Author Topic: Flickering lights...  (Read 1033 times)

BlueMR2

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Flickering lights...
« on: March 20, 2017, 10:03:01 AM »
I've got a circuit that the lights flicker on in certain circumstances.  It's a 3-way circuit (2 switches).  Off is perfectly fine (in both configurations of "off").  It also works fine when the lights are on due to both switches being "up".  However, the on position that results from both switches "down" has the lights flickering pretty bad.

I've already checked the connections and everything is tight.  What's my next step?  Replace the switches?  Or is there a wiring test I should be doing?

Butterfingers

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Re: Flickering lights...
« Reply #1 on: March 20, 2017, 10:05:52 AM »
What kind of bulbs are you using? I had this problem with CFLs activating with the small current leakage replacing with LED bulbs fixed it.

Spork

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Re: Flickering lights...
« Reply #2 on: March 20, 2017, 02:29:41 PM »
Is it at all possible one of the hot wires in the 3 conductor is nicked?  Or one of the twists is loose?

You might even be able to discern "which one"... if "both switches up" works, that should eliminate one of the paths.

edit: "hot wire", not "not wire"

edit again: 
One other thought is that one of the 3way switches is bad.  You should be able to eliminate them one at a time with a wire nut being "on".  If it were me, I'd have to draw out the circuit ahead of time and identify every wire as to know which ones to twist together -- and how to put them back where they came from.
« Last Edit: March 20, 2017, 02:34:40 PM by Spork »
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bender

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Re: Flickering lights...
« Reply #3 on: March 20, 2017, 03:03:04 PM »
I'm confused at your statement about the on/off positions.  Shouldn't it work like this?

Switch A, Switch B
0, 0 - both switches OFF - lights OFF
0, 1 - only switchB ON - Lights ON
1, 0 - only switchA ON - Lights ON
1, 1 - Both switches ON - Lights OFF

If it doesn't work like this, it could be wired incorrectly (or at least in a way that doesn't make sense to most people).  You stated that lights are on when both switches are up and flickers when both switches down.

dandarc

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bender

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Re: Flickering lights...
« Reply #5 on: March 20, 2017, 03:30:29 PM »
Yikes! I've never seen one like that except for electronic (like z-wave/zigbee) switches. 

It's not clear from the post that's the switch - maybe you have more info.  I thought it was a simple 3 way switch, where each switch has only 2 positions.

Spork

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Re: Flickering lights...
« Reply #6 on: March 20, 2017, 03:42:09 PM »
Yikes! I've never seen one like that except for electronic (like z-wave/zigbee) switches. 

It's not clear from the post that's the switch - maybe you have more info.  I thought it was a simple 3 way switch, where each switch has only 2 positions.

I thought it was a simple set of 3 way switches, too.  I presumed "both off positions" meant "both up" and "both down".  (This presumes the switches are installed consistently.  Flip one of them over and you have 2 different sets of "off positions.")
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paddedhat

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Re: Flickering lights...
« Reply #7 on: March 20, 2017, 06:55:38 PM »
My though is that one of the switched is failing. Some times it's actually possible to hear a very slight hum or crackle out of a 120v switch that's about to fail completely. Heat is another indicator, any you may be able to feel that one of the faceplates is noticeably warm. I would replace both of them, they are not expensive, or difficult to install, and it's a solid way to eliminate a source of the issue.

ShoulderThingThatGoesUp

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Re: Flickering lights...
« Reply #8 on: March 21, 2017, 05:00:34 AM »
Padded hat is the expert, but if the problem "spreads" consider your meter base as the issue. My circuits got worse and worse until I got it replaced.

paddedhat

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Re: Flickering lights...
« Reply #9 on: March 21, 2017, 07:24:43 AM »
Yikes! I've never seen one like that except for electronic (like z-wave/zigbee) switches. 

It's not clear from the post that's the switch - maybe you have more info.  I thought it was a simple 3 way switch, where each switch has only 2 positions.

I thought it was a simple set of 3 way switches, too.  I presumed "both off positions" meant "both up" and "both down".  (This presumes the switches are installed consistently.  Flip one of them over and you have 2 different sets of "off positions.")

For many folks, switch positions, and the concept of on and off, only lead to more confusion when dealing with the workings behind three way switching. The easiest way to think of it may be this.  You are sending water from the house,  through a garden hose, to fill a pool. You decide that you need two parallel hoses running to the pool, but only want to run water through one at a time. You then need a "Y" valve at each end of the parallel hoses so that you can direct the water from one hose to the other.  You open the Y valve at the house to send the water through hose "A". It flows to the Y valve at the pool and stops, since that valve is open to hose "B". No worries,  you just stay where you are,  move the house valve to hose B, and the pool starts to fill.  You walk to the pool and want to shut the water off, so you move the valve to hose A, and it's off.

So, inquiring minds ask the question,  how is this better than having a single hose with a simple valve at each end? Well, you can now stop and start water flow from each end of the hoses. If you had a single hose set-up, you would often need to walk to the other end of the hose to turn it on, since that's the end that was turned off last.

Electricity works in a somewhat similar manner. If you substitute  the hose with a current carrying wire, and the Y valve with a three way switch, you (hopefully) get the concept of three way switching. If you're still confused, don't take it personally. I have spent hours scribbling on scrap cardboard, with a sharpie, while explaining the concept to literally dozens and dozens of people. Everybody from other curious workers on construction sites, to (sadly) more than a few electricians.

Fishindude

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Re: Flickering lights...
« Reply #10 on: March 21, 2017, 07:44:59 AM »
Good advice by Paddlehat, my thoughts also.
Switch is bad or a connection is loose.  Switches are cheap.

dandarc

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Re: Flickering lights...
« Reply #11 on: March 21, 2017, 09:23:10 AM »
Yikes! I've never seen one like that except for electronic (like z-wave/zigbee) switches. 

It's not clear from the post that's the switch - maybe you have more info.  I thought it was a simple 3 way switch, where each switch has only 2 positions.
I was probably wrong about using 2 3-position switches.  Should have said "maybe" on that.
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BlueMR2

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Re: Flickering lights...
« Reply #12 on: March 21, 2017, 09:57:37 AM »
What kind of bulbs are you using? I had this problem with CFLs activating with the small current leakage replacing with LED bulbs fixed it.

Incandescent.  Fixture is only used rarely, haven't bothered to replace them yet.

BlueMR2

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Re: Flickering lights...
« Reply #13 on: March 21, 2017, 09:58:26 AM »
Is it at all possible one of the hot wires in the 3 conductor is nicked?  Or one of the twists is loose?

If so, I've been unable to identify it.  I inspected the wiring in the box pretty thoroughly and could find nothing wrong.

BlueMR2

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Re: Flickering lights...
« Reply #14 on: March 21, 2017, 10:00:43 AM »
It's not clear from the post that's the switch - maybe you have more info.  I thought it was a simple 3 way switch, where each switch has only 2 positions.

It is the simple 3-way configuration, with only 2 positions per switch.  And both lights on positions happen to be when the switches are in sync.  When they're opposite each other the lights are off .  Could be one was just installed upside down or something originally to make it different from what is expected.  Nothing fancy here, basic switches and wiring!  :-)

BlueMR2

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Re: Flickering lights...
« Reply #15 on: April 01, 2017, 05:38:32 PM »
Bought 2 3-way switches, went to install them and ran into some non-standard wiring...

Electrician friend stopped by and helped me out.  We first pulled the oldest looking switch, he tested and isolated which wire went where and we tested the switch to see what all the various unmarked but very important connections did.  Installed that one and problem solved.  He didn't want to mess with working, so left the other old switch (but still much newer looking than the antique that we replaced) in place and I have a spare new 3-way switch in my electrical stuff drawer now.

paddedhat

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Re: Flickering lights...
« Reply #16 on: April 01, 2017, 08:32:06 PM »
Good job. They really aren't too mysterious, and pretty easy to swap out. The key that there are three wires attached to the switch and one  must be removed from the odd colored screw, and installed on the same odd colored screw on the new switch. In modern three ways, typically the odd screw is brown and the other two are brass color. Once you relocate the wire to the odd screw on the new switch, it doesn't matter how the other two are installed, as there is no polarity, or wrong way to do these two. To identify your odd wire, just put a small piece of tape around it before you remove it from the old switch.

Spork

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Re: Flickering lights...
« Reply #17 on: April 02, 2017, 09:53:12 AM »
Bought 2 3-way switches, went to install them and ran into some non-standard wiring...


Can I guess? 

Neutral wire came from a different circuit and freaked you out.  You thought the circuit was turned off... but when you pulled the neutral, lights elsewhere started to flicker.

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BlueMR2

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Re: Flickering lights...
« Reply #18 on: April 04, 2017, 10:00:15 AM »
Colors didn't match...  I was expecting it to be one black and two white wires based on the reference I had, but it was the other way around.  Combined with the fact that neither switch was marked (1 had all 3 brass screws, the other as a push-in type) I decided to call for backup before I did cause lights to flicker elsewhere.  :-)