Automotive Electrical vs Home Electrical

Messages
59
Location
USA
My knowledge regarding about automotive electrical is just plain "average". I did some installation on my own vehicles in the past (back in the 80's) on accessories such as car stereo, alarm system, fog lights, add on tachometer and they all have everything in common about wiring, Black is ground and Red is power source. To make a long story short, I was installing a Light Post for my lawn and I got confused with the instructions on a 3 wire installation. The instruction state Black is power source, White is neutral and Green is ground. I researched on line that these colors are standard in home electrical. This beats the heck out of me. If I am going to install these 3 wires (without reading the instruction provided) coming from the Light Post to the home electrical plug outlet and with my knowledge about automotive electrical I would do it the wrong way and I could end up with getting an electric shock. stooges
 
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Messages
1,965
Location
USA
Partner, you might be best to not attempt wiring anything with AC (low or high voltage, single or poly phase) for safety.
 
Messages
25,820
Location
Upstate NY
If your not familiar with home wiring then maybe best to leave it to an electrician. Boats have a standardized list of what all the wire colors are to be used for. And boats and RVs may have both 12V wiring and 110/220V wiring.
 
Messages
162
Location
USA
The NEC is the best place to look for guidance. Also, some books at your local library should help. There are different standards for different swaths of industry (marine, automotive, etc.) Home wiring is standardized by the NEC and your local building codes to prevent fires and possible fatalities. Outdoor wiring not properly grounded is a big deal as you could seriously hurt yourself or others. Please study up before moving forward with this project - protect yourself and others.
 
Messages
25,820
Location
Upstate NY
Originally Posted by doitmyself
Sometimes the white wire can be hot!
The white should never be connected to one of the two legs of 220V electricity. But if there is an appliance in the circuit and you are between the white wire and the neutral bus then there will be electricity flowing. And you could get zapped.
 
Messages
17,981
Location
NH
Originally Posted by doitmyself
Sometimes the white wire can be hot!
Noticed that in my house recently, on a switch, and my reading on the subject was that, when this occurs, the wire is supposed to have black tape wrapped around it, to indicate it's now hot (or switched hot). OP, if the three colors are confusing, then I'd get someone else to hook it up for you. If you know any home DIY'ers there is a good chance one of them will be willing to help. I realize some localities may require a licensed electrician to change a light bulb, but you may be lucky where you are and can just have Joe Schmoe do it.
 
Messages
3,253
Location
USA
The hot white wire is found in a situation of a ceiling light and a wall switch, with the power fed to the ceiling box and a regular 2 conductor with ground wire run down to the switch. When the switch is on, the white wire becomes "hot" and sends power back up to the light. That is something that might be encountered in existing houses. Do not wire new installations that way because many "smart" switches will require a neutral wire, and not having one at the switch box limits options to replace the switch later. In any case, treat all wires as hot until you're sure you've turned off the right breaker(s) and confirmed the circuit is dead.
 
Messages
891
Location
NJ
All 100% accurate information, adding, NEC code now requires all new wiring at switch boxes to have a neutral white wire whether being used or not. 120v wiring, the hot wire is always black unless someone wired it wrong. It does happen. As mentioned, there are switch light applications when the white wire is used as the hot and then it must be wrapped with black tape. I have a bottle of black nail polish in my electrical bag and paint the white wire black as electrical tape can unwrap. Consider owning a non contact voltage tester pen. The mistake I see often is re-wiring extension cords with the plug where the wires are not placed in the correct screws. Using a ohm meter is invaluable. With the female plug, the black hot goes to the smaller slot opening, the neutral white wire goes to the larger slot opening.
 
Messages
602
Location
The ATL
The only way to know for sure which wire(s) actually have voltage is to test them. If you're not comfortable doing that, you need to hire someone. It only takes a few milliamps to kill you. I've seen energized ground wires before, believe it or not.
 

BEETLE

Thread starter
Messages
59
Location
USA
Hello I'm the OP. I contacted an electrician and he told me he's going to do it for $50.00 just for the connection. All I need to buy is a 50 ft 3 wire outdoor underground cable (Southwire brand), an electric digital timer and a 3-Way Straight Blade Grounding Plug. He said it will only take 30 mins. He'll drill a hole from the outside and fish the wire from the inside of the house to connect to a plug and program the timer. To bury the underground cable it will take an additional $100.00. I declined, I said I am going to that myself. Lessons learned, I guess I am going DIY only up to 12V and not beyond that. Thanks for all the replies.
 
Messages
891
Location
NJ
You need 14-2 UF-B, it must be buried 24" unless it's in green plastic tubing then it's 18", under sidewalks it's 12". Next, unless it starts off 24" under the ground, you need the green electrical tubing on the outside of the house where it enters the ground. You can't have unenclosed wire on the outside of the house.I For $100 to bury the wire 24", I'd pay the $100 for someone else to do it.
 
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Messages
2,173
Location
Cincinnati, USA
It is very common that positive on a vehicle electrical system is not red, though more often ground is black. As others stated, either hire an electrician or spend more time learning code, best practices, and becoming one with a multimeter.
 
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1,553
Yes automotive vs home electric two different animals.. Hire a licensed electrician have it done right and enjoy your lights.
 
Messages
1,447
Location
Maryland
I have seen hot ground wires more than once. As a contractor I have seen some crazy crazy wiring jobs by DIY. Do yourself and others after you a favor and hire an electrician.
 
Messages
1,965
Location
USA
Originally Posted by Oildudeny
How does a ground wire stay hot? Breaker should trip..
Not always but if ground is to earth and neutral is return path for circuit and everything is wired properly... A ground can be subject to energization due to a mechanical defect in insulation or other contact of have induced current due to other factors without enough load to trip a device.
 
Messages
4,437
Location
Guilford, CT
Bare wire, or green wire, should ALWAYS be ground. White wire should always be neutral, unless there is black tape (or black marker or paint) around the end, indicating that it is actually hot. However, it's possible someone used a white wire as a hot and forgot to re-identify it. Also, re-identifying a white wire is only allowed in a cable assembly (such as Romex cable), because cables like that only come with a black, white, red (sometimes), and a bare ground. So you have to work with the colors that are there in the cable. If you're running individual conductors in conduit, you don't have that excuse, so wrapping black tape around a white wire is NOT allowed. You'd need to pull a black (or any color other than white or green) conductor through. Hot legs are typically black or red, although you can use pretty much any color you want as long as it's not green (reserved for ground ONLY) or white or light gray (reserved for neutral ONLY, except for the exception I noted above).
 
Messages
6,040
Location
Baltimore, Maryland, USA
OP was really referring to DC vs AC home wiring color coding. I had some hatch hinge area wiring break recently (last year) in my 1995 Escort. I open the hatch about as often as I do the drivers door, almost. So no surprise there. [Linked Image from feoa.net] Anyway, what I had noticed was that the existing wire gauge seemed like it was one size smaller than the fuse would indicate that it should be. I.E.- the stuff on a 15A fuse was thinner than #14 wire. The stuff on the 20A circuit was thinner than #12 wire. I have no idea why this is the case, but the load on the 15A circuit was tiny, as in I could have replaced that fuse with a 10A or even 5A fuse and it would work just fine.
 
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