WARNING: JTL Monolights are DANGEROUS!

FYI: I recently discovered the hard way that the three JTL monolights
(Versalight series, 300 and 800) I owned are ELECTRICAL HAZARDS.
CAUTION: you may get shocked quite severely if you use these lights. I
found this out by getting a good shock when doing a portrait session
in a studio with a concrete floor. I was wearing shorts and knelt down
to get a better angle on the subject and as soon as my knee touched
the floor, I felt a strong electrical current run through my arms via
the camera. I measured 85 volts AC between the sync cable outer
connector and earth ground. THIS IS NOT NORMAL!! I tried contacting
the JTL company twice but did not receive a response. The same problem
was exhibited by all three lights, so I don't think it's an individual
defect. Instead, it seems to be a design flaw.

Yes, you might say I was an idiot for wearing shorts and shooting
portraits in a room with a concrete floor, etc. I agree, and I'll not
do that again. However, I recently took delivery of some new
monolights (from Calumet) and they do not exhibit this voltage
problem.

-John

Sounds very much like someone used a three-wire to two wire AC adapter ... and left the
ground wire on the strobe floating ... ?



"John Steven" wrote in message
om...
FYI: I recently discovered the hard way that the three JTL monolights
(Versalight series, 300 and 800) I owned are ELECTRICAL HAZARDS.
CAUTION: you may get shocked quite severely if you use these lights. I
found this out by getting a good shock when doing a portrait session
in a studio with a concrete floor. I was wearing shorts and knelt down
to get a better angle on the subject and as soon as my knee touched
the floor, I felt a strong electrical current run through my arms via
the camera. I measured 85 volts AC between the sync cable outer
connector and earth ground. THIS IS NOT NORMAL!! I tried contacting
the JTL company twice but did not receive a response. The same problem
was exhibited by all three lights, so I don't think it's an individual
defect. Instead, it seems to be a design flaw.

Yes, you might say I was an idiot for wearing shorts and shooting
portraits in a room with a concrete floor, etc. I agree, and I'll not
do that again. However, I recently took delivery of some new
monolights (from Calumet) and they do not exhibit this voltage
problem.

-John

Nor do my Paul Buff White Lightning strobes...

"John Steven" wrote in message
However, I recently took delivery of some new
monolights (from Calumet) and they do not exhibit this voltage
problem.

-John

"John Steven" wrote in message
om...
FYI: I recently discovered the hard way that the three JTL monolights
(Versalight series, 300 and 800) I owned are ELECTRICAL HAZARDS.
CAUTION: you may get shocked quite severely if you use these lights. I
found this out by getting a good shock when doing a portrait session
in a studio with a concrete floor. I was wearing shorts and knelt down
to get a better angle on the subject and as soon as my knee touched
the floor, I felt a strong electrical current run through my arms via
the camera. I measured 85 volts AC between the sync cable outer
connector and earth ground. THIS IS NOT NORMAL!! I tried contacting
the JTL company twice but did not receive a response. The same problem
was exhibited by all three lights, so I don't think it's an individual
defect. Instead, it seems to be a design flaw.

Yes, you might say I was an idiot for wearing shorts and shooting
portraits in a room with a concrete floor, etc. I agree, and I'll not
do that again. However, I recently took delivery of some new
monolights (from Calumet) and they do not exhibit this voltage
problem.

-John

Do the strobes have a plug with one prong slightly wider than the other?
Does the outlet also have one slot larger than the other? The larger slot
should be at earth ground potential (get the voltmeter back out!). If not,
your outlets are wired backwards, and could cause similar problems with
other devices plugged in these outlets, particularly those with a wide
prong. ("polarized plug")

Ken Hart

"RSD99" wrote in message .. .
Sounds very much like someone used a three-wire to two wire AC adapter ... and left the
ground wire on the strobe floating ... ?



No adapter in use. But it did occur to me that the lights might be
wired that way internally. For use in Japan, perhaps? I remember when
I was in Japan, there was no ground wire. You could always tell when
americans had been at a studio because cold water pipes had been filed
clean for a good electrical contact...

Just to make sure it wasn't the wiring at the studio contributing to
the problem, I used a line checker and everything looked as it should.
It's definitely the lights.

-John.

Sounds about right!!! RSD99, 70-80 volts on a floating neutral....easy
way to check your lights if your in the U.S. is to plug your lights
into a GFI outlet in the kitchen or bathroom, if it trips the breaker
then you have problem with the lights
Rick

"RSD99" wrote in message .. .
Sounds very much like someone used a three-wire to two wire AC adapter ... and left the
ground wire on the strobe floating ... ?



"John Steven" wrote in message
om...
FYI: I recently discovered the hard way that the three JTL monolights
(Versalight series, 300 and 800) I owned are ELECTRICAL HAZARDS.
CAUTION: you may get shocked quite severely if you use these lights. I
found this out by getting a good shock when doing a portrait session
in a studio with a concrete floor. I was wearing shorts and knelt down
to get a better angle on the subject and as soon as my knee touched
the floor, I felt a strong electrical current run through my arms via
the camera. I measured 85 volts AC between the sync cable outer
connector and earth ground. THIS IS NOT NORMAL!! I tried contacting
the JTL company twice but did not receive a response. The same problem
was exhibited by all three lights, so I don't think it's an individual
defect. Instead, it seems to be a design flaw.

Yes, you might say I was an idiot for wearing shorts and shooting
portraits in a room with a concrete floor, etc. I agree, and I'll not
do that again. However, I recently took delivery of some new
monolights (from Calumet) and they do not exhibit this voltage
problem.

-John

"Ken Hart" wrote in message ...

Do the strobes have a plug with one prong slightly wider than the other?
Does the outlet also have one slot larger than the other? The larger slot
should be at earth ground potential (get the voltmeter back out!). If not,
your outlets are wired backwards, and could cause similar problems with
other devices plugged in these outlets, particularly those with a wide
prong. ("polarized plug")

Ken Hart

Ken, good points, but I thought of them. These lights use a polarized,
grounded (3-pin) power plug. I've checked the studio wiring and there
is zero potential between return and ground. I wanted to be certain of
all these things before posting something about these lights being
dangerous.

-John

According to RSD99 :
Sounds very much like someone used a three-wire to two wire AC
adapter ... and left the ground wire on the strobe floating ... ?

That might be the case, but a ground is only meant as an emergency outlet for
power to flow. No hardware in this environment should run that much power
through the ground on a regular basis.

--
eth'nT
http://www.hydrous.net
aim: courtarro

"Ethan Trewhitt" wrote in message
...

According to RSD99 :
Sounds very much like someone used a three-wire to two wire AC
adapter ... and left the ground wire on the strobe floating ... ?

That might be the case, but a ground is only meant as an emergency outlet
for
power to flow. No hardware in this environment should run that much power
through the ground on a regular basis.

You were talking about voltage, not power. We don't know anything about how
much power is involved.

Recently, Andrew Koenig posted:

"Ethan Trewhitt" wrote in message
...

According to RSD99 :
Sounds very much like someone used a three-wire to two wire AC
adapter ... and left the ground wire on the strobe floating ... ?

That might be the case, but a ground is only meant as an emergency
outlet for power to flow. No hardware in this environment should run
that much power through the ground on a regular basis.

You were talking about voltage, not power. We don't know anything
about how much power is involved.

Technically correct, but what difference does it make to the point at
hand? Obviously, there was sufficient current power involved to be of
concern. The original post was not about the kind of "gentle tingly"
effect that one can get from the induced current passing to ground through
you when touching table lamps and such.

Neil