12V Electrical wiring - wire nuts vs crimp connections

[bricetribe]

I have a late 80's Western Wilderness Alpine truck camper which has become a bit of a project.

SEE: http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/27165648.cfm

I am in the process of replacing the clearance lights, tail/brake/turn signals and backup lights with LEDs.

When removing the OEM incandescent fixtures I noticed that the wiring connections were made with wire nuts. I would like to replace these stranded wire connections with standard automotive insulted crimp connections. Is there a reason to not make this change???

Thanks in advance.

[mrekim]

When I replace crimp connections that are exposed to the elements on a trailer I find that I have to cut back quite a bit of cable in order to get to good, un-corroded copper. Way more than if the wire was protected from the elements with a good waterproof crimp.

If it needs to be cut it can be cut right at the crimp and should have good copper and not need to be . If there's some concern about length, add wire to make a service loop that can be shortened as needed.

[Gdetrailer]

Golden_HVAC wrote:
Wire nuts tend to vibrate off in a vehicle while a house is not normally subject to nearly as much vibration, so wire nuts are fine for home wiring connections.

Crimping has been a vehicle industry standard for many years. All the light fixtures in my 1997 Bounder RV are crimped together. I never guessed at why, other than it might cost less, until the vibration problem was mentioned. Crimp on connections usually can not vibrate loose, and therefore are required in most airplane connections that are not a screw clamping the wire to it's respective connection.

Good luck with your project!

Fred.

Yes, wire nuts and vibration do not mix well.. Learned that 35 yrs ago when installing car stereos and constantly having loose speaker connections when using wire nuts..

However, spring loaded wire nuts tend to hold very well and ARE "acceptable" for use in HOME 120/240V wiring so they cannot be all that bad..

My point though is with marker lights, the manufacturer tends to leave very little slack in the RV wire. This typically means you only have an inch or two of slack..

If you use crimp connectors or solder connections, the very next time you need to remove or change the marker you will end up CUTTING OFF the crimp or solder connection CLOSER to the RV. This means you will shorten the wire available for the next connection... You will only be able to do that several times and then you will no longer have enough slack..

I think in this case putting connectors (flat or bullet style) on may be a good choice to allow for removal of the marker in the future (you WILL need to replace the putty eventually)...

[Golden_HVAC]

Wire nuts tend to vibrate off in a vehicle while a house is not normally subject to nearly as much vibration, so wire nuts are fine for home wiring connections.

Crimping has been a vehicle industry standard for many years. All the light fixtures in my 1997 Bounder RV are crimped together. I never guessed at why, other than it might cost less, until the vibration problem was mentioned. Crimp on connections usually can not vibrate loose, and therefore are required in most airplane connections that are not a screw clamping the wire to it's respective connection.

Good luck with your project!

Fred.

[Gdetrailer]

:R

jeeze folks, the OP is talking about MARKER LIGHTS.. This is not brain surgery here.

Wire nuts in this case are OK as is crimping, soldering and any other possible method you can think of which conducts electricity..

However, I will say this.. The wire length available from the INSIDE is FIXED, keep that in mind with what type of connector you use.

If you HAVE to replace marker in the future cutting the WIRE off shorter is typically not an option..

That would lead me to use WIRE nuts rather than crimp or even solder in this case since breaking wire nut connections is much less destructive to the wire than removing a crimp or solder connection..

I personally would solder the connection but only if I know there is plenty of wire to be had in case of future repairs..

Alternately since it is a marker light you could crimp or solder spade connectors to the wires allowing you to plug in the light and future replacements will be easy..

[jim1632]

I have used plastic LOckitt connectors, which seem to be a new version that combines the Scotchlock and wire nut concepts.

Scotchlock connections are not very reliable, they seem to pull apart easily unless they are installed in perfert conditions. I rarely encounter anything but undercounter, not wire slack and other problems in my RV. So I won't use scotchlocks again.

Lockitt connects are expensive, as they may be on patent and have a small distribtion. But the job does get done without the stress of the alternative.

Wire nuts only for AC. Use a more reliable method for stranded DC wire.

[time2roll]

Subject to weather I like to crimp and heat shrink.
Wire nuts are fine for interior use. Although you can get weather resistant wire nuts in the sprinkler section of the hardware store.

[MEXICOWANDERER]

Beg to differ. A FOOL is foolproof. Takes one to know the other.

Another issue is STRAIN RELIEF. This is where terminals fail and they needn't have. No terminal, from the tiniest digital size 30 gauge to 4/0 inverter cable should exert more than a gram or so pull-force on the junction. Long distance wire bridges should use standoffs even if they are home-made 2x2 wood pegs. Those nylon square zip tie mounts are great if a screw or rivet is used. Adhesive back nylon pads should have a dab of GOOP used. Natural color nylon ties and other hardware are inferior. Use black. Stronger, does not weaken when exposed to sunlight or ozone (electrical).

[D_E_Bishop]

I am not going to argue the merits of crimp vs wire nut or spike vs elliptical crimpers, what I will say is that in both wire nuts and crimp fittings, using the correct size splice for the wires being spliced is important.

I have crimp fittings for 22 AWG to #4 and I have crimpers for all those sizes. I also have wire nuts that were designed for use with two to four #22 wires up to four # 10 wires. Actually the twist on devices I have for #14 and above are generally called Scotch Locs and not wire nuts. Same principle and same rules regarding size.

I also have several "trailer splices", once again size is of the utmost importance.

Use the correct size and install according to the practices for the splice being used.

And finally, nothing is 100% foolproof.

[RWDIII]

MEXICOWANDERER wrote:
Because there are ZERO regulations RV manufacturers choose the CHEAPEST way to do things. Believe it or not twisting wire ends and taping them would be more costly because of labor time. They would use SPIT if they thought they could get away with it.

Wire nuts are appropriate for things that do not vibrate or hit pot holes. Like a house.

Crimping is the way to go. When I crimp I use a hand crimper with a die that has a spike in it. FAR AND AWAY more secure than elliptical shaped crimps, and no, the point does NOT pierce PVC or nylon terminal insulation. Some myths die hard. Before doubters chime in with their moans, try it out before you commit to eating your words. Something in the formula of the plastic changed around 10 years ago and the die spike no longer splits the insulation. Try it for yourself.

Mex is correct,When I was a comm. tech many years ago the rule of thumb was DC stranded wire with crimp in ,AC solid wire with wire ties
in static situations

[Jozzieo]

The waterproof shrink solder butt connectors are the way to go; a soldered, waterproof shrink wrap you use with a heat gun. Sweet.
https://www.youtube.com/watch?v=d83XuNDnHLI

[MEXICOWANDERER]

Because there are ZERO regulations RV manufacturers choose the CHEAPEST way to do things. Believe it or not twisting wire ends and taping them would be more costly because of labor time. They would use SPIT if they thought they could get away with it.

Wire nuts are appropriate for things that do not vibrate or hit pot holes. Like a house.

Crimping is the way to go. When I crimp I use a hand crimper with a die that has a spike in it. FAR AND AWAY more secure than elliptical shaped crimps, and no, the point does NOT pierce PVC or nylon terminal insulation. Some myths die hard. Before doubters chime in with their moans, try it out before you commit to eating your words. Something in the formula of the plastic changed around 10 years ago and the die spike no longer splits the insulation. Try it for yourself.

[MrWizard]

depends on how much excess wire is available
wire nuts make it easy to replace the fixture, with out cutting and crimping
during MFG production, wire nuts are easier to use than "overhead" crimping, while installing
NEC calls for wire nuts on fixtures , crimping NOT allowed
mfg a mobile residence, the mfg used NEC code, too avoid legal conflicts

i'm not saying NEC covers 12vdc lighting
just saying mfg covered all bases by using ONE standard

for indoor i prefer wire nuts

for outdoor AKA 'car' lighting i use crimps