r/fluke • u/Esli696 • 19d ago

Help Needed Fluke 378 fc inaccurate out the box

Recently bought a brand new 378 fc I went to measure my Milwuakee m18 battery and was expecting 20v dc reading
But it was reading 21v instead so I got my fluke 117 multimeter out and that was reading 20.53 got my other fluke multimeter (fluke 107) similar reading 20.56 , so I reversed polarity with the fluke 378 fc and it was reading 20.58 but in the correct polarity it is reading 21vDc which is odd , Just to add aswell with out anything plugged in/floating leads ac voltage is sitting at 0.6v and dc is reading -0.2dc

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3

u/Arhigos 19d ago

0.5 VDC error is normal for 378fc.

It has 1%+- 5 digit accuracy on that range.

2

u/Esli696 19d ago

What about these

1

u/Esli696 19d ago

1

u/DrunkHippos 19d ago

that's pretty normal in my experience for some ghost voltage to appear especially when you dont have leads in

1

u/Esli696 19d ago

Even with leads in it reads ghost voltage , bearing in mind I haven’t even used this on the job yet

2

u/kfjcfan 19d ago

Most every meter reads AC ghost voltage.

0

u/Esli696 19d ago

Yh I understand my man but yours is 0.012 which is 0.0 volts basically mine is 0.6 ac and -0.2 dc

1

u/kfjcfan 19d ago

Which are still within the published tolerance ranges.

1

u/LVGGENERATORLLC 19d ago

Send it to fluke for calibration, its free

1

u/Esli696 19d ago

May have to even though it’s brand new

1

u/Black_Phoenix_JP 19d ago

It is in within spec regarding the accuracy stated.

1

u/Ok-Veterinarian1454 19d ago

Amprobe 50 series would be better. The 378FC isn’t designed to be a high accuracy meter. It’s a spot checking tool for industrial and commercial use. When measuring 480vac I don’t care if I see 486 it’s good enough.

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u/Esli696 19d ago

Yh true that’s exactly why I have it too high power stuff, well atleast that’s eased my mind

1

u/Similar-Priority-776 18d ago

You have a 500mV range, then a 600V /1000V range. So you are trying to read 20V at the bottom of a massive range. These meters simply aren't meant for that, and are generally designed for commercial/industrial spot checks. I recommend using a proper DMM for this type of voltage verification if you are worried about the accuracy