Over loading?

So the 5250 =  250 watts x 5, 8 Ω / 385 watts x 5, 4 Ω.
The 2003 =  200 watts RMS x 3, 20 Hz - 20 kHz, 8 Ω, all channels driven  300 watts RMS x 3, 20 Hz - 20 kHz, 4 Ω, all channels driven.
So which do I go by? 8 or 4 ohm?

The peak current value of an amplifier is the maximum amount of current which output is capable of sourcing for brief periods of time.
Instead, you should look at the maximum power consumption specs to determine if a 15amp line is sufficient.
For 5250, the maximum power consumption is 2500watts,
the 2003 maximum power consumption is 1320watts.
2500watts / 120volt = 20.8amp
1320watts / 120volt = 11amp
It is best to run each amplifier on separate 20amp and 15amp line if you drive them to maximum rated power.
However, unless you use them to drive very low efficiency speakers in a very large room with high volume level, I believe it is OK to use a single 15amp line to both amplifiers as long as they do not tripping the circuit breaker.

+1 imhififan - I concur with everything he said. For me I changed my 15 amp breaker to 20 amps because it popped occasionally on power up only, never while playing loud. I had 9.6kW output into 4 ohms though...

Thanks hifiman. I’m running B&W s. x9 & I haven’t tipped the breaker "15 amp". I can change the breaker to a 20 amp. It’s 12/2 romex, or I can run another line. I originally had them on their own 15 amp breaker, but moved 1 amp so not to share with my Prima Luna HP & now added Isotek conditioner. Their only used for AV. Did I make myself clear? (no pun intended)

I've got news for you. It is not just the breaker. 20 Amp services have larger diameter (smaller gauge) wire to support the additional current draw. Changing the breaker and not the wire is theoretically asking for a fire. Most amps in home situations are going to do fine on a 15 Amp service. You can't drive an amp at full continuous power. It will be distorting on peaks and will sound stressed long before you get there. Just 3 dB down is 1/2 power and you are probably still distorting peaks at this level. This is why power is so important. To avoid clipping peaks and sounding stressed your loudest listening level should be 1/10th peak power or if you like listening at an average power of 50 watts, you need an amplifier capable of 500 watt peaks. Depending on the efficiency of the loudspeakers most of us are only listening at an average power of 1 to 25 watts. The outlier here is class A amplifiers. They draw a lot more idling than other designs unless they have a bias adjusting scheme.