Flickering LED Lights

[SpotOn]

I was at a job today and the customer complained of their LED lights flickering when the dishwasher was running. After running the washer for a few min there was a drastic drop in all of the LED's in the house as well as some flickering. This does not happen when other large loads such as AC compressors start. I checked the connections all the way back to the main and the main service itself everything appeared to be ok. Anyone have any thoughts on this?

 

[GoldDigger]

I was at a job today and the customer complained of their LED lights flickering when the dishwasher was running. After running the washer for a few min there was a drastic drop in all of the LED's in the house as well as some flickering. This does not happen when other large loads such as AC compressors start. I checked the connections all the way back to the main and the main service itself everything appeared to be ok. Anyone have any thoughts on this?

1. Did you try measuring the voltages at the boxes feeding the LEDs?
2. Are the LEDs on dimmers? They could be sensitive to transients on the power lines.
3. Is the dishwasher fed from an electric hot water heater? The voltage drop you are seeing could result from the heavy draw of an electric water heater rather than the dishwasher itself.
4. Some dishwashers have an electric hot water heating element which could also be a heavy power draw.
5. Does the dimming and flickering stop the moment you turn the dishwasher off?
6. Did you check neutral connections as well as hot wires?
7. Is the dishwasher hard wired or plugged into an outlet under the sink? If the latter, you can put a clamp-on ammeter on it (using a splitter adapter) or run it temporarily on an extension cord from another source.

 

[weressl]

I was at a job today and the customer complained of their LED lights flickering when the dishwasher was running. After running the washer for a few min there was a drastic drop in all of the LED's in the house as well as some flickering. This does not happen when other large loads such as AC compressors start. I checked the connections all the way back to the main and the main service itself everything appeared to be ok. Anyone have any thoughts on this?

Are they on a common LED driver or each is on line voltage with individual drivers?

 

[SpotOn]

1. Did you try measuring the voltages at the boxes feeding the LEDs?
2. Are the LEDs on dimmers? They could be sensitive to transients on the power lines.
3. Is the dishwasher fed from an electric hot water heater? The voltage drop you are seeing could result from the heavy draw of an electric water heater rather than the dishwasher itself.
4. Some dishwashers have an electric hot water heating element which could also be a heavy power draw.
5. Does the dimming and flickering stop the moment you turn the dishwasher off?
6. Did you check neutral connections as well as hot wires?
7. Is the dishwasher hard wired or plugged into an outlet under the sink? If the latter, you can put a clamp-on ammeter on it (using a splitter adapter) or run it temporarily on an extension cord from another source.

Thanks for the replies
1.The voltage was 120
2.They are on Lutron dimmers (cfl/LED)
3. The dishwasher is fed from a gas fired water heater
4. The Dishwasher Amp draw was a consistent 7 amps at the main panel. It has its own dedicated circuit
5. The flickering stops the second you turn it off.
6. Checked all conductors
7. It is plugged into an outlet

It was clearly the pump in the dishwasher causing the problem every time it cycled the lights would dim and flicker. The amp draw of the dishwasher didn't change by much however.

 

[SpotOn]

They are retrofit kits the homeowner put in

 

[weressl]

Thanks for the replies
1.The voltage was 120
2.They are on Lutron dimmers (cfl/LED)
3. The dishwasher is fed from a gas fired water heater
4. The Dishwasher Amp draw was a consistent 7 amps at the main panel. It has its own dedicated circuit
5. The flickering stops the second you turn it off.
6. Checked all conductors
7. It is plugged into an outlet

It was clearly the pump in the dishwasher causing the problem every time it cycled the lights would dim and flicker. The amp draw of the dishwasher didn't change by much however.

Bypass the Lutron to see if it solves the problem. (I seem to recall previous problems with Lutron LED dimmers.)

 

[ELA]

Is the flicker only momentary when the pump first turns on or constant as long as the pump is running?

If momentary at turn on:
Problems like this require a faster responding test instrument. Being able to take a closer look at what the line voltage/current is doing at the instant the pump turns on. Voltage may momentary drop too low for dimmers when inrush current is drawn.

If constant as long as pump is on:
Possibly EMI from pump/controls adversely affecting dimmers. Add an EMI filter to the offender.

 

[GoldDigger]

If constant as long as pump is on:
Possibly EMI from pump/controls adversely affecting dimmers. Add an EMI filter to the offender.

You should be able to find a series plugin filter module you can place between dishwasher cord and receptacle. But if some of the RFI is being radiated from the cord, you may have to add filter inside the dishwasher, or at least at the dishwasher end of the cord assembly.