Electricity shock from Hasselblad Camera, tethered

[orc73]

Hi

I'm getting electricity from the camera body, fingers and feed burning.
I experienced it on two shootings. In both I was at a higher point in the studio to shoot from above.
I was very strong yesterday, almost had to drop the camera. I could not have been shooting this way. The assistant was so friendly to give me his rubber flip flops, which solved the problem(if I wouldn't touch something else with my body).
First time was on a macbook pro 2012, yesterday on a new imac from the studio I shot. Both with the original firewire cable and with the firewire to thunderbold adapter(yesterday I used the studios adapter).
This happened also with the iphone connected to usb, which I connected to the studios imac yesterday.

best regards

[MrSmith]

Were you using a sync lead direct to flash pack? If so try a radio trigger?

[orc73]

no it was with Pocketwizards once, the other time with Elinchrom Trigger

[jerome_m]

You are telling us that two devices (camera and phone) connected to the mac computer gave you shocks. You are also telling us that it happened with two different mac computers. Therefore, the only thing that is common between these incidents is the plug the computers were connected to.

It seems that your house wiring should be checked.

[ErikKaffehr]

That situation could arise if the devices are connected to different outlets.

Best regards
Erik

You are telling us that two devices (camera and phone) connected to the mac computer gave you shocks. You are also telling us that it happened with two different mac computers. Therefore, the only thing that is common between these incidents is the plug the computers were connected to.

It seems that your house wiring should be checked.

[eronald]

I'd suspect the power outlets. In the best case it's just bad grounding of the camera or Mac, or a lack of grounding on the outlet, and you're getting some leakage. This is a nuisance but not really dangerous. In the worst case it's a bad ground in the whole studio, and if there were a short circuit of a power phase to ground elsewhere in the studio you can be set up for a dangerous ground loop with all the "grounded" metal casings of your equipment going hard-live. I'm probably talking out of my ass, but I suspect this scenario could kill you. Reality is probably somewhere between these extremes.

Of course, I'm just making this up as I type, someone who knows about power engineering will probably have a smarter opinion.


Edmund

[orc73]

It actually was is in two different studios.
Not really concerned it would kill me, though try to shoot with a camera that is "burning" in your hands.
If it is grounding issue, how can I solve it? And funny if i stayed on same hight level as the computers, its not an issue. Only if I go up. And I had to go up.

[jerome_m]

It actually was is in two different studios.

Then exchange the cable connecting the computer to the power outlet and any adapter you normally use with your computer and brought with you in the other studio. If this does not solve your problem, have your computer checked.

[Jim Kasson]

It actually was is in two different studios.
Not really concerned it would kill me, though try to shoot with a camera that is "burning" in your hands.
If it is grounding issue, how can I solve it? And funny if i stayed on same hight level as the computers, its not an issue. Only if I go up. And I had to go up.

Electromagnetic induction affecting whatever you were standing on? Why don't you get a voltmeter and probe for differences between camera case voltage and the voltage of whatever you're standing on? I'm assuming its a conductor or the flipflops wouldn't have made a difference. The different studios issue is confounding, by measuring electrical potential differnces with a voltmeter should help you track it down. Keep in mind that the voltage could be ac, dc, or both.

Jim

Jim

[EricWHiss]

There isn't enough voltage in the tethering cable from the computer to cause a shock normally.  Also odd is that the problem occurred only when you went up.  Was your ladder leaning on any conduit or wires or touching any walls?  I assume that since the flip flops help you, that the ladder or support you went on is metal and part of the electrical path that is problematic.

[orc73]

It was a stair in both locations, and yes they have metal.
I dont need a volt meter, i can feel it burning. It happens in different locations, different computers, different computer cables, different thunderbolt adapter,same camera, same firewire cable.

I assume only identical parts can responsible, camera probably being the one as the one.

[jerome_m]

Neither the firewire cable nor the Hasselblad could carry voltage over 12V if the computer /mains supply were working properly. Therefore, the computer or mains supply are not working properly. The voltage must come from somewhere. The camera battery is certainly not delivering 110V. The firewire specs do not see that this interface should deliver 110V. So where is the 110V coming from, uh?

[Jim Kasson]

Neither the firewire cable nor the Hasselblad could carry voltage over 12V if the computer /mains supply were working properly. Therefore, the computer or mains supply are not working properly. The voltage must come from somewhere. The camera battery is certainly not delivering 110V. The firewire specs do not see that this interface should deliver 110V. So where is the 110V coming from, uh?

Right, except he doesn't know whether it's 110v or not. He doesn't even know if it's ac or not.

Jim

[EricWHiss]

I've seen buildings where the hot and return lines were reversed at the circuit breaker box. This can cause things that are normally grounded to have a potential. Reversed wiring is easily tested for with one of the plug in testers sold at hardware stores.

When I went to UC Berkeley, my cheap landlord got tired of having blown fuses in the building and instead of upgrading the old electrical wiring and service from the pathetic 60amps (for 4 units) he replaced the fuses with short sections of copper pipe.   This worked for about a year until the copper got oxidized. After that the pipe would thermal cycle with load and change dimension and have varied resistance.  I could watch the lights dim and get bright.  One day some of my appliances and light bulbs burnt out.  I put in a voltmeter to the wall and saw that the voltage which is normally about 117VAC was ranging between 80VAC and 180VAC.  That's when I discovered the pipe in the fuse box.  The return or neutral side pipe had collapsed and lost contact and therefore there was no path for the electricity in the building wires to ground. Some appliances were 220 v which brought both hot legs together and this is what made up the over voltage.   Very dangerous situation.   PG&E red tagged the building and he had to fix everything and pay all the renters for the burnt out appliances.  These days most transformers are world ready meaning they can accommodate the range of 110-220 but then in the 90's only a few were.

Anyhow for the OP, I'd check the building mains…   I can't imagine getting a shock from the camera or notebook as neither has enough voltage to give you a shock.

[jerome_m]

Right, except he doesn't know whether it's 110v or not. He doesn't even know if it's ac or not

If one feels a shock, it is more than the 12V than the thunderbolt to firewire adapter delivers.

[orc73]

I'm not at a power plant.my home and most of the studios.
Does it matter? my camera is connected to the computer, not in the power plug.
And of course it is not the hasselblad battery, as written above it only happens tethered, it only happens when I move up 2-3meters, not always, sometimes stronger, sometimes less.

[jerome_m]

When I went to UC Berkeley, my cheap landlord got tired of having blown fuses in the building and instead of upgrading the old electrical wiring and service from the pathetic 60amps (for 4 units) he replaced the fuses with short sections of copper pipe.   This worked for about a year until the copper got oxidized. After that the pipe would thermal cycle with load and change dimension and have varied resistance.  I could watch the lights dim and get bright.  One day some of my appliances and light bulbs burnt out.  I put in a voltmeter to the wall and saw that the voltage which is normally about 117VAC was ranging between 80VAC and 180VAC.  That's when I discovered the pipe in the fuse box.  The return or neutral side pipe had collapsed and lost contact and therefore there was no path for the electricity in the building wires to ground. Some appliances were 220 v which brought both hot legs together and this is what made up the over voltage.   Very dangerous situation.   PG&E red tagged the building and he had to fix everything and pay all the renters for the burnt out appliances.  These days most transformers are world ready meaning they can accommodate the range of 110-220 but then in the 90's only a few were.

What you are describing would only be possible in countries using the same power distribution systems as the USA. In France, for example, you would not be able to dispense with neutral (using the ground for return), it would immediately trip the main switch. Also: reverse-phase 220V power only exists in some 110V countries, like the USA. In Europe, mostly, we only have single phase 220V and tri-phase power supply (the later being only common in some countries like Germany).

Why am I writing this? I don't intend to make a discourse about power distribution on a photo forum, obviously. I just want to point out that we do not know where orc73 lives, so we should not assume he is using the power distribution system we are used to.

This being said: if the camera is hot, there is either something wrong with the computer or with the mains power. It simply cannot happen via a firewire connection that conforms to specs.

[orc73]

well how do you define shock, definitely it's burning strong enough that I can not hold the camera. It's not that my hair goes up.
I don't know how 12v feel.
I only know how electric fence feels  for the sheeps and that is a pulsating power fed by a car battery.

[jerome_m]

I don't know how 12v feel.

You would not feel anything with 12V.

I only know how electric fence feels  for the sheeps and that is a pulsating power fed by a car battery.

There is a device between that car battery and the fence that makes sure the fence is energised with considerably more than 12V so that the sheep feels the fence.

[orc73]

I'm on a job in Thailand actualy. 220v. the buildings are of different age.
As far as I know between the laptop and the power plug, the apple charger has a transformer. So I don't understand why it matters.
But then I'm a photographer and not and a power pro.