Common grounds are "negative grounds" in the USA. Other countries-- not necessarily. When in doubt, check the connections on the battery and follow the wire, or use a volt-ohm meter. Batteries usually have a + or a - that is raised. You can feel on the battery, or have someone check for you.
Grounds are notoriously bad. In fact, “ANY” owner of any vehicle with DC connections is advised to check out the ground connection. Corrosion takes place between dissimilar metals, and that corrosion reduces the conductivity. Simply put, positive connections keep you rolling, weak connections keep you immobile.
Dielectric greases are used to keep the connections in good shape, but they don’t fix bad wire, already poor connections, or the buildup of garbage between contacts. Although this grease is the best, a substitute can be any grease or oil, but surfactants like WD-40 actually limits the grease by removing greases, and is not considered a lubricant, so be careful. Don't grease the entire battery.
At the minimum, yearly, clean your connections, replace all bad wires and connectors with proper sizes and quality parts, remove any paint and guck around the connections, lightly coat the connectors and attachments with a good grease or corrosive inhibitor-- apply greases sparingly. Then tightly connect.
For a quick study of what I’m talking about, lift the hood of a car that’s a few years old. Observe the battery and connections, wiring around this, and the surface of the battery. That surface guck is a leakage point whereby your battery will deplete over a shorter time. The old saying, “Cleanliness is next to Godliness” is correct.
And, just because you did all of this this year, you’re advised to do it next, and the year after, etc.
Generally speaking, connections that attach to a car battery in an RV should be kept to a minimum. There are a few exceptions such as HAM radios where direct connections are the norm. These may use larger current flows and noise from intermediate connections cause problems in the radio(s) and other gear.
Terminal strips are, in effect, like a fuse panel at your home, only without the fuses. Some strips actually have fuses. Nevertheless, strips allow you or others to disconnect one or more wires which may have that faulty gizmo or bad connecton in the line.
Disconnecting bunches of corroded wires off the battery is not only dangerous, but the analysis on which circuit is bad. Be certain to use proper wiring to that switch and terminal strip you put in as a distribution point. Small gauge wires cause fires with heavy loads. When in doubt, research!
Lead-acid batteries give off hydrogen gas which is extremely explosive. Remember the Hindenburg. Be cautious, wear protective glasses and use proper tools. A wrench between the terminals may draw enough current to vaporize it.