Some of the most common questions I get asked are “what type of battery wire do you use to build the cables?” and “What size cable should I use for my vehicle?“
Below are some descriptions of what we use, information on the gauges of wire and when to use it, and some other technical charts to use. I’ll even give you my opinion about if you should be using marine grade wire on your Dodge Dart…..
If you’re wondering whether to use a 2/0 battery cable or 1/0 we’ll give you the data you need to decide.
Be sure to watch the video at the bottom of the page. We explain which gauge wire is right for every application. And we’ll show you how we build cables for you.
Table of Contents
SGT Battery Cable:
We generally use SAE (Society of Automotive Engineers) SGT battery cable. SGT designates the type of insulation. (Wire is rated by several characteristics but most commonly it’s insulation type. For example ‘THHN” is probably what you have for the wiring in your house. THHN stands for “Thermoplastic High Heat-resistant Nylon-coated). SGT is a thermoplastic PVC (polyvinyl chloride) insulation rated at 50 volts. It’s typically rated for 85 or 105 degrees C.
It usually has a fairly low strand count (meaning the strands are larger), making the wire stiff enough to stay where you put it but is still flexible enough to bend around tight corners.
SGX Battery Cable:
Sometimes we use SGX battery cable. SGX uses a high-grade XLP (Cross-Linked Polyethylene) insulation which has a higher temperature rating and is more abrasion-resistant. The trade-off is the insulation is thicker and stiffer. Often it has a higher strand count. If you need a higher temp rating, it’s a good choice.
Marine Battery Cable:
There are several types of “Marine” wire. It’s usually rated for higher temperatures and “wet” (think submerged) applications. It also has a requirement that it must be “self-extinguishing”. The marine rating is a Coast Guard legal requirement for marine applications. Do not build a cable intended for marine use out of wire that does not have a marine rating.
Most of the SGT we sell also carries a marine rating (BC-2 rating)
Get all of the Marine Battery Cable specs here.
Fuse Link or Fusible Link:
Think of a fuse link as a very slow-acting (“slow-blow”) fuse that looks like a piece of wire. Fuse link wire has special very high-temp insulation that won’t burn even if the wire becomes so hot that it fuses open.
It’s most common use is in alternator wires. It protects the electrical system from a catastrophic failure of the alternator diodes. Without the fuse link, the alternator wire would melt or burn, possibly starting an underhood fire. Other common applications are the wires going to glow plug or intake grid heater relays on diesel engines.
It’s usually a 6 to 9-inch piece two wire sizes smaller than the wire it is protecting. For example, a 4 gauge wire would use a piece of 8 gauge fuse link.
OFC (Oxygen Free Copper):
OFC (Oxygen Free Copper) wire often gets sold by stereo shops to hook up speakers or a high power amp. Don’t waste your money. This stuff is just another way for slick salesmen to get more of your hard-earned money.
What’s different about it? Standard wire is AT LEAST 99.90% pure copper. OFC is 99.95% pure copper. An extra 0.05% copper sounds good. What’s the downside? COST. OFC is often TWICE the price for the same size of standard cable. So you are paying DOUBLE for 0.05% more copper. There is NO measurable electric difference (source Wikipedia).
CCA (Copper Clad Aluminum):
Just say “no”. Copper clad is nothing more than copper-plated aluminum. Aluminum has 60% the conductivity of copper so a CCA wire will need to be roughly 2 sizes larger to have the same conductivity. In other words a CCA wire would need to be 2 gauge to do the work of a 6 ga copper. Just buy copper wire.
For more info see Wikipedia.
For automotive cables, use SAE rated SGT or SGX battery cable. It works great for automotive applications at a fair price. Do NOT use welding cable, OFC or CCA for under hood applications.
For boats, you must use “marine” rated wire.
I recommend building cables larger than stock. The manufacturers make stock battery cables as small as possible that barely get the job done. Going up a size or two is worth it in the long run because they do work better and last longer. Isn’t that what you want for your car or truck? Something that will work better and last longer.
For very long cables (for example 15-foot long battery cables to relocate your battery) go one size larger.
10 gauge works for accessory leads, low power alternators, and starter trigger wires
8 gauge works for accessory leads and low power alternators.
6 gauge works for accessory leads and most stock alternators. Battery cables for small engines (like ATVs and sub-compacts). Some stock golf cart wiring.
4 gauge wire makes great accessory leads and alternator wiring (up to about 160A). Many cars use this as a battery cable. Some electric ATVs use #4 for the battery banks. It also makes very good automotive booster cables.
We recommend #2 wire for 4 cylinder and small 6 cylinder automotive engines, hi-power accessories (like winches, power converters), and alternators over 160A.
Also works great for high-performance golf cart battery banks. Recommended for professional heavy-duty, booster cable (jumper cable) kits.
We recommend 1 gauge wire for large 6 cylinder or small V8 automotive engines, hi-power accessories (like winches, power converters), and high output aftermarket alternators in 200A range.
1/0 makes a great battery cable for large or hi-performance 6 cylinder engines and stock V8s.
Use 2/0 battery cables for hard to crank engines (like high compression, big blocks, or diesel engines), electric vehicle battery banks (depending on controller amperage), and large RV power converters house batteries..
3/0 and 4/0 are for very large marine or diesel engines and high power alternative energy battery banks.
Note: This information comes from a variety of sources and it is used for reference only.
We have not personally verified all the data shown.