Just Finished A Breaker Box Test Of Security

[MEXICOWANDERER]

Out of curiosity

• 12 connection brand new tin plated aluminum bus
• Twelve wires were used
• Six wires were stripped and clamped tight TIGHT with set screws
• The remaining six were stripped, had the tips soldered
• After soldering a flat file was used one side to make a flat spot for the set screw
• Not that much material was removed
• Six wires were inserted then the set screws were tightened every bit as tight as the unsoldered wires.

Every morning at 0630 the Oster was fired up for one half hour and I made toast and between 10-30 minutes the assembly baked at a reduced 250 degrees.

The wire ranged from 6AWG to 12 AWG THHN THNN and TWNN

This morning after the buss cooled I removed it. Used a straight Snap On flat blade screwdriver.

All six unsoldered wire set screws were SIGNIFICANTLY looser than the soldered wires set screws. We're not talking a subtle difference here.

SIGNIFICANCE

Now you know.

[MEXICOWANDERER]

In my opinion strongly YES. It used to be manufacturers used solid 14 gauge in RVs. I do not know about today's models. If you know what a "Euroterminal" is, the originals were made from nylon and brass with steel set screws. Inside the barrel the threaded set screw did not screw down directly onto the conductor. There is a thin permanent sheet metal "tang" what the set screw forces down onto the conductor. The set screw never touches the conductor.

Then the Chinese came along. Polyethylene housing UNPLATED aluminum receivers. Straight set screw contact with the conductor. These terminal strips are JONQUE. They can be identified by a straight shot look into an empty barrel. If the little metal tang is not visible, avoid. Also the Soy sauce derivatives look sort of translucent rather than opaque white. Copper to straight unplated aluminum is hazardous to your fire insurance.
'
I just purchased a lot of ORANGE COLOR Euroterminal blocks on eBay. By connecting stubs and running a heavy load across the terminal I decided the orange blocks are superior. They are also heavy for their size. Wish I bought a hundred.

The best possible shape to insert into a block with set screw with no tang is a half moon wire end. When I did the Duran yard, Fernando Duran about had a heart attack when I inserted 1 AWG 3 phase feed wires into the massive set screw blocks, tightened the snot out of them, then used a pencil type butane torch to heat the terminals then let them cool. He could not believe his eyes. The next day I handed him the 3/8" drive allen driver with socket. He didn't strain pulling another quarter turn on the set screws. He had double-checked the tightness the day before. Being the cable had like 20 strands of solid 10 gauge it was not necessary to solder the tip. This was a big truck repair shop with 200 amp 3 phase 257 service -- a 20 HP 4 cylinder compressor and 8 1000 watt metal halide lights. Tecate Mexico.

It is through lazy carelessness that home rated electrical is not disallowed for recreational vehicles. The trick is to fix what ails it fast and cheap and soldered wire tips seem to do the job.

[4x4van]

Curious; did you use solid or stranded wire? I assume (could be wrong, however) that the stranded would benefit more from the soldering than solid would, correct?

[Naio]

MrWizard wrote:
bare copper strands will heat soften and compress, from the pressure of the screw holding them
the screws did not move, the bare copper wire did

the tinned/solder wire is the same as a solid terminal connector, mechanically hard and solid, it doesn't have the same thermal/mechanical properties

Thank you, MrWizard. Astonishing!

[D_E_Bishop]

When I was a teen my brother took me to work with him during the summer. My job was to solder all the solid copper wires in a junction box and then wrap with Plymouth Rubber Tape and then with Friction Tape. A lousy job in a attic.

Things have changed and now scotchlock connectors are considered better, easier and cheaper.

As an apprentice working in traffic signals, we seldom tinned wires under socket type connections or before using crimp fittings. One manufacturer of traffic signal boxes always used crimp fittings and then soldered the wires to the crimp fitting.

There are so many different ways of making wire connections. In a socket type screw down buss or terminal, I used to feel tinned was best, it stopped the wires from migrating and they looked better. Now I see quite a few wire ferrels being used instead of tinning.

So here are a couple of answers to what is better(?) stranded tinned or not. Conflicting answers they are!

Link 1

Link 2

I have found that when I tinned the wires in my towed light cable, the 6 and 7 wire plugs and sockets are good with tinned wires, my four wire plug and sockets seem to come loose often.

I feel that this is due to the loose fitting of the screws in the ferrel ends of the plugs and their small size. I had trouble with the four wire connectors this week end and I'm going to re do that plug and just tin the end about 1/16th of an inch and see if that helps.

[wa8yxm]

I have often said that many RVers have a few SCREWS LOOSE. the very screws in the original post... One of mine, just a few months after delivery, took over 3 FULL TURNS before it came tight..

It has not come loose since I re-tightened it.

[pianotuna]

Best to always tin. The same thing happens in cord ends.

[MEXICOWANDERER]

[MrWizard]

bare copper strands will heat soften and compress, from the pressure of the screw holding them
the screws did not move, the bare copper wire did

the tinned/solder wire is the same as a solid terminal connector, mechanically hard and solid, it doesn't have the same thermal/mechanical properties

[RideSlow]

I am late to the party on this, so my only question is (because I don't know the right terminology) am I looking on the back of my breaker box? And may there be another power distribution point? 2014 Forest River Stealth Toy Hauler, equipped with a solar panel, and a generator, both appear to be factory installed.

[Naio]

Well, that is a big surprise to me!

What causes the difference? The tinned ends have more surface area, so more friction against the end of the screw?

[MrWizard]

"TEST"

[BurbMan]

Why did you only tin half of the wires?

[ScottG]

Righty tighty - right? :B

[MEXICOWANDERER]

P A I N

In my wrist. With sixty years of tightening screws, wasn't born yesterday...was born the day before. When steel set screws set in aluminum make a "scringhing squeak" when tightening, they are not loose. This stuff, alll of it, was brand new.

I didn't use a lab pyrometer to qualify the thermal element either could have been off + - 10F

Mistaken uniformity of 12 out of 12 defies common sensibility. I would hope 🙂