May 15, 2021
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I've been wondering if it's safe to plug an 1500VA/900W UPS in the same outlet as the 5000 BTU window air conditioner is connected in a duplex receptacle. Can that affect the connected appliances/devices in some way if they're both running?

Living with a power grid of 120V/60Hz and having 2 available duplex outlets with NEMA 5-15R (125V, 15 amps) that is circuit breaker protected in my room (I think both outlets uses different circuits from I remember) on opposite sides, both have NEMA 5-15P plug type. The appliance/device have the following specifications:

CyberPower CST150XLU 1500VA/900W Mini-Tower LCD AVR UPS (Only going to show mostly input)
Input Nominal Voltage: 120V
Input Voltage: 90Vac-140Vac
Input Frequency: 60Hz +/- 3Hz
Topology: Line Interactive
Circuit Breaker Amperage: 15A
Volt-Amps Rating: 1500VA
Watts Rating: 900W

Continental Electric CE-WAC105 5,000 BTU White Window Air Conditioner
Voltage: 115V
Frequency: 60Hz
BTUs: 5,000
CEER: 11.0
Amperage: 3.9A
Design Pressure: 300-550PSIG
R410A: 9.17ozs

On the UPS Surge+Battery Backup side, will be connected to a 600W Non-Modular PSU (PC) and 24" ASUS VG248QE FHD LCD Monitor. Any thoughts?
 

lvt

Commendable
Apr 19, 2021
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Are you sure that each outlet has its own circuit?

Safety rules say that you shouldn't overload the outlet, the limit is about 80% of the circuit breaker capacity, says you have a 15A circuit breaker, you have about 13A max to use.
 
May 15, 2021
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Are you sure that each outlet has its own circuit?

Safety rules say that you shouldn't overload the outlet, the limit is about 80% of the circuit breaker capacity, says you have a 15A circuit breaker, you have about 13A max to use.

For clarification, one that says 15A circuit breaker is referring to the UPS own breaker.

The entire circuit and wiring of the house I'm currently living, not all of the outlets have their own breakers. About my home breakers, here's around 6 breakers installed (5 15A single pole and 1 double-pole 30A) in my home. For the total outlets, for NEMA 5-15R duplex ones There's around 2 in the living room, 1 in the dining room that is connected to a 6 outlet plug adapter with 1 device in use, 3 in the kitchen with one of them not in use (maybe broken), 1 in the bathroom, 2 in a second room, 3 in a third room and 1 in the balcony, that makes it around 10 duplex outlets (with my own room ones included). Also in the kitchen, there's a NEMA 5-20 outlet and one that is used for electrical stoves (although not sure what type of cord the stove plugged into that one uses of such model that I don't know yet).

3 of the 5 breakers constantly trip, so far I know one circuit that is wired to the bathroom and one in the third room (that one needed to be reset when about to be used since a water heater shower usually trips that one). Another one I know is where controls one of the outlets and light in my room (and not sure if is connected to another outlet somewhere). Both of the outlets in those circuits in my room are the ones I haven't seen tripped yet. Other than that I do not know much information how the wiring is distributed through the home.
 
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InvalidError

Titan
Moderator
3 of the 5 breakers constantly trip
Sounds like you need to get an electrician to upgrade the distribution panel, split all the circuits and give heavy loads like shower heater their own dedicated run and possibly a circuit rating upgrade.

As far as connecting the UPS to the same circuit as the AC is concerned, it is a small AC with only 4A rating so it should be fine as long as the rest of loads on the circuit including the UPS and everything connected to it is under 9A. If the outlet your UPS is connected to is on the same breaker as the AC, then it makes almost no difference whether it is the same outlet or the one across the room. You would have slightly lower losses from connecting the UPS to whichever outlet is closest to the breaker box wiring-wise.
 
Reactions: Mandark

jay32267

Glorious
From the UPS specs...we don't really know the maximum the UPS draws.

It says it requires a 15 amp breaker.

We know what it outputs...but we don't know the efficiency as far as I can tell.

To be safe I wouldn't put them on the same circuit.

From a practical standpoint...I would use a current meter and measure what they actually draw....and I think there's a good chance they are under 15 amps total and can both go on the same circuit.
 

InvalidError

Titan
Moderator
From the UPS specs...we don't really know the maximum the UPS draws.

It says it requires a 15 amp breaker.
15A is the maximum rating of the UPS as a glorified power bar. The UPS itself is probably under 10W once its battery is charged, maybe 60W while charging a 24V pack. Under normal circumstances, normal UPSes don't do anything, they just let current straight through and "efficiency" is close to 100%. If the UPS has AVR and AVR kicks in, then current may go up 5-10% for the AVR transformer on the protected outputs. Worst case, the UPS itself should be well under 2A.

For the most part, it is all about the loads connected to it.
 
May 15, 2021
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I will provide an update regarding this situation, I have done quite extensive research about how the house is wired, which took me a couple of weeks to get an idea of where circuits are located on which breakers and the actual amperage of those circuits (and learning more about eletricity in general, which isn't bad to learn about such topics).

The house I'm in is small, finished around 2000. They were both built by my dad and my maternal grandfather. As for the other one, goes back even further. Back then in 1970, my grandfather brought a small lot for 400 USD in a neighborhood at the time. That's where started construction and was finished in 1974, with property title and essential services like water and electricity in place and the other structure was built decades later when I was just a child.

The breaker on the home where I currently live, is connected through another one on my grandparent's small storage room where all of the eletricity is distributed throughout the lot. Looks like must be the main breaker and seems upgraded. During construction, my dad did most of the wiring. And to be honest, seems he didn't have the required skill to make such instalations in circuits. As to describe regarding of that particular circuit on the bathroom and also that is branched to other 2 outlets on the kitchen and at one room, was done quite ameaturily and outright incorrectly installed.
I do not know if they hired eletrician at some point, my assumptions mostly lies that both did most of the job. Even I consider my grandfather to have more knowledge about eletricity installation than my dad does.

For that particular circuit, is wired through an 12 AWG wire according to my grandfather. Two of the breakers are used on that circuit that tend to overload is using single pole 15A ones. Once overloaded, both of the breakers trips. He thinks that not supossed to be there since draws so much current and at least must be dedicated and on a 30A circuit, just like the range and the freezer is on those circuits and at the required safe current rating to prevent that from happening. My dad was the one who wired that specific circuit. Even the rated current rating of the windows AC installed at home draws much less current than the heater does, in a different circuit. The rated amperage of the shower heater exceeds that of the installed circuit, and as a result overloads and even burned a part of the receptacle and the hot pin of the plug and showing signs like dimming lights everytime the shower is turned on.

I'm surprised that didn't turned that into fire, yet... Once at really long time ago, that same shower model was burning while being connected, due to a worn and damaged component inside the heater. Since then was replaced by the same one but I will have to convince my mom, brothers and my dad to prevent from using the faulty heater and instead hire a licensed electrician to do changes to the home, although might be difficult to do due to economic difficulties, ignorance (mentality) and laziness of some people in my family circle and that the foundation is mostly on concrete blocks and iron poles that are used in construction, with the wires being inside of those blocks. To even add more, there's now ants and termites invading many reptacles recently and that being a fire hazard and risk of the wiring being damaged, including the ones where the UPS is connected at.

I think should not be connected at the same time the plug of the AC and the UPS cannot be used in the same outlet due to the way the UPS plug is angled and the AC plug being too big.
 
Reactions: lvt

InvalidError

Titan
Moderator
Amateur installation appears to be quite the understatement here, pretty sure most of the stuff you listed as sharing circuits with something else would be on its own dedicated circuit even in pre-2000 code. The in-line shower heater burning up its plug sounds like the shower wasn't intended to be plug-in to begin with since that sounds like the wrong plug and outlet type got used for the application. Let me guess: the in-line heater is intended to be hard-wired and your (grand)father added a plug tail to it.
 
May 15, 2021
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Amateur installation appears to be quite the understatement here, pretty sure most of the stuff you listed as sharing circuits with something else would be on its own dedicated circuit even in pre-2000 code. The in-line shower heater burning up its plug sounds like the shower wasn't intended to be plug-in to begin with since that sounds like the wrong plug and outlet type got used for the application. Let me guess: the in-line heater is intended to be hard-wired and your (grand)father added a plug tail to it.
My dad was the one who installed that circuit, as confirmed by my grandpa when I was asking about the house wiring. I don't see any plugtails (Not sure if you might be referring to pigtails connectors but I don't see those inside of receptacles, but I often see that in some home light fixtures at my grandparent's home) either as everything is hard wired and I saw how was wired like from outlets with no plates (got broken and apparently not replaced yet?) and when he was working in the kitchen to replace some kitchen tiles.

This a picture of some of the wiring at my home was done like (terrible and dirty thanks to termite infestation found it's way through holes inside or something recently) that my dad has yet to secure that in place. I know that the green one is ground but haven't figured out which color of either red or black represents hot and neutral or viceversa, however seen white wiring that is neutral around light fixtures so not entirely sure how that works for receptacle wiring. That's on a different circuit, I'm going say that's part of circuit #3. The affected circuit is also wired like that outlet so must apply to all of the receptacles of my home, and since the one that often trips is fourth and fifth 15A breaker, let's say it's circuit #4.




If construction started around late 1990s - early 2000s (most likely the latter) then must be cooper based. As for the other home however, most of the sections at the 1970s home where my grandparent's live has mostly aluminum old wiring connected to old breaker and then appears to go the newer main one. Seems only certain sections were upgraded but not all of it as I haven't researched that area long enough.

There's a close up of bare copper wires visible from a light switch in the same area, that are the stranded type. That's part of circuit #1, where all of the light fixtures are connected to. Is meant to have the cover plate back on.



The water heater in question is one that has a NEMA 15-5P plug. And that just came as it is, not hard wired at all. This how looks like as of right now:


Every time I see that makes me not want to use that anymore tbh and just deal with showering in cold water




That is the shower water heater, is like a miniature heater that turns on everytime water passes through at high pressure that is then pushed through the head with warm water as a result. Some black-ish marks can be seen, that's where the 1st one was gone smoking that smells like it's burning and then was replaced with the same model. Now I'm not sure if they used connectors somewhere inside the walls since I haven't seen the inside of that receptacle yet (not going to attempt that either, I rather leave that to professionals) and that is inside the walls and to look at the wires, must be breaken first.

In fact, my grandpa was right that must be on a 30 amp dedicated circuit because says so in the manual too.


as well exceeds the amp circuit rating as I told from the previous post if 12-gauge wire is being used on that circuit #4, with appliance being rated at 23.5 amps. Comparing to the heater at their house, they got a dedicated circuit at 30 amps according to him, being well aware of how much the water heater uses lots of current (and is even bigger than one at home, outside and possibly old rated at 1500W maximum at 120V).

There's one of the outlets that is on my parent's room within the same circuit #4 as that heater and with no cover I don't get why haven't place that one back (and maybe as terrible as the 1st one and by some reason uses 20A receptacle unlike the other 2 and left outlet is connected to a black extension/power strip? cable that then connects to a big plasma television (42", at rated maximum wattage consumption at 400W at 120V of the TV model) and not sure if other stuff are connected there too:



And the other one at the kitchen near the range also cover needs to be put back but is often not connected for prolonged periods, with a coffee maker often using that receptacle on circuit #4:



As told, once overloaded, both breakers trips at the same time but only the fourth breaker is the one that controls the distribution and power in that circuit. I know that these outlets are connected to that circuit because I've experienced when I notice I have not been receiving power and is because that breaker was tripped. Hence, for a shower heater, that outlet at the bathroom should not be in a branch circuit in the first place. From I've been told by my dad, the outlet that is near my window belongs yet another circuit that is connected to different breaker box at my grandparent's house, maybe that can't be affected at all, although seems out of place that isn't in the home's breaker box. However, if I move the setup to my other outlet with the UPS connected to that, that receptacle belongs to circuit #1 (previously setup was here with a lower capacity UPS which then was damaged by flooding almost the entire home because of broken kitchen tube that burst out while we're all asleep) which also controls some receptacles too and that might be affected that way of overloading the circuit everytime the heater turns on.

I really agree that the heater wasn't intended to be plugged here considering the limitations of the circuit and receptacle alike and the specifications of the heater that requires to run that.
 

InvalidError

Titan
Moderator
That electric shower head shouldn't have come with a 5-15P cord. If there is a switch on it to select 110V vs 220V, you could flip it to 220V which will drop it to 1/4 power and solve your shower breaker trip issue albeit with showers being quite a bit colder. Best you can do short of having the whole place properly re-wired.

An out-building should have its own sub-panel fed by 50+A breakers and appropriately sized wiring.
 
May 15, 2021
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That electric shower head shouldn't have come with a 5-15P cord. If there is a switch on it to select 110V vs 220V, you could flip it to 220V which will drop it to 1/4 power and solve your shower breaker trip issue albeit with showers being quite a bit colder. Best you can do short of having the whole place properly re-wired.

An out-building should have its own sub-panel fed by 50+A breakers and appropriately sized wiring.
Yeah I feel the entire wiring system needs to be completly rewired so I can feel safer at home and most importantly, done properly and more receptacles since I see heavy reliance on extension/power strip on both places and I'm not that fond of using such cords for permanent use.

I don't see any switch to set the heater to 220V, because the model is only 110V (entire home is 125V max, average 120V for single pole) and neither they are voltage switchers installed somewhere aside from the range in it's own dedicated circuit that on a double pole circuit.

Also discovered to on the duplex receptacle where UPS is connected as well as part of my brother's room and another one at my parents room (but that's on another circuit) they're actually split receptacles, wired such way with one of the outlets is only "dedicated" to the AC, yet branched that ends on my brother's room and other belongs to the home's circuit. Compared to the heater, they don't pull a lot of current if combined. That uses 1 breaker at home and another at my grandparent's home both being single pole (which controls the AC "dedicated" outlets. And since one at my room near the window is in the middle of the circuit, saw 1 pigtail connector being used for ground but didn't saw completly, my dad was working on checking the outlet where my UPS is connected in checking if they are any sight of termites or part of an ant colony. Also is connected to another receptacle at the living room of that circuit that also uses a 20A receptacle with an extension that goes yet another television but that's most likely part of the home's breaker (maybe that one is not split) and that circuit of the outlet at my home breaker in my room is what the UPS is connected to.

Yeah there's a sub-panel that has 50A and 100A breakers located at my grandparent's home somewhere inside the storage room. Maybe that's the one which controls the power for both my home and my grandparent's home in the lot (like the main breaker) alongside the electric counter directly to that panel, so that's shared. If counting the total sub-panels, they're around 4 sub-panels in the lot (includes the one at my home).
 

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