Joining circuits


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Old 01-11-08, 08:17 AM
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Joining circuits

I want to say thanks to all the guys/gals who volunteer and spend their valuable time with this website. Sharing knowledge is a wonderful thing.

I have read in previous posts that it is a code violation to combine neutrals at the panel.

Does this apply when the corresponding hots are combined?
If so, what is the thinking here? My thinking is that it would be just like a junction box where hots/neutrals/grounds are combined. There has to be a good reason or I am missing something?

I have 2 purposes. 1) open addtional breaker spaces 2) Combine and add 1 AFI breaker instead of 3. I want to increase the safety factor of the house in general by adding AFI breakers and GFIs in each room.

Currently all 3 bedrooms are on individual circuits. I was planning on joining these because the combined load of all three include:
3 alarm clocks (1 amp)
Lights (2 amps total)
1 TV (6 amps)

So the combined daily load will be about 10 amps on a 20 amp circuit. If I combined these into 1 circuit I would install a AFI breaker as well.

I do plan on installing AC smoke detectors as well so I would add this to the single circuit.

Curling irons and hair dryers are all used in bathrooms which are dedicated.

Thoughts?
 
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Old 01-11-08, 08:51 AM
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You can (AHJ permitting) combine wires using wire nuts and a pigtail. You can not put two wires under a neutral screw or in a breaker unless they are specifically rated for it.
 
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Old 01-11-08, 09:03 AM
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I have read in previous posts that it is a code violation to combine neutrals at the panel.
"At the panel" is somewhat ambiguous. You may not, as previously mentioned, ever put them under the same screw on the neutral bar. You may, however, combine them with a wire nut, if the resulting pigtail has sufficient ampacity for both circuits (which in turn depends on whether the circuits are on the same leg or opposite legs).

Does this apply when the corresponding hots are combined?
Some breakers allow two hot wire connections. Some do not. But you can usually combine two hots with a wire nut, which are then connected to the same breaker. However, most of the time this would be completely pointless, since the breaker size would still be limited by the smallest wire on the circuit. If you use this, for example, to combine two 20-amp circuits into one 20-amp circuit, you've just lost half the power on those circuits. In many cases, that would also probably be illegal if the combination puts stuff together on the same circuit that aren't allowed together.

I don't think you'll be happy with the result if you proceed with your plan. Even though the usage on these circuits is supposedly low, small changes in your usage pattern will cause this breaker to overload a lot. For example, you do vacuum these rooms, right? A vacuum cleaner uses a lot of power. If you ever have the carpets cleaned, the carpet cleaner is going to use even more power (although maybe he could clean the carpets in the dark).
 
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Old 01-11-08, 09:39 AM
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I as well don't like your plan.

I think you are being penny wise and dollar foolish.

I have the same reasons that John mentioned.

I also am thinking about the person who owns the house next, or even you in later years. Eventually someone will want to reverse what you did. They will want a waterbed in one of the bedrooms, or something else with a high current draw, and one circuit won't be enough for all three rooms.

If that person only half reverses what you did (hot wires only) then a real fire hazard will exist on the now overloaded neutral wire. Even if they handle the neutrals, they may very well use regular breakers (maybe AFCI breakers are not available, or they can't get to the store right away, etc.).

If you are going to spend the money to get AFCI breakers, then get them for all the breakers you want to replace. Don;t experiment with combining circuits.
 
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Old 01-11-08, 11:01 AM
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There are only a few things that I like to do in a dark bedroom (wife permitting of course). Vacuuming is not one of them. )

Amp load aside, I have an issue with the number of breakers. I guess I will have to change to 1/2" Seimens breakers as opposed to combining others.

I had my other question answered as well in regards to a pigtail back to the breaker and neutral bar. I will check if the bar is rated for a "double neutral". Additional bars are cheap so I did not want to seem like a tighta**.

Thanks for all your help.
 
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Old 01-11-08, 12:25 PM
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Originally Posted by Thonati
There are only a few things that I like to do in a dark bedroom (wife permitting of course). Vacuuming is not one of them. )


reading that made my day ahahahaha That is funnnnnny.
 
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Old 01-14-08, 01:05 PM
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Originally Posted by John Nelson
"At the panel" is somewhat ambiguous. You may not, as previously mentioned, ever put them under the same screw on the neutral bar. You may, however, combine them with a wire nut, if the resulting pigtail has sufficient ampacity for both circuits (which in turn depends on whether the circuits are on the same leg or opposite legs).
This quote caught my eye since I've noticed that I have a couple of instances of neutrals (white wires) under the same screws in my breaker panel.

Why is this not allowed since even if the neutrals are all using separate scews, those screws are all attached to the same bar? Also, all of the ground wires from all circuits are attached to the same bar as well with some of those doubled up. Is this a problem that needs to be addressed as well?

Thanks,

Dave
 
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Old 01-14-08, 02:33 PM
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Neutral wires carry current. As such they heat up and contract as the amount of current increases/decreases. The constant changing in size may lead to one wire or the other (or both) becoming loose. A loose wire can come undone or can cause extra heat which can lead to a fire.
 
 

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