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Negative Pf residential Home

Jraef

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
winnie said:
LED lights require a driver to provide the constant current that the LED junctions require. These drivers do a fantastic job of isolating the light output from voltage variations...with the downside that this makes the LED not dimmable.

Most modern LED lights have an additional circuit to detect dimming and adjust the LED driver current.

This makes different brands of LED sensitive to different electrical noises, anything that triggers the dimming circuitry.

I'm wondering if there is some load that is causing current spikes right near the AC zero cross, confusing the power factor measurement and messing with the LED dimming.

Jon
Click to expand...
I really think it comes back to this issue. The dimmable LEDs (even if not on dimmers) are reacting to something in the system, maybe not even in this house. My first suspicion though would be modern new appliances with inverter drives in them causing harmonic distortion or EMI/RFI that the LEDs are reacting to.

I installed LEDs in my house years ago, had a few issues with ceiling fans at first, but everything eventually worked out and was great for years. Put in some dimmable LED lamps in a few places, everything still fine. Bought all new kitchen appliances last year; the microwave, dishwasher and fridge are all inverter types, now all the dimmable LEDs are unsteady. Replaced them with non-dimmable LED bulbs, the problem went away. Some day soon I plan on experimenting with ferrite cores to see if that helps, if not then trying different brands of dimmable LEDs. But the truth is, we don't really dim the lights any more, at our age I need MORE light, not less, so it's not high on my honeydo priority list...
 
R

Rock86

Senior Member
Location
new york
Occupation
Electrical Engineer / Electrician
UPDATE REPORT.
Current on the neutral remains higher than required to balance the line sets. Eco-light bulbs remain to flicker while GE bulbs seem to not flicker. The refrigerator shut off randomly in the morning with no other major loads running (This apparently has been a problem as well. All new appliances.)

Jraef - No dimmers are in the house.
 
synchro

synchro

Senior Member
Location
Chicago, IL
Occupation
EE
I agree with others that the neutral current from the service needs to be measured with the main breaker off.
If that doesn't show significant current, then if you can do it put a clamp-meter around all service conductors (L1, L2, N) and see what you get. Even with a 208/120V service that current measurement should be quite small.
 
R

Rock86

Senior Member
Location
new york
Occupation
Electrical Engineer / Electrician
synchro said:
I agree with others that the neutral current from the service needs to be measured with the main breaker off.
If that doesn't show significant current, then if you can do it put a clamp-meter around all service conductors (L1, L2, N) and see what you get. Even with a 208/120V service that current measurement should be quite small.
Click to expand...
Still have not heard back from the utility company after they had installed their measuring device onto the meter. That was a couple of weeks ago now. They are not returning phone calls either.
 
Jpflex

Jpflex

Electrician big leagues
Location
Victorville
Occupation
Electrician commercial and residential
Rock86 said:
It’s a residential single family. The utility company had to 6 people on a transformer when he moved in, and then changed it to 2 homes on one pot.
Click to expand...
Some may argue that two homes on one pot is better than 6 homes sharing pot, but I don’t smoke!
 
G

GoldDigger

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Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Rock86 said:
UPDATE REPORT.
Current on the neutral remains higher than required to balance the line sets. Eco-light bulbs remain to flicker while GE bulbs seem to not flicker. The refrigerator shut off randomly in the morning with no other major loads running (This apparently has been a problem as well. All new appliances.)

Jraef - No dimmers are in the house.
Click to expand...
No dimmers necessary. Basic LED bulb can look like a regulated power supply, trying to maintain light output through variations in input voltage. In order to override that, dimmable bulbs are designed (in different ways) to react to abnormal (low voltage, partial phase conduction, etc/) input by reducing the light output. If the voltage waveform is sufficiently noisy or non-sinusoidal it can fool the bulb into reducing output.
 
Jraef

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
GoldDigger said:
No dimmers necessary. Basic LED bulb can look like a regulated power supply, trying to maintain light output through variations in input voltage. In order to override that, dimmable bulbs are designed (in different ways) to react to abnormal (low voltage, partial phase conduction, etc/) input by reducing the light output. If the voltage waveform is sufficiently noisy or non-sinusoidal it can fool the bulb into reducing output.
Click to expand...
Yep, that's what I meant.
 
R

Rock86

Senior Member
Location
new york
Occupation
Electrical Engineer / Electrician
UPDATE:
The owner had AC issues. HVAC guy told him the line and neutral were crossed and it was causing issues on the electronics. Original electrician came and said nothing was wrong. HVAC guy brought in a different electrician and found more than one crossed neutral.

Utility company has responded and will come out to conduct a more thorough test.

refrigerator and freezer (separate circuits from separate panels) shut off around 5:30-6:00am, lights flicker regardless of bulb type and brand now. I guess the GE ones didn't hold up as well as he thought. Dimmable or not, doesn't make a difference in the house.
 
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