I'm trying to do some repairs on a house on our ranch the previous owner
wired himself, which should set off a bunch of alarm bells right there.
In one room there is a window air conditioning unit that's marked as
using 230v a/c. As I remember, 230v is only one leg of three phase
service. Is this correct?
Anyway, the people who lease the ranch SAY the a/c unit was working up
until recently. I checked the wall plug, which has one verticle power
blade and one horizontal along with the round ground one, and I get
120v to ground on one blade and nothing to ground on the other.
Between the flat blades I get nothing which tells me there's some kind
of break in the line (a breaker somewhere or it's burned in two) which
goes Lord knows where. I'd need an Ouigi board to ask the guy how he
wired this as he passed away a couple of years ago and the walls are
all recycled shiplap. I'm just glad the place hasn't burned to the
The house has only 120v service to it that I can tell (the stove is
wired for 220v). How this was working up until now I don't know unless
it was just the internal fan that was blowing. Is there a way to use
120v, or 220v, on 230v system? That sounds crazy to me and the
information panel on the a/c unit doesn't hint at a re-wiring option
like I've seen on some A/C motors.
Thanks in advance for anyone's insight out there.
No such thing as 220v or 230v, only 240v; which some people insist on
calling almost anything. However, you are thinking of 208v, which is two
legs of three phase; but since you don't have 3 phase, it really doesn't
It will tell you what voltage your outlet is supposed to be. (though I have
no idea why they call it 250v!)
I am guessing you have a 6-20, but it could also be a 5-20.
If it is a 6-20, it sounds like one half your your breaker tripped, though
that isn't supposed to happen. If it is a 5-20, then perhaps you have a bad
neutral connection somewhere.
Did you try resetting all the breakers?
Sounds like your house, like just about all, has 240V service. That's
what's running the stove. The A/C sounds like it lost one leg of the
240V. You should have 120V between either leg and ground, 240V between
What voltage is 208 using two out of three legs of ? It is usually a 208
three phase system. YOu take two legs off that and get the nominal 110
volts. Not to get hung up on what to call it but whenever I hear
110,115,120 and not often but sometimes 125 volts mentioned I think of it as
the voltages the normal outlets in the home have been called over the years.
Same as for the 220 to 240 volts. But I don't think that the 208 has ever
been mentioned except as a 3 phase circuit and is not found in normal
Try again. Two legs of three phase 208 give you one phase 208. Any
single leg to the grounded current carrying conductor (neutral) gives
you 120 volts. 208 is found in normal residential service in multiple
dwellings and in single family detached homes that are located in
neighborhoods dominated by commercial occupancies or served by the same
transformer set as a larger multiple dwelling. Supply practices vary by
utility, state, dominant loads in area... A single phase appliance
rated for 230/208 supply will run on any single phase voltage between
205 and 245. With some such appliances you will have to change the
motor taps in the stuffing box on the motor to allow it to run on the
lower voltage. 230 is the nominal voltage that identifies equipment
that will run on voltages between 220 and 240. If the equipment is not
marked with the /208 it will not run on the lower voltage without a real
risk of overheating and motor failure.
Where the hell have you been?
The COMPLETE BULLSHIT answers to electrical questions are running
Go check out the Spa, GFIC and 'How do I find a buried cable' threads.
Extra credit: check out the "How do I ground my puter' thread.
Wrong. 208V 3ph is 208V phase-to-phase and 120V phase-to-neutral.
Doug Miller (alphageek at milmac dot com)
Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?
You are correct. I was thinking of the phase to neutral and did the phase
to phase mistake.
I have been working too much with the 3 phase 480 stuff at work to be
thinking of the 3 phase 208 circuits . We have some of them but not very
No offense intended here but you dont have enough knowledge to be
working on the electric service in this house. People's lives are at
stake and you don't have a grasp on the basics yet. That not a bad
thing... just get a good book and read up on it some but in the
meantime get an electrician out there to resolve the problems.
If your house is wired for 120V service, there is no way you can get proper
230V operation of any 230 V appliance..
If the stove operated it was running at about its normal wattage.
You say the stove has an "internal fan". Never heard of that. try again.
I recommend you hire an experienced , licensed electrician to check this out
before you burn out an appliance, or someone gets Electrocuted!
My guess is you simply lost a phase. Do you have a 3 wire service?
That is 240v in the US (which may be a bad assumption Are you US?)
That will be 120v to ground on each leg, 180 out of phase, which gives
you 240v across both hots. If you lose a phase yopu will "see" the
ground across the other loads so one side will be 120, zero on the
other. Try flipping the main breaker off and on a couple times.
> I'm trying to do some repairs on a house on our ranch the previous owner
> wired himself, which should set off a bunch of alarm bells right there.
> In one room there is a window air conditioning unit that's marked as
> using 230v a/c. As I remember, 230v is only one leg of three phase
> service. Is this correct?
> until recently. I checked the wall plug, which has one verticle power
> blade and one horizontal along with the round ground one, and I get
> 120v to ground on one blade and nothing to ground on the other.
> Between the flat blades I get nothing which tells me there's some kind
> of break in the line (a breaker somewhere or it's burned in two) which
> goes Lord knows where. I'd need an Ouigi board to ask the guy how he
> wired this as he passed away a couple of years ago and the walls are
> all recycled shiplap. I'm just glad the place hasn't burned to the
> ground yet.
> wired for 220v). How this was working up until now I don't know unless
> it was just the internal fan that was blowing. Is there a way to use
> 120v, or 220v, on 230v system? That sounds crazy to me and the
> information panel on the a/c unit doesn't hint at a re-wiring option
> like I've seen on some A/C motors.
If this is a residence in the USA, I would bet dollars to doughtnuts
that you have a 220 VAC service, and that the AC unit is also 220 VAC
(from your description of the receptacle). I would further guess that
one leg of the 220 circuit to the AC unit is out, for whatever reason,
bad breaker, fried receptacle, etc. You should be reading 110 between
either leg & ground & 220 between the 2 legs.
If you -aren't- in the USA though, this post may not make any sense.
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