Forget about outlets,you need to think in terms of line's,every outlet does not have it's own line,lines are shared by several/many different outlets,sometimes the line is shared by outlets in different rooms,you can check which line controls each outlet by plugging in an electrical device in every outlet in the house,then turn them all on at once,then start flipping breakers off until you find out which outlest turn off with what switch,this will tell you what outlets are ran off the intended outlet for your grow,this way you can limit whats on that line.
With that being said all lines are not equal,you need to look at the breaker to determine how much wattage the outlet is capabale of giving before flipping a breaker,15 amp & 20 amp are the most common lines/breakers in homes.
The formula for finding out the max wattage is as followed.
Amps x Volts X 80% Duty cycle.
To find the safe wattage for a 15 amp line you'd have this equasition.
15 Amps X 120 Volts X 80% Duty cycle = 1,440 watts.
A 20 Amp line's safe wattage would look like this.
20 Amps X 120 Volts X 80% Duty cycle = 1,920 watts.
If you have the old style screw in fuses it's safe to assume that the fuse's that are now in the fuse box are of improper amperage,people tend to get sick of blowing fuses,they are hard to find for most people & a pain in the ass so they compensate by installing heavier fuses,be on the safe side,install all 15 amp fuses in the fuse box & assume all lines are max 15 amp,then follow the 15 amp equasition.