Topic: Non-Bike electrical question

[my78k]

I don't care if you reply with facts or opinions 

My woes with my "house that keeps on giving" continue!

A couple of months ago my dryer died so I grabbed one cheap and used through someone at work. Seemed to run fine for the last few months. Well the other night I noticed it was getting warm in the house (outside temp was over 90f but I had the AC on....or so I thought). I looked at the thermostat and it had climbed way up and the fan was still running but apparently the AC cut out. I know this seems unconnected but the PO of my house apparently wired the Dryer and the AC on the same friggin circuit!!! Apparently the 2 of them together tripped the breaker...now what I don't understand (aside from why they are not on stand alone circuits!) is how could a dryer and an AC unit trip a double 40 amp breaker??? I am assuming there is no way that it is actually 80 amps dedicated but who knows?!?!?

Anyways, I guess what I am asking is should I tear into the dryer to look for a reason why there may be additional draw or look at the panel to see if something is up with the double breaker? The friggin thing now won't run for more than 5 minutes (even with the AC off!!) without tripping!

I hate electrical work....but I am also broke (yay me  ) so I guess I may have to get creative and tear into one or the other because dying in 90 degree heat sucks but it sucks even more when I have to wear wet clothes  Damn I sure am glad I have a pool in the back yard that I can cool off in!!! Oh speaking of which and seemingly unrelated last year the pool pump used to trip its breaker every hour or so and this year it is fine?!?!? WTF??

I may have to have an exorcist visit the house rather than an electrician...

Any and all advice gladly accepted...oh and if you are an electrician in Durham Region Ontario I have a fully stocked bar in the basement!!

Dennis

[333]

Before you tear down the dryer, look at the specs, and how many amps or watts it draws.  The AC may not have the info, but maybe.  It will probably be in watts.  There is math involved to get to amps from watts.  Sorry, but I don't have the equations.  I'm sure someone else does.  I know just enough to how to get in trouble in most cases.  But you are talking about two heavy draw units.  It is conceivable that these two on the same circuit will pop the breaker.  The other thing to look at is the breaker itself.  If it is starting to fail, it will pop at a lower current draw.

[razor02097]

A dryer could pull 4000-6000 watts... usually they are on 30 amp circuits themselves.  If its central air that would definitly need a seperate circuit
Also breakers have a constant draw that they will trip at... just cause you have a 30 amp breaker doesn't mean you can run 30 amps all the time.  More like 20-25
for the pool... is it tripping the GFI or the breaker?  Mine use to trip the GFI every so often

[my78k]

I didnt want to muddy the issue by bringing the pool into it and probably should have steered cleared but the GFI is at the breaker so I have no way of knowing which was tripping. The really strange part is that it used to trip 2 or 3 times a day (sometimes more) and now it never trips?!?!?

As for the dryer and ac...if it is a dbl 40 amp breaker is that not 80 amps dedicated? No way the 2 together should draw anywhere near that...and like I said the dryer alone trips it now quite frequently...damn I am frustrated!!

Dennis

[razor02097]

I would have to check to be sure but I think if its a central air system it requires 2 breakers.  Not sure about the rating though.

[Spanner 1]

78...A double pole 40 amp breaker is just as it says 40 amps. You can't add the 40+40 together! Were talking AC current, that's what makes the difference. If your dryer and AC are wired on the same 40amp circuit sure the breaker will trip with the AC and dryer both running...if it has tripped several times it is now 'soft' and the AC kicking-on on it's own may be enough to trip it. Just replace the breaker with the same size..do not go bigger ( fire hazard ) and turn-off the AC when using the dryer, or have to re-wire dryer on it's own.

[tramp]

spanner is right
run the dryer on it's own line
breakers do weaken with time if tripped alot
so get a new breaker for the ac
run a new line for the dryer

[demon78]

Hey 78k I used to fix major appliances in an earlier manifestation, the dryer when it runs will draw 24+ amps with the heat on, depending how big the A/C is it will run around  20  amps but when the dryer starts it'll pull at least a 1/3 more and the air/c 1/3-1/2 more so if they are on the same circuit they will stress the breaker a lot I'm not sure but I think that the breaker you're talking about is a double pole breaker which would give you 40 amps a side not 80 amps and because they are joined mechanically it doesn't matter which side is popping (dryer or a/c) they both go and yes breakers do get weak and have to be replaced, as far as doing it your self or calling an appliance tech or an electrician I don't know the costs of service calls of either trades any more, because I was an appliance tech I would lean to that side of the problem ( seems to me one of the appliances is drawing too much current ) I know if I was trouble shooting it, I'd haul out my trusty Amprobe and check current draw, right at the start before I took any thing to pieces, if you had access to a current meter (generic Amprobe) and you were comfortable using it, you'd know p.d.q. if you're not, the possibility for zapping yourself are endless and screwing with 240 is not good. This probably doesn't help much, if it does great.
Bill the demon.

[my78k]

Actually Bill and all you have all helped quite a bit. At the very least I will need to pick up a new breaker and will look into running a new line for the AC.

Actually the whole panel really should be gone through as there are 3 or 4 pony panels etc etc. The problem is that the basement has a finished ceiling and of course all the wiring and access to it are up there

Thanks again guys!

Dennis

[tramp]

good luck on the repairs

[mark]

..........  There is math involved to get to amps from watts.  Sorry, but I don't have the equations.  I'm sure someone else does.......

watts = volts X amps


it sounds like the circuit is overloaded. major appliances (a/c, dryer, range, dishwasher, etc) should have separate lines and breakers.


best of luck.

[tomsweb1]

Ok, I am an electrician. I do residential service on a daily basis, and have been for over 4 years now.
I am impressed with the amount of knowledge you guys have on the subject!
Yes, by code, your A/C AND Dryer need to be on dedicated circuits. The dryer pulls off of two phases, which is what makes it 240v, and why it's a two pole breaker.
If you are going to go ahead and replace the breaker, which is a good suggestion at this point, please please please turn off the main breaker. If you are living in an older house that does not have a main breaker, I would highly recommend  calling a pro. If you want to go ahead and do it anyway,and assuming your panel is in the basement, be aware that any concrete that you touch is DIRECT GROUND, meaning if you touch and part of the panel that is energized, you have the potential of drawing the ENTIRE capacity of the supply transformer through your body. wear shoes.

I would also highly recomend replacing your GFI breaker, it has tripped many times, and may not be protecting you as you would hope. Being that you and your family are swimming in a potential difference of 120v, it's a definite safety issue.

do you have any room in your panel left? Most likely not, that is the best reason (though highly illegal) that someone would put them both on the same circuit. if you do, you simply need to get another double breaker that matches the max breaker size, listed on the side of the AC unit. it's ok to go a little smaller, but NOT bigger. Follow the AC power line and see where it goes. if it goes to the panel, you should be able to make somethinhg work. If it goes to a junction box, you will need to run another line out of that box to the panel.

good god, I'm rambling....
I'll leave it at that for now... any more questions, do NOT hesitate to ask I am here to help...

no charge. ;p

[demon78]

Hey 78k out of idle curiosity and not much else let me know how it turns out will you? I've in the past found dryer elements that were short to ground by nails, ballpoint pen refills the metal ones and other metallic objects they would draw more current than normal but not pop the breaker.
Bill the demon.

[Duke McDukiedook]

When you go to separate with new breakers for the A/CAir from the dryer try to make sure you balance the sides of the breaker if possible. Look at your amperage pulls on both sides of the box to see if they are equal/close to equal.
If not, move them around to balance the load as much as possible. Also check your connections to the breakers and box to ensure a solid, mechanical connection.

[Dusthawk]

I would like to add one small point to this discussion. I live in a trailer park and we have a patchwork(at best) electrical panel. That said, I was hooked up to one side of a double 40 along with a neighbor who is running 240 to his mobile home. It kept popping the breaker because his system was drawing close to limit, and when I went to cook or run my AC, it would pop both. I finally got tired of it so I purchased a new double 40 and had it replaced, then had my circuit changed to one less used.

My point here is that heat also plays a big role in how often or how fast a breaker will trip. There at the end right before it was replaced it got so hot it burned my fingers when I went to reset it. If a breaker has been tripped too much it will over heat faster and more often, building more heat each time until it gets dangerous and melts or worse. One on the posts that the old one mounted to was carbonized and ruined, there was that much heat.

[my78k]

Sorry guys, I have been away for the week catching some R and R (and a few bass) up at my parent's cottage.

I have called in a favour (via my mom) to my uncle and he will come over and have a close look when he can (he is a licensed electrician). As soon as he does I will let you guys know his findings.

Thanks again guys!

As for me going into the panel....well that aint going to happen! I generally kill the breaker when I am merely changing out a socket or switch on 115 volt so there is no way in hell I am going to tackle going into the panel!!!

I told my uncle that I would gladly barter for his assistance so I will likely spend a weekend cutting firewood at his hunting camp but it beats electricuting myself! I do have 2 kids and a wife that may wanna see me around for a while yet. (ofcourse she does have a large policy on my life    )

Dennis

[tomsweb1]

Good on ya. It's always better safe than sorry. AT least you have someone like that that can help you. MOst people aren't so lucky.

[seaweb11]

Here's a better question.

If it's 90 degrees outside, why don't you just hang your clothes outside to dry.

Go green, our dryer hasn't been turned on in a couple of months........I'm just saying

[tomsweb1]

Didn't pay for a dryer for clothes to sit outside... that's a crapload of work for something I can throw all my clothes into andsd thier done in a hour. Sunlight fail.