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vinman
06-18-2005, 06:47 PM
Although I'm not an electrician I have had experience when I was in refrigeration and a/c.
i have ran my own circuits in my home before with no problem. I bought one of my sons a new window a/c. The breaker kept popping and I realized his whole room was on one circuit along with some downstairs lighting. (the house is 45+ years and has some real rube goldberg wiring that i keep rerouting and repairing when i come across it. I run a seperate circuit for the a/c (15a outlet, I run 12AWG wire instead of 14 just for extra safety). I go to Home Depot to get a twin 15a breaker so i can attach the origninal wiring to onw and the new line to the other. Everything is fine.
I went yesterday to do the same thing for my other son's room and notice that there are twin 15's for $14.50 and $10. I paid $14.50 the other night. I asked the guy what the difference was. He didn't know and we looked at the breakers. The one for the higher price was marked "For Replacement Use Only, not CTL Assemblies", the cheaper one wasn't. He had never heard of CTL. He started looking through the Murray book (that's the brand panel I have) and couldn't find the explanation. We asked to other electric guys who were buying stuff there and they didn't know what CTL meant. The two breakers were absolutely identical except for the aforementioned label on the one. After hours of research on my computer I found that newer boxes are CTL and only allow a certain amount of breakers in a box and older ones don't have this. If a box has a certain number of slots, how could someone add more anyway? My questions are these:
i have two seperate boxes in the basement because I have two seperate meters. The previous owner had a relative living upstairs and I never had the second meter removed.
The Murray box is marked CTL and has room for 12 breakers. Does this mean I can't put a double breaker in the opening of a single. The diagram shows the 12 positions but next to the top left it has number one, the bottom left -number 12, the top right - number 13 and next to the bottom right number 24. I'm trying to figure if this means I can use double breaker.
Apparently, the other night the home depot guy gave me the non-ctl breaker and i installed it with no problem. Should I remove it and replace with a regular twin breaker?
My other box is an old GE box. i couldn't find any CTL designation on it. is it okay to use a couple of double breakers in this box? (two breakers in one slot type) and does it matter CTL or non-CTL.
Lastly, what does the CTL breaker do in a CTL panel as a safety. Does it not fit? Does the breaker not work?
Thanks, Vinny

Tom R
06-18-2005, 07:30 PM
We're gonna need Sparks for this one, - - I'm sure he'll be along soon.

Sparks
06-19-2005, 08:25 AM
CTL is a designation used by UL (Underwriters Laboratories) to designate panel boards and circuit breakers. Class CTL panels incorporate physical means that PREVENT the installation of more breakers that what the panel was designed and rated for. If your panel was only rated for 12 breakers and your using all tandem breakers, your are violating the UL listing of the panel therefore violating the National Electric Code. Also, almost always, breakers are numbered from left to right, not top to bottom. Panels are designed for a certain number of breakers and double pole breakers are considered 2 breakers according to the NEC. Regardless, I realize this is done all the time for cost and convenience reasons. There are many times where different breakers will fit into different panels but it would still be a violation of the NEC and an inspector would not allow it. Are your panels that full that you can't use standard breakers approved by the panel manufacturer, these tandem breakers are usually only used as a last resort and usually on work that is done without a permit or inspection. If the breakers your using are approved by the panel manufacturer, then your fine, if not, you're violating the panels UL listing and the NEC. If you're installing non CTL breakers in a CTL rated panel, the same applies. Best bet, install breakers approved by the panel manufacturer, approved breaker types are usually listed on the back of the panel door.