DMMs...Much difference in cheap and expensive?

[uofaengr]

Flukes are considered some of the best and pretty much what I've seen every electrician use and have used plenty of them in my profession although I don't own one. However, I do own a $20 Cen-Tech I picked up from Harbor Freight several years ago.

I had access to a Fluke today and measured a used Eneloop AA in my EDC light and my unused spare. I measured 1.278V on my used Eneloop and my spare was 1.354V. Curious if my $20 meter is actually any good for measuring my battery voltage, I came home and measured to compare. My $20 meter only shows two decimal places and measured a fluctuating 1.27-1.28V on my used Eneloop and a solid 1.35V on my spare.

I was actually surprised that my meter measured the exact same as a meter 10x its cost. Relieved too that I can reliably keep track of my batteries. So what are you paying for exactly for $150 extra? And I'm not talking about clamp meters or sourcing meters.

 

[mattheww50]

There are usually three things you are paying for.

1). Reliably accuracy, essentially quality control. If you take half a dozen Fluke meters and make a measurement, they are very likely to all read the same voltage/current to 3 decimal places. Your $20 DMM is unlikely to do that well. To be honest however there aren't a lot of applications where 3 digit accuracy on low voltage is required.

2). Durability. Fluke meter are built like a tank, and will tolerate literally years of hard use/abuse. If you don't plan on hard use/abuse, it may well be less expensive to buy several $20 DMM's over the next 5-10 years. I have some nearly 20 year old Fluke meters. They still work quite well. In certain applications, accuracy needs to checked and certified annually. This is rarely a problem with a Fluke meter. You may discover that your $20 DMM lacks the
necessary adjustment capability or component accuracy to pass the required metrology testing.

3). Safety. Fluke Meters are built to, and tested to the highest safety standards (UL/ETL/CSA) and if you look up the listing numbers in the 'yellow book', you will find the Fluke meters. Many low cost DMM's may say they are UL or ETL or CSA listed, but if you run down the listing number, it doesn't exist. Often times if you know a little about the listing requirements, you can spot obvious violations of UL/ETL/CSA standards(CE is meaningless for safety) I.E. they do not meet the standards. If you are only working with 0-20 volts, it may not make much difference. If you are working with 400 volts, it might just be the difference between safety and death or serious injury. As someone who has manufactured UL and ETL listed products, it costs money to be compliant, and your compliance is checked on a regular basis with unscheduled visits from inspectors who verify that the product has been assembled correctly, safety test equipment is in calibration, and component parts are as documented in the listing and where applicable are UL listed/rated. Every time one of our vendors changed a part number in the product, we had to amend the UL paperwork to reflect the change (some vendors use part numbers to track manufacturing status, so every time the part was changed, even if the change was trivial), the part number changed.

 

[uofaengr]

Great post. [emoji106]

And no I wouldn't trust this thing to high voltage on critical equipment (480V motors for example) but it is nice for just checking my batteries, Ohming out things, and checking for live circuits in my vehicle or home.