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stinger??


Guest oscar

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Guest oscar

I have got this list from a DP and he asks for availability of a "Stinger" ( this is supposed to be on the electrical side of the job ) any Ideas what might a Stinger be?????

Thank you very much indeed

Oscar

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And typically heavy gauge cords with the heavy-duty connections, 25 and 50' lengths. Ordinary hardware store orange extension cords aren't actually stingers, although crews just ask for a stinger when they need an extension cord!

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Hi,

 

Set electrics in the US scare me. You guys don't seem to use the big chunky plastic CEEform connectors we do - the ones that are blue for 240V and red for three-phase 415. They're waterproof and practically tank-driving-over proof, and I rather like them. The use of tinfoil US domestic mains connectors always scares the hell out of me - could they possibly be any more feeble?

 

Phil

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To be a little more thorough, Stingers are 12/3 (12 gauge 3 wire) extension cords. The 3 wires consist of a Hot a Neutral and a Ground. They commonly come in lengths of 25' and 50' and occasionally 100'. The cable itself has an ampacity rating of 20a while the Edison's or electrical connectors are rated for 15a. As Mr. Nash mentioned these are not the orange or yellow extension cords (commonly 16/3 cabling) found at Home Depot, nor are they common cheap Zip cord. Just remember that when you are done with a Stinger to never wrap it over-under...

 

The use of tinfoil US domestic mains connectors always scares the hell out of me

 

Phil, could you explain that a little further for me? I've given that a little thought and I'm still unsure to what you are referring.

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Phil, in the US the voltage is 208/120V/60Hz; in the Czech Republic it is 380/220/50Hz. In rest of Europe it may be similar. 120V is a lot safer than 220V or 240V; that's why less concern for safety. Still some of the 120V plugs and receptacles used, with the flat prongs are ridiculous and many times you can't even get a contact in a residential extension cord. Plus babies pull these out of the wall and get shocked all the time. Scarry. Joe

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120V is a lot safer than 220V or 240V; that's why less concern for safety.

This may come as little surprise to the faithful around here but someone (read: ME) is yet again in the position to correct one of the baneful and erroneous posts made by UD.

 

In terms of safety versus electrocution Voltage plays a smaller role than that of frequency and amperage. The frequency of human nerve signals that control the heart travel at approximately 60Hz, the same frequency as the standard U.S. electrical system - 120 Vac 60Hz. Thus it is far easier to undergo ventricular fibrillation and possibly die under this form of electricity as it corrupts the natural nerve impulses that regulate normal heart rhythm.

 

To further complicate matters it takes an average of 60 to 100 milliamps to kill an adult male. This is regardless of the origination of the alternating current and natural frequency of the power source. ALL electricity is dangerous and all current professional electrical systems have a high degree of inherent safety but it is not an excuse to be lazy or ignorant whilst using it. Stupidity kills far more than electrons.

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I was never taught NOT to over-under a stinger... why shouldn't we do this? the answer is probably pretty obvious, but I can't quite pinpoint it.

 

Thanks....

 

-felipe

 

PS - I like his site quite a bit, I felt cinematographer.com lost some jazz when it changed its format... and this is pretty refreshing, i like the articles.

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FELIPE! It's been a long time, good to see you again!

 

There are two reasons to never wrap a stinger with the over-under method. The first is that all 12/3 cable is coiled internally with a clockwise twist. If you coil 12/3 cable over-under you will untrain the natural internal coil of the cable and cause it to kink internally and possibly break. This will also make the cable "untrainable" and very difficult to properly wrap in the future.

 

The second is that if you try to run a cable that has been wrapped over-under it will coil and twist into an ungainly mess. You would need to stretch out the entirety of the cable and whip the kinks out before you could run it. If not done, when you grab a free end to run it will typically tangle and knot.

 

All power cables should be wrapped in a clockwise over-over motion, just like wrapping a garden hose. AFAIK the only cable that is supposed to be wrapped over-under is an XLR.

 

It's good to have you aboard little warrior, keep on rockin' in the free world. B)

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Hi,

 

Two things. First, I'm not aware of any cable type whose natural lay won't be wrecked by forcible over-the-arm coiling - it's just about the only thing that makes me yell "Hey!" on set.

 

Second:

 

> In terms of safety versus electrocution Voltage plays a smaller role than that of

> frequency and amperage.

 

True-ish, but then at higher voltage it's easier to push enough current across a human body to be dangerous. In any case, the general rule of thumb is "thirty mills kills," or 30mA across the heart is sufficient to cause fibrillation, and it's so easy to end up with 30mA flowing at either 120 or 240V that it's largely irrelevant.

 

Mains is potentially lethal either way.

 

As for my opinion on US mains connectors - they're just flimsy. UK mains connectors are much nicer!

 

Phil

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Correcting the erroneous statements. And I'm very familiar with this because we had someone electrocuted on a set and court experts were involved.

 

220V/50Hz is a lot more dangerous than 120V/60Hz. The difference in frequency is of little significance.

 

100 mA is about the borderline current that will kill you. The current path is important. Less current (e.g. 50 miliamps) may kill you; a lot higher current may not kill you. It all depends if the main current path goes trough heart.

 

The available curent from house or studio power installation is very high. The actual current depends on resistance of the body which varies on a number of things and the same person may have a quite different resistance at different times of the day.

 

The current passing through the person is determined by Ohm's Law and is proportionally dependent on voltage. So 240V has a 2x the chance of killing you than 120V.

 

If the resistence to the current is extremely low, like during short, we will see kiloamps.

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Incorrect Ultra, firstly you will never see kiloamps from a standard or 3 phase mains supply.

 

To say that 240volts is twice as likely to kill you compared to 120volts is like saying being hit with a 2 tonne car at 100kph is twice as likely to kill you compared to a 1 tonne car at 100kph. Either one can kill you....I told my trade studies lecturer about that comment today & he said its the most totally reckless & silly comment he's heard.

 

Lets say your body resistance is 500ohms at a certain time of the day, at 240volts you'll get 480mA, at 120volts you'll get half obviously, 240mA, both currents will likely kill.

 

Regardless whether its 240volts or 120 volts, if your a bit sweaty & moist, not insulated well from the ground, either one will develop enough current to likely kill you. Hence the need for RCD (Residual Current Device) for safety's sake.

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perthskydiver Posted: Mar 17 2004, 04:20 AM 

 

 

Incorrect Ultra, firstly you will never see kiloamps from a standard or 3 phase mains supply.

..............

Lets say your body resistance is 500ohms at a certain time of the day, at 240volts you'll get 480mA, at 120volts you'll get half obviously, 240mA, both currents will likely kill.

 

 

At the circuit breaker you have available short circuit current in the range of kiloamps. That's why the brekers are rated in kA. 20A CB may have also 10,000 A symmetrical SCA rating.

 

There are also megaamp rated breakers, but not at this type of installation.

 

I know all this becuase I discussed it with an engineer, and a PhD, when an electrician was electrocuted on a set and it became a legal issue. It was my project however our company was not responsible; the electrician did not follow safety rules. His lawyer was asking for a ridiculously high amount.

You've just proved that 240V will produce twice as large current through the body as 120V, Thank you. Only the voltage matters and higher the voltage, higher the current. Higher the current, higher the chance of getting killed.

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You've just proved that 240V will produce twice as large current through the body as 120V, Thank you. Only the voltage matters and higher the voltage, higher the current. Higher the current, higher the chance of getting killed.

WTF???

 

I swear to whatever dark lord you worship that this is tantamount to explaining how a television works to a dog. Why is it that the entirety of your technical mastery comes from people you've talked to and never something you have actually done? I know that you are far short of the intellectual capacity to even understand much less admit defeat so this re-correction is aimed to cleanse the minds of the scant few who may take your black-words as gospel.

 

Set Lighting Technician's Handbook

Second Edition

Harry C. Box 1997 Focal Press ISBN: 0-240-80257-8

 

page 222

 

It is a common misconception that voltage is what kills a shock victim. In truth, high voltage can be dangerous because it has a tendency to arc, but it is the amperage that damages the muscles and the heart.

 

The amperage of a shock is a combination of the current in the circuit and the resistance present. The resistance of dry skin, for example, is about 100,000 Ohm's. This resistance is enough that brief contact with a 100V circuit will allow about 1 milliampere (1mA) or 0.001A, to flow through the body, which is enough to bite you, but not enough to cause damage. In contrast, the resistance of wet skin is about 1,000 Ohm's, which allows about 100mA to flow through the body. This is enough to cause ventricular fibrillation, impede breathing, and cause unconsciousness and probably death. Wearing thick rubber electricians gloves is recommended any time you are exposed to live lugs and cables.

 

AC current can be more deadly than DC current for several reasons. ...AC can freeze a body to a conductor with one fifth as much current as DC. Alternating current can more easily cause fibrillation and cardiac arrest because the 60Hz cycle is a harmonic of the rhythm of the heart and because AC has a peak voltage of 170V, while DC is a constant 120V. However this is not to say that DC power cannot hurt and kill a person.

 

Since you so eloquently misquoted Ohm's Law I will state it here in a proper manner:

 

Amps = Volts divided by Resistance

 

This is one of three ways to express Ohm's Law and it is the one that is pertinent in this case. It is an expression of the natural electrical resistance of a given conductor. In terms of electrocution this amounts to how much electricity is passed through a human body. While obviously Volts play a heavy role in this to say that a native 240V system is twice as likely to kill as 120V is preposterous. These native voltages are so close that when applied to the resistance of dry skin the differences are negligible. Perthskydiver gave a very excellent analogy as to why. Since these voltages are so close in origination you'd damn well better believe that the frequency cycle (Hertz) plays a bigger role in putting a man on the ground and keeping him there than a few extra ergs of voltage. If you are still beating your head against your padded walls see above.

 

As I originally stated ALL electricity can kill. There were even instances of old pacemaker malfunctions that killed patients with a 1.5V DC power cell.

 

When you've actually accomplished something in this industry and your life then perhaps you will have some basis on which to educate. Although I do find that prospect highly dubious. The entirety of your slack-jawed, non-linear, stream-of-consciousness, posts have only shown you to be a person of questionable moral fortitude and in no way an experienced filmmaker or professional. I, like every other member of this board work and persevere in the entertainment industry. My recent posts about electricity are from years of experience, not some winsome conversation with a phantom Ph.D. I have literally repaired and utilized more electrical systems than Hell has souls. What exactly have you done with your life?

 

All in all I think that the most depressing thing about this is the fact that Ultra isn't even intelligent enough to be a decent enemy. So it goes...

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I'm not aware of any cable type whose natural lay won't be wrecked by forcible over-the-arm coiling - it's just about the only thing that makes me yell "Hey!" on set.

Good call, I should have included that in my post. Thanks for the quick save.

 

If I ever hop across the pond I'd like to check out these "superior" UK electrical systems you speak of. The Newcastle Brown is on me. B)

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Guest oscar

Well, thank you all very much for the quick answers, . One safety rule I've always learned is that you should always work as main force with your right hand, specially when you are conecting to a geenie or to a house electrical breakers box. In case of shock, the current will go through the right side of your body directly to the ground fortunately skipping the left side of your body mostly, saving your precious heart!!! this was thought to me by a very good electrician, and is always a rule of thumb for me.

Thank you very much indeed

Oscar

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All in all I think that the most depressing thing about this is the fact that Ultra isn't even intelligent enough to be a decent enemy. So it goes...

 

 

--------------------

 

NOW IT'S DARK

Tony "Chainsaw" Myles

Cage XXI Enterprises

 

Ever heard of ground fault protection? That's what you should use when you plug a chain saw into 120V outlet. Saves lives, especially on outdoor installations.

 

Yes, current kills, but you need voltage first to create current. More voltage, more current. Very simple; high school physics.

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Re: MK Ultra

 

 

:huh: Oh, Bravo sir! Here's a well earned reply that makes only slightly more sense:

 

"It's just like the story of the grasshopper and the octopus. All year long, the grasshopper kept burying acorns for the winter, while the octopus mooched off his girlfriend and watched TV. But then the winter came, and the grasshopper died, and the octopus ate all his acorns. And also he got a racecar. Is any of this getting through to you?"

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Hi.

 

 

 

Its the amps that you should worry about.

This is a similar example to how one would die

in a head on car accident. In that situation its

not the force that would kill you but the sudden

deceleration.

 

Im a c physics student down here at the community college.

 

 

I should know. B)

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My gosh....

PLEASE NO ONE LISTEN TO ULTRA!!!

THE CLAIMS HE MADE THAT 120VOLTS IS MUCH SAFER THAN 240VOLTS IS ABSOLOUTELY REDICULOUS & RECKLESS!! 120 VOLTS IS JUST AS DANGEROUS!!

 

You said your twice as likely to get killed using 240 volts, so countries with 240 volts should in theory have twice the amount of electrocutions than countries with 120 volts, & that definetely is not true. I have had 4 years electrical apprentice training with 7 years post trade, have obtained the A & C class Australian licenses with 3 phase & my electrical contractors license so please dont try to twist my words or correct me as everything I have stated is both factual & from my own personal electrical experience.

 

AGAIN I MUST STRESS, PLEASE NO ONE TAKE NOTICE OF ULTRA'S STUPID & RECKLESS COMMENTS OF 120 VOLTS BEING MUCH SAFER. DO NOT THINK YOU CAN WORK SAFELY ON ANY MAINS SUPPLY BEING IT 120V OR 240V WITHOUT THE CORRECT LICENSE OR EXPERIENCE. GOD FORBID THAT ANYONE LISTENS TO HIS IDIOTIC COMMENTS & ATTEMPTS TO WORK UNEXPERIENCED OR UNQUALIFIED ON A MAINS POWER SUPPLY.

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It's just like the story of the grasshopper and the octopus

 

Hey Chainsaw, That explains. I agree. Joe ;)

 

 

 

Hey Perthskydiver, You have misquoted me. But I agree with you just to end this nonsense. Joe :P

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"120V is a lot safer than 220V or 240V; that's why less concern for safety."

Thats your comment, no misquoting.

 

Without doubt a stupid comment.

 

Without dropping too many hints, maybe you should go play with some 120V, hint-hint, being so safe & all..... :D

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I thought that it was clear that I was talking about less safe plugs in the US. Babies get repeatedly hit by electricity (120V) by pulling out plugs from receptacles. Their little fingers, or even tongue can touch the hot prongs. In Europe, from what I've seen, they have these deep receptacles so the prongs do not get exposed until they are disconnected from current. Also I mentioned the flimsy residential extension cords in the US that sometimes don't even make a contact. I'm in the Czech Republic right now and the plugs and receptacles are hughe compared to the US ones. Small appliences like shavers have narrow plugs but only the tips of the prongs are metal, so again no one can get hit by electricity.

 

Of course both 120V and 240V can kill you, but most of the time it does not, because the current is not high enough. So if the 240V system would produce 2x higher current, of course it is less safe. The higher is the voltage, the stringer are the requirements for protection because the higher the voltage, the higher the current will flow. It's basic high school or college physics. Ohm's law is: current = voltage devided by resistance; and resistance of the body does not change with voltage.

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Two things. First, I'm not aware of any cable type whose natural lay won't be wrecked by forcible over-the-arm coiling - it's just about the only thing that makes me yell "Hey!" on set.

Just to be clear, "over-under" coiling is not the same thing as wrapping a cable around your hand and elbow (if that's what you mean by over-the-arm). Over-under is a little hard to describe in words, but it's kind of like a half twist or roll of the cable with every other loop.

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