Can someone define what the "trip amps" on a breaker means? I have a
20A breaker that has a Trip Amps of 27A. I'm running a breaker right
at 20A and it's tripping after several minutes. I just increased it
to a 25A breaker, but I'd like to understand what "trip amps" means.

-- Geoff

GeoffSchultz wrote:
Can someone define what the "trip amps" on a breaker means? I have a
20A breaker that has a Trip Amps of 27A. I'm running a breaker right
at 20A and it's tripping after several minutes. I just increased it
to a 25A breaker, but I'd like to understand what "trip amps" means.

-- Geoff

Hello Geoff,

As you've found out, common circuit breakers are not precision devices.
The current at which a breaker will trip seems to be a function of age,
time, number of switch cycles, manufacturing tolerances, etc. Seems to
usually work out ok, though.

Generally, a 20 Amp breaker will not trip at 20 Amps, at least not
immediately. They are tested at 135% and 200% of rated capacity. So the
27 Amps works out to be 135% of 20 Amps. This is sometimes called a
"must trip" rating, which, in practice, is a must trip if you cross your
fingers thing. After all, do you know anybody who has ever tested one?

Hope that helps.

Good luck.

Chuck

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I just increased it to a 25A breaker,

Which the circuit's wiring will still support, right?

"Bill Kearney" wkearney-99@hot-mail-com wrote in
:

I just increased it to a 25A breaker,

Which the circuit's wiring will still support, right?


You mean the #14 it's wired with may be too small?

Why is it, in a boat or car, it's ok to fuse or breaker #16 wire at 30A on
a 12V DC circuit, but not on the AC circuit? That has never ceased to
amaze me.... They melt the same.


Larry
--

Larry wrote:
snip
You mean the #14 it's wired with may be too small?

Why is it, in a boat or car, it's ok to fuse or breaker #16 wire at 30A on
a 12V DC circuit, but not on the AC circuit? That has never ceased to
amaze me.... They melt the same.

Larry

The electrons in an AC circuit are like a Chinese or Italian fire drill
compared the electrons in a DC circuit. They keep rushing back and
forth from one end to the other and generating a lot of extra heat.

DC circuits are like German fire drills. All the electrons are moving
in an orderly flow from one end to other so you can have about two or
three times as many participants.

Yep, that's it. That's my story and I'm sticking to it...

Jack

--
Jack Erbes in Ellsworth, Maine, USA - jackerbes at adelphia dot net
(also receiving email at jacker at midmaine.com)

"Jack Erbes" wrote in message
...
The electrons in an AC circuit are like a Chinese or Italian fire drill
compared the electrons in a DC circuit. They keep rushing back and
forth from one end to the other and generating a lot of extra heat.

DC circuits are like German fire drills. All the electrons are moving
in an orderly flow from one end to other so you can have about two or
three times as many participants.

Yep, that's it. That's my story and I'm sticking to it...

And your switches work by pressing hard on the wire until no electron can
pass anymore, right?

Meindert

On Mar 7, 11:34 pm, "Bill Kearney" wkearney-99@hot-mail-com wrote:
I just increased it to a 25A breaker,

Which the circuit's wiring will still support, right?

It 10 AWG wire. The 20A circuit breaker is a new breaker and I
suspect that it's defective. I'm going to return it.

-- Geoff

Meindert Sprang wrote:
"Jack Erbes" wrote in message
...
The electrons in an AC circuit are like a Chinese or Italian fire drill
compared the electrons in a DC circuit. They keep rushing back and
forth from one end to the other and generating a lot of extra heat.

DC circuits are like German fire drills. All the electrons are moving
in an orderly flow from one end to other so you can have about two or
three times as many participants.

Yep, that's it. That's my story and I'm sticking to it...

And your switches work by pressing hard on the wire until no electron can
pass anymore, right?

Meindert

Right! Hey, I need some technical help while you're here. I
accidentally let the smoke out of some of my wiring, how can I put that
back? :)

Jack

--
Jack Erbes in Ellsworth, Maine, USA (jackerbes at adelphia dot net)
(also receiving email at jacker at midmaine dot com)

chuck wrote:
:GeoffSchultz wrote:
: Can someone define what the "trip amps" on a breaker means? I have a
: 20A breaker that has a Trip Amps of 27A. I'm running a breaker right
: at 20A and it's tripping after several minutes. I just increased it
: to a 25A breaker, but I'd like to understand what "trip amps" means.
:
: -- Geoff
:
:Hello Geoff,

:As you've found out, common circuit breakers are not precision devices.
:The current at which a breaker will trip seems to be a function of age,
:time, number of switch cycles, manufacturing tolerances, etc. Seems to
:usually work out ok, though.

:Generally, a 20 Amp breaker will not trip at 20 Amps, at least not
:immediately. They are tested at 135% and 200% of rated capacity. So the
:27 Amps works out to be 135% of 20 Amps. This is sometimes called a
:"must trip" rating, which, in practice, is a must trip if you cross your
:fingers thing. After all, do you know anybody who has ever tested one?

Many circuit breakers have two tripping method. There's a magnetic
breaker that trips nearly instantly on large overcurrent. Then
there's a thermal breaker that will trip on smaller overload, but not
instantly. That allows for starting motors and the like.

"Jack Erbes" wrote in message
...
Right! Hey, I need some technical help while you're here. I
accidentally let the smoke out of some of my wiring, how can I put that
back? :)

Unscrew the other end and suck on it hard. Or maybe reversing the polarity
might help. I hope it wasn't AC?

Meindert