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3

You have a Square-D Type QO (3/4" wide) breaker there. These are ridiculously common -- just about every big-box store and electrical supply house will have them, as well as industrial MRO suppliers and even small hardware stores. The other possibilities can be ruled out as follows: Eaton's CH fits a similar 3/4" form factor, but obviously would have ...


6

I can see a SquareD logo on the side, and the red indicator window on the front makes it look like a Square D QO 20-Amp Single-Pole Circuit Breaker, model #QO120CP: The overall shape of the breaker and orientation of the contacts on the back seem to match your breaker.


0

You could use the UPS to defer some of the load while the microwave runs. I did this as a kid. I had only 15 amps to live on in my room, and my microwave are up a good ten of them. So I kept a 3000kva ups charged and ready, and when I used the microwave a load sensor I installed anr programmed automatically isolated the UPS from mains and my computer ran ...


3

The fuse is there to prevent your wires from burning up in the walls. A UPS is for a short supply of backup power when the power goes out - not to bypass the tripping of a fuse/breaker. If you're not able to move these loads to different circuits, then you shouldn't use them all at once or allow them to be used together. You don't want to bypass a safety ...


2

The breaker you picked should work fine. To determine it for sure, read the fine print on the label on the interior of the door panel. It should list a series of 10-20 types of breakers that are compatible with your panel. They are often 2 to 4 letter codes. The actual breaker models will be that code, and then a number. Duplex, Triplex, and Quadruplex ...


1

Hold on, folks. The fault may not be at an endpoint. Consider a fault inside the sub-panel, i.e. your L1 feeder wire frays against the sub-panel case. It's before the sub-panel main breaker, so no help there. Without a wired ground path back to the main panel, the main panel breaker would not trip, as not enough current would flow. (earth is not a ...


1

Short answer: The fastest (more sensitive) breaker will trip first. This isn't necessarily the smallest. Which is why the code has refers to "Selective Coordination". See the definition in Article 100. Coordination (Selective) Localization of an overcurrent condition to restrict outages to the circuit or equipment affected, accomplished by the selection ...


2

Looking at a diagram, is often a good way to understand a problem. Below is a simple diagram that shows the fault current path. You can see that the fault current will flow through all the breakers, and return to the source (the transformer) along the grounding conductor. You might be inclined to think that the fault current will be extremely high ...


0

The smallest (amperage) and closest (in protection) to the fault should trip first. So if it's caused by a branch circuit in the sub, then the breaker in the sub would trip. Think of it as the fault is working back to the main, yes, but along both lines - the ground and the hot supplying it. The hot line will reach the nearest breaker and trip.


2

[I]s it possible for power surges to inflict partial damage on electrical devices? What you refer to as a power surge will most likely be a voltage spike, i.e. short but significant increase in the line voltage. This increased voltage will in the most general case lead to increased electrical currents in your devices, and this may kill them. Simplest ...


1

Yes, it is extremely likely for surges to inflict partial damage. The circuit board is the most sensitive component on most appliances, therefore it is the first to go out in a surge. The compressor on a fridge would be much more robust, therefore requiring a much larger surge to destroy it. Desktop power supplies are known to receive some damage from surges ...


0

It is not too complicated. Breakers are generally designed to protect the wiring, not the appliance or light. Lighting circuits, nonlinear loads, and non-inductive motor loads generally have a higher total wattage consumption on average than inductive motor loads. Inductive motor loads have startup and stop/fault loads. These can peak up to 6x or ...


3

It matters if there's mere overload but less than a short. 14 gauge wire cannot carry 20A safely. So why use 14 gauge? The answer is you are corralled into it by market forces: it makes for easier, faster, cheaper work. Here are the factors that come into that. Stranded vs Solid-core. Stranded wire bends much easier, but costs 5-10% more. Solid-core ...


4

Breakers protect wiring and connections. Most lighting circuits are done with #14 wire, which is adequate for the duty it performs. To prevent overheating (fire risk), 15A breakers are required by code for most circuits using #14 AWG wire. Lighter wire and other components are less expensive and easier to work with. Many power tools, appliances, and other ...


0

So the problem ended up being the contactor on the outside unit. How I went about troubleshooting the problem was to disconnect the outside from high voltage power. Then I turned on the thermostat and allowed it to cycle a few times over the course of 2 days. The fan would come on as expected and the fuse never blew. I ordered a new contactor and ...


1

I'll add one last thing.. as it seems to be your worry. Your breaker will not trip while you're gone from the house as long as those other loads are not turned on. If you're not home, then I'm guessing that the hand mixer won't be on and so the breaker won't trip. Figured it was at least worth mentioning. It's typical to give a refrigerator it's own ...


2

Refrigeration equipment may be served from another circuit aside from the kitchen circuits but it is not required. 210.52(B) Small Appliances. (1) Receptacle Outlets Served. In the kitchen, pantry, breakfast room, dining room, or similar area of a dwelling unit, the two or more 20-ampere small-appliance branch circuits required by 210.11(C)(1) ...


2

A refrigerator does not have to be on a dedicated circuit, it's simply a convention some builders/Electricians follow. A ground-fault circuit interrupter (GFCI) trips in response to a ground-fault. While a standard circuit breaker trips in response to overloads, and overcurrents. If the combined current drawn of the refrigerator, mixer, and whatever else ...


1

Your refrigerator should be on its own circuit. A refrigerator and hand mixer could easily draw 15 amps that would trip a 15 amp bkr, the GFCI is only looking for ground faults. The model of both appliances would allow us to look up the power they draw. Kitchen circuits in newer houses are supposed to have a minimum of 2 circuits to service the countertop ...


-2

just use romex 8/3 with ground or 8/2 that way you'll have your hot nuetral and ground and itll do 40 amps. Grab a 2pole 40 or a "double 40" as you put it


1

A heater often uses almost all of the current capacity of a circuit. A microwave, unless it is some tiny little portable unit, will often use enough amperage on a circuit where it should be recommended to run the unit on its own dedicated circuit. Considering the above it is playing a dangerous game to be running your computer on the same circuit as these ...


2

Install a ground lug in the panel, something like this one, or use a kit like this one. Just remember, like you said, that the neutral bar has to be isolated from the panel. It'll be on plastic/insulating stand-offs.


0

Derating doesn't work for you since it's based on the theory that you hardly ever use everything at the same time. In your case, the entire point of having two ovens is to use both at once. So you need to bring honest 50A of service to run the 2 ovens. Remember, breakers protect wires. I would make sure the breaker is 50A and the wire is 6 gauge, remove ...


1

The only 2-pole breaker? If you have whole-house A/C, that is what that breaker is for. Otherwise it may be an MWBC for the garbage disposal/dishwasher (one on each pole, shared neutral) as this is common practice. Or it may be pre-wired for future A/C service (too small for dryer or range at 20A). I'd want to know what that breaker is for sure, but ...


2

One of the easiest things to do would be install a double-tandem (aka triplex) breaker, in place of two existing single-pole breakers. The big advantage is it keeps rewiring to a minimum. This keeps the two single pole breakers, but essentially adds a 2-pole circuit in between. Quick search finds that Murray has 15 and 20-amp outer (single pole) circuits ...


1

If your panel accepts them, you could install some tandem breakers in place of a few single pole breakers. This would create open space in the panel. Depending on what the double pole breaker supplies, you might be able to wire the device on that circuit. I'd contact the manufacturer, and determine the exact installation requirements.


2

Since it's low amperage, my guess would be that it's feeding a multi-wire branch circuit - two 120V circuits fed off of a three wire two pole breaker. They share a neutral just to save on running more wire, but have to be disconnected together - which is the cause of the two pole breaker. I'd suggest flipping the breaker and see what it cuts, first guess ...


0

You can install tandem breakers which will free up some additional space in your panel. You mentioned being concerned about cost and these are relatively inexpensive ($10 range) and available at your local home store. For each tandem you use, it will free up a 1 pole space. You would need two tandems to create enough space for a 2 Pole breaker.


0

Sizing branch-circuits for cooking appliances can be complex, and I don't pretend to be an expert in this area. After reading through the NEC, I wasn't clear on how demand factors would work in your situation. After doing a bit of research, I came across this article from ECMAG which states: ...Derating is not permitted when one branch circuit supplies ...


2

NEC 220.55 The load for household electric ranges <...> individually rated in excess of 1.75 kW shall be permitted to be calculated in accordance with Table 220.55. Based on note #3; since one range is rated 7.2 kW (30A x 240V) and the other is 4.8 kW (20A x 240V), we are able to simply add the total rated kW of both and multiply it by the demand ...


6

I live in Texas, and there is a public information type site that is maintained by a group called Smart Meters Texas. Smart Meter Texas On this site you can sign up, register your electric meter, and then see the data from it in 15 minute intervals. The data is delayed about two days, but it's very informative. You may search for your area or ask your ...


-1

Some breaker panels have blank slots at the end, which could mechanically accept a breaker, but their tabs are not live, if they have tabs at all. This is done to lower manufacturing costs and reuse one chassis with different bus bar assemblies. It could also be a piece of tape, clear insulation, or severe corrosion over that spot on the bus bar. ...



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