Making connections inside circuit breaker panel

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  #1  
Old 08-24-05, 08:30 AM
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Making connections inside circuit breaker panel

After mapping out the circuits in my new old house, I have realized that some changes are in order, especially considering that I will be adding some new circuits for a dishwasher, disposer, etc. The panel itself is fairly small, so I need to be smart about how I reconfigure it. One thing I noticed is that there is one circuit that supplies power for only three bedroom outlets. I'd like to combine that circuit with another "underloaded" circuit (both are 12 gauge & 20 amps). Can I just connect the two separate circuit cables together inside the circuit breaker box using standard wire connectors, and run a pigtail to the breaker? Seems logical to do so, but I have not seen anything in my wiring books about this.
 
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  #2  
Old 08-24-05, 08:48 AM
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The method for combining the circuits is doable. Just connect the blacks to a pigtail with a wirenut and connect the pigtail to the breaker. However, if possible, I would prefer to combine them in a junction box and run from it into the breaker box, simply to keep the breaker box as clean as possible.

Whether it is OK to combine these circuits really depends on what is served by the other breaker. If it serves recepticals in the bathroom, kitchen/dining, or laundry room, it is NOT OK. Keep in mind that someone made these circuit separate for a reason.

One thing to consider is that you *might* be able to use tandem breakers (aka piggyback, aka twin) in your panel box. A tandem breaker is actually two breakers that takes the space of one. This all depends on the breaker box you have. If you want to investigate this possibility, tell us everything you can about your panel box (manufacturer, model, main breaker size, any other labels).
 
  #3  
Old 08-24-05, 09:42 AM
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Originally Posted by chirkware
The method for combining the circuits is doable. Just connect the blacks to a pigtail with a wirenut and connect the pigtail to the breaker. However, if possible, I would prefer to combine them in a junction box and run from it into the breaker box, simply to keep the breaker box as clean as possible.

Whether it is OK to combine these circuits really depends on what is served by the other breaker. If it serves recepticals in the bathroom, kitchen/dining, or laundry room, it is NOT OK. Keep in mind that someone made these circuit separate for a reason.

One thing to consider is that you *might* be able to use tandem breakers (aka piggyback, aka twin) in your panel box. A tandem breaker is actually two breakers that takes the space of one. This all depends on the breaker box you have. If you want to investigate this possibility, tell us everything you can about your panel box (manufacturer, model, main breaker size, any other labels).
Thanks for the quick reply! The other circuit serves general purpose outlets for the bedrooms and Living Room. Nothing like laundry or kitchen outlets. There are also two bath outlets on this circuit, but I plan to provide a separate circuit for those duiring remodeling as the code requires. I suspect I will be using the tandem breakers, due to space limitations. Just out of curiousity, what factor determines when my existing breaker box is too small? When I run out of slots? When there are too many wires entering the box? In a worst case scenario, is it possible for me to replace all my existing 15 and 20 amp circuits (four total, no tandems) and empty slots (two left) with tandem breakers, if it were necessary?
 
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Old 08-24-05, 09:55 AM
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Just out of curiousity, what factor determines when my existing breaker box is too small? When I run out of slots? When there are too many wires entering the box? In a worst case scenario, is it possible for me to replace all my existing 15 and 20 amp circuits (four total, no tandems) and empty slots (two left) with tandem breakers, if it were necessary?
The answer per code is 42 circuits allowed per enclosure, including the main breaker. However, your box is clearly much smaller than that, so the manufacturer's limit supercedes the code maximum. The number and type of allowable breakers will be printed on the label of the panel. If you can't find that information, try at least to find the maker and model number of the panel and someone here will probably recognize it. The bottom line is that you must follow the manufacturer's specifications; and they are different for every box.

There is also the issue of overloading the existing service. As a box approaches its limit of circuits, you may also be reaching or exceeding the electrical capability of your service. A "demand load calculation" will tell you it might be time for a service upgrade and panel replacement.
 
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Old 08-25-05, 12:16 PM
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Originally Posted by ibpooks
The answer per code is 42 circuits allowed per enclosure, including the main breaker. However, your box is clearly much smaller than that, so the manufacturer's limit supercedes the code maximum. The number and type of allowable breakers will be printed on the label of the panel. If you can't find that information, try at least to find the maker and model number of the panel and someone here will probably recognize it. The bottom line is that you must follow the manufacturer's specifications; and they are different for every box.

There is also the issue of overloading the existing service. As a box approaches its limit of circuits, you may also be reaching or exceeding the electrical capability of your service. A "demand load calculation" will tell you it might be time for a service upgrade and panel replacement.
Thanks for all your time and great information!! The paper label on my box is old and difficult to read, and I can't get anything useful off of it. Here's what I do know about the box:

1) It's 24" high x 7.5" wide. It is made by Zinsco (model: Magnatrip). The meter occupies the top 9" or so, of the box. There are a total of 8 circuit breaker slots; 6 are currently occupied, all with full width (i.e. no tandems) breakers. The box seems to be the original with the house, which was built in 1957. I have 100 Amp, 240 VAC service going into the box from the power company. On the front of the panel, stamped into the sheet metal, it says:

Service Center, MT-100W-A
120/240 VAC 100A max

Does this help? It would be nice to know the limits on the number and types of circuits I can have in this box. Seems like I keep coming up with new electrical remodeling projects on this house! Your help and time is much appreciated!!
 
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