Circuit Breaker 22AIC

On Monday, September 25, 2023 at 7:55:48 PM UTC-7, Ricky wrote:
> On Monday, September 25, 2023 at 4:57:02 PM UTC-4, Eddy Lee wrote: 
> > On Monday, September 25, 2023 at 1:39:33 PM UTC-7, Ricky wrote: 
> > > On Monday, September 25, 2023 at 4:25:39 PM UTC-4, Eddy Lee wrote: 
> > > > On Monday, September 25, 2023 at 12:31:34 PM UTC-7, Ricky wrote: 
> > > > > On Monday, September 25, 2023 at 2:44:39 PM UTC-4, Eddy Lee wrote: 
> > > > > > On Monday, September 25, 2023 at 11:22:16 AM UTC-7, Don Y wrote: 
> > > > > > > On 9/25/2023 9:05 AM, Eddy Lee wrote: 
> > > > > > > > If I unplug the fridge, or when it's silence, microwave is fine. Sound like I need a relay circuit to disable the fridge from the microwave. Namely, a fridge outlet on the microwave. 
> > > > > > > What's the nameplate rating of the microwave? Does *it* say 
> > > > > > > it requires a dedicated circuit? (because it draws more than 
> > > > > > > half of the rated branch circuit's ampacity) 
> > > > > > > 
> > > > > > > The countertops, in kitchens, tend to see lots of large 
> > > > > > > loads that are often running concurrently. Toaster, 
> > > > > > > toaster oven, countertop oven (e.g., all the toaster 
> > > > > > > ovens on steroids that you see advertised on TV), 
> > > > > > > stand/hand mixer, electric frying pan, *TV*, etc. 
> > > > > > > 
> > > > > > > Add to this the other large loads that folks tend to 
> > > > > > > think nothing of activating: dishwasher, garbage disposal, 
> > > > > > > microwave, "instant hot water", etc. Imagine mindlessly 
> > > > > > > turning on the garbage disposal (for 10 seconds) and 
> > > > > > > tripping a breaker because it shared a branch circuit 
> > > > > > > with some other appliance... 
> > > > > > > 
> > > > > > > You *don't* want to unplug/replug the refrigerator 
> > > > > > > (which is what a relay would do) as this can confuse 
> > > > > > > the defrost timer and (for poorly designed controls) 
> > > > > > > lead to the compressor starting under a (mechanical) 
> > > > > > > load that hasn't yet had time to dissipate (smart 
> > > > > > > controls will inhibit the compressor for its required 
> > > > > > > dead time on initial application of power for exactly 
> > > > > > > this reason -- but, then, you would risk the compressor 
> > > > > > > always "waiting" even without cause) 
> > > > > > > 
> > > > > > > [Microwave ovens tend to see frequent, brief use. 
> > > > > > > Would you want your refrigerator being unplugged 
> > > > > > > each time you throw something in the microwave 
> > > > > > > for 15 seconds?] 
> > > > > > > 
> > > > > > > And, refrigerators (if disabled due to a tripped breaker) 
> > > > > > > risk having their contents spoil. So, you'd like the 
> > > > > > > refrigerator to be the sole item that can cause *its* 
> > > > > > > breaker to trip (imagine the instant hot water unit 
> > > > > > > thermostatically cycled on and silently took out the 
> > > > > > > breaker for the refrigerator... which you happen to 
> > > > > > > discover the next *morning*). Ditto the dishwasher 
> > > > > > > or any other appliance that can "safely" sit, powered 
> > > > > > > off, with no ill effects (e.g., the dishes are still dirty 
> > > > > > > but aren't getting any *dirtier* in the absence of mains!) 
> > > > > > Fridge: 310KWhr/year = 35W average (no info on motor) 
> > > > > > Microwave: 1500W 
> > > > > > Laptops: 60W to 90W. 
> > > > > > 
> > > > > > No dishwasher or coffee pot. 
> > > > > I like that you provided the "average" power draw of the fridge. How do you expect to use that in solving your problem? 
> > > > You answered your question in another post: 
> > > > 
> > > > "Typically a refrigerator runs on 35% duty cycle, (65% for a freezer). This means that if you take the running watts and multiply it by 35%, you can get an idea as to how much power the average running amps will be." 
> > > I'm pretty sure I didn't post that. Regardless, that would be a combination of an average with a rule of thumb, so not of much value. The point is, your appliance has a plate with the actual power rating while running. Why don't you look at that? Not the motor, the appliance. You've also said nothing about the size of this appliance. Is it a dorm room size fridge? A massive double door kitchen behemoth? Something in between? As is usual with you, only the barest minimum of information is provided and then the guessing begins. 
> > There is an energy guide tag saying 310 KWhr/year. Nothing else. Detail info might be at the back of the fridge. Too heavy to pull the fridge out when loaded.
> Ok, but that's not the same as "nothing else". It just means you don't know the wattage and you won't do what it takes to find it. Can you read a model number somewhere? Did you look inside the fridge? 

OK, GE GPE12FGKDWW
1.2A 115VAC
Ice maker power:145W
Defrost power:180W

On Monday, September 25, 2023 at 8:43:34 PM UTC-7, Eddy Lee wrote:
> On Monday, September 25, 2023 at 7:55:48 PM UTC-7, Ricky wrote: 
> > On Monday, September 25, 2023 at 4:57:02 PM UTC-4, Eddy Lee wrote: 
> > > On Monday, September 25, 2023 at 1:39:33 PM UTC-7, Ricky wrote: 
> > > > On Monday, September 25, 2023 at 4:25:39 PM UTC-4, Eddy Lee wrote: 
> > > > > On Monday, September 25, 2023 at 12:31:34 PM UTC-7, Ricky wrote: 
> > > > > > On Monday, September 25, 2023 at 2:44:39 PM UTC-4, Eddy Lee wrote: 
> > > > > > > On Monday, September 25, 2023 at 11:22:16 AM UTC-7, Don Y wrote: 
> > > > > > > > On 9/25/2023 9:05 AM, Eddy Lee wrote: 
> > > > > > > > > If I unplug the fridge, or when it's silence, microwave is fine. Sound like I need a relay circuit to disable the fridge from the microwave. Namely, a fridge outlet on the microwave. 
> > > > > > > > What's the nameplate rating of the microwave? Does *it* say 
> > > > > > > > it requires a dedicated circuit? (because it draws more than 
> > > > > > > > half of the rated branch circuit's ampacity) 
> > > > > > > > 
> > > > > > > > The countertops, in kitchens, tend to see lots of large 
> > > > > > > > loads that are often running concurrently. Toaster, 
> > > > > > > > toaster oven, countertop oven (e.g., all the toaster 
> > > > > > > > ovens on steroids that you see advertised on TV), 
> > > > > > > > stand/hand mixer, electric frying pan, *TV*, etc. 
> > > > > > > > 
> > > > > > > > Add to this the other large loads that folks tend to 
> > > > > > > > think nothing of activating: dishwasher, garbage disposal, 
> > > > > > > > microwave, "instant hot water", etc. Imagine mindlessly 
> > > > > > > > turning on the garbage disposal (for 10 seconds) and 
> > > > > > > > tripping a breaker because it shared a branch circuit 
> > > > > > > > with some other appliance... 
> > > > > > > > 
> > > > > > > > You *don't* want to unplug/replug the refrigerator 
> > > > > > > > (which is what a relay would do) as this can confuse 
> > > > > > > > the defrost timer and (for poorly designed controls) 
> > > > > > > > lead to the compressor starting under a (mechanical) 
> > > > > > > > load that hasn't yet had time to dissipate (smart 
> > > > > > > > controls will inhibit the compressor for its required 
> > > > > > > > dead time on initial application of power for exactly 
> > > > > > > > this reason -- but, then, you would risk the compressor 
> > > > > > > > always "waiting" even without cause) 
> > > > > > > > 
> > > > > > > > [Microwave ovens tend to see frequent, brief use. 
> > > > > > > > Would you want your refrigerator being unplugged 
> > > > > > > > each time you throw something in the microwave 
> > > > > > > > for 15 seconds?] 
> > > > > > > > 
> > > > > > > > And, refrigerators (if disabled due to a tripped breaker) 
> > > > > > > > risk having their contents spoil. So, you'd like the 
> > > > > > > > refrigerator to be the sole item that can cause *its* 
> > > > > > > > breaker to trip (imagine the instant hot water unit 
> > > > > > > > thermostatically cycled on and silently took out the 
> > > > > > > > breaker for the refrigerator... which you happen to 
> > > > > > > > discover the next *morning*). Ditto the dishwasher 
> > > > > > > > or any other appliance that can "safely" sit, powered 
> > > > > > > > off, with no ill effects (e.g., the dishes are still dirty 
> > > > > > > > but aren't getting any *dirtier* in the absence of mains!) 
> > > > > > > Fridge: 310KWhr/year = 35W average (no info on motor) 
> > > > > > > Microwave: 1500W 
> > > > > > > Laptops: 60W to 90W. 
> > > > > > > 
> > > > > > > No dishwasher or coffee pot. 
> > > > > > I like that you provided the "average" power draw of the fridge. How do you expect to use that in solving your problem? 
> > > > > You answered your question in another post: 
> > > > > 
> > > > > "Typically a refrigerator runs on 35% duty cycle, (65% for a freezer). This means that if you take the running watts and multiply it by 35%, you can get an idea as to how much power the average running amps will be." 
> > > > I'm pretty sure I didn't post that. Regardless, that would be a combination of an average with a rule of thumb, so not of much value. The point is, your appliance has a plate with the actual power rating while running. Why don't you look at that? Not the motor, the appliance. You've also said nothing about the size of this appliance. Is it a dorm room size fridge? A massive double door kitchen behemoth? Something in between? As is usual with you, only the barest minimum of information is provided and then the guessing begins. 
> > > There is an energy guide tag saying 310 KWhr/year. Nothing else. Detail info might be at the back of the fridge. Too heavy to pull the fridge out when loaded. 
> > Ok, but that's not the same as "nothing else". It just means you don't know the wattage and you won't do what it takes to find it. Can you read a model number somewhere? Did you look inside the fridge?
> OK, GE GPE12FGKDWW 
> 1.2A 115VAC 
> Ice maker power:145W 
> Defrost power:180W

I just need to relay switch off half of the laptops or the fridge when using the microwave.

On 2023-09-25, Eddy Lee <eddy711lee@gmail.com> wrote:
> On Monday, September 25, 2023 at 12:31:34&#8239;PM UTC-7, Ricky wrote:
>> On Monday, September 25, 2023 at 2:44:39&#8239;PM UTC-4, Eddy Lee wrote: 
>> > On Monday, September 25, 2023 at 11:22:16&#8239;AM UTC-7, Don Y wrote: 
>> > > On 9/25/2023 9:05 AM, Eddy Lee wrote: 
>> > > > If I unplug the fridge, or when it's silence, microwave is fine. Sound like I need a relay circuit to disable the fridge from the microwave. Namely, a fridge outlet on the microwave. 
>> > > What's the nameplate rating of the microwave? Does *it* say 
>> > > it requires a dedicated circuit? (because it draws more than 
>> > > half of the rated branch circuit's ampacity) 
>> > > 
>> > > The countertops, in kitchens, tend to see lots of large 
>> > > loads that are often running concurrently. Toaster, 
>> > > toaster oven, countertop oven (e.g., all the toaster 
>> > > ovens on steroids that you see advertised on TV), 
>> > > stand/hand mixer, electric frying pan, *TV*, etc. 
>> > > 
>> > > Add to this the other large loads that folks tend to 
>> > > think nothing of activating: dishwasher, garbage disposal, 
>> > > microwave, "instant hot water", etc. Imagine mindlessly 
>> > > turning on the garbage disposal (for 10 seconds) and 
>> > > tripping a breaker because it shared a branch circuit 
>> > > with some other appliance... 
>> > > 
>> > > You *don't* want to unplug/replug the refrigerator 
>> > > (which is what a relay would do) as this can confuse 
>> > > the defrost timer and (for poorly designed controls) 
>> > > lead to the compressor starting under a (mechanical) 
>> > > load that hasn't yet had time to dissipate (smart 
>> > > controls will inhibit the compressor for its required 
>> > > dead time on initial application of power for exactly 
>> > > this reason -- but, then, you would risk the compressor 
>> > > always "waiting" even without cause) 
>> > > 
>> > > [Microwave ovens tend to see frequent, brief use. 
>> > > Would you want your refrigerator being unplugged 
>> > > each time you throw something in the microwave 
>> > > for 15 seconds?] 
>> > > 
>> > > And, refrigerators (if disabled due to a tripped breaker) 
>> > > risk having their contents spoil. So, you'd like the 
>> > > refrigerator to be the sole item that can cause *its* 
>> > > breaker to trip (imagine the instant hot water unit 
>> > > thermostatically cycled on and silently took out the 
>> > > breaker for the refrigerator... which you happen to 
>> > > discover the next *morning*). Ditto the dishwasher 
>> > > or any other appliance that can "safely" sit, powered 
>> > > off, with no ill effects (e.g., the dishes are still dirty 
>> > > but aren't getting any *dirtier* in the absence of mains!) 
>> > Fridge: 310KWhr/year = 35W average (no info on motor) 
>> > Microwave: 1500W 
>> > Laptops: 60W to 90W. 
>> > 
>> > No dishwasher or coffee pot.
>> I like that you provided the "average" power draw of the fridge. How do you expect to use that in solving your problem? 
>
> You answered your question in another post:
>
> "Typically a refrigerator runs on 35% duty cycle, (65% for a freezer). This means that if you take the running watts and multiply it by 35%, you can get an idea as to how much power the average running amps will be."
>
>> It just occurred to me. You have the fridge to chill all the laptops so you can overclock them!!! 
>
> Not really.  They are air-cooled.
>  
>> Here's the most direct route to solving your problem. Get a microwave that is 600 watts, rather than the behemoth 1500 watt monster. Do you actual defrost turkeys in it? 
>
> It's fairly standard sized microwave.  
>
> I still don't understand Fred's concern about relay switching the fridge.  I got some 30A relay contacts that should be enough.  Half of the laptops have batteries, which I can also relay switch off while using the microwave.

The induction motors in fridge compressors have low starting torque so
they don't start easily if the system has pressure already

Starting the compressor too soon after it last stopped can result in
it stalling.

Typically this causes it to overheat ans trip the thermal breaker.
(Klixon type thing) once it cools down and the breaker resets (
automatically) the pressure will have then dissipated and it will 
start.

This increases wear in the breaker and thermal aging on the
compressor, but it won't break anything immediately.

-- 
 Jasen.
 &#127482;&#127462; &#1057;&#1083;&#1072;&#1074;&#1072; &#1059;&#1082;&#1088;&#1072;&#1111;&#1085;&#1110;

> > I still don't understand Fred's concern about relay switching the fridge. I got some 30A relay contacts that should be enough. Half of the laptops have batteries, which I can also relay switch off while using the microwave.
> The induction motors in fridge compressors have low starting torque so 
> they don't start easily if the system has pressure already 
> 
> Starting the compressor too soon after it last stopped can result in 
> it stalling. 
> 
> Typically this causes it to overheat ans trip the thermal breaker. 
> (Klixon type thing) once it cools down and the breaker resets ( 
> automatically) the pressure will have then dissipated and it will 
> start. 
> 
> This increases wear in the breaker and thermal aging on the 
> compressor, but it won't break anything immediately. 

OK. i'll relay cycle the laptops.  Cutting power to the charger briefly should not be a problem.  I would have to reinstall the batteries (removed since it's not necessary when A/C powered).

For the microwave, maximum power is 1500W using the lazy single button (30 seconds per push), but there are other buttons for lower power.

On 9/25/2023 12:22 PM, Don Y wrote:
> On 9/25/2023 9:05 AM, Eddy Lee wrote:
>> If I unplug the fridge, or when it's silence, microwave is fine.  
>> Sound like I need a relay circuit to disable the fridge from the 
>> microwave.  Namely, a fridge outlet on the microwave.
> 
> What's the nameplate rating of the microwave?  Does *it* say
> it requires a dedicated circuit?  (because it draws more than
> half of the rated branch circuit's ampacity)

The  requirement is less than 80% of the circuit rating. The 80% 
requirement elsewhere in the NEC is for "continuous loads" (over 3 hr.). 
UL appears to follow the 80% for continuous rating rule. (A UL listed 
device may violate the NEC. IMHO the NEC is wrong.)

> 
> The countertops, in kitchens, tend to see lots of large
> loads that are often running concurrently.  Toaster,
> toaster oven, countertop oven (e.g., all the toaster
> ovens on steroids that you see advertised on TV),
> stand/hand mixer, electric frying pan, *TV*, etc.
> 
> Add to this the other large loads that folks tend to
> think nothing of activating:  dishwasher, garbage disposal,
> microwave, "instant hot water", etc.  

Those are all (except microwave) "fastened in place" and can only use 
50% of the circuit rating. From their location I don't believe they can 
be connected to the "small appliance branch circuits".

> Imagine mindlessly
> turning on the garbage disposal (for 10 seconds) and
> tripping a breaker because it shared a branch circuit
> with some other appliance...
> 
> You *don't* want to unplug/replug the refrigerator
> (which is what a relay would do) as this can confuse
> the defrost timer and (for poorly designed controls)
> lead to the compressor starting under a (mechanical)
> load that hasn't yet had time to dissipate (smart
> controls will inhibit the compressor for its required
> dead time on initial application of power for exactly
> this reason -- but, then, you would risk the compressor
> always "waiting" even without cause)
> 
> [Microwave ovens tend to see frequent, brief use.
> Would you want your refrigerator being unplugged
> each time you throw something in the microwave
> for 15 seconds?]
> 
> And, refrigerators (if disabled due to a tripped breaker)
> risk having their contents spoil.  So, you'd like the
> refrigerator to be the sole item that can cause *its*
> breaker to trip (imagine the instant hot water unit
> thermostatically cycled on and silently took out the
> breaker for the refrigerator... which you happen to
> discover the next *morning*).  Ditto the dishwasher
> or any other appliance that can "safely" sit, powered
> off, with no ill effects (e.g., the dishes are still dirty
> but aren't getting any *dirtier* in the absence of mains!)
> 
> 

=====================================================
It is likely there are 2 "small appliance branch circuits". Put the 
microwave and refrig on different circuits. (Someone must have suggested 
this).

===============================
The "available fault current" is the current you can get at a particular 
location with a solid short. It is important at panels, and the panel 
and breakers must have an interrupt capacity (AIC) that is larger. The 
available fault current depends on the transformer ratings and the 
primary and especially secondary wiring. At a transformer connected to 
an "infinite bus" a guess is the available fault current is 50x the 
transformer rated secondary current. What I remember is that the 
"available" is likely less that 10KA for urban detached family.

On 9/25/2023 4:32 AM, Don Y wrote:
> On 9/24/2023 6:35 PM, Eddy Lee wrote:
>> On Sunday, September 24, 2023 at 5:43:06 PM UTC-7, Don Y wrote:
>>> On 9/24/2023 4:08 PM, Eddy Lee wrote:
>>>> There are 4 breakers and 3 empty slots in the panel. I guess they 
>>>> really cut corners in this apartment. I might add some more 
>>>> breakers, but making holes for wires is the problem.
>>> The fact that it would likely get you tossed out of the apartment
>>> might factor into your decision (as it would put the owner's
>>> liability front and center should some OTHER tenant suffer harm
>>> or loss as a result of your actions).
>>>
>>> Note that you also need to know how the panel is *fed*
>>> (what ampacity circuit).
>>>
>>> And, running cable is not likely to be easy in "old works".
>>>
>>> Note that you won't be able to claim "the wires were there"
>>> as the wire will have a date code imprinted on it
>>> every few feet (unless you happen to have some old
>>> wire on hand that predates your occupancy).
>>>
>>> Seems considerably easier to just change your usage patterns.
>>
>> I'll try not to use the electric stove and microwave at the same time, 
>> although they are on separate breakers.  I'd have to unplug the fridge 
>> to use the microwave.
> 
> The Code requires dedicated circuits for these major appliances
> precisely to eliminate the nuisances that arise from two or more
> of them being used concurrently. 

Cite
And what is the NEC definition of "major appliance"?

> When people are "plagued" by
> nuisance trips, they look for ways to BYPASS those safety devices
> (that are simply doing their jobs; the Code frowns on this sort
> of behavior and tries to anticipate it).
> 
> [Ever notice how many/few receptacles are on each branch circuit?
> Do you really think they expect you to plug vacuum cleaners
> into ALL of them??]
> 
> Note that there is an EXPLICIT exception that *allows* a fridge
> (which is classified as a major appliance and thus requires a
> dedicated branch circuit) to be placed on one of the "small
> appliance" counter circuits

Cite exception.

There is an exception that a refrigerator can be on its own 15A circuit. 
("Small appliance branch circuits" are 20A.)

> -- but "best practices" (i.e., anyone
> who isn't pinching pennies) will always have the fridge on a
> 15-20A dedicated circuit (of course, an apartment application
> could be rationalized as not needing to support a big fridge).
> 
> Neighbor complained to me that his fridge would "go off" whenever
> he used his microwave oven.  His home was wired with the fridge
> on the small appliance (counter) circuit.  The *9* amps that the
> nice *Viking* fridge would draw (peak), when inconveniently timed with
> the microwave's sudden use, would promptly take out the counter
> circuit.
> 
> "Move the microwave elsewhere or get a new DEDICATED branch circuit
> installed -- like every NEW home!"
> 
> [I've heard this complaint (counter breaker tripping) so often that
> my stock response is:  "Check to see if your refrigerator is on the
> same branch circuit" as it almost always is (and appliance salesmen
> aren't keen on telling you that you need an electrician to come
> out and install a new branch circuit BEFORE they can sell you that
> shiny new fridge!)]
> 
> Ditto for a freezer, etc.
> 
> But, people don't read the Code so don't understand what it tries to
> anticipate... ("Gee, this only draws X << 20A so I can put it on
> the counter circuit!")
> 

On Tuesday, 26 September 2023 at 03:57:10 UTC+1, Ricky wrote:
> On Monday, September 25, 2023 at 7:39:07 PM UTC-4, Tabby wrote: 
> > On Monday, 25 September 2023 at 09:39:26 UTC+1, Ricky wrote: 
> > 
> > > The only individual heavy load is the microwave which ranges from 600W to 1,400W, depending on size. 
> > Output. Consumption is about 1.2kW - 2kW
> I've never seen a 120V appliance draw over 1440W. But then here it's very uncommon to see 20A circuits. 

I seldom see 110v appliances at all. Ours appliances are limited to 3.1kW, and circuits to 7.68kW continuous, at least double that short term.

It's odd to read the explanations of the problem & it's solution in this thread, neither of which line up in any way with what they would be here on 240v.
Fwiw... power consumption is far below tha capabilities of a standard 32A 240v circuit, so the trip cause would be inrush current. The standard solution is to change to a type C mcb or rcbo. No-one puts fridges on dedicated circuits, you'll notice a trip far sooner if it's on a standard shared circuit.

On Monday, September 25, 2023 at 11:43:34 PM UTC-4, Eddy Lee wrote:
> On Monday, September 25, 2023 at 7:55:48 PM UTC-7, Ricky wrote: 
> > On Monday, September 25, 2023 at 4:57:02 PM UTC-4, Eddy Lee wrote: 
> > > On Monday, September 25, 2023 at 1:39:33 PM UTC-7, Ricky wrote: 
> > > > On Monday, September 25, 2023 at 4:25:39 PM UTC-4, Eddy Lee wrote: 
> > > > > On Monday, September 25, 2023 at 12:31:34 PM UTC-7, Ricky wrote: 
> > > > > > On Monday, September 25, 2023 at 2:44:39 PM UTC-4, Eddy Lee wrote: 
> > > > > > > On Monday, September 25, 2023 at 11:22:16 AM UTC-7, Don Y wrote: 
> > > > > > > > On 9/25/2023 9:05 AM, Eddy Lee wrote: 
> > > > > > > > > If I unplug the fridge, or when it's silence, microwave is fine. Sound like I need a relay circuit to disable the fridge from the microwave. Namely, a fridge outlet on the microwave. 
> > > > > > > > What's the nameplate rating of the microwave? Does *it* say 
> > > > > > > > it requires a dedicated circuit? (because it draws more than 
> > > > > > > > half of the rated branch circuit's ampacity) 
> > > > > > > > 
> > > > > > > > The countertops, in kitchens, tend to see lots of large 
> > > > > > > > loads that are often running concurrently. Toaster, 
> > > > > > > > toaster oven, countertop oven (e.g., all the toaster 
> > > > > > > > ovens on steroids that you see advertised on TV), 
> > > > > > > > stand/hand mixer, electric frying pan, *TV*, etc. 
> > > > > > > > 
> > > > > > > > Add to this the other large loads that folks tend to 
> > > > > > > > think nothing of activating: dishwasher, garbage disposal, 
> > > > > > > > microwave, "instant hot water", etc. Imagine mindlessly 
> > > > > > > > turning on the garbage disposal (for 10 seconds) and 
> > > > > > > > tripping a breaker because it shared a branch circuit 
> > > > > > > > with some other appliance... 
> > > > > > > > 
> > > > > > > > You *don't* want to unplug/replug the refrigerator 
> > > > > > > > (which is what a relay would do) as this can confuse 
> > > > > > > > the defrost timer and (for poorly designed controls) 
> > > > > > > > lead to the compressor starting under a (mechanical) 
> > > > > > > > load that hasn't yet had time to dissipate (smart 
> > > > > > > > controls will inhibit the compressor for its required 
> > > > > > > > dead time on initial application of power for exactly 
> > > > > > > > this reason -- but, then, you would risk the compressor 
> > > > > > > > always "waiting" even without cause) 
> > > > > > > > 
> > > > > > > > [Microwave ovens tend to see frequent, brief use. 
> > > > > > > > Would you want your refrigerator being unplugged 
> > > > > > > > each time you throw something in the microwave 
> > > > > > > > for 15 seconds?] 
> > > > > > > > 
> > > > > > > > And, refrigerators (if disabled due to a tripped breaker) 
> > > > > > > > risk having their contents spoil. So, you'd like the 
> > > > > > > > refrigerator to be the sole item that can cause *its* 
> > > > > > > > breaker to trip (imagine the instant hot water unit 
> > > > > > > > thermostatically cycled on and silently took out the 
> > > > > > > > breaker for the refrigerator... which you happen to 
> > > > > > > > discover the next *morning*). Ditto the dishwasher 
> > > > > > > > or any other appliance that can "safely" sit, powered 
> > > > > > > > off, with no ill effects (e.g., the dishes are still dirty 
> > > > > > > > but aren't getting any *dirtier* in the absence of mains!) 
> > > > > > > Fridge: 310KWhr/year = 35W average (no info on motor) 
> > > > > > > Microwave: 1500W 
> > > > > > > Laptops: 60W to 90W. 
> > > > > > > 
> > > > > > > No dishwasher or coffee pot. 
> > > > > > I like that you provided the "average" power draw of the fridge. How do you expect to use that in solving your problem? 
> > > > > You answered your question in another post: 
> > > > > 
> > > > > "Typically a refrigerator runs on 35% duty cycle, (65% for a freezer). This means that if you take the running watts and multiply it by 35%, you can get an idea as to how much power the average running amps will be." 
> > > > I'm pretty sure I didn't post that. Regardless, that would be a combination of an average with a rule of thumb, so not of much value. The point is, your appliance has a plate with the actual power rating while running. Why don't you look at that? Not the motor, the appliance. You've also said nothing about the size of this appliance. Is it a dorm room size fridge? A massive double door kitchen behemoth? Something in between? As is usual with you, only the barest minimum of information is provided and then the guessing begins. 
> > > There is an energy guide tag saying 310 KWhr/year. Nothing else. Detail info might be at the back of the fridge. Too heavy to pull the fridge out when loaded. 
> > Ok, but that's not the same as "nothing else". It just means you don't know the wattage and you won't do what it takes to find it. Can you read a model number somewhere? Did you look inside the fridge?
> OK, GE GPE12FGKDWW 
> 1.2A 115VAC 
> Ice maker power:145W 
> Defrost power:180W

Your defroster uses more power than the fridge.  I don't know why you didn't include this info in your first post.  You should have included the power of all the devices.  Then you wouldn't have needed to make the post at all.  But then, that wouldn't be Eddie Lee. 

-- 

  Rick C.

  -+- Get 1,000 miles of free Supercharging
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On Tuesday, September 26, 2023 at 12:50:45 AM UTC-7, Ricky wrote:
> On Monday, September 25, 2023 at 11:43:34 PM UTC-4, Eddy Lee wrote: 
> > On Monday, September 25, 2023 at 7:55:48 PM UTC-7, Ricky wrote: 
> > > On Monday, September 25, 2023 at 4:57:02 PM UTC-4, Eddy Lee wrote: 
> > > > On Monday, September 25, 2023 at 1:39:33 PM UTC-7, Ricky wrote: 
> > > > > On Monday, September 25, 2023 at 4:25:39 PM UTC-4, Eddy Lee wrote: 
> > > > > > On Monday, September 25, 2023 at 12:31:34 PM UTC-7, Ricky wrote: 
> > > > > > > On Monday, September 25, 2023 at 2:44:39 PM UTC-4, Eddy Lee wrote: 
> > > > > > > > On Monday, September 25, 2023 at 11:22:16 AM UTC-7, Don Y wrote: 
> > > > > > > > > On 9/25/2023 9:05 AM, Eddy Lee wrote: 
> > > > > > > > > > If I unplug the fridge, or when it's silence, microwave is fine. Sound like I need a relay circuit to disable the fridge from the microwave. Namely, a fridge outlet on the microwave. 
> > > > > > > > > What's the nameplate rating of the microwave? Does *it* say 
> > > > > > > > > it requires a dedicated circuit? (because it draws more than 
> > > > > > > > > half of the rated branch circuit's ampacity) 
> > > > > > > > > 
> > > > > > > > > The countertops, in kitchens, tend to see lots of large 
> > > > > > > > > loads that are often running concurrently. Toaster, 
> > > > > > > > > toaster oven, countertop oven (e.g., all the toaster 
> > > > > > > > > ovens on steroids that you see advertised on TV), 
> > > > > > > > > stand/hand mixer, electric frying pan, *TV*, etc. 
> > > > > > > > > 
> > > > > > > > > Add to this the other large loads that folks tend to 
> > > > > > > > > think nothing of activating: dishwasher, garbage disposal, 
> > > > > > > > > microwave, "instant hot water", etc. Imagine mindlessly 
> > > > > > > > > turning on the garbage disposal (for 10 seconds) and 
> > > > > > > > > tripping a breaker because it shared a branch circuit 
> > > > > > > > > with some other appliance... 
> > > > > > > > > 
> > > > > > > > > You *don't* want to unplug/replug the refrigerator 
> > > > > > > > > (which is what a relay would do) as this can confuse 
> > > > > > > > > the defrost timer and (for poorly designed controls) 
> > > > > > > > > lead to the compressor starting under a (mechanical) 
> > > > > > > > > load that hasn't yet had time to dissipate (smart 
> > > > > > > > > controls will inhibit the compressor for its required 
> > > > > > > > > dead time on initial application of power for exactly 
> > > > > > > > > this reason -- but, then, you would risk the compressor 
> > > > > > > > > always "waiting" even without cause) 
> > > > > > > > > 
> > > > > > > > > [Microwave ovens tend to see frequent, brief use. 
> > > > > > > > > Would you want your refrigerator being unplugged 
> > > > > > > > > each time you throw something in the microwave 
> > > > > > > > > for 15 seconds?] 
> > > > > > > > > 
> > > > > > > > > And, refrigerators (if disabled due to a tripped breaker) 
> > > > > > > > > risk having their contents spoil. So, you'd like the 
> > > > > > > > > refrigerator to be the sole item that can cause *its* 
> > > > > > > > > breaker to trip (imagine the instant hot water unit 
> > > > > > > > > thermostatically cycled on and silently took out the 
> > > > > > > > > breaker for the refrigerator... which you happen to 
> > > > > > > > > discover the next *morning*). Ditto the dishwasher 
> > > > > > > > > or any other appliance that can "safely" sit, powered 
> > > > > > > > > off, with no ill effects (e.g., the dishes are still dirty 
> > > > > > > > > but aren't getting any *dirtier* in the absence of mains!) 
> > > > > > > > Fridge: 310KWhr/year = 35W average (no info on motor) 
> > > > > > > > Microwave: 1500W 
> > > > > > > > Laptops: 60W to 90W. 
> > > > > > > > 
> > > > > > > > No dishwasher or coffee pot. 
> > > > > > > I like that you provided the "average" power draw of the fridge. How do you expect to use that in solving your problem? 
> > > > > > You answered your question in another post: 
> > > > > > 
> > > > > > "Typically a refrigerator runs on 35% duty cycle, (65% for a freezer). This means that if you take the running watts and multiply it by 35%, you can get an idea as to how much power the average running amps will be." 
> > > > > I'm pretty sure I didn't post that. Regardless, that would be a combination of an average with a rule of thumb, so not of much value. The point is, your appliance has a plate with the actual power rating while running. Why don't you look at that? Not the motor, the appliance. You've also said nothing about the size of this appliance. Is it a dorm room size fridge? A massive double door kitchen behemoth? Something in between? As is usual with you, only the barest minimum of information is provided and then the guessing begins. 
> > > > There is an energy guide tag saying 310 KWhr/year. Nothing else. Detail info might be at the back of the fridge. Too heavy to pull the fridge out when loaded. 
> > > Ok, but that's not the same as "nothing else". It just means you don't know the wattage and you won't do what it takes to find it. Can you read a model number somewhere? Did you look inside the fridge? 
> > OK, GE GPE12FGKDWW 
> > 1.2A 115VAC 
> > Ice maker power:145W 
> > Defrost power:180W
> Your defroster uses more power than the fridge. I don't know why you didn't include this info in your first post. You should have included the power of all the devices. Then you wouldn't have needed to make the post at all. But then, that wouldn't be Eddie Lee. 

Is 0.4A out of 20A such an important factor?  Or you are missing the point.

On Sun, 24 Sep 2023 13:59:06 -0700 (PDT), Fred Bloggs
<bloggs.fredbloggs.fred@gmail.com> wrote:

>On Sunday, September 24, 2023 at 3:28:37?PM UTC-4, Eddy Lee wrote:
>> I have microwave, fridge and 10 laptops on a 20A circuit. Fine most of the time until I use the microwave. Should I try a 22 Amp Interrupting Circuit breaker? Existing one might be 10AIC.
>
>I think you mean 10KAIC, which is not directly related to trip current as much as breaker contact construction. Plug the smallest load, laptop (?), into a different less loaded circuit via extension cord. Or wire a new circuit, which doesn't have to be all the way to the panel, it can be a tap off an existing circuit in the proximity.


This is correct.  AIC is the maximum rated current the breaker can
interrupt.  I doubt you will have thousands of amps to interrupt but
you might.

boB