So you have planned how you are going to build your car. The type suspension, the engine and drive train components, the paint and upholstery. But have you planned the Electrical System.

It is best to start planning the electrical system before the car is complete. Many people think of the electrical system about the time they install the engine and want to hear it run for the first time. Quite honestly the installation of the wiring can be one of the last things to install just prior to the sound proofing materials and the seats and upholstery. Many times people find themselves installing the wiring in the car after its painted and find that they really need to drill a hole in the firewall or kick panel to route the wires. If you plan ahead as you assemble the cars mechanical components you can save yourself some grief during the wiring job.

Give some thought to where you will run the wiring. Such as up under the fenders where the splash shields or inner fender wells attach, or along or even inside of the frame, such as on a high boy roadster rail (not something I'm crazy about but a lot of people do it). What size is the fuse panel and where will you mount it. What holes will you need where and what about grommets.

Here are some other ideas to make you think about the wiring as you assemble the car.

Number one in my book is will it be 12 volt or 6 volt? Now I know some of you are thinking I've lost it. Why in the world would anyone want 6 volts.. Well if you are building a period correct nostalgia car you will probably want original 6 volt equipment. And if you're wanting to keep that genuine '40 Ford dash intact and use the original gauges you have some serious thinking to do.

Most original 6 volt generators can be converted to 12 volts. 6 volt starters seem to work fine if you change the solenoid to 12 volt. Dash gauges are another story. You basically have two choices, 1) send the gauges out and have them converted to modern 12 volt operation (very expensive) or use voltage reducers or resistors to reduce the voltage to 6 volts at the gauge. If you are changing from 6 volt positive ground to 12 volt negative ground you will also have to wire the gauges opposite of the original wiring for them to function properly. Six volt wire also has to be a larger gauge due to the increased amperage. For dependability and easy parts replacement I always recommend using modern 12 volt accessories and wiring.

Most rodders and custom builders want the battery hidden out of sight but accessible. GOOD LUCK and for heaven sake do yourself a favor while you're building the rest of the car - Locate the battery and test fit it and the cables before painting the car. There is nothing I hate worse than having to cut up a floor pan or battery box after the car is finished because nobody checked to see if the battery or cables fit.

Battery size (as in Amp Hours) is another thing to think about along with the output (Amperage) of the alternator you plan on using. The number of electrical options you are installing determines both. High output ignitions, stereos with monster amplifiers, halogen light bulbs, power seats, power windows, power antenna, power door locks, power trunk opener. All of these things need to be considered. If the alternator's capacity is not large enough you will end up with a dead battery.

Battery cable size is another thing to think about. I tend to go with heavier than needed cable on everything I do. On short runs I might use something like a number 2 gauge battery cable but if I'm running cable all the way from the trunk on a race car I will probably use a number 1/0 welding cable. Just remember the farther you run a cable (wire) the larger it needs to be.

Battery cable connections must be clean and tight. I always install internal and external star lock washers on all connections made to a chassis ground after properly cleaning it. Most of the electrical problems that I find on street rods and customs are related to poor grounding. Always ground the battery to the engine block and then ground the engine to the chassis and to the body. If you are set on using the frame for a ground cable, (battery mounted in the rear of the vehicle) make very sure that you properly connect the cable from the battery to the frame and another cable from the frame to the engine. Down the road when the car doesn't want to start check the cables where they bolt to the frame and the engine. They will be loose, dirty and/or corroded. One good way to use the frame for a ground is to weld a 3/8" stainless steel bolt to the frame. Tape the threads off when painting or coating it. Use a flat stainless washer followed by an internal/external star washer, followed by the battery cable, followed by another star washer, flat washer and nylock nut.

Wiring Harness and Fuse Panel

Ok now the good stuff. What should you choose for a wiring harness. If you're thinking of going out to the local wrecking yard and using something off a donor vehicle you're sick. This is admittedly the cheapest way you can wire a car. But your time has to be worth something. By the time you drive to the yard, find something that might work, spend an hour or more getting every thing you think you might need and drive home, you will have spent half a day and how many ?? bucks and all you have to show for it is a pile of spaghetti. Plus it will take you another 4 hours to sort it all out before you can even start to install it.

There are way too many, nice aftermarket wiring harnesses available that make the job a snap. I like to use a fuse for every major circuit in the vehicle. I admit this is a little over the top, but when a light bulb shorts out and blows a fuse the entire car doesn't blackout. So again do the planning and decide what you need.

The next option is the less expensive panels and harnesses most of which are already pre-terminated at the panel. Most of these use a GM style ATO/ATC blade fuse panel with the turn and hazard flasher on the panel. Painless Wiring, EZ Wiring, Centech, Haywire, and Enos Custom Components all come to mind and have good instructions on how to install their specific kit.

On the high end are the modular fuse panels and harnesses which take a little longer to install but the wiring can be located anywhere you see fit. I tend to like this style system for this very reason. Ron Francis Wire Works has long been the leader in manufacturing this style kit. Buy running the wires for every electrical device to and from the panel they have achieved a system that literally anyone can install and trouble shoot. Centech Wiring also has a very nice 13 fuse 23 circuit kit with a high quality printed circuit board with a good looking stainless steel cover that only measures 3.5 X 6 inches. Not quite as sophisticated as the Wire-Works kit, but it is definitely a very nice system and a great value too.

On the less expensive end are the GM style fuse panel kits with the wires preterminated in the panel. These panels can be installed a little quicker because of this design. We stock a selection of these kits ranging from ten to twenty-one circuits. The ones we stock are furnished with and without switches. The balance of the wiring, which is not connected to the fuse panel, has the necessary terminals machine crimped and dip soldered in place with heat shrink tube installed.

So which way do you go? I can't tell you. You will have to decide for yourself. I hope this information helps. I can say this much, plan out your wiring as well as you plan out the design of the rest of the car. Be safe and install quality products. Most of all have fun and drive careful.

Thanks for visiting and putting up with my opinion.