Some of the most common questions I get asked are things like, “what type of 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 types 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…..
Table of Contents
SGT Battery Cable:
We generally use SAE (Society of Automotive Engineers) SGT battery cable. SGT designates the type of wire. For example ‘THHN” is probably what you have for wiring your house. SFT is self-extinguishing PVC insulation rated at 50 volts. It’s typically rated for 85 or 105 degrees C. This is the lowest cost wire of the 3 wire types discussed here and it does the job just fine. The strands are larger than the other two, making the wire stiffer so it stays where you put it but is still flexible enough to bend around tight corners.
Pros: Lowest cost, SAE rating
Cons: Lowest temp rating (as low as 85C, about 185F)
Fuse Link or Fusible Link:
Fuse link wire is special wire that is intended to act as a fuse. It 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 electrial system from a catastrophic failure of the alternator where the alternator shorts to ground. With the fust link the alternator wire would melt or burn, possibly starting an under hood fire. It’s usually a 9 inch piece two sizes smaller than the wire it is protecting. For example, a 4 gauge wire with a 9 inch piece of 8 gauge fuse link. It is hard to find fuse link larger than 6 gauge. To purchase: Order Wire
High Strand Count:
Some folks are looking for high strand count battery cable. Perhaps they have heard it’s somehow “better”. Other folks think that carries more power due to “skin effect”. That is just plain false. Skin effect is a high-frequency phenomenon (think radio frequency or microwave) and is nonexistent at 12V DC. The high strand count is more flexible but in an automotive application, the cables get installed once and hopefully they never move again! So, flexibility isn’t really a huge issue.
OFC (Oxygen Free Copper):
Don’t waste your money. This stuff is just a clever way for stereo salesmen to get more of your hard-earned money. If you are seriously thinking of spending big bucks to buy OFC wire because some high school drop out salesman at the stereo shop told you it would make your stereo sound better, you really need to read our OFC (Oxygen Free Copper) page.
For automotive cables, I like the SAE rated SGT or SGX battery cable. It works great for automotive applications at a fair price. Do NOT use welding cable for under hood applications.
For boats, you have got to have “marine”. I’m no legal expert, but isn’t that a Coast Guard rule?
Welding cable makes great booster cables or portable inverter cabling. Nice and flexible for when you roll them up and put them back in the trunk.
1/0 makes great battery cable for large or hi-performance 6 cylinder engines and small V8s.
Use 2/0 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.
3/0 and 4/0 are for very large marine or heavy equipment engines and high power alternative energy battery banks.
For very long cables (for example: 15-foot long battery cables to relocate your battery) go one size larger.
Please note: You can probably get by using a size or maybe even two sizes smaller than what I am recommending. HEy, the factory does. They make the cables as small as possible but still get the job done. Copper is expensive…..(about $3.10 as I write this) if the manufacturer saves a few bucks on millions of cars…..pretty soon it adds up to real money. I recommend using cables larger than the factory because I believe they will work better and last longer. Isn’t that what you want for your car or truck? Something that will work better and last longer.
Just how big is that 2/0 cable? Check out the information in the charts below.
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.