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Two Rooms on Same Circuit

You've gotta love homebuilders. The house we have (built in 2003) is wired in a manner in which two bedrooms are on the same 15amp circuit. Occasionally (once every three to four weeks or so), when one of my kids turns an item on while other devices (lights, ceiling fan, computer) are on, the breaker trips. Now, I know enough about electrical that this is because the load has exceeded the breaker.

What I'm wanting to know is two things. One, because this is so infrequent, could I replace the 15amp breaker with a 20 amp? If not, would anyone have a guesstimate as to how I could fix this problem? Would I have to have the two rooms rewired on separate circuits? If so, any prospective ideas as to what this would cost? Thanks for any and all help.

Re: Two Rooms on Same Circuit

You could replace the 15A breaker with a 20A if all the wiring on that circuit is #12 or larger...but I doubt if it is.

You didn't say if the breaker is an Arc Fault or Ground Fault (again I doubt it). If so, the appliances being could be faulty.

So, in a typical childs bedroom one would expect four duplex receptacles and a fan/light. At 180 watts per receptacle and 300 watts per fan/light we're talking 1020 watts per bedroom or total load on a 15A breaker of 2040 watts , which is 240 watts too much.

If you have the maximum size incandescent bulbs allowed in most fans the total lighting load is 480 watts. So, just by changing the standard bulbs out to 23 watt compact fluorescent (CFL) you would obtain 800 W of light in each room vs the 240 W you now have and reduce your load on the breaker to 1744 W, slightly below the designed load of 1800 W. Smaller CFL's are also available, which would be even better.

All this assumes the appliances the children plug in are not faulty and are typical loads. If they plug in irons, hair dryers, heater etc. all bets are off and yes they need to co-ordinated their use with each other or you need to provide the bedrooms with their own breaker, preferably 20A.

CFL's can save a bunch of electricity but, the downside to CFL's is that the standard CFL lamps are not dimmable and the ones that are are not all that reliable.

Good Luck from Columbiana, Alabama
Maurice Turgeon, http://thesemi-retiredelectrician.com

Re: Two Rooms on Same Circuit

My previous 1973 Calif house had 3 BR's on the same circuit . . .

(1) Definitely would use CFL instead of incandescent or halogen to cut amperage. You can pick color temperatures, and for task lighting, go with 3500K (bright white) or 5000 (white). Avoid 6500K (sometimes called daylight for blue tint) unless for garage.

(2) Check the other outlets in the 2 BR's - they may be on separate circuits. My old townhouse has this (great) layout; 1/2 served by 1 circuit and the other 1/2 by another.

(3) Are the BR's ajoining other rooms with separate circuits ? If yes, you can tap into those circuits and add "new work" boxes in the 2 BR's close the ajoining rooms easily. If possible, stay in the same space between the 2 studs so you can tap from the box and grab the wire on the other side of the wall through the new box hole so you won't need to drill through studs.
Potentially, you can have the load over 3 circuits now.
You just need to get a few devices off the original circuit, unless you're running a space heater or hair dryer.

Re: Two Rooms on Same Circuit

Are all receptacles in the two bedrooms on the same circuit?

If yes, then the original installer didn't follow normal procedure.

If not, that's a job for a fro.

Re: Two Rooms on Same Circuit

Are they on Arc fault breakers?? 15 amps should be able to handle a couple of bed rooms, i would agree, put in CFLs.

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