Using strobes around water

juggler

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Something I've been thinking about occasionally...

Are flashes safe for use around water, e.g. a model in a pool? It's something I've seen in videos quite often with no specific mention of precautions.
Obviously if they were mains powered you'd need - as a minimum - a high speed RCD (or rather RCCB). But do the capacitors in studio heads or speedlites store enough power to do harm when dropped in water even if disconnected from the mains?
 
Around water or in water? Bit of a difference.
When I'm using my Speedlights when water is likely to be flying about I just throw a cheap plastic food bag over them. Works OK.
Never tried dropping them in water. Can't think they'd be waterproof.
 
Good question.
The capacitors store a massive voltage, but I don't understand the physics to predict how that would travel through water.
 
juggler said:
Are flashes safe for use around water, e.g. a model in a pool? It's something I've seen in videos quite often with no specific mention of precautions.
Click to expand...


I remember @JonathanRyan did (or does) quite a lot with this. His general advice was that if one fell in the water with a model and or photographer in there as well you wouldn't expect anyone in the water to survive. He took precautions accordingly. Hopefully he'll add a little more to this
 
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If we are talking about speedlites…

knowing that electricity is very lazy as it always
looks for the shortest way to the other pole

knowing that the capacitor is holding the charge
— 300+ V but with very little amps

knowing that the poles on a capacitor are some
1 ~1.6 cm apart…

Conclusion: …
––––––––
If a generator is in the chain, the current will go faster
through the wires than the water and the safety switches
will jump.
 
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There's an assignment on Strobist where they used speedlights with wireless triggers inside IP-rated waterproof plastic boxes. I think they hot glued a mount to the box so they could put stands in the pool. I'll see if I can find a link.

Using mains power sounds a bit risky.
 
Kodiak Qc said:
•
If we are talking about speedlites…

knowing that lectricity is very lazy as it always
looks for the shortest way to the other pole

knowing that the capacitor is holding the charge
— 300+ V but with very little amps

knowing that the poles on a capacitor are some
1 ~1.6 cm apart…

Conclusion: …
––––––––
If a generator is in the chain, the current will go faster
through the wires than the water and the safety switches
will jump.
Click to expand...

That rather assumes rather a lot about the electronics, I think. I'd prefer to know whether they've been designed & tested to fail safely.

Alastair said:
There's an assignment on Strobist where they used speedlights with wireless triggers inside IP-rated waterproof plastic boxes. I think they hot glued a mount to the box so they could put stands in the pool. I'll see if I can find a link.

Using mains power sounds a bit risky.
Click to expand...

Thanks for that. IP rated boxes sounds like a good idea, so long as they don't stop heat dissipating.
 
Alastair said:
Using mains power sounds a bit risky.
Click to expand...
•


An american state university along with the state electricity council
presented a blooper where an electric grill was accidentally falling
in a pool with 5 people. The council reassured that all were safe
and a university electric engineer explained why.

I've been searching for the link unsuccessfully yet.
 
Kodiak Qc said:
•


An american state university along with the state electricity council
presented a blooper where an electric grill was accidentally falling
in a pool with 5 people. The council reassured that all were safe
and a university electric engineer explained why.

I've been searching for the link unsuccessfully yet.
Click to expand...

Interesting..

A diver / electronics engineer / photographer friend agrees with this assessment - but will lend me some waterproof flashes anyway.
I'm guessing a mains strobe will be more dangerous - even if protected by an RCCB - 'cos there is a theoretical route to ground.
 
•

The last experience I had with flashes and water was shooting a
pawn of big japenese fish of a wealthy collector and I use my 3x
SB9XX in triple ziplock freezer bags along with their PW remotes.

All went well.
 
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juggler said:
'cos there is a theoretical route to ground.
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•

Yes, but the resistance is much higher than through the wires.
Electricity does not move in water like a shock or sound wave
but like lightning… always searching for the less resistance.
 
Kodiak Qc said:
•

Yes, but the resistance is much higher than through the wires.
Electricity does not move in water like a shock or sound wave
but like lightning… always searching for the less resistance.
Click to expand...

I don't know much about the internals of studio strobes but... suppose only one contact of the capacitor got wet and the other was somehow connected to earth. Then the route to ground *could* be via a model standing in a pool - especially if the water was saline.

Right, I'm going to stop speculating now and wait for some genuine evidence.
 
juggler said:
Then the route to ground *could* be via a model standing in a pool - especially if the water was saline.
Click to expand...
•

knowing that the poles on a capacitor are some
1 ~1.6 cm apart… the capacitor will be completely
discharged before anyone is surprised!
 
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I have an internal defibrillator, and have a vague memory of the surgeon testing it. Not funny. I will politely decline to offer to test:-)
 
MIKEROPHONICS said:
…will politely decline to offer to test:)
Click to expand...
•

Don't worry Mike, as they are not the same technical
approaches nor for the same purpose.

…best to you!
 
Lots and lots and lots of sandbags, and flash packs well, well away from the water, and with excess cable length to the heads.

*in* the water - peli do neat transparent top mini cases, and you can also get transparent dry bags. I'm looking at one for my profoto B1s...
 
For electrocution to occur there has to be a path through the body to ground, and a reason for the electricity to take that path. Since the human body is less conductive than water is, there is really no real risk of electrocution if they are in the water and a flash were to fall in. The only way it would occur is if there was a better path to ground thru a person which was not also present thru water (i.e. holding onto a metal railing which is anchored/buried but not "in" the water).

The risk of shock due to water is due to reducing the resistance of the human body to electricity and providing an "easier" path to ground. That and moisture making a connection that otherwise would not be present.

The biggest risk is the loss of equipment...
 
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boyfalldown said:
I remember @JonathanRyan did (or does) quite a lot with this. His general advice was that if one fell in the water with a model and or photographer in there as well you wouldn't expect anyone in the water to survive. He took precautions accordingly. Hopefully he'll add a little more to this
Click to expand...

Not really. I read an anecdote on the web of somebody being killed this way and I couldn't find anybody I trusted that would 100% guarantee it was a hoax :) I think the risk isn't as high as it looks but I would never be "would you bet your life on it" kind of sure. Sandbags and people holding them FTW.

Speedlights in the water - those plastic sandwich boxes from the pound shop are waterproof. Yes, I've bet a few hundred quid on that being true ;)
 
I used to do a lot of underwater video & the lights I use / used (still have them) make a speed light look like a candle.

These have on occasion flooded.....

I have never been electrocuted by them, although 1 went bang when the remote battery pack exploded whilst clipped to my waist.. This was due to salt water shorting it out - it did get quite warm - lol.

Battery packs in fresh water are a non issue to humans...
 
Alastair said:
Depends on the bath and the plumbing. Metal baths aren't unusual.
Click to expand...
Bare metal baths are... enamel/epoxy doesn't conduct electricity. But metal drains are not uncommon, and they always connect to ground (and therefore, so does the water).

*If* you are between the source (strobe) and the ground point *some* of the current would pass along the skin/into you (due to salts/etc). And it doesn't take much voltage at all (<10ma) to be potentially fatal. Interestingly, pure water doesn't conduct electricity at all.
 
Diving Pete said:
I used to do a lot of underwater video & the lights I use / used (still have them) make a speed light look like a candle.

These have on occasion flooded.....

I have never been electrocuted by them, although 1 went bang when the remote battery pack exploded whilst clipped to my waist.. This was due to salt water shorting it out - it did get quite warm - lol.

Battery packs in fresh water are a non issue to humans...
Click to expand...
Makes sense to me...
They would have to be reasonably "safe" in the event of a seal failure...
 
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