By Chris Dougherty
Chris Dougherty is a certified RV technician. Here is an article he wrote while he was serving as RVtravel.com’s technical editor.
There are many brands and kinds of multimeters, from inexpensive dollar store specials to Flukes and Extechs. While I’ll refrain from recommending any particular brand or mode, I will make a few recommendations for features.
AC/DC Amp Clamp: Power is measured by volts (pressure) and amps (flow). Since more than half of the electrical system in an RV is DC or Direct Current, having a way to measure DC amp draw is good to have.
Not all amp clamps have DC reading capability, so review the meter you’re considering carefully. The meter should also be able to read AC amps.
DMM, Digital MultiMeter: I prefer a digital scale to an analog one for reasons of accuracy and ease of reading.
Category III minimum: Multimeters are categorized for safety and the maximum loads they can handle. Because troubleshooting AC systems in RVs can sometimes involve high voltage, I recommend a minimum of Cat III.
Fused: Most multimeters are fuse-protected from overloads, but the really cheap ones may not be, and a mistaken overload will cause “magic” smoke to appear from the meter.
Temperature: Some of the nicer meters have a temperature sense function which I use pretty regularly. My meter has both IR (infrared) temp sense and a wired probe. This is especially good for determining if a component may be overheating, or to see if the air conditioner is working properly.
Accessories: Some things to go along with your multimeter include a case for a good meter if it didn’t come with one, alligator clip probe adapters, and spare batteries and fuses.
Editor: For more information or to order, here are multimeters at Amazon.com.
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Totally agree with the need for DC amp capability. I just bought a new meter off Amazon – about $40 with clamp on AC/DC current capability plus all the other regular attributes. Also, I suggest a digital meter because most will read plus or minus so you will not damage the meter and the reading is straight forward, not like some analog meters where you have to figure which scale you need to read. Just my opinion.
Hi Chris,
Really enjoy your posts – I’m a boondockin’ DIYer.
Care to mention your personal favorites in this category? As you know, prices vary from $20 to $1000+. I certainly don’t need Fluke equipment (tho I wish I had one – the DW would kill me!).
Thanks,
Bob in Las Vegas
Harbor Freight ‘free’ multi-meter and 12v trouble light for every day needs. Generally, just need to find where the 12 volts is lurking.
Actually carry a professional hospital grade multi-meter for heavy lifting.
For the cost, the HF meter, if it smokes, no big deal. The next one is still ‘free.’
Chris,
Have you looked at a Power Probe 3? This is an amazing tool for RVers. We got stranded 4th of July with our slides out and they would not come back in. The local Camping World brought in a tech that had one of these devices. It is able to distinguish between positive and negative wires. It can then send a 12vdc charge to whatever switch or device. Using this he was able to bring in our slides. Know which wire was bad and jump it out. Needless to say, I purchased one right away.