breaker sizes for Challenger main panel


Old 07-28-07, 12:00 AM
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breaker sizes for Challenger main panel

Sorry in advance for the long post but everything below deals with this post and another post I'm going to list.

I need some advice on the use of breaker space/type of breakers with my old Challenger panel. (I've scanned the information from the panel cover so you can read it):

The panel has a 100A main, a 20A double pole breaker in spaces 1 & 3, a 30A double pole in spaces 2 & 4, and tandem breakers in all the rest (all 15A except for one 20A). I don't need the double pole 20A any more, so I thought I'd remove it and put two tandems in its place (I'm not adding "new" circuits, just trying to break up some of the larger ones into more logical groupings.)

From what I've read, Cutler-Hammer breakers are UL certified for Challenger panels so I went to cross reference the breaker types. The Challenger types were "A" (tandems) and "C" (single or double pole). There is no type A in the C-H cross-reference, only C, which says to use C-H type "BR". When I checked at Home Depot, I found that the BR type came in single, double and tandem types all rated 10,000A, so I thought, "no problem." Then I saw that the tandems came in "limited" and "non-limited". When I asked about the difference I learned that it had to do with the size of the hot bus slot.

When I went home and checked the panel I realized that the bus has full size tabs (stabs?) for spaces 1 - 4, while spaces 5 - 20 have a V-shaped notch in them (I had never removed the 2 double pole breakers before so I never noticed this).

I then looked at the panel info and began to understand the diagram better, with solid markings for 1-4 and a white space in the middle for the rest. I also noticed that it said type C could be used throughout, but type A could only be used from 5 - 20. The thing is, the C-H tandems come in the "non-limited" variety, so they would actually fit in the upper spaces.

Not sure if it was legal use the tandems there (the panel info did say it was a 12-20 box and the original design obviously did not allow tandems in the upper spaces), I went to an electrical supply house to ask their opinion. They said the term "limited" was actually "rejectable", but that it would be okay to use the tandems in the upper spots as long as all loads together don't trip the main.

So, after this long winded explanation, I'd like to know what you folks think. Would it be okay to use two non-rejectable tandems in spaces 1 & 3, or should I put in two full size single pole breakers? I know I could put in a sub-panel, but with only 100A service figured it might be easier to squeeze a couple more breakers into the main, but that will lead to my next post regarding neutral/ground wire space.

Thanks in advance for any and all help.
Old 07-28-07, 06:32 AM
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Yes, the breakers will fit the upper slots. With that said, NO it is not OK to use them there. The panel was listed by UL a certain way and part of theat listing was with the full size breakers in the top slots. Also the panel is only listed for a certain number of breakers. To install tandems where they were not designed would cause the panel to exceed that number.

Use the full size breakers in the top slots.

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