Warning: High Leakage Current

Status
Not open for further replies.
chris kennedy

chris kennedy

Senior Member
Location
Miami Fla.
Occupation
60 yr old tool twisting electrician
Working on a relocated printing press today (208V 1? 70A) and found the warning label and large internal grounding conductors interesting. I'm running two #3 ungrounded and one #8 EGC to this thing. The internal grounding conductors look like #6's. I am going to separate the FMC from the EMT when I get this thing running to put an amprobe #8 EGC to see whats up. Anyone have any idea what "High Leakage Current" might mean? FWIW, the guy that may have the paper work on this thing was unavailable today.

Thanks.

DSCN2158.jpg


DSCN2160.jpg
 
This may give an explanation:

http://docs.google.com/viewer?a=v&q...naC1D7&sig=AHIEtbQC8h6ydfOwg7X5Cmecf7OBSQdqgA

Ac leakage current is caused by a
parallel combination of capacitance and dc resistance between a voltage source (ac line) and the
grounded conductive parts of the equipment. The leakage caused by the dc resistance usually is
insignificant compared to the ac impedance of various parallel capacitances. The capacitance
may be intentional (such as in EMI filter capacitors) or unintentional. Some examples of
unintentional capacitances are spacings on printed wiring boards, insulations between
semiconductors and grounded heatsinks, and the primary-to-secondary capacitance of isolating
transformers within the power supply.
Click to expand...

This looks like a device made in Europe. (Green wire with yellow stripes, clue #1). The NEC is pretty clear about current on the grounding conductor, but those US standards may not have been followed in the making of an European device.

What I am trying to say is that the press may not be NEC compliant due to it's design intentionally putting current through the grounding conductors.
 
Last edited:
I don't speak code very well, but I remember watching the "Grounding vs. Bonding" dvd's, and I remember Mike Holt saying something about a lot of european companies putting this kind of labeling on equipment. He went on to say (guess i'll have to watch again, kinda vague) sometimes this is actually a dangerous thing to do...BUT, if the labeling requires it, then it must be followed (per NEC) unless the authority having jurisdiction says differently (90.4 I think?).
 
CONTROL FREQ said:
I don't speak code very well, but I remember watching the "Grounding vs. Bonding" dvd's, and I remember Mike Holt saying something about a lot of european companies putting this kind of labeling on equipment. He went on to say (guess i'll have to watch again, kinda vague) sometimes this is actually a dangerous thing to do...BUT, if the labeling requires it, then it must be followed (per NEC) unless the authority having jurisdiction says differently (90.4 I think?).
Click to expand...

The only danger I see would be if a person thought an earth connection would trip an OCPD. I think an earth connection could possibly cause a GFCI or GPE to trip.
 
Maybe

Maybe

I have worked on equipment which used copper fingers to remove the charge from a moving sheet of paper; otherwise the individual sheets would not stack up properly.

ptonsparky said:
Does a printing press generate enough static that may need to be dissipated?
Click to expand...
 
Good morning



I have been retire for a few years but the last few years I worked I service and installed a few
single phase air compressors that had that label on them. All of them had a solid state contactor.


Being solid state with soft contacts meant it had a triac of scr. for the switch instead of normal
hard contacts like a mechical starter.

I always assumed that was implying that the load side was still hot or energized even in the
off position.

Like I said I assumed that and you know what assumed means some time.

Ronald :)
 
Status
Not open for further replies.
Top