New house and phantom load from arc-fault circuits

adkroot

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Hello,
New here and not certain this is the correct forum for this question. I just wired the new house I've built next door to my cabin and am experiencing a .3 amp draw, I believe, from the arc-fault circuits. It's enough to hold the inverter when there's otherwise no ac draw.

In my current cabin, which is considerably smaller, I only have a few outlets that are on a ground-fault circuit, and they don't hold the inverter, but I'm assuming that, because of the new electrical code and all the arc-fault circuits in amuch bigger house they're all combining to add up to enough draw to kepp the inverter humming.

Anybody have experience with arc-fault circuits and their draw?
Thanks, Daniel
 

svetz

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What do you mean by "hold the inverter"? As far as I know, a breaker with arc-fault detection has no phantom load (but I'm not an expert).

Where are you measuring the .3 amps? If it's at 240V that's 72 watts, sounds more like clocks, wal-warts, and of course the inverter's own consumption.
 

RCinFLA

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I would not expect more then 10 mA of average drain from arc fault breaker.

Arc fault has more electronics then GFI's. It is looking for high frequency current indicative of sparking connections.

I hate them as motors with brushes like a vacuum cleaner, or electric drill can trip them, also ham radio transmitters, but they are a valuable safety feature.
 

adkroot

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Thanks for the replies. By hold the inverter I'm referring to keeping it from going into its "sleep" or "search" mode. I have no ac loads drawing power, so my inverter typically is in sleep/search mode. In the new house there's nothing but wiring and outlets - no furnace, doorbell, appliances of any kind - and no tools are plugges in, so the arc fault circuits are the only thing that's drawing power, and apparently enough to keep the inverver producing ac.

I'm measuring the .3amp draw at my Trimetric wall meter.
 

RCinFLA

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The low voltage electronics is powered by a series capacitor to provide the voltage drop.

17 mA on 120vac 60Hz would be about 0.39 uF series cap.

The power factor for their 120vac loading is very low, almost a pure capacitive load. You see current when measuring but actual real power is low.

With enough of them in a breaker panel I can see where they might wake up an inverter sleep mode. Not really anything you can do about it other than raise the inverter sleep trip power level. Again, it is the current sensing by the inverter that is trippng out of sleep mode, not actual real power.

The inverter active idle power consumption will be hundred times more battery power then real power of all the AFI's together. The AC load impedance for each AFI is similar to a typical LED night light.
 
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adkroot

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Someone measured 17 mA for an AFCI:


Do you have 20 of them?

Any transformers, like for a furnace or doorbell?

Anything plugged in but turned off?
There's 7 afci circuits, along with several separate gfci outlets that are on standard circuits.

No transformers and nothing plugged in.
 

RCinFLA

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From an inverter point of view, the capacitors in the PWM output filter may have more shunt capacitance then all the AFI's together, but the sleep mode current sensing is done after the PWM filter.

It might be possible to put shunt inductors on L1 and L2 phase to neutral connection to power factor correct for the AFI's capacitance but the initial surge when inverter wakes up to sniff the breeze for loads may still be enough to trip out of sleep mode. In normal inverter run mode, the inductors will likely have more real power loss then all the AFI's.

Raising the sleep mode trip setting is only real way to solve it. Your concern is the idle power of non-sleeping inverter, not the power consumed by AFI's.
 
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svetz

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..I have no ac loads drawing power, so my inverter typically is in sleep/search mode. In the new house there's nothing but wiring and outlets - no furnace, doorbell, appliances of any kind
An easy way to test the "no loads" theory is to turn off the breakers. If it goes into sleep mode after turning one off you'll know.
I'd start by turning off all the AFCI breakers and see if that confirms it or not. 7 breakers even at at 20 mA should only be .14 amps.

If the inverter still doesn't enter sleep mode I'd turn them all off and make sure the inverter does enter sleep mode (possibly am inappropriate setting?)
 
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