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beachfront71 03-28-2012 12:02 PM

20 amp circuit using 14/2 wire? Overloaded
I ran into this problem recently and had an electrician fix it but when calling around I was amazed at the different opinions so I thought I would ask here.

While remodeling, we found out our kitchen lights (13 cans and 250watt chandelier), plasma TV, and 1800w microwave were all on the same 20 amp circuit that was run with 14/2 wiring.

We have lived here 2 years with no problems but do have the occassional dimming when the microwave goes on ..

The previous owners had to have been in the same boat.

I had the microwave taken off this circuit and put on its own but the opinions of electricians ranged from "not a big deal" to "definite fire hazard, not if but when ..."

I even had one guy tell me they run 14/2 on 20 all the time as the manufacturers rating is well above any code a city will implement.

What is are the opinions here?

I am sure there are homes all over that have this problem and do not know it .. if I was not remodeling I would have never known..

I was under the impressing the hazard here is that 14/2 will not trip a 20a breaker...

When we tested, with all the lights on, tv on and microwave on high we were pulling 23 amps but the breaker did not trip..although it started to buzz..We would really never have everything on at once but he wanted to check..

Amazingly the plasma TV was 7.5 amps, alot more than I would have guessed..the cans were minimal

I still have the kitchen lights and TV on a 20a breaker with the 14g wire, but the microwave is off of it ..

Look forward to some feedback.


jbfan 03-28-2012 12:10 PM

Code requires #14 to have a max breaker of 15 amps.

Breakers do not trip right at their ratings.
That 20 amp breaker could work for hours or days with a 23 amp load.

To be compliant, change the breaker to 15, and add a new circuit for the tv.

HouseHelper 03-28-2012 12:28 PM

With the microwave off the circuit, just change the breaker to a 15A and all will be well. I would side more toward the "not a big deal" guy than the "fire hazard" guy. Contrary to what many will have you believe, 14ga wire will not spontaneously combust when the amperage goes over 15A. The actual rating for the 14ga wire used in most residences is 20A, but the NEC mandates that it be protected by a maximum 15A breaker (with a few exceptions). Your circuit was overloaded and you did the correct thing by removing the microwave... which should have been on a dedicated circuit anyway.

joed 03-28-2012 12:33 PM

And don't call back the guy who runs 14/2 on 20 amp circuits all the time.

k_buz 03-28-2012 01:10 PM

I'm going to take a stab at why this was wired this way in the first place. I'm going to assume that this is hanging microwave above a range. There was probably a exhaust hood there to begin with and those are able to be on any lighting circuit. Someone bought a hanging microwave, and used the existing wire to install a recept for the new micro. Then when the 15A breaker started tripping, they just changed it out to hold the load.

Yes, fire hazard.

beachfront71 03-28-2012 02:04 PM

based on the new and old romex we found .. it looks like someone added an outlet to the lighting circuit (not sure how that would happen) then branched off from there for the TV and Microwave ...

The wall the TV and MWave are on is an 8 foot wall in the middle of the house dividing the LR and Kitchen with 8 foot opening on each side so it is isolated from the actual kitchen walls where the range, frisge, hood, sink etc are located..

I can not figure out how you could run a outlet from a light if you did not do it from the switch as the switch controls the power ...

MisterZ 03-28-2012 08:43 PM


Originally Posted by beachfront71 (Post 887390)
I can not figure out how you could run a outlet from a light if you did not do it from the switch as the switch controls the power ...

this is possible if power comes from another device to the light before the switch.
in that case, however, there would be evidence where the light is wired. (ie: extra hot wire)

i have done work in a house with this situation.
over the years people just splice off anything to supply power somewhere else.
older homes can be fun;)

Julius793 03-28-2012 09:53 PM


Originally Posted by jbfan (Post 887311)
Code requires #14 to have a max breaker of 15 amps.

Breakers do not trip right at their ratings.
That 20 amp breaker could work for hours or days with a 23 amp load.

why would that be?

plummen 03-29-2012 01:38 AM


Originally Posted by Julius793 (Post 887658)
why would that be?

Depends on how good of a breaker it is and how old it is,if its not a motor starting type load it could definately buzz for quite a while on a new breaker before tripping.
Where as a heavy load from a motor trying to start could kick it out really easily :)

kbsparky 03-29-2012 04:12 AM

Many houses were wired with a "range hood fan" connected to a standard lighting circuit. That was usually a #14 wire, connected to a 15 Amp breaker, and it was allowed to have other things connected to it, such as lights, living room outlets, etc.

As you have figured, somewhere along the line, a microwave/hood unit was installed to replace the old exhaust hood, and started tripping out the breaker.

To solve the problem, someone upsized the breaker -- almost the same thing as the proverbial penny in the fuse socket. :huh:

Installing a dedicated circuit for the range hood is your best solution here, as well as restoring the proper sized breaker on the lighting circuit.

AS for that plasma TV, they are energy hogs, as you have discovered. :mad:

I never understood how folks would change out all their light bulbs to the CFL type, only to buy a new plasma TV and leave it on all day. Then complain about how their electric bill went up.

Get an LED/LCD TV: They use less electricity. :whistling2:

Jim Port 03-29-2012 07:37 AM

Julius, try and find a breaker trip curve and you will see that the breaker can hold a significant amount over the handle rating for a long time. The greater the overage the quicker it will trip.

NoHoliday 01-02-2016 08:45 AM

20 / 15 Amp Breakers
The goal is to always have the breaker protect the integrity of the wire. You want the breaker to trip BEFORE the max. amp rating on the wire. The breaker needs to be the weak link in the chain, not the wire. This is so you won't cause wire/insulation failure from heat and possibly burn your house down. 14/2 needs a 15 amp breaker. If you want 20 amps of service, you need to convert to 12/2.

Syberia 01-02-2016 11:34 AM

He put the microwave on another circuit; a 15 amp breaker should hold with just the TV and lights on it.

Jim Port 01-02-2016 12:11 PM

I think this was settled almost 4 years ago.

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