Over loading?

Guys don’t forget to figure branch circuit wiring VD (Voltage Drop).

Example:
For a 60ft branch circuit using #14awg cu wire during short peaks of 12 amps current draw.

Voltage drop: 3.85
Voltage drop percentage: 3.21%
Voltage at the end: 116.15

15 amps.

Voltage drop: 4.81
Voltage drop percentage: 4.01%
Voltage at the end: 115.19

https://www.calculator.net/voltage-drop-calculator.html?necmaterial=copper&necwiresize=0&nec...

FWIW a 15 amp breaker will pass short quick draws of current well over the 15 amp handle rating all day long with out tripping. VD will be proportional to the length of the branch circuit wiring and the higher current draw on the circuit.

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fiesta75632 posts

08-16-2021
12:01am

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...

@ fiesta75

What is the branch circuit wiring size? If it’s #14awg cu the breaker, per electrical safety code, can not be larger than 15 amp. Solution is to install a 15 amp HM (High Magnetic) breaker. An HM breaker has a longer lag time for turn on high inrush current.

Here are three examples, of manufacturers HM breakers.
https://www.homedepot.com/p/Square-D-QO-15-Amp-High-Magnetic-Single-Pole-Circuit-Breaker-QO115HM/303...

https://www.widespreadsales.com/Products/Circuit-Breakers-Siemens/Q115HM

https://www.eaton.com/us/en-us/skuPage.BR115H.specifications.html

CH-HM Breakers

CH-HM breakers are designed with
high magnetic trip settings. Single-
and 2-pole CH-HM breakers (“HM”
suffix) rated 15 and 20 amperes are
recommended for circuits with
inherently high inrush currents.

https://bse-assets.azureedge.net/ISSheet_117983.pdf

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danmar123 OP54 posts

08-16-2021
9:22am

I (personally) ran 8/3 from my main, on a 60 amp breaker

@danmar123

#8 awg cu wire is rated for 40 amps (60* C). Breaker should be 2 pole 40 amp.

This is why I’m asking; I don’t want to harm my amps.

No harm. No VD on subpanel feeder or branch circuit wiring.
I assume the two amplifiers are fed from each Line, leg, to neutral.
Only the unbalanced load returns on the feeder neutral conductor to the source.

Subpanel EGC (Equipment Grounding Conductor) shall be part of the feeder wiring connected to the equipment ground bar in the main electrical panel. Feeder EGC connected to a separate ground bar bolted, bonded, to the metal enclosure of the subpanel.

Neutral bar in subpanel left insulated from the metal panel enclosure.
(Green color main bonding jumper screw not installed)
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