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Guy Holt

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Guy Holt last won the day on July 27 2019

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About Guy Holt

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    Gaffer
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    Boston
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    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. I don't have a url for the Film Florida Guidelines, they were sent to me as a pdf by a friend, so I had our web designer upload it to our server and establish a link from our website. You will find the link below the links to Protocol articles I have written over the years. Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental & Sales in Boston
  2. I would not try to enclose a construction style generator like the DuraMax XP12000EH in a sound blimp - it is likely to catch fire. Inverter generators can be enclosed because they are designed for air flow traveling through the generator from front to back and so can work in enclosures designed with front air intake and rear air exhaust (there are several enclosures on the market for this purpose.) The air guide of the Honda EU7000’s triple-chamber construction is part of what makes it so quiet. Put it in a properly designed enclosure and you have a dead silent generator. The air guide of the Honda EU7000’s triple-chamber construction Construction style generators, like the DuraMax XP12000EH, use an open frame construction for radiant convection cooling, which also makes them a lot noisier. The only way to not pick up the noise of a construction style generator is to get it as far from set as possible. But then you have the problem of voltage drop, called line-loss, over the long cable run to set. Voltage drop consumes power, diminishes the output of tungsten heads, and shifts their color temperature drastically. Another drawback to the DuraMax XP12000EH is that, even though it is a 12000W generator, that 12000W is not available to you in a usable form. Three 2ks will require three 20A/120V circuits, and you will need additional 20A/120V circuits to power anything else since the 2ks will monopolize the circuits they are on. The DuraMax XP12000EH has only one 20A/120V circuit. The larger circuits are 240V, which means that you will not be able to use a 100A lunch box because its five 20A circuits are 120V. Campfire scene on the beach powered by a Honda EB10000 I don’t mean to dissuade you from using a generator like the DuraMax XP12000EH, plenty of productions do. You just have to be smart in how you use them. For example the Adam Laupus film “Gasp” used a Honda EB10000 to power scenes on a beach without picking up the noise of the generator. Left: Honda EB10000 operating out of grip truck (note set at distance (bright spot on right side.)) Center: 84A Full Power Transformer/Distro <br>compensates for Voltage Drop over 400ft cable run. Right: Beach Set with 120v full line level 500ft from power source. As pictured above they ran the generator out of the back of their grip truck, 500’ from set, where it wouldn’t be heard. To compensate for the voltage drop over the long cable run to set, the crew used a 84A transformer/distro with secondary side voltage adjustment which enabled them to boost the voltage on set to get it back to 120V. The transformer/distro also stepped down the 50A/240V circuit they ran from the generator to a 84A/120V circuit. With the transformer/distro on set they then ran 100A Bates Extensions around their set and broke out to 20A Edison receptacles using 100A gang boxes in order to power an assortment of smaller tungsten fixtures to simulate the firelight and an ARRI M18 to simulate moonlight on the actors around the fire. To light the deep background the crew put a 240V Siamese in-line before the transformer/distro to power a 6kw HMI Par. Even with such a sizable load, they experienced no appreciable voltage drop on set after a 500' cable run because the transformer/distro compensated for the line loss of the cable. Left: Beach Set lit by Arri M18 and 6kw Par. Center: Secondary side power distributed with standard 100 Bates Gang Boxes. Right: Set viewed from generator (note: distance and extent of set power distribution.) Another key ingredient to their success was they used the Digital Honda EB10000. As far as I know, the EB10000 is the only construction style generator to use the new digital AVRs (DAVRs.) DAVRs are able to hold the voltage stable within ±1% of the mean voltage (as opposed to the ±3% of the best analogue AVRs.) The EB10000’s DAVR substantially improves the output capability, resulting in less voltage drop under load. What makes the output of Honda’s EB10000 more stable is that its’ DVAR is much more responsive than traditional analogue AVRs. A 10kw Honda EB10000 with a Full Power Transformer/Distro that provides a single 84A/120V circuit. Traditional AVRs use a closed feedback loop to stabilize voltage. As such, it takes comparatively longer to feedback and correct deviations from mean voltage caused by a sudden increase in load. Slower to respond, analogue AVRs allow for larger fluctuations of voltage (±5%), which, for example, can cause an HMI to cut out if the voltage drops too low. Rather than use a closed feedback loop to stabilize voltage, a DAVR uses control software with micro-second sampling rates of the output power of the main Stator windings (as compared to a sensor winding in conventional AVR systems) to more quickly and accurately detect deviations from the mean and make the necessary adjustment to the excitation current in the Rotor electromagnets more rapidly. And, by directly sampling the main Stator windings, rather than a sensor winding, the DAVR obtains a more reliable indication of the output voltage - the same one your loads see. The drawback to using a separate sensor coil is that the AVR does not see how voltage at the generator bus has been affected by changes in temperature, load current, and load harmonics. By applying true RMS calculations to the actual voltage coming off the Stator coils, as opposed to an isolated sensor coil, the DAVR of the EB10000 has a more accurate reading of the bus voltage and so is able to make more accurate corrections (use this url for more details.) With nothing more than a Honda EB10000 and house power the crew of "Gasp" was able to maintain the look and feel of a sunny summer day even when filming in the midst of a hurricane in October. The principal location for "Gasp" was an idyllic beach house right on the ocean. To light interiors of the beach house, the crew of "Gasp" used two 4k Pars outside, and an assortment of smaller HMI and Kino fixtures on the inside. The smaller fixtures were plugged directly into the house, while the 4k Pars were powered by the EB10000 running in the back of their grip truck. Left: Ready for rain on the set of "Gasp." Center: Two 4kw Pars operate on a 10kw Honda EB10000 Generator through our 84A Full Power Transformer/Distro. Right: 100A Shock Block GFCI downstream of the transformer/distro offers Ground Fault Protection for the entire 100A distro system. The indie film "Gasp" is a good example of how a transformer/distro can greatly simply set electrics so that you don’t have to be an experienced electrician to power a set. It makes it possible to record clean audio tracks with even generators as loud as the EB10000 even under the worst of conditions. Use this link to the trailer of "Gasp" to see what can be accomplished on a low budget if you work smart. Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental & Sales in Boston
  3. It depends on the type of ballast. Because of the constant improvement in HMI technology over the years there are several types of HMI ballasts available and if you are not careful how you power them you can get stuck. In ballast design you have a choice between magnetic and electronic ballasts; and to complicate matters even more, you have a choice between Power Factor Corrected electronic ballasts and non-Power Factor Corrected electronic ballasts. Magnetic ballasts draw more current during the striking phase and then they “settle down” and require less power to maintain the HMI Arc. For this reason, as Phil states, you must leave “head room” for their higher front end striking load. For the same reason you can’t load a generator to full capacity with HMIs with magnetic ballasts. By contrast, an electronic ballast “ramps up.” That is, its’ current draw gradually builds until it “tops off.” But, unless the ballast is Power Factor Corrected (PFC), an electronic ballast will draw more current than a magnetic ballast of the same wattage. Why ballasts of the same wattage will draw appreciably different current has to do with the Power Factor of the ballast. Since Power Factor Correction (PFC) is not mandatory in this country as it is in Europe, you will encounter many non-PFC HMI, Kino, CFL, & LED power supplies. And since, the adverse effects caused by a poor Power Factor go beyond an inefficient use of power, it is well worth understanding Power Factor and why it should be corrected. To learn about HMIs I would recommend an article I wrote on the use of portable generators in motion picture production. Harry Box, author of “The Set Lighting Technician’s Handbook” has cited my article in the Fourth Edition of the handbook. Here is what he has to say about the article: "Great work!... this is the kind of thing I think very few technician's ever get to see, and as a result many people have absolutely no idea why things stop working." "Following the prescriptions contained in this article enables the operation of bigger lights, or more smaller lights, on portable generators than has ever been possible before." Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental & Sales in Boston
  4. Finally we have a glimpse of what set lighting will look like in the era of Covid-19. As active discussions continue about setting industry guidelines for a safe return to production amid the coronavirus pandemic, Film Florida has released the most comprehensive set of such recommendations yet. Put out on Thursday, April 30, the six-page document by the statewide trade association features 161 recommendations for “clean & healthy” film, TV and digital production sets. According to a recent article in Deadline Hollywood "it spells the possible end of the signature canvas director’s chairs and ubiquitous actors trailers, and the introduction of personalized mics and hairbrushes as well as clear barriers for actors on stage." In addition to general guidelines, the brochure contains detailed recommendations for each department, including grip and electric. It also includes policies for on-set protocol, handling equipment and on-set communications. Use this link to see the complete report. Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rentals & Sales in Boston
  5. Time to get back to the original purpose of this thread: to share the tricks of the trade that will add more to your film’s production values than all the big budget toys found on bloated Hollywood productions. In this thread Varju Chapan asked how to light daylight interiors without 18ks. M Joel W suggested the use of mirror boards, to which Miguel Angel responded " I learnt the hard way that it is better to place a mirror with a light bouncing in it so you don't have to keep adjusting it every 2 minutes.." Working in New England I too learned the hard way that it is better to put a light into mirror boards than count on the sun. Mark Twain once said "if you don't like the weather in New England , wait five minutes and it will change." A smaller light, like a 4k, into mirror boards is a great way to replicate the feel of an 18k on an aerial lift. The objective to putting an 18k Fresnel on a lift at a distance is to replicate the angle and hard parallel rays of the sun. As you can see from the production stills of a Bose commercial below, you can accomplish similar results by bouncing a 4k ARRIMAX from the ground into mirror boards on stands or a lift. This set up gives you the hard parallel light of an 18K at a distance because, even though the light from the 4k spreads, the boards at the window collimate the light by reflecting only parallel rays. You can get away with a smaller light since the distance of the throw is not as far. And you don't have to worry about the sun moving behind a cloud or a tree (as you can see in the stills below, the sun would not naturally shine through the windows of the workshop.) A 4k ARRIMAX is a good choice of light for this purpose since it has a lot of punch for its power and can be powered off a Honda EU6500 or a dryer receptacle with a 60A transformer/distro as pictured below.) In the Bose commercial we warmed up the 4k with half CTO to partially match the tungsten heads inside. Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental and Sales in Boston
  6. Working in New England I too learned the hard way that it is better to put a light into mirror boards than count on the sun. Mark Twain once said "if you don't like the weather in New England , wait five minutes and it will change." A smaller light, like a 4k, into mirror boards is a great way to replicate the feel of an 18k on an aerial lift. The objective to putting an 18k Fresnel on a lift at a distance is to replicate the angle and hard parallel rays of the sun. As you can see from the production stills of a Bose commercial below, you can accomplish similar results by bouncing a 4k ARRIMAX from the ground into mirror boards on stands or a lift. This set up gives you the hard parallel light of an 18K at a distance because, even though the light from the 4k spreads, the boards at the window collimate the light by reflecting only parallel rays. You can get away with a smaller light since the distance of the throw is not as far. And you don't have to worry about the sun moving behind a cloud or a tree (as you can see in the stills below, the sun would not naturally shine through the windows of the workshop.) A 4k ARRIMAX is a good choice of light for this purpose since it has a lot of punch for its power and can be powered off a Honda EU6500 or a dryer receptacle with a 60A transformer/distro as pictured below.) In the Bose commercial we warmed up the 4k with half CTO to partially match the tungsten heads inside. Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental and Sales in Boston
  7. Don’t overlook this forum as a resource. I started a thread a while back as a place where we can share indie tricks-of-the-trade for realizing big budget production values on a modest budget. Or, as Phil Rhodes so eloquently put it “by the application of hard-won and exquisitely-realized skill.” It takes more skill to make an indie film than a big budget studio picture. Where a Hollywood production can throw money at a problem, an indie production must work smart. The emphasis of this thread is FILM CRAFT. For the more technically inclined I have posted on our website articles I have written for Protocol Magazine, the quarterly journal of ESTA which stands for the Entertainment Services and Technology Association. In addition to Protocol, ESTA has created a technical standards program to serve the entertainment industry in technical standards related matters. The goal of the program is to create recommended practices, to monitor standards issues around the world on behalf of its members, and to improve communications and safety within the industry. ESTA works closely with the technical standards efforts of other organizations within the entertainment industry, including USITT, PLASA, and VPLT, as well as representing the interests of ESTA members to ANSI, UL, and the NFPA. The Technical Standards Program is accredited by the American National Standards Institute and applies to places of assembly; the production of film, video, and broadcast; theatrical productions; carnivals; circuses; fairs; and similar events in North America. Use this link for my articles for Protocol. Guy Holt, Gaffer, ScreenLight & Grip, Lighting Equipment Rental and Sales in Boston.
  8. To power a small HMI off of batteries for an unlimited time in a car rig you can use a "Battverter" - which is a Battery/Inverter system. A "Battverter" system consists of a 12V DC power source (usually large Marine Cells), a DC-to–AC True Sine Wave Power Inverter, and a Battery Charger. Here is a link to some production stills that show you two Battverter systems I built to run lights in vehicles at various times. The first is a 750W "Battverter" rig wired into a Calzone case. The second is a more elaborate 1800W Battverter system that I built to run 16 - 4’ kinos tubes inside an airport shuttle bus. Use this link - https://cinematography.com/index.php?/topic/70937-indie-tricks-of-the-trade-or-how-to-get-good-production-values-on-a-modest-budget/- for details. Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental & Sales in Boson
  9. There are two reasons why you should not replace the duplex receptacles on your gang box with GFCI receptacles. First, it is a code violation and, second, they are the wrong kind of GFCIs for the loads we use. First, while the Code permits you to build your own “cord set”, it requires that cord sets utilize GFCI protection listed for portable use. The reason for this is that such GFCIs include "Open Neutral" protection, which enhances personnel safety where such devices are subject to the possibility of losing a Neutral connection. For this reason, it is not permissible to utilize GFCI receptacles designed and listed for permanent installation without Open Neutral protection in portable cord sets. The second reason not to replace the duplex receptacles on your gang box with GFCI receptacles, is that they are the wrong kind of GFCIs for the loads we use. In addition to not filtering residual currents, hardware store type GFCIs use a much more aggressive trip curve than do film style GFCIs like those manufactured by Shock Stop, Littelfuse, and Bender. To understand the difference requires a little background information. To improve the generally poor reliability of early GFCIs, in 2003 UL published a new standard (UL 943) for GFCIs designed to prevent nuisance tripping by transient conditions that are not of a sufficient duration to pose a hazard. The new standard allowed GFCIs to trip on an "Inverse Time Curve." An inverse time curve can be mathematically expressed as I2T where "I" is current and "T" is the time it takes to trip. Since this is a logarithmic equation, the plot of I versus T (as can be seen in graph below) does not follow a straight line but introduces a delay that decreases as the magnitude of the current increases. 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. And, as mentioned in my previous post, UL 943 also permits GFCIs to incorporate high frequency filters to avoid nuisance tripping from GFCIs becoming sensitized by residual currents. Attenuated by a filter, high frequency harmonic currents drawn by non-linear loads won't trip or sensitize GFCIs. Even though the UL 943 standard was meant to enable GFCIs to operate more reliably in real world conditions, manufacturers of inexpensive GFCIs, like those found in hardware stores, do not implement the exact UL943 curve because it requires sophisticated micro-processors, which makes the design more complicated and the GFCI more expensive. Nor, do they filter high frequency residual currents for the same reason. Instead they use a more aggressive response (also illustrated in the graph below) that is lower and faster than that required by UL 943 (typically 25ms 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. After all, power tools are by their nature linear loads that do not draw high frequency harmonic currents. However, the more aggressive trip curve of this style of GFCI has proven to be a problem in applications involving non-linear lighting loads, namely the type of lights increasingly used in motion picture production. And, with the number of LED fixtures that have non-pfc power supplies increasing on set, nuisance tripping of inexpensive GFCIs will only become more frequent. 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- and 20A receptacle 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” that required in 210.8, it permits the use of film style GFCIs (like the Shock Block SB100, LifeGuard LG100, and Shock Stop 60-100), with 100A Lunch Boxes to satisfy the recently expanded Section 210.8 requirement for GFCI protection on all single-phase branch circuits outdoors rated 150 volts to ground or less, 50 amps or less. This is good news for us since film style GFCIs, like the LifeGuard, Shock Block, or Shock Stop are a lot less prone to nuisance tripping because, unlike hardware store GFCIs, they employ high frequency filters and a trip curve that more closely approximates the inverse-time curve of UL943. Guy Holt, Gaffer, ScreenLight & Grip, Lighting sales and rentals in Boston
  10. Do a Google search for Shock Stop GFCI in parenthesis, that is enter "Shock Stop GFCI" in the Google Search Bar.
  11. I think you should hire a Gaffer that will keep you Code compliant. I salute your desire to learn but there comes a point where you can't expect to know everything and should hire a "Qualified Person." In Code parlance a Qualified Person is someone who has received formal training in the hazards posed by electricity and how to mitigate it. When it comes to using electricity a little knowledge can be dangerous. It may not seem like it, but this is a very complicated question. The Code requires that ground rods be 10ft, driven all the way into the ground, and the impedance to earth of the driven rod be no more than 25Ωs . If you are not able to satisfy this requirement with one rod, the code allows you to satisfy its requirement by driving a second rod not less than 6ft from the first. However, Honda EU6500s and EU7000s meet the Code requirements to be exempted from its grounding electrode requirement. They do not however meet OSHA's requirements to be exempted. To complicate the issue further, the NEC is a uniform code that is adopted into law in whole, or in part, by the local "Authority Having Jurisdiction" or AHJ. It is not uncommon for the AHJ to modify or augment the NEC in adopting it into law. For instance, in the City of Los Angeles you are not required to ground generators, but here in Boston we are required to ground generators. In the city of Boston, we are not permitted to use gas generators, but must use diesel generators. In short you need to check with the AHJ where you are shooting to see what the requirement is. To complicate the issue even further, the Code is the minimum required for electrical safety. Even though it does not require a Honda EU6500 or EU7000 to be earth grounded there are, IMO, good reasons to ground Hondas. For one, GFCIs will operate more reliably if they are, but that is more than I have time to get into now (perhaps later if you are interested). If you have not already, I suggest you read my white paper on the use of portable generators in motion picture production. It is available at http://www.screenlightandgrip.com/html/emailnewsletter_generators.html. Guy Holt, Gaffer, ScreenLight & Grip, Lighting rental and sales in Boston.
  12. The Code article that mandated that any portable generator under 10kW with 240V output be GFCI protected grandfathered generators manufactured before 2014 which permits rental houses to continue to rent their EU6500s with Bates modifications. It does not, however, exempt the users of those generators from the Article 210 general requirement for GFCIs on outdoor circuits of 150V to ground or less, and 50A or less. To meet this requirement electrical manufacturers like Woodhead and Hubble introduced inline 120V and 240V 30A GFCIs, but since the 50A Bates mod was an after market modification done on a very limited scale, large manufacturers like Woodhead and Hubble did not see a market for an inline 50A/120V GFCI. Which means that until Shock Stop introduced their inline 60A /120V GFCI (pictured above) the only option was to use one of the 100A/120V Shock Block GFCIs manufactured by Littelfuse or Bender. The ability to use high amperage "film style" GFCIs like those manufactured by Shock Stop, Littelfuse, and Bender to provide the Code mandated GFCI protection required on the 20A receptacles of lunch boxes and gang boxes is a huge benefit to us because the alternative, hardware store style GFCI dongles, are prone to nuisance tripping with many motion picture lighting instruments. Thats because many of the manufacturers of lighting fixtures that use electronic power supplies (HMIs, Kinos, & LEDs) shunt the harmonic currents they generate to their equipment grounding conductor as a means of reducing RF. Since these harmonic currents, called residual currents, return to their source via the equipment grounding conductor rather than the neutral, inexpensive hardware store GFCIs sense a current imbalance and trip. Such trips are a nuisance because the residual currents these power supplies generate do not pose a shock hazard. What makes high amperage "film style" GFCIs like those manufactured by Shock Stop, Littelfuse, and Bender worth the extra expense is that they filter high frequency currents and thereby are not tripped by these residual currents. For this reason it is far better to use a high amperage film style GFCI just upstream of a lunch or gang box than to use 15A hardware store GFCI dongles on the 20A outlets of a lunch or gang box as pictured below. Guy Holt, Gaffer, ScreenLight & Grip, Lighting rental and sales in Boston
  13. The inspector that shut down the grad student thesis film I gaffed didn't care a bit that it was a non-Sag micro-budget student film. Guy Holt, Gaffer, Screenlight & Grip. Lighting rental and sales in Boston
  14. Impugning my motives won't change the facts. Take a look around your EU7000. It is designed to be compact and quiet. To be compact there is no wasted space. To be quiet there is a steel wall between the electrical compartment behind the power panel and the rest of the generator, which means there is no place else to put the Bates connector. We used to offer this mod and if it were still possible I would happily do it for you, but it is practically impossible after the power panel was redesigned to accommodate GFCIs. Not true. The NEC is written in blood. Everyone of its requirements is the result of someone being injured or property damaged. The NEC requires GFCIs on Hondas because they present, and have always presented, a particular hazard. What happened was Hurricane Katrina when there was a surge of electrical injuries from the operation of portable generators. Because they are designed primarily for home standby power, the Honda EU6500s and 7000s do not bond the equipment grounding conductor to the neutral of the generator as required by OSHA. Without a Neutral/Ground bond, as illustrated below, a multiple fault condition exposes an individual touching faulty equipment to 240 volt potential which is lethal. The NEC is law in all 50 states, the AHJ (or OSHA most likely) will enforce this requirement and shut down your production. Years ago I gaffed a grad student thesis film project that was shutdown by the electrical inspector because he happened upon our set on his way home from work. Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rental & Sales in Boston
  15. Slow down. As someone who used to offer this mod (the picture above is from our website) and can no longer do so, I can tell you that even if you could find someone to do it these days (I doubt you will) I wouldn't do it. While the modification was very straight forward with the Honda EU6500, there are mechanical issues that make it very difficult on the Honda EU7000. And, since January of 2020 there are now Code issues that make it illegal in many states. For these reasons, any responsible shop that used to do the mod no longer does so. Let's look at the mechanical reasons first. Starting with the 2017 Code, the NEC mandates that any portable generator under 10kW with 240V output be GFCI protected. To make it code compliant Honda has put GFCIs on the latest edition of the EU 7000 leaving no room for the 60A Bates on the redesigned power panel. Those companies that continued to offer the mod (Multiquip) could only do so by completely removing the 30A Twist-Lock from the panel, moving the control circuit board, building in overcurrent protection, and machining a cover plate to cover the hole in the panel left by the 30A Twist-lock. They also had to silk screen onto the cover plate the warnings required to reduce their liability. Of course all this was not UL tested and so voided the UL listing of the generator. Fast forward to January 2020. The 2020 edition of the Code greatly expanded GFCI requirements to include all outdoor circuits of 150V or less to ground and 50A or less whether fixed or portable. Since the Bates mode provided 50A at 120V it now requires GFCI protection which is why I suspect even Multiquip will discontinue offering the modification. The only way to get a 60A circuit capable of powering a 4kW HMI or 5kW Tungsten light out of a Honda EU6500 or EU7000 is to use a small step-down transformer to convert the 240V output of the generator to 120V. Since this circuit is 60A at 120V it is not required by Code to be protected by a GFCI. The NEC is the minimum required for electrical safety on set. Our industry standards writing group, ESTA, recommends the use of GFCIs on all branch circuits of 100A or less. For this reason we now offer a listed 60A GFCI that can be used on a step-down transformer, or on any 60 or 100A Bates circuit to provide unparalleled ground fault protection. And since NEC Section 215.9 permits the use of a GFCI on the feeder of branch circuits requiring GFCIs, it can also be used to provide the GFCI protection required on the 20A circuits of gang and lunch boxes as pictured below. Guy Holt, Gaffer, ScreenLight & Grip, Lighting rental & sales in Boston.
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