AC Power - two circuits better than one?

Salmonsc,

If the circuits are fed from the same leg you will measure zero volts from the hot slot contact of one branch circuit receptacle to the hot slot contact of another branch circuit receptacle. If you measure 240V between the two measured branch circuit hots, they are fed from opposite legs.

I doubt you will find that all 3 branch circuits are fed from the same leg. Might be though.... Good chance 2 will be. Use the dedicated 20 amp branch circuit as the starting reference point. Measure from the hot of the 20 amp dedicated circuit to each hot of the two convenience 15 amp branch circuits.

You can use a drop cord to extend one lead of the volt meter. Note the smaller length slot of the two slots is the hot conductor. You can verify by measuring from the smaller slot (hot) to the equipment ground (round hole) contact. You should measure 120V.
.

Many thanks Elizabeth & Jea48, I will check this out tomorrow. Assuming I can find a second branch circuit fed from the same leg as the 20 amp circuit, I will likely connect the monoblocks (& possibly the power amp) to the 20 amp circuit & the sources to a 15 amp circuit. Does this make sense?

As predicted, apparently not all 3 branch circuits are on the same leg. Unfortunately, the configuration of outlets in the room on the same leg isn't exactly convenient. Hence my next question: If I keep all the audio components on a single leg (20amp & 15 amp), is it a major problem to have video equip (TV & DVR) on another leg - the only connection between the two systems is via HDMI routed through the preamp. I understand this isn't ideal but if they are attached to separate surge protection is it workable?

If this was me and rewiring is not an option, I would look into getting a power distribution center such as a PS Audio Premier and plugging into the one 20-A outlet and seeing if all my gear can be accommodated. It is always better, IMO, to limit the number of audio outlets to as few as practical to reduce ground loops and EMI/RFI.

If one power center isn't enough (monoblock amp draw, e.g.) then I would look to get another power center or an A/V grade power strip and plug it into the outlet without computers or motors on the circuit.

The advantage here is that you don't have to worry about phase leg anomalies (etc) because the power generators will scrub the power input.

But if rewiring is not an option due to cost, then my suggestion makes no economic sense because you can rewire for a lot less than the cost of one PS Audio Premier, let alone two.