17

There's no need to do this for computers/networking gear/... While the switching power supplies used in IT equipment are slightly more efficient when running on 240V vs when they are running on 120V, this efficiency difference is generally small enough that it can be disregarded as a practical matter. As a result, I would simply provision 120V/20A circuits ...


14

For ordinary residential usage, there is generally no need (in the US and other 120/240 areas) for 240V except for: HVAC Electric Dryers Electric Water Heaters Electric Car Chargers Electric Ovens and Cooktops (aka stoves aka ranges). Welders and some other shop tools For most computer users, 240V may give a very slight increase in efficiency, but not ...


12

The bigger problem is the transformer is going to set you back about $100, so it spectacularly fails to make sense for a $40 humidifier. Dollar for dollar, if you're coming to North America, you may be better off just adding a couple 240V circuits to your house, and running the appliances off 240V straight shot. North America has both 120V and 240V ...


8

Yes, just be sure to run a 4 wire circuit (2 hots, neutral and ground), if the current garage is attached you don't need extra ground rods. In fact, since you are planning for the future, you might install a sub-panel now that would supply your EVSE outlet as well as other circuits in the future. As many others have said here, go bigger than you expect to ...


8

Something like a dehumidifier which has a fairly high load and a high start up current, will require a larger transformer. Cost and portability will be major considerations. Smaller appliances with low current draws, will be easier to fit to a small transformer. For reasonable quality transformers, figure a loss of about 3%.


7

It's funny, how perfectly handy people, who make things all the time, assume nobody makes anything or has Maker pastimes. Atoms are the new bits, as they say. Everything from Burning Man floats to artisan manufacturing are ever more popular. More people than ever are using hooty tooty Euro or quality machine tools like Saw Stop that commonly take 240V. So ...


6

Cannot do it. Nosirree. Cannot use a MWBC As you have stated it in your question, you are describing a multi-wire branch circuit (MWBC). Singular. That is not 2 independent circuits. It is a multi-wire branch circuit. Further, it has a serious defect in that it is taking power from unrelated points on the panel. Code absolutely requires that MWBCs be both ...


6

The number of circuits isn't really the issue. You could run as many as the panel will allow, number of breaker positions. The issue is amps to the panel. You've got 40 amps to use and as long as you don't exceed that for any length of time (you'd trip your 40 amp breaker)' you'll be fine. I'd say three would be fine Think of your house panel; you've got a ...


6

This really needs to start with a conversation with your AHJ. What you need to know is if your legacy setup is grandfathered. And then you can have a talk about your options about modernizing it. That knife switch, which I see high on the wall above a walkway, is not a player. Simple as that. It's not in a legal location for any service equipment to be....


5

I assume you are in the USA for this answer. 120 volt circuits are not considered “low voltage”. Low voltage means 60 volts (I believe) or lower. 120 volts and 240 volts are the same voltage class and it is perfectly fine to run both of them in the same conduit. Besides, in the USA, 240 volt circuits are simply two legs of 120 volts in opposite phase. While ...


5

To add to JACK's answer, keep in mind... A 120/240V subpanel of 40A has two separate 120V "legs". Each leg is capable of 120V@40A. As you can see, without even having to think about it, we know we can supply four 20A 120V circuits. That was easy LOL. And if you specifically know you will be running certain combinations of tools at the same time, ...


5

You may be able to install a 120v receptacle but you would need to change the breaker to 20 amp how many wire is your existing feed would be my question if 4 wire yes you can convert if 3 wire it depends on the colors.


4

You're wasting about 2-3% of the transformer rating in inefficiency. If you're switching secondary voltage, then you're paying for the primary winding losses 24 hours a day even if there's no load on the transformer. The transformer is just one more item that can fail and leave you without your appliances.


3

I agree with Ed Beal, this is legit because you already have a separate neutral and ground wire. You must change the breaker to 20A. The receptacle size MUST match the breaker size (there is an exception to allow 20A breakers on dual 15A sockets, i.e. the common recep we use everywhere). While you're in there, disconnect and cap off the unused red wire. ...


2

Nope, no chance. You can't get there from here. The only way to do it involves some wild back-flips with a 5 KVA 120/240V transformer, but those are $400+. (you can occasionally get a find on Craigslist, but even then, the price will be greater than the price diff between this one and the generator you need.) So back it goes.... if the well is a priority. ...


2

This is really the same issue as most people have in their main panel - you can oversubscribe because, at least in typical residential applications, most circuits are not used to capacity and most circuits are not used at the same time. For example: 120V 15A or 20A lighting circuits in the past might use a few Amps - e.g., 10 x 60W incandescent = 600W = 5A @...


2

There is not reason to do it. The 120 or 240 AC is always transformed down to a very low DC voltage (1.5 to 12 Volt) to be used by the computer or other electronic appliances. If u have many appliances you can just use mutiple dedicated 120 outlets which can be used directly. I tried in the past to anticipate the future and I was very often wrong. Install ...


2

I searched for this and couldn't find a NEMA code for this outlet (no surprise there!). But in my research it appears that this has been around for a long time, terrible idea as it was. Attached is a pic of a similar outlet that is obviously quite old. There are actually 3 of them with the same configuration in the pic. I would rather have made this a ...


2

As described in some other answers, a Multi Wire Branch Circuit (MWBC), can do exactly what you want, with one exception. An MWBC lets you get 2 x 120V on 3 wires instead of 4, because the two 120V circuits share neutral. Assuming this duplex receptacle is the only thing on the circuit, it must be a 20A receptacle as each 120V section will only have one ...


1

If you split the neutral jumper on the receptacle and hot receptacle so you feed the receptacles like you want each having a hot , neutral and pigtailed ground they are 2 separate circuits and not required to be handle tied . You can have multiple circuits as long as the hot and neutral are separate 210.4 requiring a handle tie is because of the common ...


1

Box fill requirements basically make that a hard no. #6 wires need 5 cubic inches each. The device (receptacle) they connect to adds two more, so you need 30 cubic inches just for that. #12 wires need 2.25 cubic inches each, and the device they connect to adds 2 more, but you get to skip the ground (or count only 1/4 of it under 2020 rules) so 9.56 cubic ...


1

First, the two breakers need a handle-tie. Or replace them with a 2-pole breaker. When you splice or extend neutral on a MWBC, you must pigtail the neutral. You cannot use a device such as a recep to splice. Other than that, I do not see a problem, except... ok. Bear with me. Modern Code requires the laundry room have a dedicated circuit all its own. It ...


1

The fact that it is a multiwire branch circuit may have been allowed in the past I don’t remember but think it may have been ok. Today the laundry branch circuit is a required circuit and it is a dedicated circuit and can have no other receptacles so it would not be code compliant by today’s code or many code revisions back to add the GFCI receptacle even if ...


1

Dual 12/2 is not legal in a 1" conduit. (to be more precise, 12/2NM is not allowed outdoors, and two 12/2UF are too big for a 1" conduit - that's why they bind.) You can't run 2 circuits to an outbuilding of the same voltage and usage. It would be OK if one of them was on a switch at the house, or had some other characteristic distinguishing it. So the ...


1

As far as using the existing feeds to power a sub panel, no you can't. You can't parallel cables that small. The good news is, depending on the size of your conduit, you could pull some THHN in it, after removing the 2-12/2 cables. This could feed a sub panel and then you could reroute your two 120 Volt circuits into the sub panel and also add your 240 Volt ...


1

One specific consideration is provision for an electric car charging circuit per parking space. A downside is that it is really hard to know exactly what you (or a future home owner) will need for their vehicle. Could be 120V will be fine but will charge slower, whereas 240V will permit the possibility of a quicker charge, and a higher voltage like 440V ...


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