Electrical stuff

[bartz paul]

Gary:

It better be fused in your "house" electrical panel.

Paul Bartz

From: Gary Berry [mailto:duallycc]
Sent: Friday, January 07, 2000 3:31 PM

The 110v receptacle under the dinette isn't working. Is this fused on
it's own? Where should I start looking for loose connections?

 

[henry davis]

>Hey All;
>
> The 110v receptacle under the dinette isn't working. Is this fused on
> it's own? Where should I start looking for loose connections?
CAUTION: AC is dangerous stuff. Take all appropriate safety precautions.

Gary,

The Dinette outlet branch circuit also includes the galley outlet on the
same string. Check for voltage at that outlet first. If you do have power
at the galley outlet then there is a bad connection between the galley
outlet and the dinette outlet. Disconnect the GMC from all sources of AC
(gensets, inverters, land lines). Remove the faceplate from the dinette
outlet. Remove the dinette outlet and check for connections. You may have
an outlet that uses quick connections - which makes the check a bit
difficult. If no loose connections were found, do the same with the galley
outlet. Power at the galley outlet means that the break is somewhere
between the galley outlet and the dinette outlet.

If you have no power at the galley outlet either then it's time to back up
to the subpanel.

The branch circuit has a circuit breaker that it shares in common with
other branches (I don't remember which ones and my coach isn't handy). The
circuit is part of a bundle that enters the subpanel. It runs from the
subpanel behind the galley area to the galley outlet, behind your davo to
the spot behind the driver's seat where an optional outlet would be placed.
From the optional outlet it feeds up the wall behind the driver's seat and
crosses the ceiling in the rafter, and finally down the passenger side wall
behind the passenger seat.

First step is to check to see if there is power to the other circuits fed
from the same breaker. If not try flipping the breaker off and then on.
Sometimes they trip but don't indicate that they have tripped. If there's
still no power to any of the circuits it's time to change the breaker (most
likely).

If there is power to other circuits but not to the galley outlet, then
check connections inside the subpanel. You won't be able to tell which
circuit is which easily, but if there is a connection problem you should be
able to see it. DISCONNECT THE GMC FROM ALL SOURCES OF AC (gensets,
inverters, land lines) before opening the subpanel.

The worst case is that the line is broken inside the wall somewhere. The
most likely spots for this to happen are at the outlet boxes. Unless you've
drilled or cut into the wall/ceiling it's very unlikely that there is a
break in the wire itself.

Good luck,

Henry

 

[homebase1]

Patrick
>

You are correct on this . On a long shot....would this trip a GFI
circuit? The two were connected at my hot water heater and I have
had some "tripping" problems in the past ??

Mikeb

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Reply to homebase or
homebase
they're both the same......
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

 

[blank]

Mike,

That the neutral and ground aren't tied together in the service panel
shouldn't trip out a GFI. Leakage to ground from either the hot or neutral
definitely would. I know that my 73 will trip out a GFI outlet every time,
but to plug it in I have to use a 50A to 20A "dogbone" adapter. I'm not
sure where the culprit is, but I have verified that my coach ground is good
- - so this is currently at the "nuisance" level for now. One of these days
I'm gonna' open the service panel in my coach, but it looks like the cabinet
was installed after the panel which makes access to the panel screws
problematic.

OTOH, my dad's 76 gets plugged into a GFI outlet in my garage using a 30A to
20A adapter whenever he comes down with no tripping problems.

Patrick

>
> Patrick
> northern friends as I believe the CEC forbids tieing neutral to
> ground in the service panel.>>>
>
> You are correct on this . On a long shot....would this trip a GFI
> circuit? The two were connected at my hot water heater and I have
> had some "tripping" problems in the past ??
>
> Mikeb

 

[blank]

Ken,

Actually the GFCI compares current in the hot(black) vs. current in the
neutral(white). If the difference reaches about 5ma, then it trips.
Current can go to ground without coming back through the ground circuit.

Other than that, I agree with you. I don't think anywhere in my post that I
advocated tieing the ground and neutral together in the coach. I've also
checked and determined that ground and neutral are separate in my coach, so
that's not the problem.

Patrick

>
> On board ground + neutral tie vs supply GFCI:
>
> Think it through -- the GFCI works by detecting current
> through the ground
> (green) lead; when that reaches about 5 milliamps, the GFCI
> trips. If the
> neutral (white) and ground are tied in the motorhome, any ac
> load current on
> board will "come in thru the hot (white) lead" and return
> through the neutral
> AND ground lead -- approximately 1/2 thru each. Sooo, any
> load on the MH
> over about 10 ma should trip the campground GFCI. As long as
> you don't
> connect to an external GFCI, you may not know that your
> ground and neutral
> are connected...
>
> You must NOT connect the neutral and ground leads in the
> motorhome. It is
> IMPERATIVE that you DO connect the ground to the body and
> chassis; without
> it a short to ground in the coach will make the body HOT.
> You could find
> yourself lying on the ground looking up at the door handle
> wondering what hit
> you! If you're lucky!
>
> Ken Henderson
> 76 X-Birchaven
>

 

[travism]

> Patrick,
>
> I don't disagree with the mechanics of detection -- could be done either
way
> -- but we agree that the result is the same.
>
> Ken

Ken, I guess after the long discussion on phase that I had with Patrick I
will have earned myself a reputation as a natural arguer, but...

He's absolutely correct; the GFCI works by comparing the current through the
two out of phase conductors, in this case hot and neutral. It does not
measure the current through the ground. I realize that it sounds
"nit-picking" but it isn't; it is very crucial. If it were that it measured
the ground current, it could only work and thus protect you if it had a good
ground. By comparing the currents, the GFCI "knows" if there is any current
"missing" and therefore a leak. It is much like a bank teller balancing at
the end of the day---if there is a penny missing, we don't go home till we
figure out where it went.

Travis

 

[blank]

Arch,

I checked between the ground and neutral in addition to between ground and
each "hot" on the 50A plug. Don't recall the readings right now and don't
remember what range the DVOM was set on - I'll try something more scientific
this weekend.

What I have determined is this - with the 50A connector plugged into a 50A
to 20A "dogbone" and the 40A breakers in the coach off, the GFCI holds.
Then turned the 40A breakers on - no change. When ANY of the 20A branch
circuit breakers are turned on(no loads AFAIK), the GFCI trips.

I did this test back last spring and shortly after that I installed a post
next to the GMC's parking pad with a 50A RV park style box on it. After
connecting it to this new outlet, I checked between the coach frame and
earth and got a reading of 0 volts.

Patrick

>
> In a message dated 02/02/2000 1:01:03 PM Central Standard Time,

>
> > I've also checked and determined that ground and
> > neutral are separate in my coach, so that's not the
> > problem.
> >
> Patrick
>
> Have you tried this? Put an Ohm meter between the ground and
> neutral. What kind of reading do you get? What happens when
> you start throwing breakers?
>
> Just a thought. Also check it with the ACs turned on and off.
>
> Take Care
> Arch
>

 

[blank]

Heh - I have no mercy today. Both the converter and water heater were
out of the coach at the time...

Patrick

>
> In a message dated 02/03/2000 9:33:12 AM Central Standard Time,

>
> > What I have determined is this - with the 50A connector
> plugged into a 50A
> > to 20A "dogbone" and the 40A breakers in the coach off,
> the GFCI holds.
> > Then turned the 40A breakers on - no change. When ANY of
> the 20A branch
> > circuit breakers are turned on(no loads AFAIK), the GFCI trips.
> >
> Patrick
>
> WOW I am a little stumped that any 20 amp breaker will blow it. I will
> have to think on that. I think you will find the neutral
> shorted to ground
> some where. You just put in a new hot water heater but I
> would check it
> for a short to ground. I dont know what you have for a converter but
> check it too. It is easy for an electric motor to short to
> ground and still
> work just fine---so check the ACs and the vacuum cleaner. I will
> ponder this.
>
> Take Care
> Arch
>