Why didn't my breaker pop?

[brycez28]

Last night I was welding with my Campbell Hausfeld 115 Volt MIG / Flux-Core Welder. It has 4 heat settings, the frist 3 are for 15 amp circuit and the 4th is for 20amp. I've never used the 4th heat setting because I don't have a 20 amp circuit (yet). But I decided to try it, what is the worse that will happen, I'll get stuck in the dark? I already know my breaker will pop from my supervisor trying to use his plasma cutter in my garage.

Anyway, it didn't pop my breaker!? I also had 4 sets of shop lights on (two 32watt bulbs each), my radio and my drill battery may have been on the charger.

Should I worry that it didn't pop my breaker, or just go with it?

 

[kiatech]

Draw a longer arc and see what happens.

 

[brycez28]

True. I was welding two pieces of 2"x3" tube together, so my longest weld was just over 3".

 

[DenisG]

You can buy or borrow an ammeter to measure the actual current. Some meters will store the peak current, but you'll probably have to have someone watching the meter as you weld if you have the more common variety ammeter.

 

[JoeFin]

Anyway, it didn't pop my breaker!? I also had 4 sets of shop lights on (two 32watt bulbs each), my radio and my drill battery may have been on the charger.

Should I worry that it didn't pop my breaker, or just go with it?

Probably not

Breakers have a "Fault Curve" which is the response time vs: fault current to open for a fault. Of course we would have to know the exact model breaker to tell you exactly what that time is - but in your standard residential breaker the "Overload Region" of the response curve can be like 60 seconds at 125% of rated load. Not until it gets to 500% load does it get to the "Instantaneous Trip Region" of the Fault Curve

 

[ishiboo]

Probably not

Breakers have a "Fault Curve" which is the response time vs: fault current to open for a fault. Of course we would have to know the exact model breaker to tell you exactly what that time is - but in your standard residential breaker the "Overload Region" of the response curve can be like 60 seconds at 125% of rated load. Not until it gets to 500% load does it get to the "Instantaneous Trip Region" of the Fault Curve

+1.

Overcurrent problems are a function of not just amperage but time. You can safely draw 40A regularly (much more, in fact) from a #12 wire in short bursts, and it gives no time for the wire to heat up so no damage is done.

The bulbs were only about 2.5A, the charger maybe another .5A. So 23A on a 15A circuit for tiny periods of time is no big deal.

 

[brycez28]

Thanks for the replies! I'm glad to know I can use the highest setting on my welder now for short stints without worrying about my wiring. Learned
something new!

 

[laser3kw]

turn it up to "elevendy" and let'r rip

 

[volleyball]

Do you have Federal Pacific breakers?

 

[dslabuda]

I have the same welder. It takes a few seconds to pop the breaker here too on the 20amp setting. I've only used it once though.

Sent from my SAMSUNG-SM-N900A using Tapatalk 4

 

[rlitman]

Breakers have a "Fault Curve" which is the response time vs: fault current to open for a fault. Of course we would have to know the exact model breaker to tell you exactly what that time is - but in your standard residential breaker the "Overload Region" of the response curve can be like 60 seconds at 125% of rated load. Not until it gets to 500% load does it get to the "Instantaneous Trip Region" of the Fault Curve

Yep. If we knew the exact model breaker, we could look that curve up.

But from what I've seen, 125% could be a minute to trip, or it could be a few hours.

Instantaneous for breakers can be as low as around 5x the rating, but numbers as high as 12x (that would be 180A for your 15A breaker) are not unusual, or even dangerous.

ishiboo got it right. The breaker is there to protect your wiring, and overcurrent only causes damage when you combine high current with time duration. In the case if your welder, the current was only a little over the 15A, and the time duration just wasn't there.

Now if you did have Federal Pacific breakers, you have plenty to worry about, but that's a different story.