The Dreaded "Short Circuit" Message On My P10

On Monday morning 3/15/21, I noticed my two channel stereo system’s LEDs were off when I walked through the living room at 11am. The P10’s outlet zone indicators were all red and there was a red “Short Circuit” message at the top of the display. The touch display was unresponsive when I tried to restart the outlet zones. The breaker panel on the rear of the unit is difficult to reach due to being partially blocked by a large monoblock amplifier. Unplugging/replugging the P10 allowed it to restart.

A review of PowerPlay data indicated that, at 9am, incoming THD jumped from the typical average 1% to close to 3.5% for the home theater P5 and to over 3.5% for the home theater and two channel P10s. All three regenerators also showed a voltage spike at 9am. Outgoing THD for all three regenerators is typically about 0.1%. At 9am, the two channel P10’s outgoing THD increased fro 0.1% to 0.2%.

The two channel system is served by three dedicated 20 amp AC circuits. Each 20 amp circuit is terminated with a PS Audio Soloist SE in-wall passive power conditioner. One dedicated 20 amp AC circuit feeds the P10. Both monoblock power amplifiers have their own dedicated 20 amp AC circuits.
The P10 in the two channel system only runs the preamplifier, digital source components, Ethernet switches and linear power supplies.

The P5 and the P10 in the home theater system are each served by a dedicated 20 amp AC circuit. Each 20 amp circuit is terminated with a PS Audio Soloist SE in-wall passive power conditioner.

The last time I saw a significant increase in incoming power line THD was in January 2009. The Power Plant Premier in use at that time showed incoming THD of 7.7%! Via emails to the power company, I was informed that the cause of the higher THD was the substation that normally feeds my neighborhood had been taken offline for maintenance. We were being served by a different substation in the interim. When we were switched back to our normal substation, THD levels went back to normal. I assume there is a similar reason for this recent occurrence of higher power line THD.

The 20 amp breaker that serves the two channel system P10 is the 15th breaker on leg 1 of the breaker panel. The 20 amp breakers that serve the left and right monoblock amplifiers are the 14th and 15th breakers of leg 2 of the breaker panel. The 20 amp breakers that serve the home theater P5 and P10 are the 16th and 17th breakers of leg 2 of the breaker panel.

Figure 1. Home theater P5 THD increase.

Figure 2. Home theater P5 voltage spike.

Figure 3. Home theater P10 THD increase.

004 HTP10 VoltageSpike 03-15-21
Figure 4. Home theater P10 voltage spike.

Figure 5. Two channel system P10 THD increase.

006 2CHP10 VoltageSpike 03-15-21
Figure 6.Two channel system P10 voltage spike.

007 OFFICEP10 THD Normal 03-15-21
Figure 7. Office system P10 THD. All functions normal. THD typically ranges from 2% - 2.5%.

Thank goodness you don’t live in the area served by the other substation. :scream:

I’ll try to clarify how the utility grid is generally designed. For redundancy and lower system losses, when practical, loops are built so customers can be supplied by more than one source (substation, etc). If a substation or main feeder has to be taken off line, the affected customer load is supplied via the backup loop (via breaker or line switch operations). However, it may mean a longer distribution line length, or loading a substation to a much higher percent (say from 50% to 80%), which means the voltage and THD delivered to the furthest customers will be adversely affected. Overall, the grid (lines and substations) in normal conditions should have plenty of extra capacity to allow for system disturbances due to a wide variety of reasons.
In my case, in a somewhat rural area with long distribution lines, the THD is normally 5 to 6.5% and the voltage changes significantly depending on the local system load (124 VAC at night, 119 VAC daytime).
During a recent storm with very high winds, the utility power was interrupted numerous times probably due to tree branches causing temporary short circuits. The outages were very short (less than a second) and my P12 locked out so all the connected A/V gear was shut off and the P12 indicated a short circuit. I shut off the P12 power overnight until the storm passed by. I’m grateful the P12 did it’s job protecting the rest of my A/V gear.
Based on your graphs, it does look like the utility had a major system issue, which are going to happen once a while. I don’t know where you live (I’m in Canada) but hopefully you have generally reliable electricity and see the value of well built electric grids.

1 Like

@MarADyr , I live in the United States. Power in my area is very reliable and stable. Incoming THD at my home used to average 2.5% prior to 2005. Power grid infrastructure improvements which began in late 2005 resulted in an average incoming THD in the range of 1% to 1.5%.

During the 2009 high THD incident, my area was switched to a farther away substation that served a primarily commercial and industrial area of the city. During that incident, the increased THD was audible as decreased clarity, detail, and diminished sound stage. I have not perceived a difference in sound quality during this higher incoming THD event.

Incoming power is back to normal now. Incoming THD is below 1.5%. Outgoing THD is 0.1%.

1 Like

Good news. Congratulations!