type of games era. I stick with 4 games per circuit (being played) as a rule of thumb.
https://pinside.com/pinball/forum/topic/how-many-amps-does-a-pinball-use

Quoted from Dayhuff:

I'd have to count them but when I put the electrical in I really over did it with amps and circuits since the walls and ceiling were open at that time and that's the best time to do it. There is a separate 200 amp service just for the basement itself. I knew I'd have plenty of clocks, neons, signs and more game to come so 200+ outlets was the goal and that way I'd have plenty of power any place I needed it. Never had a problem.
John

Quoted from Pinbub:

Decades from now people will be scratching thier heads trying to figure out what you were doing in there!

Quoted from Pahuffman:

I have a worthwhile piece of advice. Make sure everyone knows how comfortable you are with having your machines banged around. If you are a tightwad about it (I'm not saying you are) make sure people know that. Inevitably, someone will take a good swing at a lockdown bar or glass out of frustration. It happens. Be upfront about how you will respond to that so you don't look like a jerk when you call somebody out.
If you're cool with a little rough play, let people know that too because it will ease up their anxiety about playing too hard. MOST people will be respectful and not abuse games when visiting, but they also shouldn't have to worry about playing with their fingertips (in my opinion).