Post by wisconsinjoe on Apr 15, 2021 13:09:17 GMT -8
Sorry to keep asking the same/similar things repeatedly. Instead of posing them at the end of different threads, I’m starting a new one.
First: Wire Size. I see that many of you run 14 gauge stranded wire for most things like interior lighting and tow wiring to lights, brakes, etc. Is that because the interior wiring is to run shore power (120 volt) for conventional incandescent lighting and regular household style outlets?
I ask because I’m running LED lighting exclusively, with nothing drawing any more than 6 watts, including a roof vent/fan. For shore power, I’m running 12 gauge Romex to four separate outlets. So, for this low voltage power, can’t I safely run 16 ga or even 18 ga wire? I will run separate hot and ground wires to each fixture, rather than pigtailing wires along a run. Does that make sense, or is it overkill?
Second: I’m still confused about the type of wire. I know it needs to be stranded and coupled with crimp connectors. But, I see there is solid copper wire and copper coated aluminum; the latter being a bit less expensive.
I don’t understand the differences between “primary wire,” “automotive wire,” “THHN wire,” or “heat & oil resistant wire.” Are any of those the same thing? What is the proper kind to use?
Finally, I see that Vikx uses a 7-way device to check the tow wiring. Is that made from a tow wire cord with a connector, or is it something to buy as a diagnostic tool?
We are talking about 12 volt wire here in this section. Romex (non metallic sheathed cable) is used for 110 applications. The two wiring systems are separate and are not related.
Automotive stranded wire: The most typical type of wire used in most automotive applications is automotive cross-link wire and automotive primary wire. General Purpose High Temperature automotive wire is ideal for under-hood automotive wiring applications with hard-to-fit areas. It is heat and oil resistant.
THHN (Thermoplastic High Heat-Resistance Nylon coated) is a cost-effective building wire that is typically used for carrying electrical currents between buildings and external power sources, signaling, control wiring, machine tools, and automation systems.
I use automotive wire because it is flexible and designed to resist movement and vibrations of road travel. THHN is stiffer and used in stationary situations like houses. To me THHN is much more difficult to run plus the plastic coating tends to split or peel when the wire is manipulated.
14ga is my go to wire size for interior and tow wiring. It is a bit overkill and more resistant to damage than thinner gauge wires. Also, 14ga allows for additions on a circuit after the build because of the heavier gauge. The amperage is 15 or lower. In other words, the circuit can be run on a low amp fuse up to 15 amps.
Trailer brakes normally use 12ga cable. (two wires inside a sheath)
Honestly, I would not go with skinny gauge wires. I'm curious why you want to? With the trailer apart, 14ga is easy to run. Copper coated aluminum is a lesser quality than solid copper. I use solid copper.
I made my 7 way tester. It is a vehicle side receptacle with clips on the wire ends. That makes it easier to connect to the trailer wiring, frame and power source. The 7 way color code is correct so I know which wire does what.
Post by wisconsinjoe on Apr 16, 2021 16:39:34 GMT -8
Thanks Vikx. Actually here I am talking about a 12 volt wiring system. I'm glad you recommend "Primary Wire" and I'll definitely go with all copper stranded 14 gauge. I brought up the THHN question because I thought I read a post by John Palmer, saying he uses that. Figured you made your tester.