Installing Tandem Breakers

Reply

  #1  
Old 02-08-08, 04:47 AM
Member
Thread Starter
Join Date: Feb 2008
Location: buffalo ny
Posts: 18
Received 0 Votes on 0 Posts
Installing Tandem Breakers

hello,,,,I am new to this forum.I have done some remodeling, and have run 7 new 14 g lines to 15 amp tandem breakers. I have a 200 amp service, and had 6 open spots on panel. I moved some of the other breakers, so that I could put all these new breakers together. These circuits are for overhead lighting, and outlets. The problem I am having is, when turning on lights, every once in a while I get a flicker in the lights. The overhead lights are 6" can lights. All of the light circuits are doing this. The breakers are cutler hammer, and are matched to what I have in there already. Should I have split the breakers up to randemly place them on circuit panel? Is there a special way to placing tandem breakers in panel. I have checked, and rechecked all connections, and everything is perfect. Grounds, and neutrals are connected to the neutral bar. Thanks for your info............
 
Sponsored Links
  #2  
Old 02-08-08, 04:56 AM
Banned. Rule And/Or Policy Violation
Join Date: Dec 2007
Location: Chicago
Posts: 1,011
Received 0 Votes on 0 Posts
Are there any multi-wire circuits (two black or red, or a red and a black) sharing a neutral (white) wire?
 
  #3  
Old 02-08-08, 07:02 AM
Member
Join Date: Sep 2000
Location: United States
Posts: 18,497
Received 0 Votes on 0 Posts
kskier, the answer to all of your questions is "no".

Can you more precisely describe "flicker"? What is the duration of the flicker, and does it get dimmer or brighter when it flickers. How many flickers do you get?

You mention that it occurs "when turning on lights". Can you more precisely describe that too? Does it only occur in the first few seconds after you turn a light on? Does the flicker occur only in the light you turned on?

Can you also more precisely describe "every once in a while"? Can you establish any pattern to the flicker? Does it occur when any other even happens? Does it seem completely random?
 
  #4  
Old 02-08-08, 08:10 AM
Banned. Rule And/Or Policy Violation
Join Date: Dec 2007
Location: Chicago
Posts: 1,011
Received 0 Votes on 0 Posts
Originally Posted by kskier View Post
Should I have split the breakers up to randomly place them on circuit panel? Is there a special way to placing tandem breakers in panel.
For Starters:

- A standard electrical panel is constructed such that the circuit breakers on either side (left or right) of the panel are on alternating legs (phases) of a 240V circuit – any two vertically adjacent full size single pole breakers will be on opposite phases.

- When you have a Multiwire circuit - two ungrounded (hot) conductors sharing a common grounded (neutral) conductor - the hot conductors must be on opposite phases.

- Because of the "crossover" of the bus bars in a standard panelboard, if you power a 120V multiwire circuit off a standard two-pole breaker taking up two breaker positions, the two 120V hot conductors are "automatically" powered from opposite phases of the 240V circuit.


From http://www.ecmweb.com/nec/704ecm%20CBfig3.jpg

- However two tandem circuit breakers in a given single pole breaker position will be on the same phase.

- Therefore, you cannot use to two tandem breakers in the same slot (or any breaker position which places then on the same phase) to power such a circuit.

Various kinds of problems can then result, which is why I asked if you have multi-wire circuits

A few other rules about tandem breakers:

– They must be listed for the panelboard and used and installed per the manufacturer's instructions and minimum code requirements. The panelboard will be marked to indicate the acceptable use and installation of these circuit breakers, ex: of “8-16 circuit” means any combination of eight twin circuit breakers or sixteen full size circuit breakers

- The panelboard and/or circuit breaker may have a mechanical feature to limit the use and installation of twin circuit breakers to specific panelboards or breaker positions – don’t try to force them in.

- From a Code standpoint, prior to 2008 NEC 408.15 limited the number of overcurrent devices on a lighting and appliance panelboard to 42.

For these and a lot of other reasons many AHJs restrict or prohibit the use of tandem breakers.
 
  #5  
Old 02-09-08, 04:02 AM
Member
Thread Starter
Join Date: Feb 2008
Location: buffalo ny
Posts: 18
Received 0 Votes on 0 Posts
I have no multi-wire circuits being attached to these breakers. I found the source of the flicker,,,,,,,,,I have an old boiler system, and every time the pump kicks on, it would flicker a very small amount. Thanks for the info arranging the tandem breakers on the panel. I was also told at the local electric supply store that there could be a problem if you arrange to many tandem breakers all in one location on the buss, that if any of those incoming lines are drawing alot of amps, it could create a hot spot on the buss. I don't how true that is....thanks
 
  #6  
Old 02-09-08, 11:15 AM
Member
Thread Starter
Join Date: Feb 2008
Location: buffalo ny
Posts: 18
Received 0 Votes on 0 Posts
Well,,,again I am stumped. I thought I had problem fixed,,,,,but after rechecking all wiring to all 3 way switches, all wiring into panel,,,,,I still get a slight flicker every once in a while. Would you get a flicker if common and travelers are switched on 3 way switches, or would they just not work at all? I checked all tandem breakers, and installed properly.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: