Why Don’t Both of My Car’s Battery Terminals Have Covers?

With the negative car battery terminal connected to the frame, covering only the positive battery terminal minimizes the dangers of short circuits.

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Let’s say you’ve got your car’s front hood up and you accidentally set a wrench on top of the battery. If the wrench touches both the positive (+) and negative (-) battery terminals, it could cause a spark that ignites the battery’s mixture of hydrogen and oxygen gases.

And there will be an explosion.

Battery terminal covers greatly reduce the risk of this happening. New covers provide a professional look while protecting battery terminal ends from shorting and corrosion.

What Is a Car Battery Terminal Cover?

Made from PVC, rubber or plastic, a car battery terminal cover shields a battery cable terminal to protect it from damage and creating a short circuit. They come in different colors: red for the “hot” 12-volt positive terminal, and black for the negative “ground” terminal.

A short circuit is a dangerous connection between two parts of an electrical circuit that should never touch each other. Both top- and side-post batteries should have battery terminal covers.

What Is the Purpose of Car Battery Terminal Covers?

Battery terminal covers greatly reduce the chances of accidentally short-circuiting battery terminals to each other, or the 12-volt positive terminal to ground. They also help protect battery terminals from corrosion-causing contaminants and keep the engine bay looking spiffy.

Why Don’t Both of My Car’s Battery Terminals Have Covers?

Although most vehicles come with two battery terminal covers, only the positive battery terminal needs to be covered. Why? Because the positive terminal carries 12 volts and can easily short circuit.

But the volts aren’t the problem — it’s the scary number of amps (more than 400) a car or truck battery can produce if the positive battery terminal becomes shorted to ground. You can easily melt or weld one-quarter-inch-thick aluminum with 250 amps!

Any conductive material that short circuits will quickly become hot enough to melt metal or skin, as well as cause dangerous sparking which can quickly ignite battery gases.

Covering the negative terminal protects it from corrosion.

What To Do if a Car Battery Terminal Cover Is Missing?

If your vehicle lacks battery terminal covers, you can install new ones when servicing your battery. Here’s how:

Remove both battery cables. Always remove the negative cable first.

It may be tricky sliding the new covers over the cable terminals. Try coating the cable end of the cover with a little petroleum jelly or clear silicon gel to help ease it over the terminal. If that doesn’t work, cut a slit in the small end of the cover to slide it over the battery cable, then secure it in place with a small plastic zip-tie. Or you can leave this task for your mechanic.

Safety first! A battery contains sulfuric acid that can cause serious burns. Always wear gloves and eye protection when working around a battery or jump-starting a car. If you come into direct contact with battery acid, flush with plenty of water and seek medical attention immediately.

Bob Lacivita
Bob Lacivita is an award-winning ASE and General Motors auto technician, vocational educator, Career and Technical Center administrator and freelance writer who has written about DIY car repairs, vehicle maintenance and other self-help topics for more than 20 years.
At the age of 12, Bob took his first engine apart, a 2-cycle Briggs and Stratton from a lawn mower he found in the trash. At 14, he rebuilt a seized 256cu.in. Chevrolet engine in a 1956 Belair that he drove for three years. He spent most weekends, as well as the money he earned working a gas station, at Atco Dragway in Atco New Jersey.
Although trained as an architectural drafter, he never worked a day in that field. Still, the skills he learned helped as he renovated and rehabbed his homes. His true love was cars and so he made that his life’s profession. Bob worked for one of the largest Oldsmobile retailers in the country and earned Pontiac and Oldsmobile Master Technician Elite status as one of the top 20 GM technicians in the country.
Bob was also a Pennsylvania Department of Education (PDE) certified career and technical educator for 25 years, teaching automotive technology for 11 of them. He's been a Certified Vehicle Safety Insructor and an Emissions Inspector, too. Bob earned his master’s degree in educational leadership, as well as his PDE K-12 Principal Certification and his Career and Technical Education Directors and Curriculum Supervisors certificates, to become a school administrator. When it comes to education, Bob has two sayings: The kids are the best part of teaching, and teaching was the hardest job he ever had. It was the best job he ever had, too.
Since retiring, Bob has continued to maintain his ASE Master Technician; MACS Section 609 Refrigerant Recycling Certification; PA safety and emissions inspector certifications, credentials, and licenses; and participated in more than 100 hours of update technical training through MotorAge, Snap-On, Dorman Products and Automotive Technician Training Services, Mitchel1 and others.
Bob currently writes regularly for Family Handyman and works as a consultant with one of the largest automotive retailers on the East Coast, setting up an automotive technology training and apprenticeship program in partnership with a local catholic high school.
Bob and his wife lived through 40 years' worth of DIY home remodeling while parenting two (now grown) boys, and now relax by watching their three fabulous granddaughters.