Electricity 101

[Poboy kartman]

After reading some of the old wives tales and misinformation touted as fact in another thread......

Thought I'd start one here to explore the fact and fantasy concerning Alternating. Current......

To start off with: splitting a 220 volt circuit into two 110 volt circuits....what is the cause and effect on amperage? ???

EDIT: Please do not refer to the other thread I mentioned specifically here...I started this so there could be a discussion and hopefully....we can all become more knowledgeable. If you want to dispute a statement there do it there....

 

[KartFab]

Rather than trying to prove a point, why don't you educate us all? It's nice to be right, but it's more important to be nice.

Amperage? Size of wire determines how much before it fries, so does length, and what you plug your electrical device demands. If the demand is there, you get the amps until the wire/length can no longer support the load and converts the energy into heat? I honestly don't know. Breakers are there to protect the wires from overheating. I have a bus with a 200 amp to protect the house, then smaller breakers within to protect each circuit. ... Let's hear your write up. Code vs what is possible (e.g ground vs 'neutral') should be explained.

 

[Poboy kartman]

I don't care about being right.....but misinformation does bother me....certainly...there must be some members here extremely more qualified than me to educate us all.....me included....and that's who I would like to respond to this thread.....

Yes....there were statements in another thread I think are wrong.....at any rate...they disagree with what I believe.....

I'm no expert....and could be wrong myself.....I started this thread to have a discussion about it....not a p!##!@ match.....

And it's not just this one facet..... but....many others.....I'm here to learn and help.....not boast....or I'd just make YouTube vids......

 

[chancer]

1. Is it technically possible to get 110V AC by splitting a 220V AC system?

The answer to question one is "Yes". It's perfectly possible. Every other 110V circuit in your house is powered by splitting this same three-phase 220V AC into sub-circuits. If you look at your panel, the circuit breakers are either 110v and are on one leg or 220v and use both.
Leg 1 Leg 2
|------- |
| -------|
|------- |
| -------|
|------- |
| -------|
|------- |
| -------|


So you can just use one leg of a 220v breaker to get 110v. You should consult an electrician or know what you are doing. But you still have the amperage rating that is on the 220 breaker.
I did this very thing on my house and my Dads.
Why?
He bought a cute little Lincoln 110v welder. It required a 20amp Circuit. He had in his Garage a Dedicated 20amp circuit. But he kept blowing the Breaker. He also had a 30 amp 220v outlet in his Garage he was not needing. So we split the 220 30 amp to 2 110 30 amp. Now he can max out the amps on his welder to 20 and not throw the 20 amp breaker.
Later when I bought my welder I did the same thing.
*Warning* Consult an electrician- Not my post!!
1.Most 110v outlets are only rated to 20amps.
2. You need the correct size wire for the amp draw you are using.
3. I felt confident doing this knowing that the new name brand welders we were using should only draw 20 amps anyway. We really did this to prevent tripped breakers at 21 22 amps.
4. You could overheat wires and burn down your shed/ carport/garage/shop

 

[chancer]

Doug please tell me if I am wrong here.
I saw the other thread and the guy thought he split his 30amp 220v drier to 2 15amp 110v. The breaker amps will not change just cause he split it.
I am not an electrician. I install Heating and AC. I have run many 110v circuits to power Heaters and many 220v circuits to power AC units.

 

[Poboy kartman]

I really don't know either....but I can tell you it's what comes back that matters....not what goes out.....

Typical. 3 wire 110 volt circuits have a "hot" or current carrying wire which is black...(which messes with DC guys minds where it's. ground..)

Then a white wire which is neutral ......meaning it can either carry. current or not....and a ground is actually. the neutral's understudy....and usually carrys no current unless there is a problem.......

When current becomes present in the ground wire the GFCI trips. more in a bit on breakers and wire sizes.....

 

[Badot]

Depends on how up to code you want it, or if you want your breaker to function properly.

If your two new outlets split the two 110v lines but share the same neutral and ground (this is assuming your 220 was an up to code 4 wire of course), the TOTAL of the two breakers installed to replace your double pole cannot exceed the amperage of the previous installation (now limited by the neutral/ground wires).

On top of that, standard outlets are 15A so each breaker must provide at least 15A individually.

The better option would be to just remove one of your 110v lines from the 220v circuit (both ends and replacing the double pole breaker of course) and use it as a single (not split) 110v line.

I'm no electrician, so none of this is to be taken as advice of course.

 

[Poboy kartman]

Doug please tell me if I am wrong here.
I saw the other thread and the guy thought he split his 30amp 220v drier to 2 15amp 110v. The breaker amps will not change just cause he split it.
I am not an electrician. I install Heating and AC. I have run many 110v circuits to power Heaters and many 220v circuits to power AC units.

I kinda just covered that....look at it this way.....Your. house has only 3 wires that come into your service.....A 220 volt wire, a neutral wire. and a ground.....the 220 is split at the breaker box into 110 circuits....and the amount of amperage that leaves that breaker is controlled by it.....

 

[Badot]

When current becomes present in the ground wire the GFCI trips. more in a bit on breakers and wire sizes.....

Also thought I'd add on... this is close, but not quite correct.

GFCI monitors the current going from the hot line to the neutral line (the normal path it should take), and when there's a disparity between the two shuts off.

That means that when the electricity goes anywhere other than the neutral line -- this can include the ground of the outlet, or more importantly, a completely separate ground such as a person, it realizes the electricity is taking a different path than normal and shuts it off.

 

[Poboy kartman]

I started another post because this is where it gets a lil funky......so... by code....a 15 amp breaker is meant for 14 gauge wire, a 20 amp for 12 guage wire....(now here is where I'm. not sure....but pretty sure) ....that it is not heat that trips breakers....but the disparity between amperage leaving and returning.... so....a 15 amp breaker will trip if too much amperage is not returning.....exceeding the carrying capacity. of the 14 gauge wires ability to handle that much usage....

 

[Poboy kartman]

Also thought I'd add on... this is close, but not quite correct.

GFCI monitors the current going from the hot line to the neutral line (the normal path it should take), and when there's a disparity between the two shuts off.

That means that when the electricity goes anywhere other than the neutral line -- this can include the ground of the outlet, or more importantly, a completely separate ground such as a person, it realizes the electricity is taking a different path than normal and shuts it off.

You are 100% correct.....and that is why they also trip when something that draws too many amps is used.....

So what's the difference between GFCI. and a normal breaker and why????

 

[chancer]

Just wanted to add this.
It is difficult if not impossible to find a 110v breaker that is more than 20amps. In my particular case I knew the use, was for my own 20amp welder. So part of the reason for messing with the wiring was to get a stronger breaker.
We used the dedicated 220v to not have to run new higher gauge wire, since it already existed at the 220v outlet.
Again I am not an electrician

 

[Badot]

Amperage on a circuit with no shorts is consistent throughout the circuit. Modern breakers are generally either electromagnetic or bimetallic.

Electromagnetic runs the current through an electromagnet in the breaker... when the current gets higher, the electromagnet gets stronger, and when it reaches a certain point (the break amperage) the electromagnet becomes strong enough to physically disconnect a switch inside of the breaker.

Bimetallic essentially work in the same way as old turn signal flashers -- amperage through a strip heats it up, and the strip is designed with two different materials (hence the 'bi' in bimetallic) which expand at different rates when heated, making the strip flex sideways. Generally the flex is used mechanically to trigger a break.

 

[Badot]

You are 100% correct.....and that is why they also trip when something that draws too many amps is used.....

So what's the difference between GFCI. and a normal breaker and why????

Normal breakers trip from too many amps. GFCIs trip from current going to the wrong place. They have completely different jobs with no overlap.

GFCIs absolutely can be overloaded and should always be run downstream of standard breakers. GFCIs are used in places where an alternate path to ground is likely such as outdoors or wet areas like bathrooms and kitchens. If you get electrocuted on a circuit with a standard breaker only, it will not stop electrocuting you unless the circuit becomes overloaded.

Also worth noting, if your body becomes the bridge between hot and neutral of the outlet and you are not grounded, a GFCI will not trip.

 

[itsid]

I'm so glad I don't have to deal with that 110V shirts...

But, let's get back to what Grant started.. heat...

find the resistance between your breaker and the outlet...

pure Copper has a specific resistance of 0.01721 Ω mm²/m
funny enough, that's the average resistance for quality copper wire as well (0.0169.. - 0.0175)
but let's play safe and take the WORST case scenario... 0.0175 Ω mm²/m

in germany all copper houshold wiring is 1.5mm²
so ~0.012 Ohm / m of wiring.
to make a full Ohm that's roughly 85.71 meters of wire (281.2 feet in case you wonder)
that's A LOT! right?

one Ohm on the other hand will (if you attach a 20 Amp welder)
create 20 Watts of heat!

per second that's 20 Joule of thermal energy heating the copper wire

Copper has a specific heat capacity of 0.382 kJ / (kg*K)
a meter copperwire (single strand 1.5mm²) weighs ~0.002 kg so we heat
0.17142 kg of copper
in other words...
we need 65.5 Joule to heat our entire 280 feet of copper wire up one degree Kelvin (or celsius )
roughly three seconds!

No big deal you'd think, but after one minute we doubled the temperature of the wiring.
and the hotter the wire gets, the higher it's resistance, the faster it heats up...

two more minutes and we can boil water with our wiring...
you get the idea, right?

So: keep your wiring as short and thick as possible.

'sid

 

[Poboy kartman]

Well....I'm speculating here....(waiting on the real electricians) .....but I think you nailed it Badot...GFCI'S work by detecting the disparity between hot and neutral.....normal breakers when the demand for amperage exceeds the amperage of the breaker.....as the neutral for that circuit, as well as the ground wire, and every other neutral and groung wire is tied together in one big bar......

 

[mckutzy]

Crikey,...sorry guys, Poboy... I didn't expect such a response like this.
By all means wasnt trying to stir up crap here.

 

[Poboy kartman]

Crikey,...sorry guys, Poboy... I didn't expect such a response like this.
By all means wasnt trying to stir up crap here.

Neither was I....and I still don't know even the answer to my original question in post one.....and would like to know......

I ran 10 guage 220v extension cords because the temporary poles during construction were always far from the house....I used 220v because I got far less amperage drop than the same length of 110v extension cord would.

I simply split the 220 into 110 by using each leg independently but they shared the same ground.....

So I had usually a double pole breaker at the temporary pole with 30amps....so my extension cord was 30 amps....so...splitting that without breakers....what amperage were the 110 v outlets????

And why does using the higher voltage/ amperage cord work better?????

And God bless you 'sid....but if I could understand what you posted...I'd be an electrical engineer instead of a carpenter.....you might as well have posted that in German......

 

[Poboy kartman]

Doug please tell me if I am wrong here.
I saw the other thread and the guy thought he split his 30amp 220v drier to 2 15amp 110v. The breaker amps will not change just cause he split it.
I am not an electrician. I install Heating and AC. I have run many 110v circuits to power Heaters and many 220v circuits to power AC units.

It is my belief...(and I'm fairly confident I'm correct) that the breakers control the amount of amperage leaving downstream....so he in fact had 2 15 amp circuits from that point on.....

EDIT: HVAC units use a separate 110v circuit for a couple of reasons: one, it's safer, and two, that way the 110v fan motor (or whatever) won't rob any of the fully needed amperage on the 220v circuit.....

 

[chancer]

Wait a minute. Whats wrong with stirring up crap?
Maybe I was confused at what he said he did. But If he kept the original 30amp breaker he still had 30amps. He just split the voltage. Yes the breakers control the max amps sent downstream.

MCkutzy:
For me...
I made a cable to split the drier power of 220vac/30amp into 2- 120vac lines with independent breakers.
So now I'll have two lines of 15amps and I have never blown the fuse, just the machine's overheat shutdown