ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Top Posters(30 Days)
Trumpy 5
Recent Posts
Another generator question
by HotLine1. 09/23/17 10:58 AM
What do you do?
by gfretwell. 09/22/17 10:37 PM
Supporting conduit bodies
by ghost307. 09/18/17 12:12 PM
Thermal Imaging Camera upgrade
by Potseal. 09/18/17 11:57 AM
Linear Power Supply Quits Under Load
by JoeTestingEngr. 09/15/17 11:37 PM
New in the Gallery:
Gallery Test
Popular Topics(Views)
240,886 Are you busy
176,646 Re: Forum
168,551 Need opinion
Who's Online Now
0 registered members (), 66 guests, and 10 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate This Thread
Page 1 of 2 1 2
#193443 - 04/02/10 01:07 AM the lights flicker when OFF  
Niko  Offline
Member
Joined: Aug 2006
Posts: 356
Campbell, CA
client has 6 recessed cans with two three ways controlling them. He has the BR30 type fluorescent bulbs in each of the cans. The problem is when the switch is OFF the bulbs flicker.

Here is the items that i have checked in the device box. (No neutral available in the device box)
>Voltage to grounding with the lights ON 119V
>voltage to grounding with the lights OFF 23V
>The 23V disappears as soon as i connect a resistive load (obvious Phantom voltage)
>NO dimmer connected
> client has already replaced the switches with new ones.

The existing CFLs are about 1 year old so I asked the customer to change the bulbs with new CFLs and see if the flickering goes away.

What could be causing the flickering on the CFLs


Be kind to your neighbor, he knows where you live


Work Gear for Electricians and the Trades

#193444 - 04/02/10 02:35 AM Re: the lights flicker when OFF [Re: Niko]  
twh  Offline
Member
Joined: Mar 2004
Posts: 918
Regina, Sask.
I had that problem with a motion switch and a CFL.


#193446 - 04/02/10 07:53 AM Re: the lights flicker when OFF [Re: twh]  
Alan Belson  Offline
Member
Joined: Mar 2005
Posts: 1,803
Mayenne N. France
Programmable switches or dimmers can cause this, due to a very small leakage voltage triggering a capacitor somewhere in the bulb. Any 'leakage', [say a track on switch insulation] can cause this too- it can be so small as to be unnoticed when using filament bulbs. Since it is a 'load' it will not trigger an RCD or GFCI. Some CFLs also glow dimly for a short while when turned off. IMHO, not worth worrying about.

Last edited by Alan Belson; 04/02/10 07:54 AM. Reason: syntax

Wood work but can't!

#193451 - 04/02/10 08:10 PM Re: the lights flicker when OFF [Re: Alan Belson]  
Tesla  Offline
Member
Joined: Jun 2004
Posts: 1,273
Sacramento, CA
Consider running a snubbing resistor in the circuit. Select a resistance high enough to do the job without drawing significant power... say 10kOhms.

If you really HAVE to.


Tesla

#193454 - 04/02/10 09:52 PM Re: the lights flicker when OFF [Re: Tesla]  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,116
Estero,Fl,usa
Replace one of the bulbs with an incandescent.


Greg Fretwell

#193455 - 04/03/10 01:46 AM Re: the lights flicker when OFF [Re: gfretwell]  
bigrockk  Offline
Member
Joined: Jan 2003
Posts: 174
Middle of Canada
Switches with the lighted handles can cause this as well.


#193492 - 04/05/10 09:59 AM Re: the lights flicker when OFF [Re: bigrockk]  
harold endean  Offline
Member
Joined: Feb 2002
Posts: 2,233
Boonton, NJ
Just a shot in the dark, but is this an old house where the hot and neutral wires might be reversed?


#193496 - 04/05/10 01:17 PM Re: the lights flicker when OFF [Re: harold endean]  
Niko  Offline
Member
Joined: Aug 2006
Posts: 356
Campbell, CA
Thank you for your replies.

The switches are not lighted and the wiring to that part of the house is new.
one of my colleagues suggested a shared neutral with another circuit or a minor short between the ungrounded conductors with another circuit.

I will go back out on Thursday to troubleshoot.


Be kind to your neighbor, he knows where you live


#193497 - 04/05/10 04:50 PM Re: the lights flicker when OFF [Re: Niko]  
Trick440  Offline
Member
Joined: Aug 2005
Posts: 248
Waterford, MI, USA
I see this regularly on my ghetto houses. Usually I find voltage from neutral to ground. Other devices on that circuit might have the same problem. The pain in the butt ones get run a new neutral.


Shake n Bake

#193519 - 04/06/10 01:16 PM Re: the lights flicker when OFF [Re: Trick440]  
geoff in UK  Offline
Member
Joined: Dec 2002
Posts: 184
UK
I've seen this problem with LED (GU10) lamps, but perhaps it could happen with CFLs too.
Found that capacitive coupling between the cores of (fairly long) switch runs, used for multi position switching, was the cause.
The fix was a small capacitor accross the first lamp in the chain. If I remember correctly a 0.1 microfarad, as used for interference suppression, did the trick. Obviously needs to be rated to be accross supply voltage.


Page 1 of 2 1 2

Member Spotlight
Alan Belson
Alan Belson
Mayenne N. France
Posts: 1,803
Joined: March 2005
Show All Member Profiles 
Featured:

2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Shout Box
Powered by UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.028s Queries: 16 (0.007s) Memory: 0.8183 MB (Peak: 0.9996 MB) Zlib enabled. Server Time: 2017-09-23 18:04:48 UTC