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How do you know a new circuit breaker is protecting the circuit properly?

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BobH

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Dec 1, 2006, 12:31:58 PM12/1/06
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I am changing a 50-amp breaker to a 30-amp one to install an oven that
draws less current than the old one did. I have seen information here
about testing a bad circuit breaker, but how do you test a good one? In
other words, if I install a new breaker, how do I know it will trip if
the load exceeds 30 amps?

Mikepier

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Dec 1, 2006, 12:40:47 PM12/1/06
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Other than shorting both legs of the 220 line and creating an
impressive spark, you just assume, as the rest of us, that the breaker
works, and chances are that it will.

What is the current draw on your new oven at full load?

CJT

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Dec 1, 2006, 12:47:21 PM12/1/06
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BobH wrote:

Put a >30 amp load on the circuit?

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Steve Barker LT

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Dec 1, 2006, 12:59:00 PM12/1/06
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The breaker is there to protect the wiring, not the appliance. And there's
no need to check them.

--
Steve Barker

"BobH" <bob.h...@gmail.com> wrote in message
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spamT...@yahoo.com

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Dec 1, 2006, 1:14:31 PM12/1/06
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There is no need to change the breaker to match the load, as long as
all the associated wiring is rated for 50A.

Dave

Pop`

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Dec 1, 2006, 1:21:12 PM12/1/06
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You pretty much have to trust to their design and Quality operations, but
... if it has UL, CSA, EU or other comparable safety markings (which are
required in order to sell them), you can pretty much assume they'll do the
job they're designed for.

Do NOT short the leads to "test" a breaker! You may or may not have a
functionally, to-spec breaker after that! Just in case the idea sounded
good to you <g>.

Pop`

Pop`

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Dec 1, 2006, 1:24:14 PM12/1/06
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Well, actually, there is. In fact, many local codes would require a change
in this case. 48 amps thru a 50 amp breaker into an appliance that is rated
for 30A would indeed be a fire hazard at the appliance itself or wherever
the extra current is going to.

Calls to the local code enforcement are quick, short, and the best way to be
sure of what the codes say, and logic and common sense says to use the right
sized breaker.


avid_hiker

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Dec 1, 2006, 1:24:50 PM12/1/06
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Good and sound advise POP!!

Chris Friesen

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Dec 1, 2006, 1:42:01 PM12/1/06
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Pop` wrote:

> Well, actually, there is. In fact, many local codes would require a change
> in this case. 48 amps thru a 50 amp breaker into an appliance that is rated
> for 30A would indeed be a fire hazard at the appliance itself or wherever
> the extra current is going to.

Given that "standard" range circuits are 50A, I would expect that any
UL/CSA listed range will be safe to plug into such a circuit.

It may actually have a smaller fuse (or a thin wire designed to act as
one) in the appliance itself--this is what many kitchen appliances do,
and why they can have such tiny cords and still plug into 20A receptacles.

Chris

Terry

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Dec 1, 2006, 3:11:49 PM12/1/06
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Will the plug go in a 50A recpt? If it does then I see no reason to
change it.

You would only have to change the breaker if you changed the outlet.

I think most receptacles are keyed somehow to keep you from using an
incorrect appliance.

You can plug a 15A device in a 20 Amp recpt, but you can not plug a
20A plug into a 15A recpt.

Heathcliff

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Dec 1, 2006, 3:23:26 PM12/1/06
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> Do NOT short the leads to "test" a breaker! You may or may not have a
> functionally, to-spec breaker after that! Just in case the idea sounded
> good to you <g>.
>
> Pop`

Does that mean anytime a breaker opens it is thereafter suspect and
should be inspected by an electrician? If so, I have not been leading
a safe life. -- H

Steve Barker LT

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Dec 1, 2006, 5:24:14 PM12/1/06
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ACTUALLY, not.

The breaker is there to protect the wiring, not the appliance. And there's
no need to check them.

--
Steve Barker

There is no need to change the breaker to match the load, as long as


all the associated wiring is rated for 50A.

Dave


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"Pop`" <nod...@devnull.spamcop.net> wrote in message
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Steve Barker LT

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Dec 1, 2006, 5:25:31 PM12/1/06
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I'd like to see a 20a plug. They're so few and far between, they might as
well obsolete them.

--
Steve Barker

"Terry" <Kilo...@charter.net> wrote in message
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hal...@aol.com

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Dec 1, 2006, 5:39:46 PM12/1/06
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> Do NOT short the leads to "test" a breaker! You may or may not have a
> functionally, to-spec breaker after that! Just in case the idea sounded
> good to you <g>.
>
> Pop`

I disagreee with the idea shorting a breaker either intentially or
accidently can damage a breaker......

I used to fix office macxhines at Westinghouse Beaver, a plant that
produced circuit breakers of all sizes.

spent a LOT of time there and made friends, at one point they offered
me a job, no interview necessary. just drop application with gorgeous
secretary, give notice to current employer start in 2 weeks. it was a
fascinating place.

they cycled breakers thru hundreds of dead shorts and other hard tests.
then tore them aart to see what failed.

some dead shorts arent a problem for a breaker, its part of normal
operation.

just like turning on a lamp is.........

given all this i would not makew a habit of it..........

but dangerous to the breaker thats like saying slamming on the brakes
of a car make it less likely to stop the next time

hal...@aol.com

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Dec 1, 2006, 5:39:52 PM12/1/06
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> Do NOT short the leads to "test" a breaker! You may or may not have a
> functionally, to-spec breaker after that! Just in case the idea sounded
> good to you <g>.
>
> Pop`

I disagreee with the idea shorting a breaker either intentially or

Stubby

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Dec 1, 2006, 7:25:04 PM12/1/06
to hal...@aol.com

Right. You're not testing fuses.
I assume your worked at Beaver, PA. Right? I used to know Donald C.
Burnham in Mt. Lebanon.

hal...@aol.com

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Dec 1, 2006, 7:54:04 PM12/1/06
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> Right. You're not testing fuses.
> I assume your worked at Beaver, PA. Right? I used to know Donald C.
> Burnham in Mt. Lebanon.

yeah beaver a nice place wonderful workers. cafeteria was great!

I decided to not take the job, but it was a very close decision. kinda
far from home and a family member was ill at the time. Great
oppportunity at the time

I made a good decision within 3 years everyone with less than 20 years
was let go. part of the general Westinghouse fiancial mess from its
fiancial services division they lost a fortune. I worked in lots of
westinghouse plants east pittsburgh the mother plant, Large pa, some
fiancial offices:( others serviced the nuclear division I never got
cleared for that.

Sad what happened to westinghouse, today I service the blairsville
plant that makes nuclear fuel rods..........

I pass the beaver plant often, its owner has changed the parking lot
largely empty:(

some of the last automated equiptement was awesome watching it run.

they had robots delivering stuff.

I fixed opffice machines now all obsolete

volts500

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Dec 1, 2006, 9:14:50 PM12/1/06
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Connect it to a load that exceeds 30 amps.

Don Young

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Dec 1, 2006, 9:59:18 PM12/1/06
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"Steve Barker LT" <railph...@not.hotmail.com> wrote in message
news:OMSdnYeVD7NLNu3Y...@giganews.com...
Some heaters and lots of airconditioners use 20 amp plugs. They are sold in
our local hardware stores.

Don Young


Bud--

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Dec 4, 2006, 12:16:51 PM12/4/06
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Steve Barker LT wrote:

> ACTUALLY, not.
>
> The breaker is there to protect the wiring, not the appliance. And there's
> no need to check them.
>

The breaker protects the wiring and the appliance (some exceptions, like
motor circuits). What do you think protects the appliance from faults
and failures? For instance Pop's 48A failure in a 30A appliance.

--
bud--

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