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I need a time-delay Square D breaker for a new air compressor.

G

Guy Doucet

Jan 1, 1970
0
SITUATION
I have a 200 Amp electrical panel in my home. It's says QO Combination Load
Center Cat QO-40M Ser T4.

I built a garage a few years ago and brought a 12/3 wire to it which I had
connected to a 20 Amp SquareD circuit breaker I bought.

I have the following in my garage
- garage door opener, 8 x 100Watt light bulbs, Table saw, Old Shop Vac,
etc...

I just bought a Delta Air Compressor but it popped my 20Amp breaker. Nothing
else in the garage was on, except maybe the 60Watt light bulb in the garage
door opener.

So then I read in the compressor manual where I found the following
specifications:
- Voltage-Single Phase 120V/60Hz/1Ph
- Minimum Branch Circuit Requirement 15 amps
- Fuse Type Time Delay (circuit breaker is preffered)


QUESTION
How can I differentiate from a reqular SquareD circuit breaker and a Time
Delay SquareD circuit breaker. There doesn't appear to be any indications on
the breaker itself.

Thanks for any and all information.

G Doucet
 
F

Fred

Jan 1, 1970
0
Sounds like you should take a look at the motor amp rating and horsepower on
that new compressor of yours.

A compressor motor will draw up to three times its rated running amperage to
start up. Could be up to 45 amps in your case depending on the motor
horsepower.

Have never heard of a "time-delay" circuit breaker???

Fred
 
Guy Doucet said:
I built a garage a few years ago and brought a 12/3 wire to it which I
had connected to a 20 Amp SquareD circuit breaker I bought.

About how long is the run from the breaker panel to the garage?
I have the following in my garage
- garage door opener, 8 x 100Watt light bulbs, Table saw, Old Shop Vac,
etc...

If all 8 light bulbs are on then you probably will pop the breaker if
you try to run the compressor.
So then I read in the compressor manual where I found the following
specifications:
- Voltage-Single Phase 120V/60Hz/1Ph
- Minimum Branch Circuit Requirement 15 amps
- Fuse Type Time Delay (circuit breaker is preffered)
QUESTION
How can I differentiate from a reqular SquareD circuit breaker and a Time
Delay SquareD circuit breaker.

The terseness of the label is a bit confusing. "Time delay" refers to
the fuse type, not the breaker type. A better way to put it would be:

---
If you use a fuse on the circuit for this compressor, use a time delay
type fuse. A regular fuse will blow when the motor starts.

Using a circuit breaker, instead of a fuse, is preferred.
---

Nearly all circuit breakers that you're likely to encounter in your
house are already "time delay". They are made this way for precisely
your application: starting motors. Motors draw a lot more current when
they start up than they do when they are running, but if the motor is
working correctly, this high current draw only lasts for a few seconds.
If the high current draw persists for longer than that, the breaker will
trip.

In a perfect world, the compressor would have a 15 amp breaker all to
itself. One thing to check is that all connections on the circuit,
starting at the breaker panel, are clean and tight. If you have a bad
connection, the resistance of the circuit will go up, which will lower
the voltage at the compressor motor. Within certain limits, the motor
will attempt to draw more current to compensate, which might trip the
breaker. If you have a voltmeter, you might be able to tell. Measure
the voltage at an outlet in the garage with everything or nearly
everything in the garage shut off, and note the reading. Then go around
and turn on all the lights and maybe the vacuum, then with all that
stuff running, take another reading at the same outlet. It will be
lower than the first reading by a volt or two, but if it's 10 or 20
volts lower, you have a problem - either a bad connection somewhere, or
the 12/3 wire was too small for the distance between your garage and the
breaker panel.

If you used "push in" connections that did not require you to also
tighten a screw, redo each connection like this, this time putting the
wire under the screw head. Make sure all wire nuts are on tight, and
so on.

Warning: Electricity can kill you, so be careful. Get help from an
electrician if needed.

Matt Roberds
 
G

Guy Doucet

Jan 1, 1970
0
Stephen B. said:
indications

Always check the specks before buying. I am a mech. engineer, not an
electrician, but I think all breakers are time delay. Some are GFCI, or arc
fault, leading to other things to check for.You do not give much information
as to the event, but it sounds to me like a wiring, or compressor problem
not a breaker problem.
How far does the wire run from the main panel to the garage (voltage drops
under load at the outlet)?
Is this a plug in compressor or a hard wired one?
Did the motor start up then blow the breaker, or did the breaker trip
without the motor turning?
With the compressor disconnected from the power and the air lines open,
assuming it is accessible can you turn the motor by hand?
Did you remove all the shipping materials?

- The circuit breaker popped as soon as I turned on the power switch of the
compressor - the compressor itself didn't come on at all.

- It's a plug in compressor, it's not hard wired. I plugged it into the
outlet in my garage.

- The specifications in the manual says that I need a time-delay fuse but a
circuit breaker would be better.

- "Perhaps circuit breakers are all time delay".

Anyway, I reset the breaker and decideed to try it again - and it actually
works now, HURRAAAAYYYYY!!! :)

Perhaps the compressor popped the breaker the first time because it was new
and had not been turned on before???


Besides that, the 12/3 wire that I have running to the garage is about 40
feet long. I think I'm gonna try to get 10/3 or bigger, and perhaps even
I'll try to install a sub electric panel in the garage!

Thanks for all.

Guy Doucet
 
G

Guy Doucet

Jan 1, 1970
0
About how long is the run from the breaker panel to the garage?


If all 8 light bulbs are on then you probably will pop the breaker if
you try to run the compressor.



The terseness of the label is a bit confusing. "Time delay" refers to
the fuse type, not the breaker type. A better way to put it would be:

---
If you use a fuse on the circuit for this compressor, use a time delay
type fuse. A regular fuse will blow when the motor starts.

Using a circuit breaker, instead of a fuse, is preferred.
---

Nearly all circuit breakers that you're likely to encounter in your
house are already "time delay". They are made this way for precisely
your application: starting motors. Motors draw a lot more current when
they start up than they do when they are running, but if the motor is
working correctly, this high current draw only lasts for a few seconds.
If the high current draw persists for longer than that, the breaker will
trip.

In a perfect world, the compressor would have a 15 amp breaker all to
itself. One thing to check is that all connections on the circuit,
starting at the breaker panel, are clean and tight. If you have a bad
connection, the resistance of the circuit will go up, which will lower
the voltage at the compressor motor. Within certain limits, the motor
will attempt to draw more current to compensate, which might trip the
breaker. If you have a voltmeter, you might be able to tell. Measure
the voltage at an outlet in the garage with everything or nearly
everything in the garage shut off, and note the reading. Then go around
and turn on all the lights and maybe the vacuum, then with all that
stuff running, take another reading at the same outlet. It will be
lower than the first reading by a volt or two, but if it's 10 or 20
volts lower, you have a problem - either a bad connection somewhere, or
the 12/3 wire was too small for the distance between your garage and the
breaker panel.

If you used "push in" connections that did not require you to also
tighten a screw, redo each connection like this, this time putting the
wire under the screw head. Make sure all wire nuts are on tight, and
so on.

Warning: Electricity can kill you, so be careful. Get help from an
electrician if needed.

Matt Roberds

- The circuit breaker popped as soon as I turned on the power switch of the
compressor - the compressor itself didn't come on at all.

- It's a plug in compressor, it's not hard wired. I plugged it into the
outlet in my garage.

- The specifications in the manual says that I need a time-delay fuse but a
circuit breaker would be better.

- "Perhaps circuit breakers are all time delay".

Anyway, I reset the breaker and decideed to try it again - and it actually
works now, HURRAAAAYYYYY!!! :)

Perhaps the compressor popped the breaker the first time because it was new
and had not been turned on before???


Besides that, the 12/3 wire that I have running to the garage is about 40
feet long. I think I'm gonna try to get 10/3 or bigger, and perhaps even
I'll try to install a sub electric panel in the garage!

Thanks for all.

Guy Doucet
 
A

Andrew Gabriel

Jan 1, 1970
0
Sounds like you should take a look at the motor amp rating and horsepower on
that new compressor of yours.

A compressor motor will draw up to three times its rated running amperage to
start up. Could be up to 45 amps in your case depending on the motor
horsepower.

Have never heard of a "time-delay" circuit breaker???

They're standard in Europe. Breakers are rated Type B,
Type C, or Type D. Type B will allow through 3-5 times
the rating for a short time without tripping, type C is
5-10 times, and type D is 10-50 times.

Type B is the standard breaker used in the home. Type C
is normally used for things like aircon and other large
motors. Type D is specialist use and not found in the home.
Square D manufacture this range for Europe (might not go up
to Type D -- generally only industrial breaker ranges do).

(In the UK, we used to have Type 1, 2, 3, and 4 with similar
meanings, but have switched over to the common EU types now.)
 
B

Brian

Jan 1, 1970
0
Update the wiring to your garage. Run a dedicated line for the compressor for starters. Or put a
sub panel in the garage. Or call a qualified electrician before your house burns down.



| QUESTION
| How can I differentiate from a reqular SquareD circuit breaker and a Time
| Delay SquareD circuit breaker. There doesn't appear to be any indications on
| the breaker itself.

The standard breakers have a combination magnetic trip and thermal trip.
The magnetic trip is generally set at a few times the breaker rating.
That should trip in the case of a short circuit. The thermal trip would
be close to accurate, and this is the time delay part.

Apparently the starting current for your compressor is pulling quite a
lot of current. How fast does your breaker trip? If immediate, then
it is the magentic element doing the job. Increasing the breaker rating
would not generally help because that element is usually around the same
rating for breaker from 15 to 60 amps.

If there is any delay from compressor start to breaker trip, it could be
that the compressor is pulling locked rotor amps for too long of a period.
Maybe it needs some appropriate maintainance, lubrication, etc.

Breakers that can be adjusted for magnetic trip point and time delay do
exist, but they are expensive (well over $1000).
 
B

Ben Miller

Jan 1, 1970
0
Guy Doucet said:
QUESTION
How can I differentiate from a reqular SquareD circuit breaker and a Time
Delay SquareD circuit breaker. There doesn't appear to be any indications
on
the breaker itself.

You need a QO-HM breaker ("high magnetic"). They are designed to withstand
much higher inrush current than the standard QO, and they are physically
interchangeable. Available in 15 or 20 amp rating. You probably won't find
them at the local home center store, however.

Ben Miller
 
B

Bob

Jan 1, 1970
0
- The circuit breaker popped as soon as I turned on the power switch of the
compressor - the compressor itself didn't come on at all.

- It's a plug in compressor, it's not hard wired. I plugged it into the
outlet in my garage.

- The specifications in the manual says that I need a time-delay fuse but a
circuit breaker would be better.

- "Perhaps circuit breakers are all time delay".

Anyway, I reset the breaker and decideed to try it again - and it actually
works now, HURRAAAAYYYYY!!! :)

Perhaps the compressor popped the breaker the first time because it was new
and had not been turned on before???


Besides that, the 12/3 wire that I have running to the garage is about 40
feet long. I think I'm gonna try to get 10/3 or bigger, and perhaps even
I'll try to install a sub electric panel in the garage!

Thanks for all.

Guy Doucet
That was likely your problem. 40' of 12/3 cord might have just enough
voltage drop to cause the breaker to trip IF the utility voltage
happened to already be a bit low that moment. Probably the 2nd time
you tried it, the utility line was back to normal and it worked
without tripping the breaker. If I were you, I would do exactly as you
indicated; buy a 10/3 cordset if you need to go that far.

And that other post was correct. You were taken in by the poor wording
of that label. "Time Delay" was refering to only the fuse, all circuit
breakers are "time delay" by nature of their design.
 
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