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-   -   Convert 220V to 110V (http://www.diychatroom.com/f18/convert-220v-110v-26799/)

wrldruler 09-13-2008 09:09 PM

Convert 220V to 110V
 
Hello,
I am converting my garage into an office. Still in the design phase.

I am going to install a 220V A/C and Heater unit.

Eventually, I may decide to buy a 110V ductless minisplit system. When that happens, I won't need the dedicated 220V anymore.

How do I install the wiring to allow me to most easily switch the dedicated 220V circuit into a dedicated 110V circuit?
Thanks, Chris

DVLCHLD 09-13-2008 10:06 PM

220V to 120V
 
A 220 Volt circuit uses two 110 Volt wires so you could just run the 220 circuit then when you decide to change to 110 you could disconnect one of the 110 Volt wires at the breaker box and the outlet and install a lower amperage breaker and outlet. The only problem is, the wire guage would be larger than it should be for a 110 Volt circuit. The breaker might still protect the circuit but I'm not sure. You could just go ahead and run the 12 or 14 guage wire you will need for the 110 so it will be there in the wall waiting to be used.

Billy_Bob 09-13-2008 10:34 PM

Find out the amperage required for the A/C-Heater (window unit?).

Then find out the amperage for the split system. There may need to be an outlet inside as well as outside for this. Might be easier to run the wiring now and install the boxes in the wall if you have everything torn apart.

I would just run the wiring for both right now. You might want to locate the split system elsewhere, so you can just run the wiring for that now.

Also there are never enough outlets for things, especially an office. I would suggest running the wiring now for additional outlets. Best if they are on 20 amp circuits.

SD515 09-13-2008 11:21 PM

Attached or detached garage?

jerryh3 09-14-2008 07:51 AM

Quote:

Originally Posted by DVLCHLD (Post 157890)
A 220 Volt circuit uses two 110 Volt wires so you could just run the 220 circuit then when you decide to change to 110 you could disconnect one of the 110 Volt wires at the breaker box and the outlet and install a lower amperage breaker and outlet. The only problem is, the wire guage would be larger than it should be for a 110 Volt circuit. The breaker might still protect the circuit but I'm not sure. You could just go ahead and run the 12 or 14 guage wire you will need for the 110 so it will be there in the wall waiting to be used.

Huh? A 220 circuit uses two 110V lines?

wrldruler 09-14-2008 08:39 AM

Quote:

Originally Posted by Billy_Bob (Post 157898)
I would just run the wiring for both right now. You might want to locate the split system elsewhere, so you can just run the wiring for that now.

I agree. I think it would be best if I ran TWO new dedicated circuits: A 220 for my A/C Window unit, and a seperate 110 for my future minisplit. Then I won't have to worry about manipulating the 220 to work with my minisplit. and they can go to seperate locations, with seperate amperages.

Quote:

Originally Posted by Billy_Bob (Post 157898)
Also there are never enough outlets for things, especially an office. I would suggest running the wiring now for additional outlets. Best if they are on 20 amp circuits.

But once the window unit is out, I will likely never need a 220V in that office again. Don't plan on cooking or drying anything in there. So it would just be a wasted outlet, taking up space in my breaker. Hence the reason I am asking about converting it to 110V.

Can the 220V be converted to a 110V? Otherwise it will be a wasted outlet.

Quote:

Originally Posted by SD515 (Post 157904)
Attached or detached garage?

This is an attached garage.

Thanks

fw2007 09-14-2008 09:11 AM

It's really simple.
You install the 220V line now, using the gauge of wire that will fit your future, 110V plans. You install a double-pole breaker for the 220V line now, and a 220V outlet.

When you decide to convert to 110, you remove the double-pole breaker, replace it with a single pole, and run the white wire in the cable to the panel's neutral bus. Then you change the outlet to a 110V. If you wish, you can then add more outlets to the same line.

You could also run a 3-wire (3 + ground) cable now, and don't use the 3rd wire. Then, when you want to change to 110V, you keep the double-pole breaker, and connect the 3rd wire to the neutral bus and change the outlet to 110V.
You then have two 110V circuits from the double-pole breaker.
You would probably want to run additional outlets from the original one, to make use of the second 110V circuit. You can easily do that using pigtail and run cables to new boxes.

Since you would be using a double-pole breaker for the 110V line, using a common neutral is OK, and conforms with NEC.

If you do use 3-wire cable, leave the white off for the 220V line, using just the red and black, since 220V both sides are hot.
Be sure to leave enough of the white wire in the outlet box and the breaker box for later connection.

You could (please check NEC and local codes on this) connect the white wire to the neutral bus in the panel now, even if you're not going to use it right away, just don't connect it to anything in the outlet box. Tape up the ends of any unused wires.

One further note: If your 220V appliance calls for only 15A, forget that, and use #12 wire and 20A double-pole breaker. Running 15A circuits with #14 wire is a waste, since it doesn't allow much expansion.

If you are unsure of what wire/breaker to use, post the appliance's specs here, and someone will help you out.

Hope this helps

FW

fw2007 09-14-2008 09:12 AM

Quote:

Originally Posted by jerryh3 (Post 157966)
Huh? A 220 circuit uses two 110V lines?

Well, I think he was referring to the fact that each wire is 110V above ground, so is hot and there is no neutral.

FW

Speedy Petey 09-14-2008 09:21 AM

Quote:

Originally Posted by DVLCHLD (Post 157890)
A 220 Volt circuit uses two 110 Volt wires so you could just run the 220 circuit then when you decide to change to 110 you could disconnect one of the 110 Volt wires at the breaker box and the outlet and install a lower amperage breaker and outlet. The only problem is, the wire guage would be larger than it should be for a 110 Volt circuit. The breaker might still protect the circuit but I'm not sure. You could just go ahead and run the 12 or 14 guage wire you will need for the 110 so it will be there in the wall waiting to be used.

DVL, in one post you are asking about how to do basic electrical work. Then in another you are giving advice on how to do electrical work?

This reply here is completely wrong and misleading. What does the voltage have to do with wire size??? Are you suggesting that wire used in a 240v circuit would be larger than for a 120v circuit???
What do you base this on??

I have to say, and take this as constructive criticism no an insult, PLEASE do not give advice in areas you are obviously not qualified to.
LOTS of folks read these boards, not just the one you are replying to. If you give bad or even dangerous advice it stays up here for a long time, or until someone corrects it.
Luckily there are many of us here who watch out for this.

Billy_Bob 09-14-2008 09:23 AM

Quote:

Originally Posted by wrldruler (Post 157982)
...Can the 220V be converted to a 110V? Otherwise it will be a wasted outlet...
This is an attached garage.

Yes the 220 could be converted to a regular outlet. For this you would probably use the same wiring as for a 110*. So just switch the breaker and outlet, then you are good to go.

*The wire size and breaker you use depends on the amperage needed. Best to check on this for before doing any work. If your window A/C turns out to be an energy hog requiring a lot of amperage and a large wire, then you could probably still connect a regular outlet to this large wire...

The only thing is that you would need to find a regular 120V outlet which allows a large wire size. They make cheap 50 cent outlets, "commercial grade" outlets, and "industrial grade" outlets. As I recall, the industrial grade outlets have lugs on the back which will accept a larger wire size. Might need to go to an electrical supply for this.

Something to check before installing anything... Length of cord for window A/C? If the window is high and you install the outlet at regular height with an eye toward that outlet being a "regular outlet" in the future, be sure the A/C cord will reach. (Sometimes these window A/C outlets are mounted high up.)

Also don't forget phones, stereo?, computer wiring, intercom?, doorbell, etc. If the walls are open, it is a good time to wire for everything you might need in the future.

jerryh3 09-14-2008 09:29 AM

Quote:

Originally Posted by fw2007 (Post 157993)
Well, I think he was referring to the fact that each wire is 110V above ground, so is hot and there is no neutral.

FW

Maybe. But when adivce like "when you decide to change to 110 you could disconnect one of the 110 Volt wires at the breaker box" and "The only problem is, the wire guage would be larger than it should be for a 110 Volt circuit" is given out, it needs to be verified first. I'm glad you brought up the point about the Multiwire branch circuit.

Billy_Bob 09-14-2008 09:31 AM

P.S. I can't hear my doorbell if I am in my garage. I found a doorbell which allows for additional remote speakers to be connected. Just regular speakers as would be used for a cheap stereo. So something to consider in the planning...

DVLCHLD 09-14-2008 10:46 PM

wow
 
Sorry, I thought a 220 outlet had two 110 volt wires going into it. I apologize for mis-speaking. To ensure member's safety I will never give advice on these forums again. I'll just use it as a learning tool and refrain from posting replies to questions. Thanks.

fw2007 09-15-2008 11:55 AM

Quote:

Originally Posted by DVLCHLD (Post 158209)
Sorry, I thought a 220 outlet had two 110 volt wires going into it. I apologize for mis-speaking. To ensure member's safety I will never give advice on these forums again. I'll just use it as a learning tool and try to refrain from posting. Thanks.

In a way, that is correct. If you were to measure the voltage from each side of a 200V outlet to ground, you would get 110V.
The thing is, when the breaker is installed, it must take power from both sides of the 220V bus, otherwise you get no voltage at the outlet.
That's why we use double-pole breakers.

That said, I used to have a Federal Pacific panel, and if you weren't paying attention to the bus when installing a double-pole breaker, you could have both poles connected to the same bus, and get no voltage between poles.

The CH I have now is configured so this cannot happen.

FW


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