neighbors Air Conditioner making lights flicker

[Alexagyagos]

I have a customer complain to me that every time the neighbors Air Conditioner kicks on it making her lights flicker. I haven't been out there yet to tighten/check connections, but SDG&E deployed something at her house for about a week then removed and didn't tell her anything.
Anybody have a similar issue?

 

[petersonra]

I have a customer complain to me that every time the neighbors Air Conditioner kicks on it making her lights flicker. I haven't been out there yet to tighten/check connections, but SDG&E deployed something at her house for about a week then removed and didn't tell her anything.
Anybody have a similar issue?

if it is a VD issue I don't see how tightening her connections is going to help any. in any case, it is not the greatest idea to be tightening up connections that were properly torqued in the first place.

maybe they are on the same utility xfmr that might be a little undersized.

she may just have to live with it unless she is will to spend some money to get it fixed.

I am kind of curious how she knows that it is the neighbor's A/C kicking in that causes her lights to flicker.

 

[Little Bill]

if it is a VD issue I don't see how tightening her connections is going to help any. in any case, it is not the greatest idea to be tightening up connections that were properly torqued in the first place.

maybe they are on the same utility xfmr that might be a little undersized.

she may just have to live with it unless she is will to spend some money to get it fixed.

I am kind of curious how she knows that it is the neighbor's A/C kicking in that causes her lights to flicker.

I have the same curiosity!

 

[Frank DuVal]

By hearing the compressor kick on..... I presume. I can hear the neighbors compressor kick on, and they are >500 feet from my house!

 

[petersonra]

By hearing the compressor kick on..... I presume. I can hear the neighbors compressor kick on, and they are >500 feet from my house!

My neighbor's compressor is pretty close. I don't hear it unless I am outside.

 

[ramsy]

I have a customer complain to me that every time the neighbors Air Conditioner kicks on it making her lights flicker..
Anybody have a similar issue?

Yes, common issue in residential - especially when few transformers serve the area, or your neighbor's HVAC contractor got a commercial 40A+ unit installed for their residence.

 

[Todd0x1]

I wonder if they thing the utility deployed was one of those "lost a wire autotransformer box" things. That would double the inrush current on one phase. Did the problem only happen while the utility device was there or is it still happening? Perhaps a hard start kit on the neighbor's AC would help.

 

[OldSparks]

The same thing happens here. I am in a rural area, only me and my neighbor are on the pole-mounted transformer. He's got a four or five ton unit and it briefly dims my lights when it starts. It' an older unit, nothing "soft start" about it. Been consistent for twelve years, does not concern me on bit.

 

[gar]

221003-1745 EDT

Every time this question comes up I make new measurements. I have a 50 kVA pole transformer followed by about 60 ft of wimpy wires.

At the input to my main panel I made a voltage drop measurement. Thus, the energy meter is part of this impedance.

For a 12 A resistive load at about 122 V my change in voltage at the main panel input terminals was 0.9 V. Thus, 120 V source loop impedance is about 0.9/12 = 0.075 ohms. Assume the air conditioner pulls 200 A starting current at 240 V, then I can assume a change of about 0.0375 * 200 V in a 120 V circuit, or about 7.5 V. This will be easily seen as flicker in a typical incandescent or LED bulb.

.

 

[ptonsparky]

By hearing the compressor kick on..... I presume. I can hear the neighbors compressor kick on, and they are >500 feet from my house!

Bragging or is it that dang noisy?

 

[JohnE]

if it is a VD issue I don't see how tightening her connections is going to help any. in any case, it is not the greatest idea to be tightening up connections that were properly torqued in the first place.

maybe they are on the same utility xfmr that might be a little undersized.

she may just have to live with it unless she is will to spend some money to get it fixed.

I am kind of curious how she knows that it is the neighbor's A/C kicking in that causes her lights to flicker.

OP did say he would check/ tighten the connections. He didn't say he would blindly tighten them.

 

[Todd0x1]

I wonder if you could connect a high wattage resistive load switched on for a couple seconds with voltage sense and time delay relays, so when their AC tries to start you draw 20kw too, preventing their AC from starting then maybe they would have it fixed.

 

[ptonsparky]

I wonder if you could connect a high wattage resistive load switched on for a couple seconds with voltage sense and time delay relays, so when their AC tries to start you draw 20kw too, preventing their AC from starting then maybe they would have it fixed.

It works fine as far as I can tell. My lights don't blink.

 

[ggunn]

It seems to me that what you are describing is a momentary dimming of lighting due to lowered voltage because of voltage drop when high current is demanded. "Flicker" means something different to me - more like a rapid binary (on and off) of lights - which would be (to me) more worrisome.

 

[kwired]

I wonder if they thing the utility deployed was one of those "lost a wire autotransformer box" things. That would double the inrush current on one phase. Did the problem only happen while the utility device was there or is it still happening? Perhaps a hard start kit on the neighbor's AC would help.

If they put something on for few days then removed it, my first presumption would be recording equipment.

Hard start kit might very well make the VD worse, though maybe for lesser duration.

 

[__dan]

I have a customer complain to me that every time the neighbors Air Conditioner kicks on it making her lights flicker. I haven't been out there yet to tighten/check connections, but SDG&E deployed something at her house for about a week then removed and didn't tell her anything.
Anybody have a similar issue?

A/C compressor LRA will do that. Sorry did not read the thread if it's been covered

If it persists longer than two seconds or so, neighbor should call an electrician.

 

[motormuff]

sounds like the utility company may need to increase their transformer size.

 

[kwired]

sounds like the utility company may need to increase their transformer size.

Or either increase secondary conductor size or shorten it in some way.

 

[Hv&Lv]

I wonder if they thing the utility deployed was one of those "lost a wire autotransformer box" things. That would double the inrush current on one phase. Did the problem only happen while the utility device was there or is it still happening? Perhaps a hard start kit on the neighbor's AC would help.

“Service saver”
There are a couple of different companies that make them Under different names

 

[Frank DuVal]

By hearing the compressor kick on..... I presume. I can hear the neighbors compressor kick on, and they are >500 feet from my house!

Bragging or is it that dang noisy?

It is a noisy unit, noisier then mine, but also quiet out here except for gun fire, as the street is further than the neighbors. Certainly not bragging about my hearing anymore!