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07-25-2017, 03:13 PM
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#61
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Rivet Master
2015 25' Flying Cloud
2016 30' Flying Cloud
Blenheim Ontario
, Ontario
Join Date: May 2015
Posts: 1,263
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Quote:
Originally Posted by switz
When using an adapter to plug the 30 amp rated trailer power cord into a 50 amp trailer park power outlet, the trailer 30 amp rated power cord (which is #10 copper wire rated exactly 30 amps) from the trailer to the pedestal is no longer protected if it shorts out for any reason. If one uses an extension power cord (usually 25' or 30' long), the user should check for voltage drop when the air conditioner is running.
While a short is under way, damage could occur to the trailer wiring the way Airstream wires their panels. The trailer's 30 amp "main" limits how much electric power demand can go outside of the trailer to the pedestal. A 30 amp breaker on the pedestal is there to protect the 30 amp power cord from the pedestal to the trailer.
50 amp power cords use #6 copper wire which is rated for at least 55 amps and is probably rated 65 amps if it has THW wire inside. So the wire could be fully protected by the 50 amp breaker if it works according to specifications.
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What is "THW" wire??
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07-25-2017, 03:28 PM
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#62
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Rivet Master
2015 25' Flying Cloud
2016 30' Flying Cloud
Blenheim Ontario
, Ontario
Join Date: May 2015
Posts: 1,263
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Quote:
Originally Posted by m.hony
That big black unruly snake gets even stiffer when its cold.
I've started a new routine:
Leave the big black heavy snake coiled up.
Set the entire coiled up heavy black snake over the power pedestal.
Just pick up the male/surge protector off the ground and plug in.
Uncoil just as much as you need to reach the female/trailer end- sometimes just 1 or 2 could.
Then when I get ready to go just replace the 1-2 coils and lift the entire heavy black snake up over the pedestal and stick it in the rear storage right by the power hookup on the trailer.
Do the water hose the same way.
Possibly a it OCD...
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The danger there, is pulling a lot of power through a coil.
The cable has a chance to overheat due to the magnetic field generated, and catching fire.
It's much like a coil on magnetic actuator, or a transformer.
Most knowlegable people lay the cord out.
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07-25-2017, 03:40 PM
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#63
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Half a Rivet Short
2017 30' Classic
2022 Interstate 24X
Carlisle
, Pennsylvania
Join Date: May 2017
Posts: 15,684
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Quote:
Originally Posted by MelGoddard
.......
The cable has a chance to overheat due to the magnetic field generated, and catching fire.
......
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Hi
...... ummm ..... not so much .... The conductors in the cable have equal and opposite currents. The magnetic field from those currents cancels out. It's the same reason you run stuff like telephone and ethernet signals over twisted pair. Yes, it's slightly more complex than that, but not by a whole lot.
Bob
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07-25-2017, 05:38 PM
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#64
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Rivet Master
2024 Interstate 19
Fulton
, Maryland
Join Date: May 2010
Posts: 3,872
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Quote:
Originally Posted by MelGoddard
What is "THW" wire??
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http://www.wesbellwireandcable.com/E...W-acronym.html
__________________
- - Mike
--------------------------
2024 Airstream Interstate 19e AWD
Previous: 2013 Airstream Interstate 3500 Ext Lounge
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07-27-2017, 08:33 AM
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#65
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3 Rivet Member
2011 20' Flying Cloud
Lemont
, Illinois
Join Date: Nov 2013
Posts: 114
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"When using an adapter to plug the 30 amp rated trailer power cord into a 50 amp trailer park power outlet, the trailer 30 amp rated power cord (which is #10 copper wire rated exactly 30 amps) from the trailer to the pedestal is no longer protected if it shorts out for any reason."
I disagree. The trailer to the pedestal connection IS protected in the case of a short in the cable - by the 50 amp fuse in the pedestal. We're talking about a short here, not just a slight overuse of power in excess of 30 amps.
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07-28-2017, 07:49 AM
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#66
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Half a Rivet Short
2017 30' Classic
2022 Interstate 24X
Carlisle
, Pennsylvania
Join Date: May 2017
Posts: 15,684
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Quote:
Originally Posted by Glenn T
"When using an adapter to plug the 30 amp rated trailer power cord into a 50 amp trailer park power outlet, the trailer 30 amp rated power cord (which is #10 copper wire rated exactly 30 amps) from the trailer to the pedestal is no longer protected if it shorts out for any reason."
I disagree. The trailer to the pedestal connection IS protected in the case of a short in the cable - by the 50 amp fuse in the pedestal. We're talking about a short here, not just a slight overuse of power in excess of 30 amps.
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Hi
There is still a gray area of pulling 48A through the 50A breaker. In any normal case, you are protected by the 30A breaker in the trailer. Setting up a "short" in the cable that pulls 10's of amps is not easy. It's also a very unstable situation. Either it self clears or it goes hard short fairly quickly. You are putting > 1KW into the "defect".
Further confusing things, you get the power rating on #10 wire from heat rise. The insulation (not the copper) is what actually limits things. Put 2X the current through it and the heat rise is larger. Twice the current would give you 4X the power to heat the wire. If the rated current gives you a 30 degree heat rise, twice the current will give you around 120 degrees.(Yes, both are steady state and that takes a while). Will a 120 degree rise nuke the insulation? Is there snow on the ground? How long did you "heat" things? (Yes, there a bunch of other grubby details that make the real case a bit more confusing ...)
Lots of strange corner cases ....
Children please do not run any of these experiments at home. YouTube does not need any more videos like this. Burning insulation gives off all sorts of awful crud. Picking up hot metal pieces will burn you. People die of electrocution at an alarming rate.
Always leave slack in the cable. Tighten down the "ring" on the trailer side of the connector. The breaker in the pedestal goes OFF until everything is connected and goes OFF again before you disconnect anything. When turning on the breaker, "flip" it on, don't push it and hold it.
End of today's safety lesson ...
Bob
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08-17-2017, 12:33 PM
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#67
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Rivet Master
2015 25' Flying Cloud
2016 30' Flying Cloud
Blenheim Ontario
, Ontario
Join Date: May 2015
Posts: 1,263
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Quote:
Originally Posted by Boxster1971
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Very interesting. Thanx.
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08-20-2017, 01:47 PM
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#68
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Silver Bullet
1986 34.5' Airstream 345
choctaw
, Oklahoma
Join Date: Mar 2006
Posts: 839
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I'm not sure I should even admit to re-wiring the Silver Bullet into a 50Amp service. It's been 10+ years and nothing has melted. No even the #10-3 cord or contacts on the reel. Did have to change the wiring of the reel as neutral was hooked to ground.
The front a/c still goes through the selector switch. The rear a/c is on the other leg of the 50Amp cord tied in at the generator changeover relay. So, that being said I never pull more then 30Amp per leg. Works great. I do have a 10 gauge wire I connect for earth ground to keep the sparks down in the rain.
Would I do it again? YES
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08-20-2017, 02:26 PM
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#69
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Rivet Master
2017 26' Flying Cloud
Tampa
, Florida
Join Date: Feb 2017
Posts: 7,638
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Quote:
Originally Posted by thiel
Could this be another benefit of the EasyStart? I can run AC and microwave at the same time (but I can't pile on with the water heater) on 30amp power.
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And it cures Gout!
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08-20-2017, 04:12 PM
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#70
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Half a Rivet Short
2017 30' Classic
2022 Interstate 24X
Carlisle
, Pennsylvania
Join Date: May 2017
Posts: 15,684
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Quote:
Originally Posted by Mollysdad
Even though my AS will be 50 amp, I have a 30 amp cable to keep handy for the generator. It has a 50 amp female and a 30 amp male. Then, If I'm limited to 30 amps, I'll just pull that cable to the power post. It wasn't that expensive.
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Hi
Ok, so I GIVE UP !!! where did you find that cable !!!!
This is the third campground where it would have come in handy. Not quite sure what I'd do for a surge suppressor though ....
Bob
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08-20-2017, 07:07 PM
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#71
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Rivet Master
1974 Argosy 26
Morrill
, Nebraska
Join Date: Nov 2009
Posts: 6,014
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Other than a short in the cable or the wiring to the 30 amp breaker in the coach.
The 30 amp breaker will protect the coach wiring and prevent an interior overload.
One could build their own 50 amp to 30 amp adaptor.
Using the standard RV 30 amp receptacle along with a 30 amp circuit breaker. Wire the line side of the breaker with #6 copper wire. Then use #10 copper wire on the load side of the breaker to the 30 amp RV receptacle.
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08-28-2017, 12:57 PM
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#72
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Rivet Master
2015 25' Flying Cloud
2016 30' Flying Cloud
Blenheim Ontario
, Ontario
Join Date: May 2015
Posts: 1,263
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You guys are making my head hurt!
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