Is the outlet on a 15 or 20 Amp circuit? Verify by looking at the rating of the circuit breaker (or fuse) in your homes' power control box that controls the outlet you are questioning.

You have probably heard that commercial arcades put 6 pinball machines on each 20A circuit.

How did they come up with that formula?

The National Electric Code wants circuit breakers to see 80% of their rated load. So for a 20A breaker, the ideal number is 16 amps.

Most pinball machines draw about 1.6 to 2 amps peak.

Some pinball machines with a ton of lamps may even draw 2.4 amps.

If you take any random 6 pinball machines at at arcade and measure their amperage draw at the breaker panel, you see that each breaker is seeing ~13 amps. Well under our 16 amp goal.

In your home, where you don't have to worry about employees moving games around and messing up your breaker loads, if you measured a 13 amp draw on a circuit, you could safely add one additional game and still be under your 16 amp target.

The only exception is TZ. It seems this beast needs his own plug lol

I have 6 per every 15 amp breaker and have had no problems

TZ was good when it was new, but it's overstressed power supply has not aged all that well.

I had to put TZ on its own dedicated circuit. Pulled. Another one as well to take a bunch of games off the existing load.

So if I’m reading this correctly the answer is more saying 6 machines per circuit not an outlet. In my basement I have a line in one room I want to junction and add an outlet that I’m dedicating 4 pins to, however in the other room I found that the breaker is also for the outlet 2 other pins are on. So this being the case I shouldn’t see the pins playing weak if all are on or tripped breakers?

That's the consensus is no more than 6 per 20A circuit, which assumes an 80% max load at ~2.5A per machine. Yours might be different depending on your machines. I've seen spikes of up to 5.5A on WoZ, but that appears to be an exception to the norm. You'll want to make sure that isn't a 15A circuit for some dumb reason. Being outlets, it shouldn't be, but you never know.

I posted this the other day that might help:

https://pinside.com/pinball/forum/topic/current-amp-draw-from-pinball-machine#post-5151645

My set-up on 1 wall:
7 WMS games and an LED controller on 3 outlets, on a dedicated 20 amp line:
FT, HS II and an LED controller - outlet 1
Flintstones and WW - outlet 2
F-14 and Diner - outlet 3
Rollergames - also on outlet 3 but temporary and just hand-connected when F-14 not in-play.
Has worked out fine.