Installation of Plugs on Cable some notes on cable and plugs. Plug Types and Brands: I have divided the installation of general stage/entertainment plugs into 8 general categories for simplicity in use. In each category there are many brands and type of plug which can require different methods of application. The general types will be covered in each category. Otherwise, most plugs are similar in construction and type which follow the NEMA code. General principals about the Nema Code are if it starts with a number designating it’s type, it’s a straight blade plug. If it has a “L” before the number, it’s a twist lock plug. Following the type is a dash and the plug’s amperage rating. A 5-15 NEMA plug is a U-Ground Parallel blade 15 Amp “Edison” plug. A L5-15 plug is also a 15 amp plug, but it’s twist lock and what we would call mini-twist in style. A 5-20 would be a 20 amp Edison plug which is the same only with it’s neutral prong perpendicular to the hot which is in normal position. A 5-15 plug will fit into a 5-20 receptacle but will not work in the reverse. This prevents overloading of circuits. It’s a good idea if you have something such as a high amperage air compressor which is still 120v, or other equipment with power ratings over 1800 Watts/15 Amps to install 5-20P plugs on them. A 5-15P plug is normally constructed using the same materials as a 5-20P but installed into a receptacle only rated for 15 amps it is likely you can burn something up in the circuit be it wiring or receptacle, long before the circuit breaker pops. You will also note the “P” following the amperage rating. This as opposed to “R” designates Plug verses Receptacle. Than it’s just a question of knowing if it is a cord mount verses panel or wall mount receptacle much less single verses duplex. Details Details, but for the most part, if you understand the basic NEMA system for plugs you will get along. Twist verses straight blade, Classification of plug, a Dash (-) than the amperage rating and male verses female. The NEMA system uses a base set of standards be it hook or barbed pin in verses pin out, or the general size of pin and it’s spacing in preventing one plug from plugging into another when not safe. A 6-15 plug for instance is very similar to a 20 Amp Edison plug only it’s “6" is opposed to the “5" of a Edison plug is different in the nomenclature, that and the hot and neutral blades are aligned and parallel to each other so there is no chance such a plug will fit within a Edison outlet. Or more importantly you cannot plug a Edison fixture into a 6-15 power source. 6-15 Outlets are 250v rated connectors normally used for two hot phases of power instead of one hot and one neutral. Such plugs are useful for high power motors, air conditioners and moving lights. A 6-20 receptacle given it also does not have a neutral will have what on- it’s hot perpendicular to the hot which is in normal position of a neutral on a 125v Edison plug. In other words, this connector is the exact opposite as the 125v 20 Amp Edison plug. Such 15amp connectors will either fit a 6-15 or 6-20 plug into it, the same as the Edison above, only it’s two phase of power with ground and no neutral thus the opposing prongs which will not work with the 125v equipment. Remember that a “5" is for 125 volt (120v) and a “6" is for 250 volt (208v). Nema really is fairly simple. Add a twist lock plug on the above and you have the entertainment industries main lighting cable plugs and receptacles. The L5-15 is the original stage standard for power in twist lock, as with a L6-15 for 208v power. Such plugs are the same relative size as a Edison plug but were not able to hold up in amperage rating to that of larger power requirements and the L5-20 and L6-20 series of larger twist lock plug was gone to at a higher cost. During the 80's and early 90's twist lock was the way to go over stage pin cable because it would remain locked together unlike stage pin plugs that were yet to be improved to a more safe and easy to use style. Stage pin manufacturers such as Union Connector at one point even tried to keep up with this locking practice with the development of locking stage pin connectors which never lasted that long in the industry - too many problems with them and you had to have both male and female locking or the plugs would not lock. Anyway, after time it was discovered that twist lock plugs would have safety problems if you were not able to pull them loose, much less sometimes some gorilla would attempt to twist them loose but in the wrong direction which would short out the plug in their hands. That and with weather tight boots over the plugs for out door shows, often there would be a vapor seal in both mechanically and by suction ensuring the connection would never come apart safely. Today the standard has gone back to stage pin and other than for 208v purposes such as moving lights, Stage Pin connectors are to be used in all modern installs over twist lock again. Before such standards came out, the stage pin connector developed out of the un-grounded connector just as a Edison plug grew out of a ungrounded one - the NEMA 1-15. In other words, you can plug in both a ungrounded and ground two pin plug into a grounded receptacle. The 15 amp twist plug was also developed and used in 1970's theater and entertainment for use in the new concept of plugs that would stay locked. Such a mini-twist standard remains in debate with the 208v moving light power in the industry though the 125v/15Amp version is much less used. Given small cords and lower amperage loads in moving lights there is some merit to using a smaller plug on the gear rather than having a plug that weighs more than the fixture’s entire cable in weight, plus one with a strain relief that will grip the wire adequately in concept. On the other hand, with the advent of 1,800w and twofering equipment, some even lower amperage moving light 208v loads are better using the more unified 20 amp L6-20P plugs in matching up the rating of the plug with the load. The plug weight and size in comparison to the cord, verses the amperage is a ongoing silent debate in which both standards are used dependant upon who you are. Unfortunately a 20amp twist lock plug will not fit into a 15 amp twist lock receptacle so many 208v adaptors are necessary in the industry as with twist to stage adaptors and every other type of adaptor. In the end, there are five main plugs used in the industry. For 125v it’s 15amp twist which is getting more rare but still found, than 20amp twist that is used much more but no longer the standard or parallel blade Edison plus some ungrounded Edison plugs used in some places but not really rated for industry use. For 208v you will find a complete mix and match of 15 and 20 amp twist with 20amp twist being more common, and no parallel blade Edison types in service except perhaps in some bars. Above this is the Stage Pin plug which is rated for 120v use at 20 amps and 208v at 10 amps. It is most used in the theater under 125v and has found use in moving lights with switchable voltage between 120 and 208v. Beyond these main plugs there is the Non-Nema 125/250v plug, the L6-30 for follow spots, that the L10, L14 and L21 series plugs for various two and three phase applications with and without a neutral in powering up small dimmers and power distribution units. The L21-30 three phase with neutral and ground plug being the most common for small AC distribution units. There is lots more types and styles of plug in use from the ML-2 that I use on my flexi-flash units, to various 50 amp plugs. Just a question of the need and purpose of those using the plug. Plus what is available cheap in many cases. Cable Types and Materials: There are three base types of stage cable with subcategories to all. By code, all stage cable is required to be either heavy duty rubberized or stage feeder cable of two types, but it depends upon what classification of the code your application falls under as to how closely you have to follow these rules. Type S. This is the main stage cable, it has a thick rubberized/neoprene jacket which makes it heavy duty Hard Service Cord as required so it is highly damage resistant to the more industrial abuses it will receive on stage such as use in pendant situations. It has two or more stranded conductors with a woven cotton, paper, plastic fiber, fiberglass or jute between the insulated conductors to make it round and add strength. This cable will normally have a right hand twist to it with one revolution per foot when new. In general, type S cable is rated for 600 Volts which can become important in certain situations, and it’s rated for 90°C. in temperature. As a general classification for this grade of cable I term it as type SO in having a double digit nomenclature for all of it. You can get grade SO even S alone, but more common types will be SOOW or SOW. The “S” stands for Rubberized Neoprene/thermoset or similar materials rubber like in construction. The first “O” stands for Oil Resistant outer jacket. The Second “O” stands for Oil Resistant also but the inner conductors are also oil resistant. “W” Stands for Water Resistant. Water resistant and oil resistant cable in general is no more in cost and a much better value to ensure the cable will not rot or be adversely effected by what chemicals and conditions it is exposed to. Note, it is resistant to these things but not water or oil proof. Should you cable become dirty with oil or be left in water or similar things, it will still be effected by it. In general, this type of cable has a 7 to 10 year life span under normal all the time usage. It has been known to last up to 20 years and more but at that point the inner conductors will begin to break down and oxidize causing a higher resistance, heat and voltage drop. Any type of cable is required to have it’s grade, gauge and brand printed on it once every foot unless very specialized in type. Once these markings printed on or molded into the cable are removed, you are required to get rid of the wire by code as it is no longer serviceable. In more realistic conditions, no more than 60% of the cable should have it’s identification removed. Excessive wear on the cable’s jacket is often an indication that the inside conductors or insulation is also about shot. Overall, in high school theater, you should not be using anything other than SO grade cable. This means other than for powering up your drill on stage, you must not be using those orange extension cords or any other form of junior insulated cable to power the lighting equipment. Type SJ. You are allowed to use junior jacketed cable on stage but only in lengths three feet and under such as in a twofer or distribution tail. This cable however is allowed to be used with truss supporting it in temporary entertainment wiring such as for rock concerts, so it gets a bit grey with what type of cable you need to use in an assembly hall, stage, verses concert hall or convention center. This in addition to specific uses of each where SO wire is required over SJ. Type SJ wire has a much thinner outer jacket than SO but otherwise is rated for the same load rating and resistance types. It’s available in SJ, SJO, SJOW and SJOOW with the above descriptions. In addition to these types, it is also available in a thermoset which is Thermoplastic Elastomer instead of Thermoset/rubberized Neoprene making it up. Such cable will have a SJ designation directly followed by a “E” or "T" for SJE/SJT even SJEOOW grade. In addition to SE grade, SJ cable is commonly available in a SJT grade which is completely thermoplastic and not rubberized in texture. This is the major difference between junior grade cables, how it’s constructed and what it’s temperature rating is. Thermoplastic cable is rated for less in temperature than SJ or SJE wire, it also will show stress/bending cracks with age or exposure to UV light, sooner than the above. This type of cable is frequently used for low wattage fixture wiring or equipment wiring but not general service power cord. SJE wire is designed to be a cost effective alternative to the rubberized neoprene SJ thermoset types. How similar the enhanced product is to rubberized cord depends much on the manufacturer. Coleman for instance as a manufacturer makes a almost similar textured wire to rubber with the same temperature rating. The conductors while still plastic have the suppleness of rubber. The main limiting factor of plastic wire verses rubberized wire is the rubberized wire while it’s insulation will break down at the same certain 90C temperature, it will not melt away until a much higher temperature yet is reached, even than it will often become brittle. On the other hand, the plastic types might be a little more rot resistant. SJT and SJE insulation at the rated temperature melts away exposing conductors. It is also harder to repair and frequently will not coil up as well especially when cold. For stage or industry usage, SJE might seem a value, but in the long run normal SJ wire will probably last longer. Under normal conditions, SJ cable can be expected to last about 3 to 5 years with 10 to 15 years being on the outside of it’s service life. Such cable is cheaper in initial cost, but once you figure in labor and replacement, SO wire is more economical where maximum cable weight is not a factor given you do not have to use the heavier wire. Type SC: Flexible Stage and Lighting Power Cable. This is the type of wire designed for stage usage but it’s size starts at 8AWG and gets larger after that. Anyone saying you have to use SC cable on stage and nothing else needs to re-read the NEC above a superficial reading of what is required and where. Mostly this type of cable is used for high amperage loads feeding dimmers and distribution equipment in #2 thru 4/0 size. This type of cable has a very heavy duty, extra hard duty rating to it and is very damage resistant but normally single conductor wire. Same basic rating as welding cable or SO, but far heavier jacket and thicker strands to it which will not break as easily. Do not use grade SO or welding cable on stage for loads larger than 60 amps or for any single conductor above cable. It will not cool properly nor be damage resistant enough. Such grades in welding use are intermittent power not as constant. Such welding cable will be cheaper per foot but is defiantly to be avoided. Grade SC replaces type W feeder cable. Both are acceptable for stage usage but type W has a double layer of insulation separated by a braided fiber. This extreme heavy duty construction while extreme in damage resistance will at times especially in short lengths but large sizes, not allow a CamLoc plug to twist and lock into position due to it’s braiding and thickness of insulation. SC cable will provide sufficient insulation and still allow some flex and twist to lock. Type W cable if still available should be avoided for anything other than permanent installs or it is likely especially as a short rack to rack jumpers, your cable will untwist from it’s locked position and cause a safety hazzard. Welding cable also has the disadvantage of being smaller and more numerous strands of wire - much easier to break causing heat. Welding cable as well as SO on single conductor cable rips off in chunks when snagged. Definately not something you want to be around. Marking your cable: This step can take as much time as doing the actual wiring if not even more, and can be just as important to do well and properly. Marking even the least important piece of gear adds a certain amount of pride and professionalism into it beyond the utility purposes of designating ownership and details such as length and type about it. It’s gear you have enough pride into owning and calling yours, you would take the time to make it so and wire properly. Such gear that is yours and you took the extra time in marking you also don’t take for granted. You don’t allow crew members to drop connectors, you don’t allow people to hot patch with it. Pride in your materials is shown in many ways, part of it is in taking the extra time to say it’s yours. When I build cable for theaters, or even wire up plugs onto fixtures, my primary question after how soon do you need it is always do you have any label you would like me to install onto it? For our largest customer we even printed up some labels on heat shrink for them, it was not overly expensive but certainly impressed the customer we would do such a thing. You can be sure any other suppliers would not be taking the time to purchase and install your markings and color code on what you buy, at best your cable will be provided with a length of clear heat shrink so you can mark your own cable, or if you specifically ask them to they might as long as you provided the materials and sometimes extra labor cost. I have even gone so far as to create a logo, company name and description for places without one, to which it is a extremely pleasant surprise which makes what I do stand out and the service more valuable. I look at it this way, I don’t want your cable. When shows come back, they always have other people’s gear in them as well as our own. That gear I can identify as belonging to someone else, gets sent back at our cost as a courtesy that normally is only one sided. Between all the broken gear and new gear I’m tasked to make, I don’t have time to be marking someone else’s gear as mine to the extent of taking off the Sharpie or paint marker initials of the old owner and electrical tape rings off the cable when I have no idea of who CS might be as it were. Than there is the question of compatibility and quality. Sure free gear since it can’t be sent back is free gear, but than I am liable for any gear someone else wired that I put on the shelf given it lives up to my standards in the first place. If it does not it’s trash. Even if it’s only something with markings designed and printed up on paper, than double sided taped to a electrical tape backing than covered with clear heat shrink. Installing markings on your gear somehow is the industry standard, it’s only a question of how lazy or lax you are with making it well marked enough so that if your gear winds up somewhere across the country you stand the chance of getting it back even if they had never heard of you before. But we don’t have guests or other productions in our theater, why bother marking it with the theater’s name and phone number? Pride in your gear and equipment. Even if the maintenance staff never “borrows” your gear, even if you don’t do shows in other rooms and forget things, there is a difference you will feel between a stack of cable with peeling off electrical tape markings and something with good markings that you installed and last with your company name and other easily perminantly installed markings on it. If you have cable that you don’t want to walk out the door with visitors, or is left behind at shows, than you had at best mark it with who it belongs to. If you want to have cable that is easy to determine how long it is than you had at best mark your cable. Electrical tape might work, but just as frequently just peels off. Some tips: avoid pvc based heat shrink, go with the Polyolefin types. Keep your markings 5" or less with the optimum size being 3" for the markings. Lengths of markings over 5" tend to break down with flexing too easily. Colored electrical tape works but frequently will suffer from the tape getting warm and creeping unless good quality and under heat shrink. A better method might be to have your heat shrink supplier print up your company name and phone number along with a logo on colored heat shrink to match the color of your cable length. Such pieces of heat shrink are available in colors to match your cable type designations or colors, or a cheaper solution since you have to buy in bulk amounts, would be to get all of them in the same color than just use a stripe of electrical tape color next to it to designate length. 3/4" Expanded 3:1 heat shrink seems to work best for this since it will allow the heat shrink to fit cable sizes from 12/3 SO to many microphone or data cables - even with fitting over the plugs to them. If your data cable is smaller than 1/4" OD. Than you have the option of either using a filler under the heat shrink to expand it, using a smaller size of heat shrink and taking off the plugs or purchasing a 4:1 heat shrink to cover all applications for it, but dealing with a very thick tubing once fully shrunk. If you have sufficient budget, there is all kinds of heat shrink on the market. Up to 4:1 heat shrink that will start expanded in 4" dia, than shrink down to 1" at a cost of about $10.00 per foot. Such heat shrink is useful for replacing labels on Socopex multi-cable even. Companies such as Heat Shrink .com have developed a line of better quality heat shrink specifically for the sizes needed on stage, and of a quality that will not yellow or crack with age. Stuff you can slip over some types of molded Edison plugs, than shrink down to the size of SJ wire, etc. Heat shrink such as this wears and cuts up with time and abuse, but at least you don’t always have to live with it or take the plugs off to replace it. Another option you have is to use adhesive under the heat shrink to bond it to the wire and markings. 3M rubber/neoprene adhesive #2141 works well in bonding heat shrink to cable as long as it's fresh or it will at times bubble up under the heat shrink because it's too thick, it when old will also turn your stuff yellow/amber in color. A search for a all around clear adhesive would be the best option. The idea is that the adhesive will bond the shrink tubing to the cable so there is no chance with flexing and abrasion the heat shrink will re-expand slightly than slip off your markings, or it will not get little cuts in it also exposing your markings. Should your markings be especially abused such as on a wrench that lives in a bag of bolts, you can purchase clear adhesive lined heat shrink which will make the heat shrink especially damage resistant especially if adhesive is added to the tool surface to bond with the hot melt glue on the heat shrink.