The black terminal is the ground, and the red probe is for the active current. This matters more if you’re checking voltage, and there isn’t any special difference between the cords themselves though. The terminals are the exposed metal pieces at the end of the black and red cords. They measure electrical currents.
If your multimeter doesn’t have a dedicated continuity setting, you can still perform a continuity test by turning the dial to the lowest number in resistance mode. Resistance is measured in ohms, and its symbol is Ω. When in doubt, consult your multimeter’s manual to figure out how to set it to continuity mode.
Most multimeters will also beep if the signal is good to indicate that the continuity setting is working properly. If there is no beep or you get a high reading, check the dial to make sure you’re on the right setting. Then, check the ports that your terminals are plugged in to. Finally, try replacing your terminals before consulting your manual to find out how you can reset the multimeter. If the screen displays a 1 all the way on the left-side of the screen and not where it normally displays readings, it usually means that the signal is broken. This is a sign that your terminals are bad. It’s okay if the number fluctuates a little.
If you’re testing an outlet that is already installed, flip the breaker on the fuse box for the room that the outlet is in to shut off the current. Some devices, like hot tubs, radios, or car systems, will store a charge even after the power is off. Wait at least 1 hour after unplugging these systems before testing them. You obviously can’t unplug a wire or fuse. Don’t worry about turning these off if they’re not already installed in something. Take any removable fuse out and test any hooked up wire by turning the appliance, car, or device off first.
If you’re testing an outlet, unscrew the faceplate and unscrew the outlet’s mounting screws. Pull it out a little and put the black terminal on the metal screw on the side. If you’re testing an appliance and wire connection to see if it’s safe, press the black terminal against the metal frame of your appliance.
If you’re testing a switch, there should be no continuity reading when you flip the switch to the off position. If you’re testing a fuse, put the red terminal anywhere on the body of the fuse but don’t let your 2 terminals touch. It’s not dangerous, but it will mess with your reading. If you’re testing soldering, put the red terminal on the other end of the material that you’re testing. If you’re testing an appliance and wire connection for safety reasons, press the red terminal against the wire or fuse that you’re testing.
A constant 0 indicates a perfect connection. The continuity doesn’t need to be 0 to be safe though.
It is perfectly safe to use a wire, fuse, or device with a continuity reading lower than 1. If the number bounces up and down from a high number to 0, it means that your multimeter’s battery is probably dying.
Check to see if there is an X or M in front of the ohm symbol on the reading. If there is, it means that it’s actually reading megaohms, which means that there are zeroes that won’t fit on the screen. This means that your multimeter is reading the signal in thousands and your connection is dangerously high. If there’s a 1 on the left-hand side of the screen, it probably means that the reading is too high for the screen to register. Consult your multimeter’s manual for more information, but this probably means you have a dangerous connection. If the reading is higher than 10, then your device, wire, appliance, or fuse will overheat. While this may not be an issue for short-term use, it can lead to long term problems and is dangerous.
If the number is blinking, it is usually an indication that the current is broken, but some signal is getting through. This blinking function is only available on some multimeters.
