Difference between commercial and automotive wiring?

[farm boy00]

What is the real difference between regular commercial wiring and automotive? Only thing I can think of is automotive is more flexible but I could be wrong?

Asking because I'm doing some aftermarket lights on a 98 ford ranger and have piles of commercial wiring out of a restaurant and it's all free. My plan was to use some 8ga with a fuse for main line to toggle switches then 12 ga to lights. Yes I know 12ga is over rated but it's free.

Picture is just some of what I have.

 

[ning]

Consider a relay for activating the lights circuit (switch --light gauge wire-- relay --heavier wire-- bulbs), especially if they're incandescent.
I can't answer your question; I've always used whatever wire I had lying around in my truck...

 

[3Ts]

There is also marine wiring. I assume by commerical wire you mean stuff like romex or THHN type wire. I don't have an official answer for you, but here are things that are considered when making wire.
- voltages that will be on the wire - determines how thick and what type of insulation to use
- the environment the wire is expected to be used in - determines the type of insulation to use (wet, dry, heat, cold, sunlight exposure) and how to structure the conductors (i.e. size and number of conductors)
- what frequencies it is expected to carry - determines the structure of the conductors (this is not really a factor until you get into high frequencies as in radio)
- the anticipated application - metals have a tendency to work harden and get brittle when they are bent, when they get brittle, they break.

Note - If you're using wire in an auto and in the engine compartment, it gets really hot under there and I doubt that "common wire" will withstand that very long. There is a special insulation for wire used in this environment and most likely have to be special ordered. If you're staying within the cabin, it can still get around 140* F. Can your wire insulation with stand that?

 

[jaxs]

There are several differences based on what environmental conditions,temperature,vibration/flex and other things wire is expected to see. "Commercial"really isn't a type wire. The single most important factor to be aware of when replacing wire is # of strands that make up the guage. Comparing 14 gauge residential home wire to automotive you will notice romex has a single strand,THHN multiple strands and automotive has even more strands than THHN. More strands not only increase's flexibility,it directly increase's ampacity,esp dc current. Where you can see how difference in strands make's a difference in amp capacity is battery booster cables. The super star amoungest ever day use wire is welding cable,good one's have hair size strands.

 

[quicksandfarmer]

In a building normally solid wire is used, the assumption is that once it's placed it will never move. In a vehicle normally stranded wire is used, the assumption is it will be subject to vibration and flexing. Solid wire will crack if it is repeatedly flexed.

Vehicles are typically 12 volts, buildings are typically 120 volts or more (in the US). Power is volts times current, so to transmit the same power vehicle wiring has to carry ten times as much current. On 120 volt household wiring a 500 watt light needs 4 amps of current, which can easily be carried by an 18 gauge lamp cord. The same 500 watt light on 12 volts needs 40 amps of current, which would require an 8 gauge wire.

 

[farm boy00]

Consider a relay for activating the lights circuit (switch --light gauge wire-- relay --heavier wire-- bulbs), especially if they're incandescent.
I can't answer your question; I've always used whatever wire I had lying around in my truck...

Will be doing either all led lights or lights within toggle switch ratings. Don't really have much space for relays under the hood in the first place let alone after wiring for a plow (needs solenoid but may put on plow frame itself)harness, lighting harness, and maybe a salter.

 

[4570Man]

It’s hard to connect a big wire to a little light wire especially if it’s solid conductor but besides that I don’t see a problem.

 

[farm boy00]

There is also marine wiring. I assume by commerical wire you mean stuff like romex or THHN type wire. I don't have an official answer for you, but here are things that are considered when making wire.
- voltages that will be on the wire - determines how thick and what type of insulation to use
- the environment the wire is expected to be used in - determines the type of insulation to use (wet, dry, heat, cold, sunlight exposure) and how to structure the conductors (i.e. size and number of conductors)
- what frequencies it is expected to carry - determines the structure of the conductors (this is not really a factor until you get into high frequencies as in radio)
- the anticipated application - metals have a tendency to work harden and get brittle when they are bent, when they get brittle, they break.

Note - If you're using wire in an auto and in the engine compartment, it gets really hot under there and I doubt that "common wire" will withstand that very long. There is a special insulation for wire used in this environment and most likely have to be special ordered. If you're staying within the cabin, it can still get around 140* F. Can your wire insulation with stand that?

This is not romex so I'm guessing it is THHN but I can check tomorrow

Volts will be only 12v. Where this came out of was 120v and 240v.

Environment isn't as much of a worry because it will be wrapped well in electrical tape and then put in a plastic sleeve.

All connectors are going to be heat shrink besides ones in cab connecting to switches.

I did think some about the heat but this same style is used all the time for rooftop units and in kitchens where it does get hot. But it will also be wrapped together with electrical tape then put into a sleeve to protect it.

 

[farm boy00]

There are several differences based on what environmental conditions,temperature,vibration/flex and other things wire is expected to see. "Commercial"really isn't a type wire. The single most important factor to be aware of when replacing wire is # of strands that make up the guage. Comparing 14 gauge residential home wire to automotive you will notice romex has a single strand,THHN multiple strands and automotive has even more strands than THHN. More strands not only increase's flexibility,it directly increase's ampacity,esp dc current. Where you can see how difference in strands make's a difference in amp capacity is battery booster cables. The super star amoungest ever day use wire is welding cable,good one's have hair size strands.

Was posted earlier of the name of the wire but I will check again. THHN. This has multiple strands in it unlike romex but not as many as the heavy gauge automotive wire that I have does ( just some scrap 2ga) I'm not worried too badly about flexability because this is bent hard in electrical boxes all the time and used in flexable tubing for line sets to rooftop units.

 

[farm boy00]

In a building normally solid wire is used, the assumption is that once it's placed it will never move. In a vehicle normally stranded wire is used, the assumption is it will be subject to vibration and flexing. Solid wire will crack if it is repeatedly flexed.

Vehicles are typically 12 volts, buildings are typically 120 volts or more (in the US). Power is volts times current, so to transmit the same power vehicle wiring has to carry ten times as much current. On 120 volt household wiring a 500 watt light needs 4 amps of current, which can easily be carried by an 18 gauge lamp cord. The same 500 watt light on 12 volts needs 40 amps of current, which would require an 8 gauge wire.

I will not be running anything close to 500w. The one incedecent light I have is 35w but I'll probably use led which are less.

My wiring is 12ga but most lights have 16 ga or so wiring so I'll be over sized for wire size