From: John De Armond
Subject: Re: Electrical PROBLEM!!!!
Date: Mon, 03 Jan 2000 23:22:32 EST
Newsgroups: rec.outdoors.rv-travel

Rednip wrote:
> 
> Stanley, thanks for the clarification.  I finally understood what you were
> describing.
> 
> Since there are 50 Amps in each socket, I would be worried that people might
> leave this device plugged into the CG power supply for longer than a minute to
> test the polarity/grounding status of their power.
> BTW, is a 20 or 30 Amp tester able to withstand the testing of a 50 Amp 110
> Volt supply?
> Or, to put it in other words, have you actually fabricated and used the tool
> you have suggested ?
> Rednip

Sure.  Used one for years with my catering trailers.  It allows
supplying a total of 100 amps of 120 volt loads.  No worry about
overloading the cordage laying out on the ground.  The rating is
conservative for when the cord is enclosed.  Laying out on the
ground I've found that I can crank at least 80 amps through a 10
gauge type SO cord before it gets warm enough to make me
uncomfortable. I carry 100 amp breakers (including a 100 amp 120
volt breaker made by cutting a 240 volt breaker apart) in my
"concession survival kit" that I can install and pull near 200 amps
of 120 volt power.  On your RV, internal breakers will still limit
the max amps to 30 amps or whatever.  

One tip - use "industrial" rated convenience outlets.  The plastic
is of much higher quality and the contacts are much heavier.  The 20
amp version (with the "T" shaped neutral slot) is the most rugged. 
Another reason to use the industrial grade convenience outlet is
that many brands are designed with captive terminals so that the
stranded SO wire can be used.

For RV use, it might be better to use RV-type 30 amp outlets instead
of convenience outlets.  I have several cordsets made up that are
universal.  I use a 4" waterproof plastic pull box.  The box
contains 2 20 amp convenience outlets, 2 30 amp RV outlets and a 50
amp 240/120 volt 4 wire (standard RV/dryer type) outlet.  The 240
volt outlet allows more than one cord set to be hooked in series. 
If one feels really paranoid, there is room in the box for
appropriate sized breakers for each outlet type.

I have another cord that has been a lifesaver on for
catering/concession work that might also be useful for those who
need to hookup at other than campground sites.  This cord has the
above multi-outlet box on one end and flying leads on the other. 
Each hot lead has a blade from a 50 amp 240 volt plug.  The ground
and neutral leads each have a round plug and an "L" blade with half
the L ground off so it will fit either the "L" or the flat type
neutral pin.  The terminal end of each blade is enclosed in a hunk
of heat shrink tubing into which thin epoxy has been added.  When
hard, the heat shrink is shrunk.  This makes a nice tough handle for
each terminal.  IN use, after the polarity of a candidate outlet is
determined, the blades are simply inserted one at a time, starting
with the ground blade.  This "Jesus box" (so named cuz it'll help
you meet Jesus a bit sooner if misused) will allow the extraction of
power from almost any sort of either 120 or 240 volt outlet.

I have one other box set up like the above except that each lead has
a heavy duty 200 amp alligator clip.  This allows me to remove the
cover of a breaker panel and clip directly onto the internal bus. 
This is very handy when I have to pull power from a
temporary/construction pole where the largest breaker is typically
30 amps.  Since this Jesus box is almost always connected hot, a set
of lineman's hot gloves are mandatory.

I keep a Jesus Box of the First Kind in my RV's ditty box.  Haven't
had to use it yet but it's there if I do.  Nice to have when one
visits a relative and the only outlet available with more than 15
amp, 120 volts is the dryer outlet in the garage.

John

From: John De Armond
Subject: Re: Campground Electrical Hook-up????
Date: Fri, 07 Jan 2000 01:43:43 EST
Newsgroups: rec.outdoors.rv-travel

hugh wrote:
> 
> John, I just looked at the 30 amp dryer outlet in my basement. It has
> two blades and the third blade is L shaped. Will the straight lug (I
> assume its ground) on the rv plug fit this? Would be a heck of a lot
> cheaper if your suggestion works. Thanks
> Hugh

Hugh,

Your dryer outlet is 30 amps at 240 volts.  If it is a 3 prong
outlet, each of the two blades has 120 volts to ground and 240 volts
between them while the "L" is ground.  The RV 30 amp plug is 30 amps
at 120 volts.  One of the blades has 120 volts to ground, another is
the neutral (normally at ground potential) and the third is earth
(safety) ground.  If you somehow figured out how to plug your RV
plug into the dryer outlet, you'd get 120 volts to ground on the hot
lead, 120 volts to ground on the neutral and ground on the ground. 
Since most (all?) RVs connect the neutral and ground leads together
in the breaker panel, a dead short would result.  If a short didn't
result, there would be 240 volts between the hot and neutral leads
which would burn out everything in the  RV.  When I used the term
"form factor", I meant that the flush mount RV plug looks and mounts
quite similarly to the dryer outlet.  The connection is quite
different.

Now you could place a second box beside the dryer outlet, install
the 30 amp RV outlet and connect it to the dryer feeder wire.  The
hot wire would go to one of the dryer hot wires, the neutral would
go to the dryer neutral and the ground would go to the dryer
ground.  One of the dryer hot legs would remain unconnected.  You
would then have the option to run the dryer or the RV but probably
not both, depending on the load of each.  Of course, the breaker
would still protect the dryer wiring from overload.  It might just
blow if the dryer was on and the RV was drawing any significant
power.

Did that clear things up?  If not, i'll make a drawing and put it on
my little web page.  Picture being worth a thousand words and all
:-)

John

From: John De Armond
Subject: Re: Campground Electrical Hook-up????
Date: Fri, 07 Jan 2000 16:48:38 EST
Newsgroups: rec.outdoors.rv-travel

hugh wrote:
> 
> No John, I know the dryer outlet is 240 volts. I was inquiring about the
> physical configuration of the outlet and the 3 blade rv 30A 120V plug.
> I'm dubious about the rv plug mating up to the dryer plug outlet. I
> still like your idea, of using a less expensive outlet (dryer style),
> just wonder if you are sure about the proper mating surfaces of the rv
> plug to dryer outlet configuration. Thanks
> Hugh

OK, picture's worth a thousand words sooo..  Click on my web page
below and then go to /files/rv/outlets.jpg.  This is a scanner
picture of the 30 amp 240 volt outlet and the 30 amp, 120 volt RV
outlet side by side.  You'll notice that they look practically
identical except for the pin configurations.  Sorry about the pix
quality - I don't yet have a digital cam.  But you get the idea.

John

From: John De Armond
Subject: Re: Campground Electrical Hook-up????
Date: Fri, 07 Jan 2000 17:01:38 EST
Newsgroups: rec.outdoors.rv-travel

George Lowry wrote:
> 
> On Fri, 07 Jan 2000 01:49:17 -0500, Neon John
> <johngdNOSPAM@bellsouth.net> wrote:
> 
> >
> >
> >hugh wrote:
> >>
> >> John, I just looked at the 30 amp dryer outlet in my basement. It has
> >> two blades and the third blade is L shaped. Will the straight lug (I
> >> assume its ground) on the rv plug fit this? Would be a heck of a lot
> >> cheaper if your suggestion works. Thanks
> >> Hugh
> >
> >Hugh,
> >
> >Your dryer outlet is 30 amps at 240 volts.  If it is a 3 prong
> >outlet, each of the two blades has 120 volts to ground and 240 volts
> >between them while the "L" is ground.  The RV 30 amp plug is 30 amps
> >at 120 volts.  One of the blades has 120 volts to ground, another is
> >the neutral (normally at ground potential) and the third is earth
> >(safety) ground.  If you somehow figured out how to plug your RV
> >plug into the dryer outlet, you'd get 120 volts to ground on the hot
> >lead, 120 volts to ground on the neutral and ground on the ground.
> >Since most (all?) RVs connect the neutral and ground leads together
> >in the breaker panel, a dead short would result.

True today.  However probably not so when my MH was built in 82 - I
no longer have an NEC that goes back that far so I can't say for
sure.  Since both the ones I've owned have been wired with the
neutral and ground bonded, I generalized only enough to cover mine
while allowing for modern wiring.  Did I really have to say that?

> If you check out the dryer receptacle, I think you will find there are
> two conductors and a ground, NO neutral.   The advice you are giving
> could cause someone problems....  What you are proposing is to use the
> ground as the neutral which is in direct violation of the NEC....

I've previously referenced a picture on my web page of the old style
30 amp dryer outlet.  The NEC required 4 pin outlet (this is a 50
amp version - I don't have a 30 amp one handy) is pictured at
/files/rv/50ampoutlet.jpg on my web page below.  The 4 pin
requirement is a relatively new requirement so most people's houses
will likely have the 3 pin version.  That's why I paid the most
attention to it.  The 4 pin plug "solves" a problem that is so rare
as to be almost incredible (typical of what the NEC natters about
these days.) so I have absolutely no problem using the neutral for
ground.  This was actually the norm not so many years ago.

John

From: John De Armond
Subject: Re: 50 / 30 Amp service?
Date: Thu, 24 Feb 2000 14:32:48 EST
Newsgroups: rec.outdoors.rv-travel

Fastpace98 wrote:
> 
> Hi,
> Hooray.  Just bought our first motorhome,a 1993 Class A Seabreeze.  We have so
> many questions.  Been reading your board and it is VERY helpful.  Here is one
> concern I have not seen mentioned.
> Some campgrounds say 30 AMP service some say 50 AMP service.  If my motorhome
> has 30 AMP, and I am not even sure of this, what do I do if the cg has 50 AMP.
> Also how can I be sure what AMP I have.
> Know this sounds real stupid to you experienced rvers, so sorry.  Really would
> like an answer though.
> Thanks for being there for us newbies.
> Pat

"30 amp" service is 30 amps at 120 volts.  It uses a funky
RV-specific 30 amp, 125 volt plug.  Go to my web site below and then
go to /files/rv/outlets.jpg.  The outlet on the RIGHT is the 30
amp/125 volt outlet.

"50 amp" service is 50 amp, 240 volt service.  It uses a 4 wire plug
like the one on modern stoves.  On my web site, look at
/files/rv/50ampoutlet.jpg for a photo of this type outlet.  

50 amp service is used on large RVs that require two air
conditioners, an electric water heater, etc..  The service is almost
always split so that if only 30 amp service is available, one AC
isn't powered.

The 50 to 30 amp "dogbone" adapter simply picks up the ground,
neutral and one hot leg of the 50 amp outlet and conveys it to a 30
amp outlet.

I've never been to a campground that had 50 amp service but not 30
amp.  Just in case you run into this, it's a good idea to keep one
of the dogbone adapters in your RV.  Much more common are the
campgrounds that offer only 30 amp service.  A 30 to 50 amp dogbone
is required for RVs that require 50 amp service.

Don't feel bad about being confused.  Even though I'm an engineer, I
was quite confused with this in the beginning.  Most salesmen don't
really know what "30 amp" or "50 amp" service is so they confuse
things even more.

John