Anyone An Electrician?

Matt_ · March 13, 2010

I just wanted to get a second opinion on this since I am not an electrician...

First off, i have an ANCIENT Pushmatic panel. Yes, I am going to upgrade to a new panel soon.. and in doing so have a 200 amp service run to the house because I currently only have 100 amp (i know how this stuff works, don't worry i'm keeping 15 amp breakers on my 14awg circuits! The 200 amp service will help out down the road when we put an addition on and so I can run a few more dedicated circuits in my garage for high amperage tools)

With that said... i have a 15 amp circuit that seems to trip way too easily IMO. I used to be able to run a small 700 watt heater in my sons room with no problem; recently that started tripping the breaker. So i think its "getting worse" which tells me that the breaker is "going bad". There's nothing big on that circuit... two bedrooms and the light in the hallway... and yet I try to run a vacuum today and after a few minutes the breaker trips. No way in hell did I pull 15+ amps!

I already have a new breaker to put in.. well, hopefully its new. I ordered it offline since the only local store that has Pushmatic breakers charges $100ea , so I bought 2 breakers online for a total of $100 (i wanted a spare in case I need it before I replace the panel).

So... for those of you who have experience with this stuff; is this a sign of a breaker going bad?

- I checked my neutral wires and all looks good there.

- I don't think I have a short anywhere. I've been cleaning up the wiring in this house from day 1 and have been over that entire circuit. Plus, it only trips when I put a load on it... i just think its tripping closer to 10amps. It's also not a particular receptacle that causes it to trip.. and all the receptacles are new too.

....its a cold/windy/rainy/crappy day. If it was nice outside so I could open my garage doors to get some light in there, i'd just kill the main and replace the breaker. But since its not, im going to sit here comfortable and post this thread since i cant get my mind off of it

502ci · March 13, 2010

Definately sounds like it is going bad as those breakers are famous for doing so.

I know you already bought and have the breaker but you could have flopped the wire in the panel to another breaker to make sure it was the breaker...that would have involved using a breaker in your panel that is on the same phase as the bad breaker (in case a 12/3 romex is being used and two circuits are sharing the same neutral) unless you are sure and can see it's a 12/2 romex then any 15 amp breaker would do...granted the wire in your panel is probably not even romex as it's probably very old.

Anyways remove the existing wire temporarly and install the wire that has been tripping to the good breaker and load test it with the heater you mentioned.

But most likely it's a bad breaker and your problem will be solved when you install the new one...let us know how it goes.

Matt_ · March 13, 2010

Thanks man, thats a good idea... i do have another 15 amp in there that I can pull the wire off of to load test the circuit. Maybe i'll give that a shot in a bit when police academy is over

brims · March 13, 2010

With a 15A breaker, that's 1,800W so a 700W heater shouldn't do anything to the breaker, like it was said, put a new/different breaker in.

gregrocks89 · March 14, 2010

im all electrical man. First things first try chaning your breakers out. also another thing how old is the house? code has changed alot the past years now, You should only have 12 items on a circuit well thats for our code now anyways. Is the the Wiring alluminum or copper? if its alluminum it has a higher chance of getting hotter and tripping your breaker. Find out

Matt_ · March 14, 2010

Its all copper.

And there's 6 receptacles and two lights on the circuit... nothing on the circuit pulls much amperage; just when i plug in a heater or vacuum the breaker trips.

Hence, im pretty sure it's the breaker. But i wasn't sure if these "symptoms" matched those of a breaker going bad since i dont troubleshoot electrical circuits often.

I'm going to swap the breaker out tomorrow.

gregrocks89 · March 14, 2010

alright man yeah sounds like a faulty breaker. Try the new breaker first and we will have to see from there

louie730 · March 14, 2010

alright man yeah sounds like a faulty breaker. Try the new breaker first and we will have to see from there

The best way for sure is to put a clamp on ammeter on the 15 amp circuit at the circuit breaker and check the actual load on the circuit. I know a 700 watt heater by itself will not trip a 15 amp greaker (700 divided 120= 5.83 amps) but some vacums have quite large motors ( I have seen quite a few 1000 watt vacuums- but most are smaller)- 1000 divided by 120= 8.88 amps- with the heater 5.83 + 8.88 =14.18 amps which is mighty close to a 15 amp breaker-so if you even have a light or two it will blow the breaker in time so I would check the actual load befor I bought expensive breakers. But after all is done you're probably right it is a "weak breaker". Never hurts to pull out a meter and make sure, if you have access to a clamp on AC ammeter.

As a rule of thumb a 15 amp circuit or any ciccuit for that matter should not draw over 80% of the load for extended times.

Hope this helps.

Westlotorn · March 14, 2010

Great replies so far. I agree that the breaker is the most likely cause. One other test I use is at the plug where you are tripping the circuit. Run your 700 Watt heater and do a voltage test while it is running. If it is 120 volts while not loaded it should stay 120 volts with the load. If you have a voltage drop when loaded you have an issue with the wires, ground or supply. I know still vague but it would point to something other than the breaker.

Matt_ · March 14, 2010

Thanks for all the replies guys.

replaced the breaker and that did the trick as expected.

just a few notes for some of the above replies:

1) it wasn't a certain receptacle that would tirp the breaker.. if it was i'd be triple checking the wiring at that receptacle. the 700 watt heater would trip the breaker from one room, and the vacuum would trip the breaker when plugged in the other room.

2) i never tried running the heater and the vacuum at the same time. it would trip with one or the other which was bothering me. If i was running both and the breaker tripped, then i'd probably chalk it up to "getting close to 15 amps". But one or the other plus a few lights shouldn't pop it.

I don't have a clamp on ammeter but may get one to add to my tool collection.

Thanks for the replies everyone. there's some quality info posted above