Over loading?

My 5250 says - Current Capacity 45 amps peak per channel, x5.
The 2003 says - Current Capacity 60 amperes peak, per channel, x3.
Correction. 405 total.

Darn if it doesn't say 60 amps peak per channel. Somebody smarter than me will be along shortly but if it was an issue it would have a 30 amp plug. There are very few amps that require 30 amp service. I have had amps that will dim the lights with each beat of the music but I was very young back then and don’t do that stuff anymore.

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.  

Look at the wattage on the back of the unit. So long as you don't exceed a combined 1500 watts you are fine.

The watts on the input and output are more or less the same, however because P = Current x Voltage, when you change the voltage (downwards) the Current may go upwards. 

That instant current capacity is not drawn from the outlet but from storage capacitors in the power supply.

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

.

Never ever increase the size of a breaker unless you know the wiring from end to end supports it.

If a 15 A breaker is popping it is doing so for a reason.

It is however sometimes useful to exchange a breaker for the same size.  They don't last forever and a new one may fix your problem.

jea;  I never, tripped the breaker, just don't want to put a strain on my amps.  Like I wrote earlier, is that there’s 12/2 romex to a 15 amp rec. which is fine. I’m sure I can still change the breaker to 20 amps with 12/2, which should be code, & leave the 15 amp rec.. This is for my AV, I don’t think I use 1/4 of the max of power when watching a movie. Now when listening to music, sometimes I just jam. Different system. Thanks for you response!

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.

.

Seems odd to me that there is a 15 amp breaker on 12/2 wiring. I would check that the entire circuit is wired in 12/2. 

I (personally) ran 8/3 from my main, on a 60 amp breaker at a length of 20’ to my subpanel. Now, if the 12/2 from the subpanel to the outlets are nor more then 3’ per outlet x3. This is why I’m asking; I don’t want to harm my amps.

Mark, why is it weird, 12g wire is fine for 15 amps. When doing lighting, 14 is code, outlets get 12g. If you read the entire post, I wanted to segregate my tube amp & power conditioner, which now share a 15amp socket & breaker.

I've seen this before where a 15 circuit had a mix of 14 ga and 12 ga wiring. It was just a caution to you to check as a 20 amp breaker would not be a good idea in this case.

I grew up in NYC, & the stuff I've seen in my days, still give me the chills. :)

I guess I'll just leave it for now, in the event I trip the breaker then I'll change it, or add anther line. Thanks 

I just double checked my panel and it's 12awg on the breaker I changed to 20amps. Same wire is used for the kitchen which has 20amp breakers. I don't know what the run length is but it's closer to the panel than the kitchen...

Understood.

Some math and other things:
a) If the specification for your amplifier does not clearly state the AC peak current, take rated max. audio output power per channel, multiply by 3 (efficiency of Class A amplifier is ~30% - the worst case), and divide by 110V and you have your max. AC current.   Regrettably, most of audio gear is spectacularly short of specifications. For someone from the industrial world this drives me crazy, and each such gear gives me an impression of "touchy feely" design approach and "we have no idea what we are doing, and neither do our customers" message.  Will never fly for the factories.
b) You can approximate the length of the wire between the distribution panel and your outlet. Double this (for return current - don't forger that the power company gives you current, charges for it, and then takes all the current back - great business model) and use one of countless online voltage drop calculators such as https://www.prioritywire.com/calculator_voltage_drop.php Some calculators already take into account return current path, so don't double in this case
c) Don't neglect wire connections in all the hidden boxes in your house - twist-caps and all. Every such connection is a subject to eventual oxidation and adding resistance (and heating up along the way). I would add at least 1 Ohm for that just in case.
The most problematic voltage drop is dynamic, i.e. in response to current drain to drive your subwoofer ad perhaps mid-range (tweeters don't take much power comparatively speaking). Such dynamic voltage drop would add intermodulation distortion which adds sideband frequencies to what you though was double bass sound. To deal with this you would need sufficient "inertia" at the end of the long wires.   Tooting my own horn, our CleanSweep AC filters (https://www.onfilter.com/ac-emi-filters-af-series) provide just that.

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)
.

I stand corrected, the wire is #-6/3 into a 2 pole 60 breaker. Thanks for clearing that up.


jea48;
" 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)"
I don't remember, I'll look in the morning.