I just recently installed a new microwave/hood combo in my kitchen. Previously only a hood existed in that space. Now it seems that I'm overloading that circuit. It's on a 15A circuit shared by the kitchen lights, garage lights, and 1st bedroom outlets (including the computer). Kitchen outlets are on their own circuit. When the microwave (1000W unit) and the computer (300W) are both on the breaker buzzes and occasionally trips. If I turn off all the lights and computer the breaker still has a very faint buzz when running the microwave. My plan is to put the microwave on it's own circuit. The breaker box is in the garage just on the other side of the kitchen wall. Running wiring will be pretty easy because I have an attic space above. My question is if I can just plop in another 15A breaker into the box. I've got plenty of space in the box, but I don't know if I'd have to get a permit or not, and if there are any caveats I should be aware of. Should I use a 20A breaker since the 15A breaker still buzzes when only the micowave is on? I'm not afraid of doing my own wiring. I've done plenty of it in the past. I've just never had to deal with the breaker box before. Thanks in advance. ------------------ Bill
to pull a new circuit you would need a permit, and need it inspected. Easy enough to do, usually they're more than willing to help homeowners out. My question is why not put in a larger breaker for that circuit? or, is that 15a breaker going bad? you might just replace that with a 20 or 30 amp (15 seems way too small anyway) rather than pull a new one? it'll be easier. anyway. if you're dead set on doing the wiring it's really easy, just pull the romex from where you want it and into the box, hook up the ground to the strip in the box, and the 2 wires to the breaker and snap the new breaker in place. when you go to buy the breaker you'll need the make and model # of your box of course.
ya know, the more I think about it, I bet that 15 amp breaker is just bad. Here's why. it's been a long time since I've taken physics, so this MIGHT not work in AC, I'm not sure, maybe someone with some physics background can tell me. So, if P=I*E and P=wattage I=amerage and E=voltage 1000=I*120 so I= about 8. if this works for AC (I really dunno, it could be DC only) the microwave maybe uses say 10 amps with some loss there (I dunno what kind of efficiency microwaves have but that's 75% I bet it's higher than that) just the microwave shouldn't cause the breaker trouble (unless of course my rusty physics failed me)
You're right on with the physics. So I too am a little baffled why a 15A circuit is giving me troubles with the microwave. I can't just swap in a 20 or 30A circuit because the wiring is 14awg. I'd have to have 12awg for a 20A circuit. From what I understand I would be presenting a fire hazard by putting in a 20A breaker. I've considered just replacing the old breaker with a new high quality 15A like you suggest. Theoretically I should be able to handle 1650 watts on that circuit (assuming I'm only getting 110 volts and not 120). With the microwave, computer and 4 lights that are no greater then 80 watts each, that's a total of 1620 watts. Ooo, cutting it close there. ------------------ Bill
Yeah, that's cutting it pretty close. One thing you may not know is that circuit breakers "weaken" with every trip, making them susceptible to tripping at progressively lower current levels. If this breaker has been tripped a lot, replacing it with a new 15-amp breaker could buy you significant time. But once it starts tripping, cutting it as close as you are, the party's over until you run a new circuit or get another new breaker. Also, if your computer is on a UPS, then the UPS can draw a significant amount of current for short periods of time, possibly overtaxing the circuit. (This is why UPS makers recommend avoiding plugging UPSs into surge protectors.) If this is the case, the a new circuit is probably the only way to go.
In Canada, a built in microwave requires its own circuit according to code. I would have to recommend a new circuit, rather than increasing the breaker capacity. While the microwave may only draw 1000W it can have peaks higher than that, which would blow the breaker. ------------------ Zardoz Online | Burt Lancaster is The Swimmer | dOc
Hmm...it seems that my microwave/hood is actually requires 1800 watts. It seems the first time I read it there wasn't enough light and I thought that 8 was a 0. That really explains a lot! But it's going to cost me $50-$75 for a permit. It will cost me no more than $15 to make the change. I'm really thinking I can just not get the permit. Would I also have to pay for an inspector, or is that part of the permit cost? What's that $50 permit going to get me? ------------------ Bill
I guess I'm going to have to go downtown and talk to somebody there to get the details of everything I need to do then. I really think it's ridiculous that I'd have to pay even $50. That raises the cost of the project over 400%. I think it's the permit costs alone that keep people from getting one when it's just a simple job. In my opinion permits should be priced as a fraction of the overall expected cost. Let's say 20%, not to exceed $100. So my permit would cost me about $3. I like that. Then the insurance company can send out an inspector. After all, the insurance company already has my money, and it's their own butt their looking out for. I should also clarify, the oven says "Input...1800W; Output...1000W." So whatever that means. That's where I got those numbers from. I need to go get my eyes checked too. ------------------ Bill
I wired my entire basement. This includes special circuits for my home theatre. I didn't want any problems with my CRT projector so I ran extra circuits. I got a permit. It is true if nothing happens you will never care if you got a permit. BUT if you have a fire that starts anywhere near your new wire you will NOT, and believe me I checked, be covered for anything by your insurance. For $50.00 you have an inspector come out and check your work and give you heaps of advice for free. They then send you a 'passed inspection' sticker for your Breaker box and you get peace of mind. I have done my own wiring for years and I still made a mistake. Small one but if you're not sure what fuse strength and so on, don't you think it would be wise to get a professional to check your work? My 2 cents worth.
i don't know, but i'm pretty sure if my house burned down and i tried to do a 300K claim and my insurance company found out it's because i did a faulty wiring job... they'd tell me to go fly a kite. but if i had an approved permit, even from some guy who doesn't know anything, then i'd have a legal argument on my side... definitely worth 50 bucks... my .02 ------------------ You step in the stream, But the water has moved on. This page is not here.
having worked in HVAC a tiny bit I second the inspectors are a joke. BUUUUUUUUUT it's just not worth it. Get a permit, the permit cost includes the inspection... it's worth it to know you've complied with the current building code (which your old wiring may not depending on the age, I've seen aluminum wiring still out there..)
Thanks for all the replies. You've all been a big help in getting some questions answered. Well, my wiring is only 20 years old and it does comply with current codes (all copper). But I plan on running new wiring out anyway. I also plan on rounding up the help of an electrician friend of mine, if I can every get him over here. One of my other concerns with having an inspector come out is him not signing off because of other projects that are lying around incomplete. I've been rewiring the garage to actually fix previous code violations and have left some wire dangling from the ceiling (properly capped so it's 100% safe) where I'm going to eventually drop it down and install plugs for my workbench (if I ever get that built). The problem is, the inspector will have to come into the garage to inspect the breaker box and surely will see the other things (there won't be a problem once I'm finished with them). Although it may not be an issue because it is safe. My biggest concern though is still not wanting to spend that money. That permit is going to cost me 2 DVDs! Also, I've been doing a lot of rewiring throughout the house (added 2 ceiling fans, garage outlets, garage lights, an entire wall rewired and switches relocated) all without permits, and all required pulling new wiring. Why should this by any different? ------------------ Bill
I'm not 100% on this, but as far as I know the inspector can ONLY look at what's permitted.. the rest? oh the previous owner did that, I'll have an electricial look into it ASAP sir
Well...I'm finished. I talked an electrician friend of mine into coming over and helping me pull wire into my breaker box. He also gave me a few pointers to make sure I do everything to code. I installed a new 20A breaker, a new box by the microwave, and pulled 12/2 Romex (12 gauge, 2 conductor with a ground) into the new box. Everything works great. No more breakers buzzing or tripping. Woohoo! Thanks again for all your input. ------------------ Bill
