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Guy Holt

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    Gaffer
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    Boston
  • Specialties
    Custom Honda generator systems for motion picture production including paralleling systems with 100A output.

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    http://www.screenlightandgrip.com

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  1. You can use the 1kW Iris lights without flicker. The reason that you get flicker from small filament bulbs (<5kW) is that at high speeds the camera will capture the changing intensity of the light output of the bulb as it rises and falls as the voltage waveform rises and falls. If you use three 1kW Iris where you would normally use one, and put each fixture on a separate phase of the power service, the light output between the three fixtures will be constant as each compensates for the drop in intensity of the other. Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rentals & Sales in Boston
  2. No. It depends on the ballast. I have only been able to do limited testing of HMIs but for example an Arri 4k power factor corrected ballast dumps 16.22mA of current into the EGC while a Power Gems 4k non-power factor corrected ballast dumps only 2.47mA. In order to reduce the amount of RF emitted, UL permits but does not require manufacturers of electronic devices to capacitively couple high frequency harmonic currents to ground (UL1244, UL1950, UL3101.) To accomplish this, some but not all ballast manufacturers include a mains input filter to stop electrical noise from being passed in or out of the ballast via its mains lead. Such filters typically include a pair of small capacitors, one connected between the hot and earth and the other between the neutral and earth wires of the incoming mains. The value of the capacitors is chosen to snub the high frequency noise by shunting it to ground. As such, these RF filters can be a source of appreciable leakage current on the EGC. Arri shunts the noise their ballasts generate while apparently Power Gems does not (use this link for more details.) Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental and Sales in Boston.
  3. Not really supposed to market products on these boards. Contact me off list through message or at rentals@screenlightandgrip.com for details. Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental & Sales in Boston
  4. Let's try this again. Use this link to Shock Stop's marketing material and training guide. Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental and Sales in Boston.
  5. Use this link to Shock Stop’s marketing literature and training guide. Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental and Sales in Boston.
  6. The GFCI outlets on portable generators are not portable. They are hardwired into the generator. UL943 requires open neutral protection of portable GFCIs because they are likely to be used on wiring of questionable integrity that could have an open neutral, such as the temporary power systems of construction sites or the portable power systems of motion picture sets. Where open neutrals with GFCIs can create hazardous conditions UL943 requires portable GFCIs to interrupt power to the load if there is a break in the line side neutral conductor. It is nearly impossible for the neutral conductor of a GFCI hardwired into a generator to break. Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental and Sales in Boston.
  7. Don’t try to power an ARRI 1200 HMI Par with non-pfc electronic ballast with the Voltec. To reduce the amount of RFI emitted into the atmosphere, the ARRI 575/1200 non-pfc electronic ballast shunts the high frequency harmonic currents drawn by the ballast to the EGC. The end result is 16.4mA of leakage current on the EGC that trips unfiltered GFCIs like the Voltec every time. I’m not sure the Guardian LG20 has harmonic filtration (I haven’t found an inline GFCI dongle that does.) I don’t know for certain, but I suspect the Guardian LG20 is a rebranded Southwire Model 25230. They look identical and Southwire sells them unbranded in quantity only. If that is the case, they don’t provide the harmonic filtration required to eliminate nuisance tripping with non-linear loads. Fortunately, where 15- and 20A circuits must be GFCI protected, Section 215.9 of the Code permits the feeder to be GFCI protected instead. Section 215.9 reads as follows: “Feeders shall be permitted to be protected by a ground fault circuit interrupter installed in a readily accessible location in lieu of the provisions for such interrupters as specified in 210.8 and 590.6(A).” Since this section prescriptively identifies feeder GFCI protection “in lieu of” that required in NEC Section 210.8, it permits the use of film GFCIs (like the Shock Block SB100, LifeGuard LG100, and Shock Stop 60-100), with 100A Lunch Boxes to satisfy the Code's requirement for GFCI protection on all single-phase branch circuits of 150V to ground or less, rated 50 amps or less. With a more accommodating trip curve and high frequency filtration, it is better to use a film GFCI just upstream of a 100A Lunch Box, then to use individual GFCI dongles on each 20A circuit of the Lunch Box. Unfortunately you can’t buy the Shock Block SB100, or LifeGuard LG100 (they can only be rented.) Shock Stop, however sells the SS60-100. Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental and Sales in Boston.
  8. Yes, but this is the same company that calls a product (the LG400) that does not meet the NEC definition of a GFCI by that name and promotes the use of it in a manner that does not satisfy the NEC requirement for GFCI protection where prescribed by the Code. It would be great if you could send me that picture. My email address is rentals@screenlightandgrip.com Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental and Sales in Boston.
  9. They also state their LG400 is a GFCI when it clearly is not. Shock Block prevaricates whether their LB100 (also made by AC Power Distribution) conforms to UL943 or UL1640. As I said before, I could be wrong and there is a wall box style GFCI receptacle with open neutral protection. There is only one way to settle this debate definitively. That is for Kyle to take the cover off his Guardian boxes to get the manufacturer and model number of the wall box style GFCI receptacles on the box. A Google search of the part number will tell us if it provides open neutral protection as required by UL943 and by extension the National Electrical Code. Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental and Sales in Boston.
  10. This is a complicated topic because there are three standards that can apply to the ground fault protection equipment we use: UL943, UL943C, and UL1053. As well as a standard for portable power distribution equipment: UL1640. There exists a lot of confusion and misinformation about “GFCIs” because too often manufacturer’s and their representatives conflate these standards, gloss over the differences, and use a single brush to paint everything as a “GFCI” when it is not. The NEC is very precise in its definition of what constitutes a GFCI. The NEC Article 100 definition for a GFCI is: “A device intended for the protection of personnel that functions to de-energize a circuit or portion thereof within an established period of time when a ground-fault current exceeds the values established for a Class A device” An attached informational note states: “Class A ground-fault circuit interrupters trip when the ground-fault current is 6mA or higher and do not trip when the ground-fault current is less than 4mA. For further information, see UL943, Standard for Ground-Fault Circuit Interrupters.” (The bold and underscore are mine) Which is very different than the NEC Article 100 definition for Ground Fault Protection Equipment (GFPE) that must conform to UL1053. Ground Fault Protection Equipment is: “A system intended to provide protection of equipment from damaging line-to-ground fault currents by operating to cause a disconnection mean to open all ungrounded conductors of the faulted circuit. This protection is provided at current levels less than those required to protect conductors from damage through the operation of a supply circuit overcurrent device.” As an example of how manufacturer’s and their representatives play fast and loose with these classifications, take Guardian’s description of their Model LG400 3-phase device rated for up to 400A and up to 480V: “The LG400 is the workhouse of the larger GFCI's! With a total capacity of 1200 amps (400amps a leg) it is the perfect tool to protect those 4/0 cable runs. Larger GFCI's like this are classified as equipment protection. However, Bender was able to utilize the same technology incorporated in the smaller "Class A" devices into a large GFCI. When desired the user can have the trip level changed from 20mA to 5mA to be at the same level of protection available in our smaller devices. The LG400 is also capable of a voltage selection of 480, this is very handle when you need to protect those 480 volt power systems that are more and more common these days.” (the poor grammar is their own.) The LifeGuard LG400 is not a GFCI according to the NEC definition. The NEC Section 100 definition of a GFCI is a “Class A device” as specified by UL943. UL943 defines GFCIs as devices having a fixed trip setting of 5mA (+/- 1mA). Even though it can be set-up to trip “at the same level of protection available in our smaller (Class A) devices”, the Guardian LG 400 is not technically a GFCI because they offer user adjustable trip thresholds. Since they do not meet the complete UL943 standard, they technically do not meet the Code requirement for GFCI protection where prescribed. The LifeGuard LG400 is sometimes erroneously described as a Class C GFCI. It is not a Class C GFCI because the UL943C standard requires a fixed trip threshold of 20mA and ground-connection monitoring not provided by the Guardian LG400. To meet the UL943C standard, a Class C GFCI must automatically disconnect the supply if the load is not properly bonded to ground (the total ground resistance must be less than 38 ohms.) To assure that happens an insulated pilot wire from the device to the load, and a termination device located at the load are required to monitor the load-ground connection – neither of which exist in motion picture applications. Since this monitoring function is required for Class C GFCIs installed in NEC applications, the LifeGuard LG400 is technically not a Class C GFCI either. So clearly the LifeGuard LG400 is not a GFCI regardless of what their website says. If the LifeGuard LG400 is not a GFCI, what are they? I put this question to Nehad El-Sharif, a former engineer in Littelfuse’s industrial GFCI division, and author of many articles on the UL943C standard (Littelfuse is the manufacturer of the Shock Block brand of film GFCIs.) He thought they must conform to a different UL standard than GFCIs, UL1053, making them instead Ground-Fault Protection Equipment (GFPE.) The distinction is important because GFPE uses very different trip parameters than GFCIs. Ground fault protection devices generally fall into four different classifications. To improve the generally poor reliability of early GFCIs, in 2003 UL revised the standard for Class A GFCIs (UL943) to prevent nuisance tripping by transient conditions that are not of a sufficient duration to pose a hazard. The revised standard allowed Class A and subsequently Class C GFCIs to trip on an "Inverse Time Curve." The advantage to an inverse time trip curve is that it permits transient spikes in leakage that are sufficiently short in duration so as not to pose a shock hazard to pass while keeping current through the body to safe levels. UL943 also defines outer limits to the curve. A Class A GFCI must trip within 5.59 seconds if the differential between the current going out on the hot and returning on the neutral exceeds 5mA (+/- 1mA), and 20 ms if it exceeds 300 mA. Class C GFCI’s must operate within the same inverse time curve as Class A devices, except that their operating threshold is 20 mA (non-adjustable). There is a third category of device, Equipment Ground-Fault Protective Devices (EGFPDs) that also operate within the Class-A formula but have a 6- to 100-mA threshold setting range. And finally, Ground-Fault Protection Equipment (GFPE) that must conform to the UL1053 standard. I asked Nehad El-Sharif if high amperage multiphase devices like the LifeGuard LG400 could be EGFPDs and he couldn’t say with certainty but thought not. The distinction is important because GFPE uses very different trip parameters than the inverse time curve of EGFPDs. In UL1053 there is no fixed inverse time trip curve as in UL943. Instead, to conform to the UL1053 standard, the operating time (the time from which the trip threshold is exceeded to the time the circuit is interrupted) depends on the percentage of the current differential relative to the trip threshold. If the ground current is 85% of the trip threshold, the device shall not trip. At 115% of the trip threshold, the device will ultimately trip – there is no set time. At 150% of the trip threshold, the trip time can’t be more than 2 seconds. At 250% of the trip threshold, the trip time can’t be more than 1 second. It could be a lot less than one second, but it can’t be more than 1 second. In other words, under the UL1053 standard the operating time is the same regardless of the trip threshold. Besides using different trip parameters, the operating principle of GFPE is very similar to GFCIs. A sensor comprising a toroid that surrounds the conductors detects the algebraic sum of the current in the live conductors (phases and neutral). In the absence of a ground fault, the algebraic sum of the currents in the conductors is equal to zero and the toroid does not detect any flux. If a fault occurs, the sum is no longer equal to zero and the current difference in the toroid generates a current in the winding. This current is rectified, filtered for high frequency harmonics and amplified. If the resulting signal is greater than the user adjustable threshold (usually between 10 and 30mA), a time delay is initiated (it may be equal to zero for an almost instantaneous response or prolonged for a delayed response). If the fault is still present at the end of the time delay, an opening order is issued to a control device (usually a breaker rather than a contactor as in the case of most GFCIs.) Since this is consistent with Guardian’s description of their LG400, it is likely a GFPE rather than a GFCI. But because Guardian conflates these different standards and refers to all their devices as GFCIs, regardless whether they meet the NEC definition or not, it is not clear whether the LG400 is an EGFPD or GFPE. The Shock Stop 400D, with Bender RCM420 residual current monitor, is clearly a GFPE. Like the Guardian LG400, the Shock Stop 400D is a 3-phase device rated for up to 400A with adjustable trip thresholds. Rather than use the maximum operating time allowed by UL1053, the RCM420 uses a more aggressive trip curve, similar to that used in European RCDs (1 x ID ≤ 180ms, 5 x ID ≤ 30ms, where ID is the trip threshold.) As such, the operating time of the SS400D is very short in comparison to the UL943 curve. For instance, a SS400D set for a trip threshold of 10mA must trip within 180ms at 10mA, compared to approximately 4 seconds required by the UL943 curve. This more aggressive trip curve makes it possible for the user to program a time delay yet still fall within safe limits (superimposing the time-current characteristic curves for the SS400D with thresholds 10, 30 and 100 mA over the safety curves published in IEC 60479-1:” Effects of current on human beings and livestock” clearly illustrates this.) And, since user handled loads statistically account for most shocks, a time delayed GFPE, like the SS400D, can provide adequate ground fault protection for personnel if set up properly, given the low touch voltages involved in a solidly grounded 120/208V service (ungrounded (two prong) systems require Class A protection). How does this relate to Kyle Perritt’s lunchbox? It establishes that manufacturers and their representatives play fast and loose with UL classifications in their marketing material. Sometimes what they don’t say is as revealing as what they do say. For example, the Shock Block marketing literature for their 100A GFCI with Bates Connectors (model SB100) clearly states that it is “UL Listed per UL 943 Class A”. In contrast their marketing literature for their GFCI Lunchbox (model LB100), which is also made by AC Power Distribution, simply states that it is “UL listed” without specifying to which standard. Is this because it is not listed to UL943 as is the SB100? What UL standard could it be listed to if not UL943? AC Power Distribution boxes are UL listed, but to Standard 1640 – the standard for portable power distribution equipment. The requirements of UL1640 pertain to protection against contact with live conductors and placement of breakers and not ground fault protection with GFCIs. Under UL1640, GFCIs can be incorporated into portable power distribution equipment as “supplemental devices” without changing its classification. Given that I can’t find a wall box style GFCI receptacle like those found on the AC Power Distribution, Guardian, and Shock Block GFCI Lunchboxes that has open neutral protection, leads me to believe the only UL standard these boxes conform to is UL1640. I could be wrong and there is a wall box style GFCI receptacle with open neutral protection. There is only one way to settle this debate definitively. That is for Kyle to take the cover off his Guardian boxes to get the manufacturer and part number of the wall box style GFCI receptacle. A Google search of the part number will tell us if it provides open neutral protection as required by UL943 and by extension the National Electrical Code. Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental and Sales in Boston.
  11. This is a good case in point why electrical distribution should be left to qualified persons. As you may recall from my post above, NEC Article 530 requires that an individual using portable lighting and power distribution equipment know how to comply with NEC safety rules when performing installations. The NEC Section 100 definition of a GFCI is a “Class A device” as specified by UL943. Among UL943’s many requirements is that portable GFCIs trip if there is a break in the line side neutral conductor of a circuit. It does not require the same of GFCIs meant to be permanently installed in a wall outlet box. Since the GFCI Lunch Boxes you bought from Kayelites incorporate wall box style GFCIs without open neutral protection they do not meet the code requirement for the use of portable GFCIs outdoors. (For the same reason Phil’s shop made RCD boxes would not pass US code.) A qualified person, trained in ground fault protection, would know the difference between GFCIs suitable for portable use and permanent installation. The same is true of OSHA. OSHA29 CFR 1926.404(b)(1)(i) states: “The employer shall use either ground fault circuit interrupters as specified in paragraph (b)(1)(ii) of this section or an assured equipment grounding conductor program as specified in paragraph (b)(1)(iii) of this section to protect employees on work sites . . .” Under §1926.404(b)(1)(ii), when using GFCIs to comply with paragraph (b)(1)(i), the employer must use an "approved" GFCI. Under §1926.449, approved equipment is equipment that is "acceptable." Section 1926.449(a) defines acceptable equipment as follows: “(a) If it is accepted, or certified, or listed, or labeled, or otherwise determined to be safe by a qualified testing laboratory (like UL) capable of determining the suitability of materials and equipment for installation and use in accordance with this standard…” As I mentioned previously, UL requires portable GFCIs to offer protection against an open-neutral condition. Why the different requirements for portable vs. permanently installed GFCIs? Since portable GFCIs are likely to be used on wiring of questionable integrity, such as the temporary power systems of construction sites or the portable power systems of motion picture sets, UL943 requires portable GFCIs to interrupt power to the load if there is a break in the line side neutral conductor. Given the wear and tear equipment receives in these environments, it is more likely that one of the circuit conductors could be broken on the supply side of the GFCI. If it is the energized, or Hot, conductor that is broken, no hazard exists at the GFCI, and it is readily obvious because there is no power. If, however, it is the grounded circuit conductor, or neutral, that is broken on the line side of the GFCI, it is less obvious. The line voltage terminals would still be energized. The only indication of an open neutral would be that a load plugged into the circuit doesn’t turn on. Since the brain of the GFCI relies on a complete circuit in order to operate, under this circumstance the GFCI would not trip if there were a ground fault on its load side. Of course, the problem would be detected if the unit were tested with the test button before each use as required by Code, but we know that precaution is seldom taken. It is because of this possible hazard that UL943 requires that the load terminals of portable GFCIs must be de-energized when the neutral is interrupted on the line side of the device. Portable GFCIs accomplish this by using “NO”, or normally open, relays rather than the more common “NC”, or normally closed, relays. With NO relays power must be complete to the relay in order for the contacts to be closed. If there is no power, such as from an open neutral, the relay contacts are opened by spring pressure. Power is necessary to overcome the spring pressure, closing the contacts. Sorry to say that your GFCI Lunchbox is not a UL approved Class A GFCI and therefore does not meet Code where a Class A GFCI is required. Guy Holt, Gaffer, ScreenLight & Grip, Lighting equipment rental and sales in Boston
  12. The problem with this type of industrial GFCI is that they are prone to nuisance tripping with HMIs, Kinos, & LEDs. To improve the generally poor reliability of early GFCIs, in 2013 UL revised the standard for GFCIs to allow them to trip on an “inverse time” curve. An inverse time curve introduces a delay that decreases as the magnitude of the current increases. The advantage to an inverse time trip curve is that it permits a transient imbalance that is sufficiently short in duration so as not to pose a danger to pass while keeping current through the body to safe levels. To assure the latter, UL943 requires that as fault current increases the maximum allowable time to open a circuit decreases, with an almost instantaneous response time required (no more than 20 milliseconds) if the fault current is greater than 300 mA compared to 5.59 seconds at 6 mA. In other words, the higher the current, the faster the GFCI must trip. The advantage of UL943’s trip curve is that it minimizes nuisance tripping from surges in residual current while providing protection from shocks. The manufacturers of industrial GFCIs like these choose not to use the more accommodating UL943 safety curve because it requires sophisticated microprocessors, which makes their product more expensive. Instead, they use a more aggressive response that is lower and faster than that required by UL943 (typically 250ms at 6mA where UL943 permits 5.59 seconds at 6mA.) The more aggressive response of these GFCIs is permissible because the UL943 standard is the absolute highest current vs. time response allowed but it is not mandatory. That is, a device will fail UL testing if it responds slower than the standard requires; but will pass if the response time is less than the standard requires, even if it is a lot less. While the more aggressive trip curve of industrial GFCIs does not generally pose a problem in the one-tool-per-circuit application for which they are designed, it has proven to be a problem in electrically noisy environments like motion picture production. “Film” GFCIs, like LifeGuards, Shock Blocks, and Shock Stops use sophisticated (read expensive) micro-processors to trip more closely to the UL inverse time curve and so are more forgiving of transient surges caused by switching on other lights, which greatly reduces nuisance tripping. Industrial GFCIs like these are also prone to nuisance tripping with lighting loads because they do not filter out harmonic currents. Non-linear lighting loads (HMIs, Kinos, & LEDs – the predominant loads these days) by design leak a small amount of harmonic current to the equipment grounding conductor called ‘residual current.” If the GFCI does not incorporate filtration of harmonic currents (most all industrial GFCIs do not), these residual currents will nuisance trip the GFCI. For that reason, it is important to use “film” GFCIs that incorporate low band pass filters to filter residual currents (the GFCIs you get at hardware stores do not because they make the GFCI even more expensive.) Use this link for more details. Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental & Sales in Boston
  13. Without meters you are tethered to the camera and the camera can be a real bottleneck when it comes to each department of a production (Electric, Grip, Camera, Wardrobe, Make Up, Set Dec, etc.) having to accomplish what they have to accomplish before the camera can role again. The value of meters, and knowing how to use them, is that they provide you the information you need to light a scene in your mind's eye and then translate that to reality. Rob Draper, when he was teaching at the Maine Film Workshops, used to call it the Zen of Cinematography and tell this story about how he works. He said he would always plot the lighting for a scene in advance on paper – specifying every detail down to the FC candle output from each instrument. This allowed him to pass off to his Gaffer all the details he needed when he arrived on set. Rob would then go off to craft service to get a cup of coffee. By the time he finished saying good morning to everyone (client relations are very important for a DP), and got back to the set, the lights were starting to come up. With a cup of coffee in hand, he possessed a clarity of mind that enabled him to now take the lighting to the next level. He found time within time to address the finer nuances of shading and color: the Zen of cinematography. This is what you lose when you tether yourself to the camera. The old school method was that the DP would choose the camera stop, which would establish the Key Tone - say T5.6 for deep focus. Having chosen his exposure he can then calculate how many Foot Candles (FC) he needs on different elements of the scene. To figure out how many FC you need for exposure, all you need to know is that it takes 100 FC to get an exposure of 2.8 with an ISO 100 film with a 180 degree shutter at 24 FPS (1/50th of a second shutter speed.) If your digital camera is 2 stops faster than an ISO 100 film, you will need 100 FC to get a stop of 5.6. Once you know how many FC you need for exposure you can simply calculate how many FC will give you the effect you see in your mind’s eye. Of course, it helps to have done a lighting test of what effect over and underexposing a subject will give. Such a lighting test for talent (you may also want to do one for key props or sets) would consist of testing in a systematic fashion the effect of Key, Fill, Back Light, Kickers, Hair Lights, and Liners that are over and under exposure. For example, to test the effect of your key light on flesh tones, set your exposure with two doubles and a single in your key light. Then remove them a half stop at a time (without changing your camera exposure setting or exposure of the chip chart), and systematically note on a slate in the frame what you are doing. Once you have removed all the scrims, your flesh tone will be two and a half stops over exposed (since you have not changed the camera setting.) Put all the scrims back in and now, using single and double nets, systematically under expose the flesh tone in half stop increments (remember rotating a net relative to the light source will make it "fatter" or "thinner", which will enable you to "dial in" the exact level you want from the light.) If you want to play on the lower register continue to under expose the flesh tone until it becomes a pure silhouette. Do the same for Fill, Back Light, Kickers, Hair Lights, and Liners in isolation and in specific combinations that you plan to use them. Having systematically tested each light, you can now see the effect that different ratios of each has on the scene and can even use the test as a reference on set when lighting the scene. An example of this type of pre-visualization would be say you are shooting a couple conversing at a bar. After working through in your minds eye that you want a low-key look with selective (shallow) focus you might settle on a stop of 2.8. Say the script calls for the guy to be somewhat mysterious and distant and the women to be very open and receptive, then you may choose to keep him in deep shadow with just enough of a liner to separate him from the subdued background of the bar. This type of lighting on him could be motivated by a practical fixture you establish behind him, which would be consistent with the more frontal key you want for her, since you would want to light her more frontally so that her character is clearly apparent, but not him to retain some mystery to his character. Having roughed out your style and light placement you can begin to set your levels and balance your lights based on lighting tests you have shot over the years. For instance, if your camera is two stops faster than an ISO 100 film, you will need 24 FC to properly expose your key tone (mid gray) at a T Stop of 2.8. 24 FC would then give you a “properly” exposed flesh tone on her. But this is a bar with subdued lighting, so you don’t want full exposure on her. You liked the feel of a half key (1 stop under) in your lighting tests so you would light her with 12 FC from a high frontal key. Again, because the scene takes place in the subdued lighting of a bar, you don’t want to over fill her. Going back to your lighting tests you like the look and feel of an 4:1 key to fill ratio so you would give no more than 3FC of fill light. You need to separate her from the dark background of the bar and so you might give her a backlight of 6 FC because that's what looked appropriate in the lighting tests to separate her hair color from a dark background without looking over-lit. You would want to make sure you flag her backlight off him since you want to play him in near silhouette and so have to keep any frontal light on him to under 1 FC because four stops under exposure was a near silhouette with just the right amount of detail in the lighting test. For the liner to separate him from the dark background of the bar you will need a fairly strong fixture capable of delivering 48FC from directly behind him since your lighting tests established you need to be at least a stop over exposure for the liner to read. Once you have figured out how many FC you need for the effect (a liner in this case) you can figure out which lights will give you that using the photo-metrics that manufacturers provide on their websites, or you can download Arri’s handy photometric calculator (be wary of the photo-metrics given for LED lights.) With a little experience you begin to develop a feel what light will give you what you need in different situations. You wouldn’t want to try to use the practical fixture that you are flying in behind him to motivate this lighting scheme as the source for the liner on him because, first of all it’s placement in the shot may not be far enough around his back to serve as a liner. But, also to deliver 48 FC on him, it would be screaming hot in the shot. For this reason it is better to use a separate light to light your talent and treat the practical so that it looks realistic in the shot. I find that practical lamps never look convincing unless one treats the lampshade as well as boost the bulb wattage. Unless it is completely opaque, you typically need to treat the shade to keep it from burning out (remember stopping down to keep it from blowing out will throw off the balance you have set with your other lights) You can put a lower wattage lamp in it, but then the output of the practical on the bar will look rather anemic. I find you get a more realistic look if you boost the wattage of the bulb and line the inside of the shade with ND gel. It is a delicate balance to achieve. You can achieve this balance without a monitor, by using the old school method with incident and spot meters and a selection of practical bulbs including PH 211, 212, and 213 bulbs. Years ago Walter Lassaley, BSC, instructed me to balance practical’s such that an incident reading of the direct output one foot away from the bulb is one stop over exposure which in this case would be 48 FC. I have found that rule of thumb gives a realistic output to the practical. After establishing the practical’s output using an incident meter, you then use a spot meter to determine how dense an ND gel is needed to line the inside of the glass shade. You can do all of this pre-visualization, setting of levels, and balancing based upon a location scout, blocking with stand-ins, and your lighting tests. In other words, almost everything can be worked out ahead of time so that when you arrive on set you know exactly what you need to do. This is especially helpful on low budget projects since, generally the time spent with minimal crew in scouting and blocking with stand-ins, is considerably less than the time wasted working these things out on set with a large crew and principle talent. Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental & Sales in Boston
  14. American Grip makes a 4x4 frame on which you can mount 16 1x1 mirrors on their mirror holders. This rig will allow you to redirect the output of the M18 in 16 different directions, so that you can aim light to each opening in the curtains. Another approach I have used in situations like this is to use a convex mirror like those used to see around corners. The convex of the surface spreads the light while maintaining its hard quality. Guy Holt, Gaffer, ScreenLight & Grip, Lighting rentals and sales in Boston
  15. That about sums it up, and I haven’t even got into half of it. For example, Massachusetts now requires GFCIs on outdoor set lighting of 150 V or less, and 50 A or less (Section 210.8 (B)(4)). Whereas the City of Los Angeles, where much production takes place, exempts outdoor sets from the requirement for ground-fault protection with GFCIs. How two AHJs, on opposite sides of the country, can come to opposing positions says a lot about the nature of the Code. Let’s explore how it came to this, its ramifications for the distribution of power on set, and what we can do about it. The benefit of using GFCIs is indisputable. According to research done by the National Electrical Manufacturers Association, household electrocutions have fallen in proportion to the number of GFCIs being used from 1976 to 2001. So, it was inevitable that during the 2020 Code review cycle, there would be a general agreement among Code panel members that GFCIs should be used more widely. A spate of electrocution accidents—a child in Oklahoma retrieving a pet from behind a clothes dryer, a 10-year-old Houston boy playing hide-and-seek, a 12-year-old in Chicago being electrocuted when he touched an AC condenser unit with an electrical fault—sealed the deal resulting in the 2020 Code setting a higher standard across more areas of the Code. For instance, Section 210.8(B)(4) now requires GFCI protection for all outdoor outlets supplied by branch circuits rated 150 V to ground or less, 50 A or less. This update extends the GFCI requirement to include all fixed or portable power connections outdoors—even hard-wired equipment outdoors, like AC compressors. Since there are no readily available dimmer rated Class A GFCIs, Code Panel 15 (which includes mainly LA entertainment industry representatives), sought and was granted an exemption to Section 210.8 in Article 530, motion Picture and television Studios and Similar Locations. This exemption would be good news for us if not for the fact that Article 530, is widely interpreted by AHJs outside California to mean that it does not pertain to location filming. Section 530.2 defines a “Motion Picture Studio” as: “A building or group of buildings and other structures designed, constructed, or permanently altered for use by the entertainment industry for the purpose of motion picture or television production.” And a “Shooting Location” as: “A place outside a motion picture studio where a production or part of it is filmed or recorded.” So, by definition they are not the same occupancy. Many AHJs take this to mean that the exemption to Section 210.8 permitted by Article 530 does not extend outside the confines of a stage. LA County, by comparison, extends the Article 530 exemption to include location filming outdoors. that’s because the AHJs in California interpret the intent of the Code so that obtaining a location permit temporarily changes the occupancy of a location to a “motion picture studio.” This simple provision accommodates a local industry while keeping the Code in force generally. Why not grant the LA film industry an exemption? With an average annual rainfall of only 14", the likelihood of receiving a lethal electrical shock while working outdoors is much lower in Los Angeles than it is in Massachusetts where the average annual rainfall is three times greater (43"). This is just one example, of many across the country, of an AHJ modifying the code to suit the needs of a local industry. So, despite its authoritative position and having “National” in its title, NEC standards are merely a template local governments use to create and enforce their own electrical code that meets their own needs. This leaves us here in Massachusetts with a problem: Section 210.8(4)(B)) applies to outdoor location filming—not only to craftie and video-village, but also to small cord set lighting as well. Unless the Code is revised, our dilemma will eventually become your dilemma as the 2020 Code is adopted by more states and municipalities across the country. Aware of the potential downside for motion picture production across the country, an industry trade group has formed to advise Code Panel 15 to make explicit in the 2023 Code that Article 530 exemptions extend to production on location as well as in the studio, but until then we are stuck with this Article 210 requirement to use GFCIs on small cords outdoors. This presents set lighting technicians with a challenge: the readily available inline GFCI dongles you get at hardware stores are prone to nuisance tripping with motion picture lighting loads and are only rated for 15 A, not 20 A. The residual currents generated by the electronic power supplies used in HMIs, fluorescent luminaires, and now LEDs sensitize these GFCIs so that they are very susceptible to tripping. To improve the generally poor reliability of GFCIs, in 2003 UL published a new standard for GFCIs (UL 943) designed to prevent nuisance tripping by transient conditions that are not of a sufficient duration to pose a hazard. The new standard allows GFCIs to trip on an “Inverse Time Curve.” An inverse time curve introduces a delay that decreases as the magnitude of the current increases. The delay allows transient conditions that do not pose a hazard to pass without tripping the GFCI. UL 943 also permits GFCIs to filter high-frequency currents to eliminate residual currents and thereby further reduce nuisance tripping. Even though the UL 943 standard was meant to enable GFCIs to operate more reliably in real world conditions, manufacturers of inexpensive Class A GFCIs, like those found in hardware stores, do not implement the UL 943 curve because it requires sophisticated micro-processors, which makes the GFCI much more expensive. For the same reason, they do not filter high-frequency residual currents. They use a more aggressive response than required by UL 943 (typically 250 ms at 6 mA where UL 943 permits 5.59 seconds). This more aggressive trip curve and lack of filtration does not generally pose a problem in the one-tool per circuit applications for which hardware store GFCIs are designed. However, the more aggressive trip curve of this style of GFCI has proven to be a problem in applications involving non-linear lighting loads, (the lights increasingly being used in motion picture production and event staging.) So, what’s a set electrician to do? Fortunately, NEC Section 215.9, Ground-Fault Circuit-Interrupter Protection for Personnel provides general permission for a feeder to be GFCI protected where it supplies 15 A and 20 A branch circuits requiring GFCI protection under Section 210.8. the section reads as follows: “Feeders supplying 15- and 20-ampere receptacle branch circuits shall be permitted to be protected by a ground-fault circuit interrupter in lieu of the provisions for such interrupters as specified in 210.8 and 590.6(A).” Since this section prescriptively identifies feeder GFCI protection “in lieu of,” it permits the use of “film style” GFCIs with 100 A Lunch Boxes to satisfy the expanded Section 210.8 requirement for GFCI protection on all branch circuits rated 150 V to ground or less, 50 A or less. This is good news for us. Film style GFCIs, like the Lifeguard, Shock Block, or Shock Stop are a lot less prone to nuisance tripping because they employ high-frequency filters and a trip curve that more closely approximates the inverse-time curve of UL 943. (use this link for more detailed information on the benefits to using film-style GFCIs on set). So, given the variety of code interpretations, it is important to always check with the local AHJ for regional differences from the national Code. Guy Holt, Gaffer, ScreenLight & Grip, Lighting rentals and sales in Boston
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