electrical problems - Printable Version

wrote:
> >>>>>>>
> >>>>>>>> I've experienced two serious electrical problems on
> > our
> >>>>> current trip.
> >>>>>>>> I'm hoping the second problem (solved) was the cause of
> >> the
> >>>>> first, but I
> >>>>>>>> can't get my head around exactly how it would be, so I'm
> >>>> hoping
> >>>>> someone
> >>>>>>> with
> >>>>>>>> more RV electrical experience than I have will have a
> >> clue. I
> >>>>> will rest
> >>>>>>>> easier if I know what caused the first problem.
> >>>>>>>>
> >>>>>>>> The first problem I talked about here earlier, but will
> >> run
> >>>>> through for
> >>>>>>>> clarity:
> >>>>>>>>
> >>>>>>>> With a lot of draw going on, I had the 50-amp breaker on
> >> the
> >>>>> park pole
> >>>>>>>> blow, plus the main inside breakers, plus the breaker
> > for
> >> the
> >>>>> inverter.
> >>>>>>>> Power was lost on the inverter circuit, and did not
> > return
> >>>> when
> >>>>> breakers
> >>>>>>>> were turned back on with reduced draw. The inverter, a
> >> ProSine
> >>>>> 2.0, is
> >>>>>>> toast
> >>>>>>>> - burnt components obvious when opening the case. I
> >> removed
> >>>> the
> >>>>> inverter
> >>>>>>> and
> >>>>>>>> wired input/output together for power on the inverted
> >> circuit
> >>>>> when on
> >>>>>>> park
> >>>>>>>> power, and bought a small charger to keep the batteries
> > up
> >>>> while
> >>>>> parked.
> >>>>>>>>
> >>>>>>>> Xantrex sent out a new ProSine 2.0 (half-price, well out-
> >> of-
> >>>>> warranty)
> >>>>>>> and I
> >>>>>>>> will get it tomorrow. I've been worrying about hooking
> > it
> >> up
> >>>>> without
> >>>>>>> knowing
> >>>>>>>> what caused the failure.
> >>>>>>>>
> >>>>>>>> Problem number 2: Yesterday I moved, and on arrival at a
> >> park
> >>>> in
> >>>>> Ogallala
> >>>>>>>> the 50-amp park breaker blew as soon as turned on. After
> >>>> turning
> >>>>> off the
> >>>>>>>> internal main breakers I was able to get the park
> > breaker
> >> to
> >>>>> hold after
> >>>>>>> one
> >>>>>>>> more failure. The breaker was "spongy" so I wasn't sure
> > if
> >> it
> >>>>> was just
> >>>>>>> weak.
> >>>>>>>> Turning on the main breakers inside worked fine.
> >>>>>>>>
> >>>>>>>> Moved again today, and the problem repeated except that
> >>>> nothing
> >>>>> would
> >>>>>>> make
> >>>>>>>> it work. In trying various things I found that my 30/50
> >> cord
> >>>>> worked fine.
> >>>>>>>>
> >>>>>>>> So, I took the coach connector apart and found:
> >>>>>>>>
> >>>>>>>> Screw for black wire fell out, and was quite black on
> > the
> >> end.
> >>>>> White and
> >>>>>>>> Red attached, but screw not tight. Green was not
> > attached
> >> at
> >>>>> all - screw
> >>>>>>> all
> >>>>>>>> the way in, and wire laid across the top. Contacting
> > case,
> >> but
> >>>>> who knows
> >>>>>>> how
> >>>>>>>> well.
> >>>>>>>>
> >>>>>>>> It is amazing I had power at all. I cut the end off and
> >>>> rebuilt
> >>>>> the
> >>>>>>>> connector, and had no problem turning on the power.
> >>>>>>>>
> >>>>>>>> It would seem to be an odd coincidence if problem one
> > was
> >> not
> >>>>> caused by
> >>>>>>>> problem two, but since the ProSine 2.0 should in theory
> >> work
> >>>>> regardless
> >>>>>>> of
> >>>>>>>> what occurs on the input side I'm not sure what the
> >> connection
> >>>>> is.
> >>>>>>> Anybody
> >>>>>>>> have thoughts on this?
> >>>>>>>>
> >>>>>>>> Don Bradner
> >>>>>>>> 90 PT40 "Blue Thunder"
> >>>>>>>> Posting today by satellite from Grand Island, Nebraska
> >>>>>>>> My location: http://www.bbirdmaps.com/user2.cfm?user=1
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>> --
> >>>>>>> Curt Sprenger
> >>>>>>> 1987 PT38 8V92 "MacAttack Racing"
> >>>>>>> Anaheim Hills, CA
> >>>>>>
> >>>>>
> >>>>
> >>>
> >>
> >
> >
> >
> > ------------------------------------
> >
> > Yahoo! Groups Links
> >
> >
> >
>

electrical problems - Juergen - 08-30-2008 02:21

Mike
Here is where I am at a loss as to why you get 250 V when only one wire either green or bare makes contact. I know that 2 hot and one ground =250V I do not understand why the bare wire contact then allows two 110 V. And like I said before, I never try to put or pull the plug UNLESS the CBs are OFF. The way I read your post, I could survive or not even get a 250 surge even if the bare wire is not making contact. I cannot say for sure, but I also will never try it. Electric system is too costly. All I know is 250 V will really brighten up your lights for a brief moment and fry all the other components. Been there done that (in my house.)
Juertgen in PA
1991 WLSP36

--- On Fri, 8/29/08, mbulriss <mbulriss@...> wrote:

From: mbulriss <mbulriss@...>
Subject: [WanderlodgeForum] Re: Electrical problems
To: WanderlodgeForum@yahoogroups.com
Date: Friday, August 29, 2008, 3:45 PM

As much as I dislike messing with electrical problems, especially 30

and 50 amp stuff, I agree with Gary on this one - there is only one

common wire in the cable, two hot, and one ground.

I just recently posted about losing my neutral connection in my power

cord plug that goes into the pedestal, so it is somewhat fresh in my

mind. The round or 'u' shaped lug is the ground wire (green

sheathing). The two spade lugs on either side are hot (black and red

sheaths) and the bottom spade lug opposite the rounded one is the

shared neutral (white wire). There is only one shared ground for both

legs and one shared neutral for both hot legs.

Given the recent problems for Don and myself, this should be an item

on everyone's to-do list to open their plugs and check to make sure

the wire connections are tight. I know, hard to do on a molded plug.

These plugs and cords get lots of play wiggling them in and out of

the pedestals and coaches. I replaced mine with the new style yellow

plug end that has a molded handle built into the back. That way I

have a better grip to firmly insert/remove the plug without having to

wiggle the cord also. (Just remember that I then had to replace my

50-30 dogbone converter since the heavy ground lug on the new plug

would not go into my old converter cord.)

This is the way I understand the plug wiring. And yes, I am

relatively happy that I lost the neutral rather than the ground. At

least I did not fry anything really important to me (like me, my wife,

friends, pets, bus) other than the pedestal outlet.

That's my story and I'm sticking to it - at least for this post!

TGIF! TGIF!

Mike Bulriss

1991 WB40 "Texas Minivan"

San Antonio, TX

--- In "WanderlodgeForum%40yahoogroups.com", "Juergen"

wrote:

>

> --- In "WanderlodgeForum%40yahoogroups.com", "Gary Smith"

> wrote:

> >

> > While I have some minor disagreements with some of what Juergen said

> (there is only one common wire in the cable, two hot, and one ground),

> with loose wires, it is possible you crossed the two 120v hot lines,

> providing the high voltage he suggests. I believe the whole problem

> was caused by the poor connections, Don. Not sure how the ProSine

> should react to 240v hitting it, but could well weld some contacts, as

> you found.

> > Gary

> > SOB

> > ----- Original Message -----

> > From: Juergen

> > To: "WanderlodgeForum%40yahoogroups.com"

> > Sent: Friday, August 29, 2008 8:27 AM

> > Subject: Re: [WanderlodgeForum] Electrical problems

> >

> >

> > All I do know is that if you put the 2 hot wires, or put the

> 2 hot spades into the socket and let only the third wire do the

> ground, you will get a 250V zap. The 4th wire is the ground for the

> other hot one. I don't know the details exactly, but whenever you let

> 2 hot and only 1 ground enter, you go BOOM. I know that you must have

> all 4 wires, contacts, firmly connected before you turn the breakers

on.

> Black=hot

> Red=Hot

> White = Ground,

> Bare wire = ground

> These four must be in solid contact.

> Juergen in PA

> 1991 WLSP 36

>

electrical problems - Don Bradner - 08-30-2008 02:47

Juertgen, you can only get 240V across the two hot wires. when that happens, the
neutral (white) is not carrying any load at all.

The neutral line carries only the differential. If you have 50 amps of 120 in
use on one leg, and 50 amps on the other leg, again the neutral is not carrying
any load.

If one leg is drawing 30 amps and the other 50, the neutral will have 20 amps of
current present.

The three statements above are true because the two hot legs are opposite phase.
When viewed as a sine wave, when one is on the upside of the cycle the other is
on the downside of the cycle.

The separate 4th wire (green or bare) is ground. It is not intended to carry any
current, and is a protective line only.

In a home system the common and ground are bonded, but under RV code they are
not bonded, so they are not at all the same thing.

On 8/30/2008 at 7:21 AM Juergen wrote:

>Mike
>Here is where I am at a loss as to why you get 250 V when only one wire
>either green or bare makes contact. I know that 2 hot and one ground =250V
>I do not understand why the bare wire contact then allows two 110 V. And
>like I said before, I never try to put or pull the plug UNLESS the CBs are
>OFF. The way I read your post, I could survive or not even get a 250 surge
>even if the bare wire is not making contact. I cannot say for sure, but I
>also will never try it. Electric system is too costly. All I know is 250 V
>will really brighten up your lights for a brief moment and fry all the
>other components. Been there done that (in my house.)
>Juertgen in PA
>1991 WLSP36

electrical problems - mbulriss - 08-30-2008 04:46

Hi Juergen,

+1 on what Don said.

The big rig/MH 50 A service is actually two split phase 110V 50A legs
(the two legs in your main box) or 220V 50A across the two hot legs.

> The way I read your post, I could survive or not even get a 250
> surge even if the bare wire is not making contact. I cannot say
> for sure, but I also will never try it.

That is how, and here is how, I understand it. The neutral or white
wire is the differential or 'return' flow. The green is ground for
safety. If I have to lose one, I am much safer to have lost the
neutral rather than the safety ground. As I understand it, when you
lose the neutral on the RV wiring configuration, any return
differential is now going down the other the hot line in the case of
imbalance. If you lose the safety ground and any of the hot wires
touches metal, you potentially fry stuff, and/or you can become the
ground when stepping on/off the bus. Not a good thing, for sure.
That's why I said if I have to lose one, I was happy it was the
neutral - less potential risk to me personally.

> I never try to put or pull the plug UNLESS the CBs are
> OFF.

Excellent idea, which everyone should also follow (always ticks me off
when I come to a pedestal that still has the CB on after the last
person left). However, when pulling out those sometime slippery 50A
plugs, I know we probably all often also grab the wire below the plug
to help 'wiggle' the plug out. The constant handing and wiggling
torques the wire bundle which eventually loosened my neutral, if it
had ever been tightened properly in the first place. That's why
everyone should check their plugs for tight wiring connections.
(Thinking about it now, my old plug also did not have any strain
relief collar around the wires behind the plug to help reduce the
wiggling wires in the plug.)

FWIW. In any event, I do not like working on 30/50A wiring, but I
enjoy the end results of using it.

Off to the Bird to maybe go somewhere.... everyone have a good weekend.

Mike Bulriss
1991 WB40 "Texas Minivan"
San Antonio, TX

--- In WanderlodgeForum@yahoogroups.com, "Don Bradner"
wrote:
>
> Juertgen, you can only get 240V across the two hot wires. when that
happens, the neutral (white) is not carrying any load at all.
>
> The neutral line carries only the differential. If you have 50 amps
of 120 in use on one leg, and 50 amps on the other leg, again the
neutral is not carrying any load.
>
> If one leg is drawing 30 amps and the other 50, the neutral will
have 20 amps of current present.
>
> The three statements above are true because the two hot legs are
opposite phase. When viewed as a sine wave, when one is on the upside
of the cycle the other is on the downside of the cycle.
>
> The separate 4th wire (green or bare) is ground. It is not intended
to carry any current, and is a protective line only.
>
> In a home system the common and ground are bonded, but under RV code
they are not bonded, so they are not at all the same thing.
>
> On 8/30/2008 at 7:21 AM Juergen wrote:
>
> >Mike
> >Here is where I am at a loss as to why you get 250 V when only one wire
> >either green or bare makes contact. I know that 2 hot and one
ground =250V
> >I do not understand why the bare wire contact then allows two 110
V. And
> >like I said before, I never try to put or pull the plug UNLESS the
CBs are
> >OFF. The way I read your post, I could survive or not even get a
250 surge
> >even if the bare wire is not making contact. I cannot say for sure,
but I
> >also will never try it. Electric system is too costly. All I know
is 250 V
> >will really brighten up your lights for a brief moment and fry all the
> >other components. Been there done that (in my house.)
> >Juertgen in PA
> >1991 WLSP36
>

electrical problems - Gregory OConnor - 08-30-2008 11:46

Don, MikeHolt site has good info about electrical crap. In it he has an article about bonding neutral and groundanda electromagnetic issue with electronic equipment. there is too muchthere to paraphrase in this post. he does a good job with explanation of the particulars. I use an outside search engine to look at his forum because there are too many threads with redundent info.

GregoryO'Connor

94ptRomolandCa

electrical problems - jim riordan - 08-30-2008 15:11

This is why a Bluebird is better than a Prevost

mbulriss <mbulriss@...> wrote:

Oh my! I wonder is that was a monocoque framework on that bus rather
than the solid steel frame rails the BB has?

Mike Bulriss
1991 WB40 "Texas Minivan"
San Antonio, TX

--- In "WanderlodgeForum%40yahoogroups.com", "Kurt Horvath"
...> wrote:
>
>
> Mike,
> It worked this time.
> Notice the millisecond timer in the
top left corner on the interior
> portion of the video, S--T happens fast. The second you don't respect
> one of these machines is when they let you know who's boss.
> Kurt Horvath
> 95 PT-42
> 10Ac
>
> --- In "WanderlodgeForum%40yahoogroups.com", "Kurt Horvath"
> > wrote:
> >
> > I see that Mike, here's the address again , You might havr to copy
> > and paste in address bar???
> > http://www.youtube.com/watch?v=rrZr-QZbfxo
> > Kurt Horvath
> > 95 PT-42
> > 10Ac
> >
> > --- In "WanderlodgeForum%40yahoogroups.com", "mbulriss" <mbulriss@>
> > wrote:
> > >
> > > Kurt,
> > >

> > > That link as posted does not work. YouTube says "the video you
> > > requested is not available".
> > >
> > > FWIW,
> > >
> > > Mike Bulriss
> > > 1991 WB40 "Texas Minivan"
> > > San Antonio, TX - not a real good weekend to go to the coast!
> > >
> > >
> > > --- In "WanderlodgeForum%40yahoogroups.com", "Kurt Horvath"
> > > > wrote:
> > > >
> > > >
> > > > John,
> > > >
> > > > Your so right, "The thing can crush you, electrocute you, you
> can
> > > > fall off, and then there is the road risk. I guess we can say
> it
> > can
> > > > get you coming and going as well as a couple ways in between."
> >
> >
> > > > Speaking of road risk here's a vivid reminder of what can
> happen.
> > > >
> > > > Bus Crash Tes.tEver wonder what a bus crash looks like, check
> > this
> > > > out.
> > > >
> > > > http://www.youtube.com/watch?v=rrZr-Qzbfxo
> > > >
> > > > Kurt Horvath
> > > > 95 PT-42
> > > > 10AC
> > > >
> > > >
> > > >
> > > > --- In "WanderlodgeForum%40yahoogroups.com", "bubblerboy64"
>
> > > > wrote:
> > > > >
> > > > > The 30 amp cord is pretty much a standard 110 with a funny
> plug
> > on
> > > >
it
> > > > > then? I knew that 220 was essentially two 110 hot wires but
> > did
> > > > not
> > > > > know that the 50 was similar. Having been in a RV store not
> > long
> > > > ago
> > > > > I noticed they had a featured item up near the check out a 50
> > amp
> > > > > plug with a distinct pull handle on it. I think they also had
> > 30amp
> > > > > plugs similar. Didn't impress me at the time nearly as much
> as
> > it
> > > > > does now. I don't have 50 amps into my coach but I learned
> > > > > something. I also did not realize the risk involved in the
> > battery
> > > > > campartments. I was informed last year at the Maxton rally
> > about
> > > > > that. I guess the low voltage stuff can
be rather nasty as
> > well.
> > > > > Perhaps some one will review and explain what the risk with
> the
> > low
> > > > > voltage. Does make a rather nasty spark if you short the
> > positive
> > > > > against the metal I know that. All kinds of ways a fellow
> can
> > get
> > > > > hurt. I was up on the roof of my bird this morning and I was
> > VERY
> > > > > careful. I remember seeing Don's X rays. I don't much like
> it
> > up
> > > > > there but once a year I go up to check it over and see that
> all
> > is
> > > > > well. Lets see. The thing can crush you, electrocute you,
> you
> > can
> > > > > fall off, and then there is the road risk. I guess we can
> say
> > it
> > >
> can
> > > > > get you coming and going as well as a couple ways in
> between.
> > > > >
> > > > > John Heckman
> > > > > central Pa
> > > > > 1973 FC
> > > > >
> > > > >
> > > > >
> > > > > >
> > > > > > I may not have been clear: It was the coach end of the
> shore
> > > > cord,
> > > > > not the connector that is part of the coach. The pole end is
> a
> > > > molded
> > > > > connector, but the coach end is not; don't know if that is
> > original?
> > > > > >
> > > > > > There is a plastic ring cinched down to the cord, just
> behind
> > the
> > > > > connector. I never gave it much thought, but now I
wonder why
> > that
> > > > is
> > > > > there. It lends itself to be the point that is grabbed to
> pull
> > the
> > > > > connector out, but that puts strain on the wires in the
> > connector.
> > > > > Clearly I should grab the connector body to pull it out, not
> > the
> > > > > wires.
> > > > > >
> > > > > > On 8/28/2008 at 8:31 PM Curt Sprenger wrote:
> > > > > >
> > > > > > >Don,
> > > > > > >
> > > > > > >Great Post...Everyone...All of us with our older coaches
> > need to
> > > > > do what
> > > > > > >Don
> > > > > > >just did, check our coach connectors. I'll add that we
> > should
> > >
> also
> > > > > check
> > > > > > >our
> > > > > > >shore cord coach ends.
> > > > > > >
> > > > > > >.On Thu, Aug 28, 2008 at 5:34 PM, Don Bradner
> > > > > > >>wrote:
> > > > > > >
> > > > > > >> I've experienced two serious electrical problems on
> our
> > > > > current trip.
> > > > > > >> I'm hoping the second problem (solved) was the cause of
> > the
> > > > > first, but I
> > > > > > >> can't get my head around exactly how it would be, so I'm
> > > > hoping
> > > > > someone
> > > > > > >with
> > > > > > >> more RV electrical experience than I have will have a

> > clue. I
> > > > > will rest
> > > > > > >> easier if I know what caused the first problem.
> > > > > > >>
> > > > > > >> The first problem I talked about here earlier, but will
> > run
> > > > > through for
> > > > > > >> clarity:
> > > > > > >>
> > > > > > >> With a lot of draw going on, I had the 50-amp breaker on
> > the
> > > > > park pole
> > > > > > >> blow, plus the main inside breakers, plus the breaker
> for
> > the
> > > > > inverter.
> > > > > > >> Power was lost on the inverter circuit, and did not
> return
> > > > when
> > > > > breakers
> > > > > > >>
were turned back on with reduced draw. The inverter, a
> > ProSine
> > > > > 2.0, is
> > > > > > >toast
> > > > > > >> - burnt components obvious when opening the case. I
> > removed
> > > > the
> > > > > inverter
> > > > > > >and
> > > > > > >> wired input/output together for power on the inverted
> > circuit
> > > > > when on
> > > > > > >park
> > > > > > >> power, and bought a small charger to keep the batteries
> up
> > > > while
> > > > > parked.
> > > > > > >>
> > > > > > >> Xantrex sent out a new ProSine 2.0 (half-price, well out-
> > of-
> > > > > warranty)
> > > > > >
>and I
> > > > > > >> will get it tomorrow. I've been worrying about hooking
> it
> > up
> > > > > without
> > > > > > >knowing
> > > > > > >> what caused the failure.
> > > > > > >>
> > > > > > >> Problem number 2: Yesterday I moved, and on arrival at a
> > park
> > > > in
> > > > > Ogallala
> > > > > > >> the 50-amp park breaker blew as soon as turned on. After
> > > > turning
> > > > > off the
> > > > > > >> internal main breakers I was able to get the park
> breaker
> > to
> > > > > hold after
> > > > > > >one
> > > > > > >> more failure. The breaker was "spongy" so I wasn't sure

> if
> > it
> > > > > was just
> > > > > > >weak.
> > > > > > >> Turning on the main breakers inside worked fine.
> > > > > > >>
> > > > > > >> Moved again today, and the problem repeated except that
> > > > nothing
> > > > > would
> > > > > > >make
> > > > > > >> it work. In trying various things I found that my 30/50
> > cord
> > > > > worked fine.
> > > > > > >>
> > > > > > >> So, I took the coach connector apart and found:
> > > > > > >>
> > > > > > >> Screw for black wire fell out, and was quite black on
> the
> > end.
> > > > > White and
> > > > > >
>> Red attached, but screw not tight. Green was not
> attached
> > at
> > > > > all - screw
> > > > > > >all
> > > > > > >> the way in, and wire laid across the top. Contacting
> case,
> > but
> > > > > who knows
> > > > > > >how
> > > > > > >> well.
> > > > > > >>
> > > > > > >> It is amazing I had power at all. I cut the end off and
> > > > rebuilt
> > > > > the
> > > > > > >> connector, and had no problem turning on the power.
> > > > > > >>
> > > > > > >> It would seem to be an odd coincidence if problem one
> was
> > not
> > > > > caused by
> > > > > > >> problem
two, but since the ProSine 2.0 should in theory
> > work
> > > > > regardless
> > > > > > >of
> > > > > > >> what occurs on the input side I'm not sure what the
> > connection
> > > > > is.
> > > > > > >Anybody
> > > > > > >> have thoughts on this?
> > > > > > >>
> > > > > > >> Don Bradner
> > > > > > >> 90 PT40 "Blue Thunder"
> > > > > > >> Posting today by satellite from Grand Island, Nebraska
> > > > > > >> My location: http://www.bbirdmaps.com/user2.cfm?user=1
> > > > > > >>
> > > > > > >>
> > > > > > >>
> > > > > > >
> > > > > > >
> >
> > > > >
> > > > > > >--
> > > > > > >Curt Sprenger
> > > > > > >1987 PT38 8V92 "MacAttack Racing"
> > > > > > >Anaheim Hills, CA
> > > > > >
> > > > >
> > > >
> > >
> >
>

electrical problems - jim riordan - 08-30-2008 15:12

four wires Two hot for 240v one ground one common

Jim Riordan

Juergen wrote:

--- In "WanderlodgeForum%40yahoogroups.com", "Gary Smith" .>
wrote:
>
> While I have some minor disagreements with some of what Juergen said
(there is only one common wire in the cable, two hot, and one ground),
with loose wires, it is possible you crossed the two 120v hot lines,
providing
the high voltage he suggests. I believe the whole problem
was caused by the poor connections, Don. Not sure how the ProSine
should react to 240v hitting it, but could well weld some contacts, as
you found.
> Gary
> SOB
> ----- Original Message -----
> From: Juergen
> To: "WanderlodgeForum%40yahoogroups.com"
> Sent: Friday, August 29, 2008 8:27 AM
> Subject: Re: [WanderlodgeForum] Electrical problems
>
>
> All I do know is that if you put the 2 hot wires, or put the
2 hot spades into the socket and let only the third wire do the
ground, you will get a 250V zap. The 4th wire is the ground for the
other hot one. I don't know the details exactly, but whenever you let
2 hot and only 1 ground enter, you go BOOM. I know that you must have
all 4 wires, contacts, firmly connected before you turn the breakers on.

Black=hot
Red=Hot
White = Ground,
Bare wire = ground
These four must be in solid contact.
Juergen in PA
1991 WLSP 36

electrical problems - Juergen - 09-02-2008 13:13

I believe I am getting the picture now. That white and the bare make more sense as you guys explained. Thanks a lot for your posts. I really do appreciate those.
Juergen in PA
1991 WLSP 36

--- On Sat, 8/30/08, Don Bradner wrote:

From: Don Bradner
Subject: Re: [WanderlodgeForum] Re: Electrical problems
To: WanderlodgeForum@yahoogroups.com
Date: Saturday, August 30, 2008, 10:47 AM

Juertgen, you can only get 240V across the two hot wires. when that happens, the neutral (white) is not carrying any load at all.

The neutral line carries only the differential. If you have 50 amps of 120 in use on one leg, and 50 amps on the other leg, again the neutral is not carrying any load.

If one leg is drawing 30 amps and the other 50, the neutral will have 20 amps of current present.

The three statements above are true because the two hot legs are opposite phase. When viewed as a sine wave, when one is on the upside of the cycle the other is on the downside of the cycle.

The separate 4th wire (green or bare) is ground. It is not intended to carry any current, and is a protective line only.

In a home system the common and ground are bonded, but under RV code they are not bonded, so they are not at all the same thing.

On 8/30/2008 at 7:21 AM Juergen wrote:

>Mike

>Here is where I am at a loss as to why you get 250 V when only one wire

>either green or bare makes contact. I know that 2 hot and one ground =250V

>I do not understand why the bare wire contact then allows two 110 V. And

>like I said before, I never try to put or pull the plug UNLESS the CBs are

>OFF. The way I read your post, I could survive or not even get a 250 surge

>even if the bare wire is not making contact. I cannot say for sure, but I

>also will never try it. Electric system is too costly. All I know is 250 V

>will really brighten up your lights for a brief moment and fry all the

>other components. Been there done that (in my house.)

>Juertgen in PA

>1991 WLSP36