Prime Products 12-4055 AC Voltage Line Meter

I bought two of these meters for neutral and voltage drop tests before we use electric heaters this winter. The two meters are reasonably well made, and the two I received were correctly calibrated.The good: The meters I'm using are accurate and very sensitive, they register slight voltage changes smoothly and accurately, and are quick and sensitive enough to register small, rapid changes in voltage up to 30 or 60 cycles per second if the voltage oscillation is within a volt or so (fast enough to tell modified sine wave from true sine wave if one uses a magnifying glass).The interesting: The meters are designed to operate in the needle-above movement with the gauge face vertical (as is pictured). The two I received were accurate in any orientation. Also, on large voltage changes (often 0 to 120 VAC RMS when connected), the meter is softly-sprung enough that the meter needle will oscillate around the correct reading for about one second, after which the oscillations damp down the needle indicating the correct voltage. There is a calibration screw in the movement, but it is inaccessible to an unmodified unit (no hole drilled into the face). Also, the manufacturer apparently calibrated the meter in two ways, adjusting the calibration screw, and bending the needle slightly at its base--both methods work. Also, highly accurate work is possible, but one has to use a flashlight directly in front of the meter and use the needle's shadow to mitigate parallax errors (The needle is about 1.5 mm above the gauge's face.) The legend on the gauge is usably consistent and accurate, with the tick marks reasonably accurately spaced (wider at 130 than 100, concentrated more between 100 and 110).The bad: There isn't really anything bad about the meters at all. However, I read many of the reviews before I added mine here, most of them from RV'ers and campers about vibration sensitivity. The meters are electrically and mechanically sensitive, meaning physical shocks (including vibration and dropping) will readily affect the movement in the meter, and likely knock the meter out of calibration or cause small parts to fall out of alignment or break. These meters will give years of excellent and reliable service given they are not operated in high vibration or physical shock environments, kept in a clean and dry environment, and not exposed to voltages beyond 135 VAC RMS. (High physical shocks will break them, high humidity will contaminate and rust the movement, and high electrical voltage will slam the movement or melt the coil.)Pretty good meters! I'm happy to have them.

The good - the unit arrive earlier than I expected.... thank you Amazon Prime.The not so good - when I compared the voltage displayed on this AC Voltage Line Meter, it was almost exactly two volts lower than my other measuring equipment displayed. For reference, I used a Fluke 115 True RMS Multimeter and a Progressive Industries EMS-PT50C Surge Protector. Both the Fluke meter and the Progressive Industries Surge protector showed the same voltage: 111 volts while the Prime Products 12-4055 showed 109 volts. (Yes the voltage was lower than normal but it was a very hot day with many air conditioners running)The good news is that if you're somewhat mechanically inclined, it's an easy fix. Pull off the clear plastic face. Take a jeweler's screwdriver and adjust the center screw so that the needle will match the voltage of a known accurate voltage measuring device.Would I buy it again? Yes, providing I had the ability to compare the voltage displayed on this 12-4055 meter to a known accurate voltage meter AND I had the ability to adjust this meter to the correct voltage.

I purchased this item while on our once-in-a-lifetime trip to Alaska from Florida. This item help me discern whether or not the power that I was receiving from the polls in various RV Parks was enough to adequately run my air conditioning on my 24 foot travel trailer. I learned of this item from a neighbor who was camping next to me and boy am I glad I purchase this device simple easy to read easy to understand easy to use I highly recommend it.

I bought two of the Prime Products A/C voltage meters, along with a couple of circuit testers in order to build a power pedestal tester for my RV. I have used the tester many times to insure the 50 amp power outlets in various campgrounds are providing the correct power and are correctly wired, prior to my plugging our coach into the pedestal. These meters have worked as I expected they would and contrary to several reviews I've read about them being somewhat fragile, I have not had problems even though I don't treat them with kid gloves. I feel I have gotten my moneys worth.

The Prime Products 12v AC line meter provides an accurate readout. In reading others' reviews, I'm a little worried about how sturdy it will be, as I travel with this in a storage bin in my RV. So far I've only taken it on a couple of short trips and it's still working perfectly. Hopefully it will hold up for the long haul, but for now, given the other reviews and my personal evaluation that it "feels fragile," I'm providing 4 stars.If this one breaks, I will buy another one.

Have use this item several time. I did have a problem with my battery charging system but after I used the meter a few time I found out that I have a bad or dead cell on house battery. Removed and replace battery and system checked out perfect. Great item to carry with you all the time. You can just about use it on any autombile, truck or RV. Easy to use and easy to store............Would highly recomment this item and would purchase is again.........

A must have for all RV'ers that want to keep an eye on the incoming voltage to the RV... many RV parks do not use large enough gauge wiring for the power pedestal which results in under-voltage conditions if more than one 120V appliance is used at the same time. We leave our meter plugged in at the galley outlet so we can keep an eye on the voltage all the time. Work's great and doesn't interfere with appliance use.

I was looking for an AC meter to monitor the power on the outlet that supplies the power to my charging stations for my cell phone, ear piece, battery chargers and radios. This little meter filled the bill quite nicely since it can be plugged into the same outlet my charger station is plugged into just above it. Now I have a good idea of what the voltage is coming into my charging station. It is rather handy to take anywhere in the house and check the vogtage of any outlet anywhere.