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Boy, I sure am asking quite a bit lately!
Have a room addition with a baseboard heater in it that barely runs. It is capable of running 110 or 220 but is running at 110 now.
It is the only item on the circuit run with 12awg wire.
Can I just mark the nuetral (white) wire and connect it to a second breaker ( I have an available 220 double gang breaker from an old electric water heater that is unused.)
Would this work. I have read that this is an option.
Awaiting your knowledge!
Curtis
I would think you want 3 wire for 220. Two are hot one is ground. 220 has 3 wires in it plus a ground. Im no electrician but that dont sound right. Just my 2-cents worth
good luck Larry
You can make this work, but it is not code. The problem being (IMO) that if anything happens that causes a fire in your house, the insurance co. will find this non-code method and may deny you any coverage.
My advice would be to run another wire from the service entry to the heater. At least make it meet the code for your own protection. There are good reasons for having the neutral and the ground wire along with the two hot wires. But they are not necessary to get the 220 to work, just more sensible.
But, just my opinion.
I do have a ground wire, so that should be fine.. but I have read that 220 wiring has no neutral wire. Now I am confused...
Thanks for the inputs though.
Any more thoughts?
You right and you will acomplish the same thing with another wire. But as long as your running the other wire. You might as well run the right one instead of introduceing another 110 line into the box. Ive ran a new line for 220 from the panel but never doublin up 110 or doing other cob jobs to get it to work. But then again im no electrician or speller for all that matters [img]/forums/images/icons/grin.gif[/img]
Larry
the reason there is no neutral wire is because it does'nt matter what hot wire goes on either hot wire of your appliance. like a dryer it doesnt matter what hot wire you put on either side of the receptical. Hopes this dont confuse ya more. [img]/forums/images/icons/confused.gif[/img]
I'm confused now too. If I run a 12-2 wire for 110 I've got a hot (black), neutral (white) and ground (bare). Can't I use that same wire for 220 with hot + (black), hot - (white) and ground (bare)? Is there a neutral with 220? [img]/forums/images/icons/smile.gif[/img]
First of all, what is the amperage of the heater, make sure that the 12 gauge is adequate, when some people have wired they sometimes take shortcuts. In addition make sure that the breaker is adequately suited for the purpose intended, it is not to wise to use a 40 amp breaker when a 20 amp is called for.
On your 220 connections on your heater, how many connecting points are there? If there are only for the two hot and the ground, that is all you need. If this is the case, make sure that you wrap black tape around the white at the fuse panel and at the heater so that there is no mistake that this is a hot wire.
If there are 3 connecting points for the 220, plus the ground, then you will have to run another wire that has 3 strands plus the ground. More than likely you will only have the two hot and the ground unless the heater is designed to run off of 110 and 220 at the same time.
If you are used to 110 and start doing 220 it is like trying to wire a 3 way switch.
Thanks for all the input..
The heater only has two wires (plus ground.) and the wire was a relatively new 12awg 12-2 wire with ground and the one heater was the only thing on the circuit. I marked the white as hot and put it in a 20 amp breaker ( as that is what I was told is the max for 12awg wire. All works great. Only trouble is the heater smelled for a half hour cuz it never had come up to temp before on the 110!
Found a ton of info here Handyman wire in the forums.
Thanks all!
Curtis
Curtis,
You're absolutely on your right thinking. It only takes 2 hots and a ground for the 220V heater to work. Actually, ALMOST ALL of them are wired that way. I see no need for the comment to be safer with the neutral wire being there.....there's nothing to connect it to. Make sure the white wire is re-identified as a hot wire, change the outlet if there is one, put in the 2 pole breaker and you're all set.
Chief Electrical Inspector
I told ya i was no electrician [img]/forums/images/icons/grin.gif[/img]
Larry
As you've found out, you only need two 110V inputs and a ground for a 220 circuit. No neutral is needed. However, you should use a true 220 breaker at the box instead of two individual 110 breakers. There are two reasons for this. The 220 breaker will pull the two 110 leads from different legs of the input. This keeps the current draw of the two legs even. You currently may or may not be pulling from different legs, it depends upon which breakers you selected to use. Generally, the row of breakers on one side of the box are on one leg, the other row is on the other leg. The 220 breaker is designed to tap into both rows of breakers. There is also a safety issue. With two separate 110 breakers someone who is not aware of how you wired the circuit could flip open one of the breakers and think he had killed all voltage to the circuit. The 220 circuit breaker has both breakers connected togeather, so flipping the breaker opens both legs of the circuit.
HTH,
Dave
<font color="blue">""You currently may or may not be pulling from different legs""</font color>
I believe if hooked both wires to the same "leg", one could not get 220V. Each "leg" is 180 degree out of phase, and you get 220 between these two. When 110 is desired, it comes between one leg and the neutral wire (ground).
But the rest of your reasoning for a true 220v double breaker is valid. You want to break both "legs" if there is a problem on that circuit, not just one.
I don't mean to be correcting here, but it only is so others who read this get the correct information (or if I am wrong, I get corrected too [img]/forums/images/icons/grin.gif[/img] ).
There are only a few limited manufacturers that did things that way. Most are alternating phase A then phase B all on the same side.
Now I probably got everyone REALY confused.
Thanks for the accurate corrections guys. I need to learn to keep my mouth shut if I'm not sure of something, especially at 1am in the morning.
Dave
this is all great info.. It's always good to see how much more I can try to learn!
Most of this actually makes sense to me!
[img]/forums/images/icons/wink.gif[/img] Thanks
Curtis
I installed baseboard electric heaters in our three upstairs bedrooms. The rest of the house is forced hot air, but there was no easy way of getting ducts upstairs. (House is a 100 year old log cabin)
I ran a separate 10/3 with ground 220v circuit to each heater . The heater is on the longest outside wall in each room while the thermostat is on the opposite inside wall. It was real fun fishing 10/3 through the walls! In fact, one of the rooms required 10/4 with ground because of the need to go to the thermostat before the heater (or maybe it was the heater before the thermostat - can't remember - this was over 20 years ago!). I just followed the instructions that came with the heater.
Lots of comments posted but a quick scan and I didn't see anything along the lines of what I'm about to say...
A typical way construct a 110/220 heater is to have two equal sets of resistance wire, each getting 1/2 the current. Say for example (hypothetical) that the resistance each element was 11 Ohms. Each would get 10 amps and the heater should produce (I squared R or I times E whichever you prefer...I is current and E is voltage and R was resistance in Ohms) 1100 watts. The elements are in parallel so you draw a total of 20 amps (10X2) and a total output of 2200 watts.
Wired for 220V the elements are in series. You have 22 ohms with 220 volts and again there is 220/22 or 10 amps. And again 2200 watts total.
In tht above description the assumption is made that there are two different connection schemes for the two different voltages. If you just put 220 into a 110 volt heater it might not like it. If it is a 220 volt heater with only 110 applied, no doubt it didn't get very hot. Power produced varies as the square of the applied voltage P = E*E/R
A 110 volt heater with 220 volts applied will produce 4 times the heat, if it doesn't die trying. The original problem statement makes it sound as if it may have been a 220 volt heater wired to 110 volts which would produce 1/4 of its normal output.
For safety reasons the metal chassis of a heater should be grounded (not neutral...GROUND/Green wire) A 220 volt heater has no use for neutral unless there is a 110 volt fan or inidicator light involved. Power is supplied by two hot wires, one from each leg (both sides of the breaker box).
Most residential wiring is single phase. Your transformer supplies 220 volts via two wires. Neutral is a "center tap" on the transformer winding. A way to visualize that is to consider two 1 1/2 volt flashlight batteries in series to give 3 volts. If you measure across both batteries you get 3 volts. If you measure from the "center tap", analgous to neutral, to either end you get 1 1/2 volts.
Don't be confused by anyone confused by multi-phase power. Virtually all residential power is SINGLE phase. There are NOT two phases. The transformer has a secondary winding that supplies your 220 volts. A mid point, i.e. center tap, measures 110 volts to either LEG.
Assume a long and complete caveat and disclaimer follows. I am not a lisc electrician and it has been a long time since I stayed at a hotel wired by one. Note: Just this afternoon I wired up a 200 amp breaker pannel with 4 each GFCI 20 amp breakers and a 220 volt GFCI ($85). I wired up 8 duplex 20 amp outlets in 4 two gang outdoor boxes. Testing this I blew a house breaker twice and arc welded a couple times. Seems that I had miswired TWO of the duplex outlets, creating direct shorts. ALWAYS put the white wire to the silver screw and the black wire to the brass screw even when talking to someone while wiring.
Best of luck to you. Let us know how it turns out.
Patrick
<font color="blue"> ""Don't be confused by anyone confused by multi-phase power. Virtually all residential power is SINGLE phase. There are NOT two phases. The transformer has a secondary winding that supplies your 220 volts. A mid point, i.e. center tap, measures 110 volts to either LEG."" </font color>
Are you saying that the 220v is not obtained between the two single phase legs that are 180 degree out of phase?
beenthere... Au contrair, mon ami... You have stated it precisely correctly. Unfortunately, folks frequently erroneously interchange the term leg with phase when discussing single phase home power circuits.
Phase has to be measured with respect to something. The phase relationship between the center tap and a leg takes some desciribing to unambiguously communicate with precision what is in fact relatively simple.
I'm sure, from your last post that we are in agreement. So that others can follow along, I have attached a precise engineering drawing of a power transformer. (too bad I never had mechanical drawing).
The neutral wire comes from the center tap. The voltage from the center tap to either end (leg) of the transformer) is 120 volts (nominal). The voltage across the entire secondary is 240 volts. For purposes of a simple explanation it is as if each side of the secondary of the trasformer were a "D" cell. Two D cells in series gives about 3 volts. Measureing from the middle of the two series cells to either end is about 1 1/2 volts.
Are the legs out of phase? Depends on your reference. If you use the center tap as a reference then the two legs are out of phase by 180 degrees as one leg is increasing in the positive direction and reaches max pos as the other leg is increasing in the negative direction and reaches max neg.
However, if you use one of the legs as a reference then the center tap and other leg are in phase with each other, with the leg being twice the voltage of the center tap. This changes nothing as far as the circuit is considered, just makes the description different and potentially less clear.
Note, I did not refer to a PAVM or O'scope.
Pat
I think with all the theory, we might confuse 'ol exeter. After reading his original post, I think his heater is fed with 110V but wired internally for 220V. He did say it was a combination unit.
But if he decides to replace it with a 220V unit, he can do it with the present wiring that is installed. The spare breaker from the water tank may be a bit too large for the heater. Some HWH need a 30 amp breaker, where the heater will only need a 15 or 20 amp breaker.
Exeter, let me know if you need anymore help with this.
Jerry
My head hurts!!
Did the research.. Turns out that it was a 220 unit wired for only 110. Marked the white as hot, switched the breaker..(Yep the water heater was a 30 so I put in a 20 amp breaker) and Hey Hey!! I have heat in the mud room..
Thanks for all the info though. I truly have learned quite a bit from this!!!
there is no such thing as too much information... well there is! [img]/forums/images/icons/blush.gif[/img]
but not here!
Curtis
Hey inspector, I'm not going to underestimate Exeter's ability to learn/understand. Your emphasis on the mismatch of the DHW breaker with what he probably needs for his heater is RIGHT ON! Oversized breakers are nearly as dangerous as not having one.
Not trying to confuse anyone, just thought it might do a couple things:1. offer a reasonable explanation for why the output of his heater is so low (could be miswired) 2. explain some about how 110/220 heaters are inplemented. I know when I get into something where my experience is real slim, getting some background info helps me establish a general framework on which to "hang" pieces of info as I learn.
If a dual voltage heater is wired for 220 but powered by 110 it would only give 1/4 the normal output which seems to fit his observations. As far as wiring size, can't be sure from here but changing to 220 will double the amps in the current wiring. This might be entirely safe or not, it depends...
Pat
<font color="blue"> As far as wiring size, can't be sure from here but changing to 220 will double the amps in the current wiring. This might be entirely safe or not, it depends...
</font color>
Well I'm a little confused:
For a given amount of power or heat, 220 vs 110 will half the amperage draw. But if it was wired wrong and only getting 1/4 the power, if it wire wired correctly for 110, he'd be using 4X the amps, but at 220 V this would only be 2X the amps (vs the "incorrect" wiring)
Hazmat, Confused? Maybe a little. Your statement of relative currrents is wrong. Your assumption regarding a "given amount of power or heat" is the likely culprit. The heater is a dumb resister or pair of resisters actually and has no active regulation to ensure constant output with varying input voltages.
Let us take a simple example: Let's say we have a heater built to run on either 110 or 220 volts and that it is rated at 4400watts (when correctly connected to either 110 or 220 volts).
If it is configured for 110 volts then each heater element (resistor) has 110 volts applied to it as if they were two seperate heaters each wired independantly to 110 volts. Each half producing 2200Watts.
I'll just write out a couple forms of Ohm's law for easy reference: P=IE and I=E/R Where P is power in Watts, I is current in Amps, and R is resistance in Ohms.
So we see that 2200 = I times 110 which with a little algebraic manipulation becomes I = 2200/110 which simplifies to 20 amps. This is 20 Amps to each resistive element and there are two so total current at 110 volts would be 40 Amps.
Now with the current (to one element) AND the voltage we can solve the second equation for resistance: I=E/R is restated as R=E/I. Substituting the known values we get R=110/20 or 5.5 Ohms for one element.
If we reconfigure the heater for 220 volt operation we have two resisters in series adding up to 11 Ohms (5.5 X 2). Combining the two equations we get P= ExE/R (power is voltage squared over resistance) and substituting in the knowns and solving for the unknowns we get P= (220x220)/11 which is 4400 Watts.
The heater, when correctly connected to either 110 volts or 220 volts, produces 4400 Watts. On 110 volts it draws 40 Amps and on 220 volts it draws 20 Amps.
Alternatively you can consider the two resistors in parallel to solve the 110Volt version. For two resistors in parallel you have 1/2 the resistance or 2.75Ohms. Using P=ExE/R (E squared over R) you get 110x110/2.75 which is (drum roll please) 4400Watts.
So you see if our imaginary heater was configured for 220Volt operation its R would be 11 Ohms which at 110 Volts gives (using P equals E squared over R) 1100Watts which is what we would expect, 1/2 the voltage so 1/4 the power.
Since I don't know the wire size (Ampacity), or run length I don't know that it is safe to just hook up 220Volts even if it is currently supplied with 110 while configured for 220. If the ooriginal wire was sized correctly to get rated power with 110Volts then the wire is generously oversized and safe to be used for 220. This needs to be confirmed before risking burninig the building down.
I have attached yet another precision engineering drawing depicting notional connections for a 110/220 volt heater. I did NOT show a ground wire which is for safety and does NOT get involved in our calculations. In the drawing NC means No Connection. I show a 110 and a 220Volt source but for simplicity did not show breakers etc.
If this was neither clear, helpful, nor seemingly correct to you, I'd be glad to answer any pecific questions or listen to any dissenting view. If continuing this topic risks boring too many folks or uses too much bandwidth (Censors/moderators please chime in) I'll be happy to take it to private email or drop it.
I can recall when I didn't understand some stuff and appreciated when others would take the time to satisfy my curiosity about how it was so I owe it to pass a little on as well.
Pat. (Note to Egon: This works in Canada too.)
[blue]If this was neither clear, helpful, nor seemingly correct to you, I'd be glad to answer any specific questions or listen to any dissenting view. If continuing this topic risks boring too many folks or uses too much bandwidth (Censors/moderators please chime in) I'll be happy to take it to private email or drop it.[/blue]
Actually it was quite clear. Thanks for the explination, saved me from having to dig my physics book out of the attic.
I'm assuming E = Electro Motive Force also known as Voltage or V?
Hazmat, Yup.
And we didn't have to resort to using curl or the left or right hand rules or... Physics book? Doesn't the instructions for giving a physic come on the package?
OK, OK, I confess, in a past life I did physics (and electricity) before I found true religion (Software Engineering). Trying to be a specialist I studied more and more about less and less until in the limit (like in calculus) I knew everything about nothing. Then I tried my hand at being a generalist where the goal is to know less and less about more and more until you know absolutely nothing about everything. I'm nearly there!
Pat