Multimeter help

[peejman]

I've no idea why a consumer level meter even has a micro-volt range.  It's way more nuisance than useful. At the least you ought to have to manually select it to prevent this very problem. 

[Mark A]

A long time ago in my former life as an HVAC tech we had a server farm that had pretty bad power (not a good combination). We would lose motors and boards on a semi-regular basis. One of the onsite maintenance men acquired a new Fluke meter. He found transient voltage everywhere including the building steel. Didn't show up on our analog meters so we all went out and bought new Flukes and  sure enough there was voltage EVERYWHERE!!!

We started in the switch gear room and began working our way outward. This is 4 journeymen techs. We spent a week trying to isolate the problem with no resolution. We rented very sensitive chart recorders from GE instrumentation and set them in 10 different locations and worked for another week and couldn't find the source of the transient voltage.

The chart recorders of course didn't pick up anything. So, we called the GE rep and the Fluke rep out to meet with us. Had a big meeting in the conference room with all the bigwigs and explained the problem. We first went to a couple of the chart recorders and the GE guy calibrated them and assured us they were working properly. Then we got our shiny new fluke meters out and as soon as we took a measurement the fluke rep started laughing. We were measuring something like .00005 of a volt but because the meters were auto ranging the number looked big.

 

Now we had around 400 man hours and all the cost for the recorders etc. The CEO listened to the entire story, and the maintenance man stood up for us and said he'd sent us on a wild goose chase. The CEO asked everyone if they'd learned anything and we all said yes. He looked over and the CFO and said pay the bill and walked out. The project manager for us on that account about passed out.

We scheduled a mandatory after hours training meeting the next week for all service techs and the construction start up guys and went over what happened and how to properly use the new digital meters we were getting. Service had 92 techs and construction had 10 so it wasn't a cheap meeting but we worked for a great company and they wanted to make sure nothing like that ever happened again.

 

Mark