Do circuit breakers become more trip-prone over time?


Old 01-06-13, 12:12 AM
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Question Do circuit breakers become more trip-prone over time?

I need to calculate the total load I'm putting on my circuit breaker, but I did not previously have this problem. It was not until my wife started running 2 heaters at once that this became an issue.

The way my (recently purchased) house is wired, the master bedroom is on the same electrical circuit as the two(-ish) living rooms (and the kitchen lights)... Which is also where my home office resides.

I used to be able to leave my old, clunky PC turned on (~400W power supply) along with our bedroom heater (a 1500W radiator)... But now they'll both be on and the circuit breaker will eventually trip.

Also, the circuit (when I go to switch it back on) feels warm when I hover my hand over it. That concerns me.

A.) Does a circuit breaker wear out, or does it spontaneously die (always working the same until then)?

B.) Is there an easy way to split my master bedroom off from the rest of the house? I imagine that will fix the majority of my problems. I know the bare minimum about household electricity.

Edit: House was built in 1972. I'm not sure how much of the electricals are original and how much were installed after the fact.
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Old 01-06-13, 01:07 AM
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Circuit breakers can be magnetic trip or thermal trip.
Yours are most likley of the thermal trip type which is why they feel warm.
Yes....under a load they can run warm.
With age their trip rating can change and they could trip quicker then they were designed to.

You're telling us that you have 1900 watts of connected load on that circuit. That translates into 15.8 amps of load. (wattage = volts x amps)
So if that is on a 15 amp breaker you are over by a bit.
A continuous load should not be more than 80% of the amperage of the breaker.
A 15 amp breaker can handle a continuous load of 1450 watts without tripping.

A 20 amp breaker can handle a continuous load of 1920 watts but requires # 12 wiring

How easy splitting the bedroom from the rest of the house comes down easy is it to get a wire from the electrical panel to that room.
Attic ? Basement ? Crawlspace ? Combination ?
You may end up leaving the bedroom where it is and change over a room that is easier to get to.

You may have to call an electrician and tell him what you want to do. Most in our trade will give you a free estimate.
Old 01-06-13, 07:41 AM
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Circuit breakers are not exact. It does not work like, when there is 14.9 amps on a 15 amp breaker it will hold, but at 15.1 it will trip, there is much more variance to this. I have seen breakers run with more than two amps over their rating for a hour before they will trip. It all has to do with heat. A breaker with other warm breakers next to it will trip sooner.

Note: A computers power supply wattage is the output rating. The watts used will depend on how much stuff it is running (hard drives, GPU's CPU's, etc.)
Old 01-06-13, 09:45 AM
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It hasn't been specifically spelled out yet but heaters best practice should be on a dedicated circuit.
Old 01-06-13, 08:00 PM
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Thanks everyone! I'll give an electrician a call.

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