When I plug-in a conventional heating pad or a hair dryer into any bedroom duplex, the lights dim; and/or trips the circuit breaker. The home is of new construction-- placed in service 31 Dec 2013. My question is: Can I safely replace the existing 15 AMP Breaker with that of a 20 AMP? . . . the service cable is of 14 Gauge Copper Conductor.

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    I'm surprised that in new construction they put the lights and receptacles on the same circuit. I thought it was best practice (but not required) to put them on separate circuits?
    – Johnny
    Commented Dec 11, 2013 at 0:20
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    Check around, plug into other receptacles see if you can find an outlet that does not dim the lights, that should be a different circuit than the lights. DO NOT, DO NOT change the breaker!! the items you are running are already taxing the system and tripping breakers. The tripping is part of the design of breakers, they trip before the wire gets too hot. Changing the breaker, in essence, will keep the wiring from telling the breaker there is too much plugged into it. It really does not work that way, but the effect is the same. Wallyk is telling you right.
    – Jack
    Commented Dec 11, 2013 at 0:28
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    I'm guessing you mean 31 Dec 2012, or you have a time machine. If you have the time machine, might as well go back and hire a competent electrician (or possibly whoever told the electrician to put in absurd circuits to save a few bucks.) It will be expensive and messy to fix well, since that would involve running new wire and new circuits. if you have a house warranty you might want to see about having it independently inspected in time to file a complaint if this cheapskate attitude actually resulted in code violations (none actually obvious from what you've written, but it leads that way.)
    – Ecnerwal
    Commented Dec 11, 2013 at 2:34
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    It was placed into Service December 31 2013? That's in 3 weeks...
    – user18554
    Commented Dec 11, 2013 at 3:14
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    In the old days, people would install copper pennies in the fuse sockets to prevent them from blowing. As a result some buildings have burned down. The equivalent to that would be installing a larger breaker than the wiring can handle. Obviously, that would not be a good idea. Commented Nov 5, 2015 at 15:23

4 Answers 4



The only safe way to increase the circuit's capacity is by replacing the wire with one of adequate gauge. For 20 amps, 12 AWG copper is adequate for up to about 100 feet.

If you simply replace the breaker, the wire can overheat and ignite the building from inside the walls.

To resolve the dimming issue, check that the outlet is in good condition and that the wires are securely fastened and not showing any signs of overheating: blackening or loss of the copper shininess. Also, check the end of the wire inside the service panel, both neutral and "hot" (black) wire. If those are okay, set the appliances to a lower wattage setting or replace them with lower wattage models.

  • My apologies, the actual date was 31 Dec 2013-- long day.
    – user18550
    Commented Dec 11, 2013 at 4:12

Absolutely NOT.

National Fire Protection Agency (NFPA) Standard Number 70, National Electric Code (NEC), adopted by most states (exceptions are Missouri, Mississippi and Arizona), requires the branch circuit Over Current Protection Device (OCPD --typically a circuit breaker (CB) nowadays, rather than a fuse from days of yore) to protect the cable/wiring buried in your walls from overheating by de-energizing (shut off/open circuit) all outlets (lighting & receptacles) for that circuit by tripping/blowing.

Lights dimming and CBs popping is a sure sign your house was not built to handle heating blankets and hair dryers in the bedroom. Swapping out a 20 amp breaker for the 15 amp breaker will violate NEC 210.19(A)(1) and provide cause for your insurance company not to reimburse your losses from fire & smoke damage and the water damage from the fire department flooding your house.

Wire is made smaller when manufactured by drawing/stretching it. The more times its stretched the smaller it gets. This is why American Wire Gauge (AWG) seems backwards, i.e. 14AWG has a smaller diameter than 10AWG because it was stretched more.

15 amp rated circuit breakers use 14 AWG current carrying conductors (black hot & white neutral) + a green ground wire which normally carries no current in industry standard outer white non-metallic sheathed cable called NM-B 90 degree Centigrade rated "Romex".

20 amp rated circuit breakers use the same configuration but 12 AWG, which is a larger diameter wire than 14 AWG, and therefor has less resistance for the same distance/footage from the load center/panelboard circuit breakers. 12 AWG NM-B sheathing is colored yellow.

10 AWG with orange sheathing would be even better electrically, but more expensive and not required by "code", the NEC.

Blame all this mumbo jumbo on Physics and a German named Georg Simon Ohm who created a Law that even Donald J. Trump can't repeal. Voltage loss (V) = current (i amps) times resistance (r ohms). And Power loss = current squared (i to the twoth power) times resistance (R).

When you draw too much current through a skinny wire, since its not a superconductor, you're converting electrical energy into heat energy from Ohm's resistive loss, resulting in less electrical energy (a voltage drop) reaching your load (appliance, light bulb, stereo, ...). The excess heat in the wire and inside your wall causes the insulation to fail over time, creating a potential short circuit accompanied by sparks that ignite flammables.

Have a licensed and insured electrician (Journeyman or Master) or electrical contractor add a new 20 amp circuit, or replace the existing 14 AWG cabling with 12 AWG cabling, or use your hair dryer in the bathroom which should already have a GFCI per NEC 210.8(A)1) and 20 amp receptacle per NEC 210.11(C)3) installed within three feet of the edge of a basin per NEC Article 200, Section III Required Outlets, 210.52 Dwelling Unit Receptacle Outlets, (D) Bathroom.

When it gets cold I put on an additional non-electric blanket, long thermal underwear, a hat and scarf, and let the dog sleep on the bed with me.

During the winter you might want to become a "snow bird" and fly south to Florida instead of having to deal with electricity, aka "Organized Lighting" according to George Carlin.


It's like this... Wireing is sort of like tubes you use to run water. Breakers are like an on off valve that also controls how much water(electricity) can to into the tube(wire). If you force too much water in a tube, it breaks and water gets everywhere. If you force to much electricity in a wire it breaks(melts) and gets fire everywhere. Fire is a lot more of a pain to clean.


perhaps you can but please let the competent person to do it.firstly the wire must be in good order and do not use too many apliances with higher wattage at the same time.The best is to buy you a new mcb with the same rating to replace the old one,generally this will solve most of similar iissue.

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    This would be a code violation 14 awg wire is only rated for 15 amps.
    – Ed Beal
    Commented Dec 14, 2016 at 14:23

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