DIY Home Improvement Forum banner

Flickering lights on dimmers

6656 Views 8 Replies 5 Participants Last post by  dmxtothemax
I have added dimmer switches to two light circuits in my house since I have moved in. Previously, when these lights were on, the lights never dimmed much, if any when appliances started. After installing the dimmer switches, the lights really flicker and dim when anything starts or stops in the house. My wife and I sit there wondering what is starting and stopping all the time.

One circuit has track lights with LED bulbs in our office room. THe other circuit is a chandlier in or dining room with incandescant bulbs in it, so I am not thinking it's the lighting technology. They will lighten and dim when the oven cycles, which is not even a motor load. The oil burner, which is 120 volts and only pulls about 4 amperes according to the label, causes flickering are some of the many things that we see starting and stopping. Other circuits in the house don't really show the flickering much at all.

Is this just something of using dimmers, or is it a sign of inadequate power service that is only showing itself when the dimmers are dimmed down. The house has 100 ampere service and the main panel is original to the house when it was built in 1961. We are looking to upgrade this summer to a breaker box and 200 ampere service
1 - 9 of 9 Posts
Previously, when these lights were on, the lights never dimmed much, if any when appliances started.
So before you added the dimmers, the lights flickered occasionally?

What kind of dimmers did you add? Rotary, sliding or did you install electronic dimmers? Like Lutron Maestro?
It is most likely caused by the dimmers !
Some dimers are very suseptable to noise & spikes.
I would try some better quality dimers.
I have added dimmer switches to two light circuits in my house since I have moved in. Previously, when these lights were on, the lights never dimmed much, if any when appliances started. After installing the dimmer switches, the lights really flicker and dim when anything starts or stops in the house. My wife and I sit there wondering what is starting and stopping all the time.

One circuit has track lights with LED bulbs in our office room. THe other circuit is a chandlier in or dining room with incandescant bulbs in it, so I am not thinking it's the lighting technology. They will lighten and dim when the oven cycles, which is not even a motor load. The oil burner, which is 120 volts and only pulls about 4 amperes according to the label, causes flickering are some of the many things that we see starting and stopping. Other circuits in the house don't really show the flickering much at all.

Is this just something of using dimmers, or is it a sign of inadequate power service that is only showing itself when the dimmers are dimmed down. The house has 100 ampere service and the main panel is original to the house when it was built in 1961. We are looking to upgrade this summer to a breaker box and 200 ampere service

Power draw is too large. Lights dim when appliances are turned on, because not enough power is flowing through to run it all at once.

20amp breaker will only be able to draw as much wattage continuously as a 20amp circuit can. Have you tried/considered running your appliances off another circuit? (Install a new breaker and run the proper wiring to make an additional circuit)?
The light fixtures that were attached to the dimmers did not dim much, if any prior to installing the dimmers. In fact, the one in the dining room I remember only dimming with the air conditioner started up this summer. I am seeing dimming and flickering when appliances start that are NOT on the same circuit as the lights, and that's what has me concerned...Like the washing machine and the oil burner...both of which are on the same circuit

The dimmers that I am using are 3-way Lutron Skylark dimmers, sort of like the one in this link which is a single pole. I believe these are standard SCR semiconductor dimmers like have been made since the 60's:

http://www.amazon.com/gp/product/B0..._m=ATVPDKIKX0DER&pf_rd_r=1S55Y7BFP2X8T1TKTZXV
You could try putting a power filter on the power feed
to the dimmers !
Power draw is too large. Lights dim when appliances are turned on, because not enough power is flowing through to run it all at once.

20amp breaker will only be able to draw as much wattage continuously as a 20amp circuit can. Have you tried/considered running your appliances off another circuit? (Install a new breaker and run the proper wiring to make an additional circuit)?

This is simply not true. A circuit will normally continue to provide current well past a magnetic circuit breaker rating for a some time period. I have seen 20 amp circuit breakers with a 22 amp load for hours at a time. It'll do this until the thermal strip finally expands and trips the handle. So that is not the problem here. I also used to demonstrate to my classes that a #12 AWG wire will "handle" 60 amp current for almost ever without destruction. However, a wire's current rating has a safety factor built in and should [read shall] never be surpassed.

That said, I would remove the dimmers, re-install single pole switches, and see if the problem is rectified. If so, then your dimmers need to be upgraded. If not, then you probably have a connection problem somewhere.
av-geek - There are a couple of things you said that caused me to squirm. I've probably wired a hundred or more houses, townhouses and condos in the last 40 years (I work, primarily, commercial jobs). I've done numerous renovations on homes too. I have never had a call back because of circuiting issues. It's usually the product failing.

When I design the electrical on a house, I always put the following 120v loads on their own circuits:

  • Furnace
  • Dishwasher
  • Disposal
  • Microwave
In the kitchen, all receptacles are 20A rated, on a 20A circuit with 12ga wire and only three receptacles to a circuit. All 240v loads are on their own dedicated circuit, in the kitchen and elsewhere.

General circuitry has no more than 10-12 devices on a circuit and are on 15A circuits with 14ga wire. A device can be a can light, receptacle, wall sconce or ceiling light. If there is a light fixture with numerous bulbs in it, I add the total wattage, divide by voltage, to compute amperage. Roughly, for every amp, I count the load as one device.

You should know the loads on a given circuit.

Always separate motors from general loads (lights and receptacles).

When loading breakers, I take the amperage of the breaker and multiply by .8 and determine that as my maximum load on that breaker. 15A breaker = max load of 12A. 20A breaker = max load of 16A. And so on.

I built my house with these rules in 1986 and the only time I've had a breaker trip is when a device short-circuits (the original cooktop just did that and it's being replaced). I have never had an overload trip. Usually, lights dim when there's a dip at the power company end but lately some original rotary dimmers have shown signs of failing with flickering lights they control. They are being replaced with electronic dimmers.

Service calls I've made regarding dimmed lights have been caused by:

  • Landscapers nicked the underground feed to the house so every time it rained, some of the lights dimmed. Those lights were all on the same leg (side) of the panel as the nicked wire.
  • Neutral wires were improperly paired. Wiring should be done with no more than two circuits (hot wires) per neutral. Neutral wires coming from the panel should never be wired together.
  • The ground system was used for a neutral.
  • Loose terminations.
  • Imbalanced loads.
  • Failing switching devices.
  • Failing circuit breaker (rarely).
  • Poorly seated circuit breaker.
  • Power company issues.
There are probably other reasons but these are the ones that come to mind right now.

I'm telling you this because I can't look at your wiring and troubleshoot it. There are countless potential problems leading to your problem. But you stated you already had occasional dimming prior to the dimmer install. You also said your dishwasher and boiler are on the same circuit as some of your lighting. So the first thing I would do is take the dimmers back and install a different type. And I'd definitely separate the lighting and receptacles from all other loads, like the DW and boiler.

Since you plan on installing a new 200A panel, I would separate loads as described above and run the wiring back to the panel. When the new panel goes in, put them on their own breakers. It's not just load, it also makes servicing them easier.

Everyone has their own way of doing things. I'm sure some here will tell me mine is overkill, but everyone in my union local and surrounding locals all adhere to pretty much the same rules and things work just fine.

You can "get by" on less than I described. However you tackle this problem is up to you. But we have a saying here, "Short cuts lead to short circuits."
See less See more
It's probably really a two fold problem !
1 - some dimers are suseptable to spikes and surges !
2 - your power supply system is struggling,
but it could be your system and / or POCO's system
we all know poco usually run there systems well
past there safe operating area.

So addressing only one issue might help a little,
but in order to make your problems go away
completely, you will have to address BOTH issues.

I.E. upgrade electrical sysyem and use good quality dimers !
1 - 9 of 9 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top