Wiring Safety - Fiberglass RV


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 08-16-2006, 11:54 PM   #1
Senior Member
 
Byron Kinnaman's Avatar
 
Name: Byron
Trailer: 2006 Scamp 13' towed with a 2005 Dodge Dakota 4.7l Magnum W/full tow package (over kill)
Oregon
Posts: 7,027
Registry
Something was said on the forum about electrical safety. I don't think I've ever seen here anything brought up about what kind of wire to use. Actually the insulation is the important part. Most wire you purchase at Wal-Mart, Radio Shack, etc. is insulated with vinyl. Automotive wire is insulated with Teflon.

It matters because;

1. Teflon will with stand a much higher temperature before if will burn than vinyl will.
2. Teflon is much more resistant to abrasion, thus is less likely for the condutor to be exposed.

There are primarily two Teflon insulations called out in SAE specifications. SAE is Society of Automotive Engineers. One is refered to as GXL, the other SXL. GXL stands for General purpose cross Link, SXL stands for Special purpose cross Link. (X = cross, cross link = Teflon).
The difference between the two is the thickness of the insulation. SXL has thicker insulation than GXL thus SXL will take more abrasion than GXL. The SAE specification number that calls all this our if J1128.

What all this means that I would recommend that when doing any vehicle wiring you use wire with Teflon insulation. If it's marked J1128 GXL or SXL you know it meets automotive industry standards.

What's important is to NOT use vinyl insulated wire if you can avoid it.

Another thing on wiring safty -- The biggest cause of problems is poor connections. Poor connections a best will cause something to not work, or not work all the time. At worst a poor connection can get hot. Make sure your connections are solid. Are your crimp type connections good? An easy test is attempt to pull a crimp connection apart. The wire should break before the connection fails. I would never put a wire under a screw. Put a crimp lug on the wire, then the lug under the screw. I wouldn't recommend soldering connections unless you've had some type of soldering instruction and have done some soldering.

Last, but not least, use the proper size wire. It's ok to use a larger wire than required but not a smaller. Larger gauge number = smaller wire diameter.

Interesting side note on wire size. PACCAR, maker of Kenworth and Peterbilt trucks, won't allow anything smaller than 18 gauge in their trucks. There are times when a 30 gauge wire is more than large enough, but 18 gauge is use.

Safety
__________________

__________________
Byron & Anne enjoying the everyday Saturday thing.
Byron Kinnaman is offline   Reply With Quote
Old 08-17-2006, 12:14 AM   #2
Senior Member
 
Bigfoot Mike's Avatar
 
Name: Mike
Trailer: Bigfoot 25 ft
Posts: 7,316
Thanks Byron, good info.

__________________

Bigfoot Mike is offline   Reply With Quote
Old 08-17-2006, 12:49 AM   #3
Senior Member
 
Name: Per
Trailer: 2000 Burro 17 ft Widebody towed by Touareg TDI
Oregon
Posts: 867
Registry
Appreciate the information, Byron. I routinely use automotive primary wire for my trailer, and try to err on the "hefty" side. My knowledge is still somewhat limited, so maybe you could clarify one little mystery (or rather gap in understanding) for me?

I have been trying to make my frig work acceptably on 12v for traveling but without luck. The element checks out to the 1.4 Ohms prescribed by Dometic. I measured the voltage at the frig with and without it being on and discovered approx. 1.5v drop. Then I replaced the entire run of incredibly thin 14 gauge with the recommended 8 gauge and yet I measured the same drop. I'm sure I'm not understanding how to measure voltage drop correctly, so where am I going wrong? (I have not had the opportunity to test the changed wiring/element out on the road yet but I am not very optimistic.)

Dometic says the 12v is just a "holding action." I should be so lucky.
Per Walthinsen is offline   Reply With Quote
Old 08-17-2006, 07:58 AM   #4
Senior Member
 
John & Sandy M's Avatar
 
Trailer: 1999 Scamp 16 ft
Posts: 130
A crimp-on connection is a lousy way to join two wires... particularly in any application where the connection is exposed to any adverse environment (eg. automotive/trailer electrical). I learned this the hard way with marine electrical connections... the wiring oxidizes to the extent the connection is lost and the equipment fails. Even worse, the corrosion works up the wire under the insulation.

Soldering is not rocket science and a few practice connections will get you up to speed. I had the electrical work done on our tow vehicle at a local RV shop in prep. to pick up our Scamp last year. The left turn signal failed about a month later. I went through every connection made and removed the crimps. Removed about an inch of insulation from the original wire (did not cut). Did the same for the trailer connection splice and slipped on a piece of shrink tubing. I spliced the connection and soldered. I wripped the soldered splice with electrical tape starting with the original wire and then back up the trailer splice. I slipped the shrink tubing down the trailer splice and over the end of the electrical tape. I heated the tubing to shrink it around the end of the electrical tape so it can't come loose. This is the same splice connection I've used on my boat and trailer used exclusively in salt water and have never had a failure (after 15 years).
John & Sandy M is offline   Reply With Quote
Old 08-17-2006, 08:45 AM   #5
Senior Member
 
Byron Kinnaman's Avatar
 
Name: Byron
Trailer: 2006 Scamp 13' towed with a 2005 Dodge Dakota 4.7l Magnum W/full tow package (over kill)
Oregon
Posts: 7,027
Registry
A properly done crimp connection is reliable. Soldering done by somebody that doesn't know how to properly solder might or might not be a reliable connection. Every connection in your automobile is a crimp connection. I think that says something about crimp connection reliablility.

Soldering is not rocket science, but it take practice and a bit of knowledge. You need to know a good solder connection looks like and to know what good technique is. Of course what goes along with what a good solder joint looks like is what bads ones look like. One of my other hats is soldering instructor. Before I turn anybody loose on soldering on a product we sell they make sometimes hundreds of practice connections. That depends on how long it takes them to get the feel of it. You may have been able to pick it easily, or you may have just been lucky.
Speaking rocket science and soldering. The last I hear to get certified by NASA to solder on rocket components required a 1 onth, or a 2 month soldering classs. I don't remember know remember for which. So maybe it is rocke science.
__________________
Byron & Anne enjoying the everyday Saturday thing.
Byron Kinnaman is offline   Reply With Quote
Old 08-17-2006, 09:42 AM   #6
Senior Member
 
Byron Kinnaman's Avatar
 
Name: Byron
Trailer: 2006 Scamp 13' towed with a 2005 Dodge Dakota 4.7l Magnum W/full tow package (over kill)
Oregon
Posts: 7,027
Registry
I just thought of something else about solder connections. John did the right thing when he added shrink tubing, however wire movement when taping could cause wire strands to break. You'd never know untill the connection got hot. It's not a bad idea to put shrink tubing over crimp connectors, too. The shrink tubing acts as a strain relief when reduces breakage at the crimp or the solder joint. Soldering does on more thing, the strands of wire become brittle at the edge of the solder. The shrink tube will reduce movement at the edge of the joint and help prolong the connection's life. A shrink tube with adhesive inside will also improve the joint, either crimp or solder.
__________________
Byron & Anne enjoying the everyday Saturday thing.
Byron Kinnaman is offline   Reply With Quote
Old 08-17-2006, 09:45 AM   #7
Senior Member
 
Byron Kinnaman's Avatar
 
Name: Byron
Trailer: 2006 Scamp 13' towed with a 2005 Dodge Dakota 4.7l Magnum W/full tow package (over kill)
Oregon
Posts: 7,027
Registry
Quote:
Appreciate the information, Byron. I routinely use automotive primary wire for my trailer, and try to err on the "hefty" side. My knowledge is still somewhat limited, so maybe you could clarify one little mystery (or rather gap in understanding) for me?
Per, are going to be at the Northern Oregon Gathering? If so I'd be happy to take a look and see what I can find.
__________________
Byron & Anne enjoying the everyday Saturday thing.
Byron Kinnaman is offline   Reply With Quote
Old 08-17-2006, 01:38 PM   #8
Senior Member
 
Name: Per
Trailer: 2000 Burro 17 ft Widebody towed by Touareg TDI
Oregon
Posts: 867
Registry
Byron:

The Gathering is very much in doubt for me at this point. In the meantime I'll be looking for ways to make sure I understand how to measure voltage drop. That's where my knowledge gets a bit fuzzy. Who knows, maybe the change to 8 gauge wires (ground and hot) will end up to have made a difference in real life testing anyway. Thanks!
Per Walthinsen is offline   Reply With Quote
Old 08-17-2006, 01:56 PM   #9
Senior Member
 
Byron Kinnaman's Avatar
 
Name: Byron
Trailer: 2006 Scamp 13' towed with a 2005 Dodge Dakota 4.7l Magnum W/full tow package (over kill)
Oregon
Posts: 7,027
Registry
Quote:
Byron:

The Gathering is very much in doubt for me at this point.
Darn, we're gonna miss you and frig trailer.

Quote:
In the meantime I'll be looking for ways to make sure I understand how to measure voltage drop. That's where my knowledge gets a bit fuzzy. Who knows, maybe the change to 8 gauge wires (ground and hot) will end up to have made a difference in real life testing anyway. Thanks!

There's only one real way to measure voltage drop across a piece of wire or anything thing else. That's one meter lead at each end of the wire.

However you can get pretty close by;

Measuring the voltage at the frig with it off then again with it on. Then measure at the battery with the frig on and then with it off.

If the "entire run" doesn't go all the way to battery and there's a smaller wire between the battery, the smaller wire will account for most of the drop. It's kind of like trying to feed a 12" pipe with a 1/2" hose, you'll never get the 12" pipe full.

Hope this helps a bit.
__________________
Byron & Anne enjoying the everyday Saturday thing.
Byron Kinnaman is offline   Reply With Quote
Old 08-17-2006, 11:08 PM   #10
Senior Member
 
Pete Dumbleton's Avatar
 
Trailer: Scamp
Posts: 3,072
Send a message via Yahoo to Pete Dumbleton
Umm, a fuse is a short piece of smaller "wire" inserted in the larger wire.

One thing to NOT do is tin or solder wires and then crimp them or put them in a screw connection -- Over time, the pressure on the wire will cause the solder to "cold flow" and the connection will become looser.

Liquid electrician's "tape" is a good way to seal connections (Or SCUBA wet suit glue, for that matter).
Pete Dumbleton is offline   Reply With Quote
Old 08-17-2006, 11:48 PM   #11
Senior Member
 
Byron Kinnaman's Avatar
 
Name: Byron
Trailer: 2006 Scamp 13' towed with a 2005 Dodge Dakota 4.7l Magnum W/full tow package (over kill)
Oregon
Posts: 7,027
Registry
Quote:
Umm, a fuse is a short piece of smaller "wire" inserted in the larger wire.
Yup. The amout of current is still restricted by the smallest wire which should always be the fuse. However if there's two pieces of wire in the system and the system if fused for the larger wire, you will still be restricted to the smaller wire. If pushed the smaller wire will get warm and pushed too much will burn.

If it's still not clear I can try again.
__________________
Byron & Anne enjoying the everyday Saturday thing.
Byron Kinnaman is offline   Reply With Quote
Old 08-18-2006, 09:18 PM   #12
Senior Member
 
Byron Kinnaman's Avatar
 
Name: Byron
Trailer: 2006 Scamp 13' towed with a 2005 Dodge Dakota 4.7l Magnum W/full tow package (over kill)
Oregon
Posts: 7,027
Registry
We were talking about voltage drop across a length of wire. Here's a site that has chart and calculator to calculate voltage drop.

Enjoy.
__________________
Byron & Anne enjoying the everyday Saturday thing.
Byron Kinnaman is offline   Reply With Quote
Old 08-18-2006, 11:02 PM   #13
Senior Member
 
Pete Dumbleton's Avatar
 
Trailer: Scamp
Posts: 3,072
Send a message via Yahoo to Pete Dumbleton
I guess the point I was trying to make is that the voltage drop is indeed a function of distance, so I believe the end result of charging a battery over a long large wire plus a short small wire will be different than a long small wire plus a short large wire.

In my case, I have a long large wire from the truck battery to the bumper connector and then the relatively short factory wire from the connector to the battery on the trailer tongue. Clearly, I'd be better off with large wire all the way, but I know the battery gets more fully charged than it would with truck wire the same size as the trailer because the final fill on the battery is dependent on the voltage, not the amperage (the amperage has more to do with how long the charging takes).

I believe amperage is equivalent to flow in hoses, and voltage is equivalent to pressure.

Without doubt, when it comes to low-voltage wiring, bigger gets the job done better.
Pete Dumbleton is offline   Reply With Quote
Old 08-19-2006, 07:09 AM   #14
Senior Member
 
Donna D.'s Avatar
 
Name: Donna D
Trailer: Escape 5.0 TA, 2014
Oregon
Posts: 25,064
Quote:
A properly done crimp connection is reliable. Soldering done by somebody that doesn't know how to properly solder might or might not be a reliable connection. Every connection in your automobile is a crimp connection. I think that says something about crimp connection reliablility.
There are huge differences in crimp connections. The ones on your tug are made by machine. Vehicle manufacturers build a wiring harness (or loom) totally by machine, not by hand (okay maybe a hand-built car like the LaNay hand builds the harness.) A good friend of mine who works for a Chevrolet dealership, told me that he believes the reason why vehicle manufacturers use crimp connectors, rather than solder the connectors, is they're cheaper to fix...in today's economy that makes sense to me.

Just like learning to rivet, there is a learning curve to make a good crimp connection. Most often people buy an El-Cheapo crimping plier and even a cheaper box of connectors...then they wonder why they have wiring problems.
__________________
Donna D.
Ten Forward - 2014 Escape 5.0 TA
Double Yolk - 1988 16' Scamp Deluxe
Donna D. is online now   Reply With Quote
Old 08-19-2006, 07:32 AM   #15
Senior Member
 
Trailer: Casita 17 ft Spirit Deluxe
Posts: 509
Test after test has demonstrated that crimp connections for wiring are more reliable than solder connections. The problem with solder connections is they are highly susceptable to corosion and vibration.

The entire aircraft industry, both commercial and military depend on crimp connections. If the industry could find a way to crimp printed circuit board connection they would use it there also.
__________________
CD and Joyce Smith - Lily, Violet, and Rose
1999 Casita 17' SD - "The Little Egg"
2007 Escalade - 6.2L V8 - 6L80E Trans - 3.42 Diff
CD Smith is offline   Reply With Quote
Old 08-19-2006, 07:34 AM   #16
Senior Member
 
Joe MacDonald's Avatar
 
Trailer: Trillium
Ontario
Posts: 887
What Donna said.

the crimp tool that dealerships and repair companies use for the GM style weatherpak connectors costs 250.00 us, and it is indeed a special quality tool, it is called a controlled cycle crimper, meaning you cannot over, or under crimp the connection, every one is the same. (I have one)

most standard crimpers are not this kind of quality. hovever there are still different levels of quality even in cheap ones. I would advise you to stay away from all in one tools, like crimper/stripper/boltcutter combos.
they may be ok for the first few crimps, but wear out quick, and are not high quality.
if you want crimpers buy a pair of crimpers, that do insulated and uninsulated connectors.
that is all they should do.
the same goes for wire strippers; just for stripping.


Crimp connections can last forever if done right, so can solder connections.

the biggest thing is::

TAKE YOUR TIME !!!!!

if you are going to rush or do a half job, don't bother doing it.

Practice makes perfect. if you are unsure, try working on scrap pieces first.


rant now off. Have an enjoyable day.
Joe MacDonald is offline   Reply With Quote
Old 08-19-2006, 08:49 AM   #17
Senior Member
 
Dan Meyer's Avatar
 
Name: Dan
Trailer: Scamp
Minnesota
Posts: 627
On August 17th, Per Walthinsen said:
Quote:
I replaced the entire run of incredibly thin 14 gauge with the recommended 8 gauge and yet I measured the same (voltage) drop.
In this case I would check two places for voltage drop. The first is the connector to the tow vehicle. Most are subject to very poor environmental locations and as consequence of road splash all of the connections (wiring side and trailer side) get very corroded. The plug on the trailer pigtail isn't much better, being exposed to the weather all of the time; make certain connections are clean there also.

The second place to check is where the trailer charge line attaches to the battery. I don't need to go into how little time it takes for these connections that are probably right at the battery to get corroded. Don't forget to check the negative (ground) connections as well.

Using Ohms Law and doing the math, 12 volts and 1.4 ohms results in an 8.6 amp current flow. It also results in about 100 watts of heat. I just checked the specifications on my Scamp's 'fridge. It is rated at 120volts and 1.2 amps, or 144 watts. On gas, it is rated at 1000 BTU's input, or about 300 watts. It is little wonder why most RV 'fridges work best on gas!

Finally, I've never seen more than 7 or 8 amps come in on the charge line from the tow vehicle. Even with brand new trailer connectors and a brand-new tug, it is hard to get a significant amount of power from the tug to the trailer.

Let us know what you find.

-- Dan Meyer
Dan Meyer is offline   Reply With Quote
Old 08-19-2006, 10:25 AM   #18
Senior Member
 
Name: Per
Trailer: 2000 Burro 17 ft Widebody towed by Touareg TDI
Oregon
Posts: 867
Registry
Thanks, Dan!

Your calculations resulting in 100w for the element jogged my consciousness, because the element is supposed to be 125w. I incorrectly quoted the Dometic spec to be what I found: 1.4 Ohm. It is indeed supposed to be 1.1 Ohm. Doesn't help when I quoted a false spec, does it?

Aside form rechecking the element specs and contacting Dometic for comment (and perhaps a replacement), I should note that all the checking I did was with the tow vehicle not connected, just two fully-charged, almost new group 31 batteries with the converter both off and on-line.
The element appears to be quite inadequate all by itself. Your point is well-taken about the line from the TV, and I am planning to review the wire gauges and replace whatever is undersized, but it doesn't appear that that is the fundamental problem at this time.
Per Walthinsen is offline   Reply With Quote
Old 08-19-2006, 04:35 PM   #19
Senior Member
 
Pete Dumbleton's Avatar
 
Trailer: Scamp
Posts: 3,072
Send a message via Yahoo to Pete Dumbleton
BTW, thanks to Byron for pointing out the different insulations used in automotive and household wiring -- I hadn't been aware of that.
Pete Dumbleton is offline   Reply With Quote
Old 08-21-2006, 07:55 AM   #20
Senior Member
 
John & Sandy M's Avatar
 
Trailer: 1999 Scamp 16 ft
Posts: 130
Quote:
A properly done crimp connection is reliable. Soldering done by somebody that doesn't know how to properly solder might or might not be a reliable connection. Every connection in your automobile is a crimp connection. I think that says something about crimp connection reliablility.

Soldering is not rocket science, but it take practice and a bit of knowledge.
I did a bit more checking on the internet and the following site does an excellent job showing the proper way to solder connections splicing wires- right and wrong. Of interest, Toyota Motor company in their shop manual recommends using both a barrel crimp and solder for wire splices.

The box crimp connections used by most shops to splice connections don't make a strong reliable connection.
__________________

John & Sandy M is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Safety bar for top bunk bed Rob Carmody Problem Solving | Owners Helping Owners 4 06-02-2008 10:22 AM
RV Safety Bruce B. General Chat 6 02-14-2008 09:50 AM
Gas Safety Taylor General Chat 4 05-30-2007 03:43 PM
Safety Tip Toodie General Chat 3 08-24-2006 08:09 AM
Safety Tip Problem Solving | Owners Helping Owners 0 01-01-1970 12:00 AM

» Upcoming Events
No events scheduled in
the next 465 days.
» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 11:03 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
×