I frequently work on AC and DC industrial drives. Measuring 480 VAC
is common and sometimes the DC bus on a 480 Volt input drive as well. I
decided to "retire" two of my older Flukes to lesser duties and stick
with the new one rated at 1000 volts just for the reasons you mentioned.
I don't want a meter flashing over internally. Age degrades insulation
and it just isn't worth the risk.
I have a few other meters which are cheap Chinese knock offs but I keep
those around for 240 VAC and below. I would not use one at 480VAC
even though they scale to 600 VAC.
If you can afford to work on 480 VAC systems, you can afford a high
quality meter.
Also, keep an eye on the meter leads. If they start looking worn,
replace them.
I've got life insurance, but I don't want to use it.
Dave
On 7/14/2017 11:26 AM, John Kasunich wrote:
On Thu, Jul 13, 2017, at 03:48 PM, Nicklas Karlsson wrote:
Fluke work great but are a little bit expensive. Unless accuracy is important I
guess any would do.
Fluke is indeed expensive. However, I would change the last part to "Unless
_safety_ is important I guess any would do".
Cheap imported meters are often as accurate as brand-name meters costing 5-10
times as much. But one of the differences is the input protection. What
happens if you accidently hook your meter probes across line voltage when it is
set to measure current?
Most meters, even cheap ones, have a fuse that will blow in that case. If you
accidentally tried to measure a 24V power supply or even a 120V AC line while
set for current, you'll probably be fine. If you accidentally tried to measure
a 480V line with a Fluke, you'll still be fine - the fuse in a Fluke is rated
600V and has a high interrupting current rating. But the fuse in a cheap
knock-off meter can't interrupt 480V fault current and is likely to explode in
your hand trying.
I have a Fluke and a cheap meter. On the bench when I'm working with low
voltage I'll use whichever one is handy. Both are accurate, and the cheap one
actually has a few features that are nicer then my (older) Fluke.
But for anything higher than 120V, I only use the Fluke.
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