Wiring System Identification

NOTE This standard governs the marks that travel with the wiring rather than with the equipment: the color of a conductor's insulation or the tape on it, the marker at its end, the tag on a feeder in a pull box, the band and legend on a raceway, the words on a box cover, the circuit number on a receptacle plate, the ribbon in the trench above a buried run, and the legend posted at the panelboard that tells a reader what the colors mean. Each one is read by someone who has opened a box, pulled a cover or dug a trench and needs to know what is in front of them before they touch it. (1.1)

NOTE The labels on the enclosures themselves, the nameplate that names a panelboard, the directory in its door, the warning signs and the arc-flash label, are governed by Equipment LabelingElectrical Equipment LabelsResolves to the current adopted revision.sync/equipment-labeling. The two standards share the equipment designations of the one-line diagram and the system color convention selected here, and neither restates the other. (1.2)

NOTE The following are governed elsewhere and are outside this standard: (1.3)

NOTE The decisions the engineer makes under this standard are the project's color convention, in two parts, the phase colors of each voltage system and the colors assigned to the special systems; the form of the posted legend; the marker and tag products and where they are applied; which raceways carry markers and how often; how box covers are marked; and the warning tape over buried runs. What the NEC fixes, the white and gray of the grounded conductor, the green of the equipment grounding conductor, the orange high leg and the posting of the legend, is not a decision and is stated here as a requirement. (1.4)

NOTE The one error this standard exists to prevent is two crews coloring the same phase differently in one building; the cure is a single recorded convention, reviewed before the first conductor is pulled and handed to every crew, which is why the convention is a submittal rather than a closeout record. (1.7)

NOTE NFPA 70 fixes the few colors it reserves and requires that everything else be identified by a recorded means; UL 969 and UL 969A are the tests that a flat label and a wrap-around or flag marker stay adhered and legible for the exposure they are listed for; ANSI Z535.1 names the safety colors a red or orange band is matched to; the APWA code is why the tape over a buried electric line is red and the tape over a buried communications line is orange, so that an excavator who finds either knows what is under it without reading it. (2.3)

NOTE The record convention is the document the Owner's electricians color the next circuit to, and it is kept with the operation and maintenance data so that an addition ten years on uses the same brown for A phase. (3.2.2)

NOTE A legend written in marker on a sleeve wipes off with the first solvent and fades in the first summer, and a listed stock printed with an unlisted ribbon does the same; the listing is of the printed marker, and the printed marker is what the inspector and the next electrician read. (4.3)

NOTE Most markers under this standard live inside a conditioned building, in a panel, a box or above a ceiling, and the products offered as the norm are rated for that service; a marker in an outdoor enclosure, a handhole, a wet well, a wash-down room or a hot panel is in a different service, and the clauses below raise the product at those locations without changing the selection for the rest of the project. (5.1)

NOTE The concealed box is the one that is opened by someone who has never seen the building, and it is the one most often found with no marking at all because the crew knew the ceiling would close; the standard is the same above the ceiling for that reason. (5.7)

NOTE The NEC reserves white and gray for the grounded conductor, green for the equipment grounding conductor and orange for the high leg, and requires the special systems to be identifiable, but it assigns no color to a phase and no color to an emergency system; those colors are the project's convention, selected once here and applied to the conductors, the raceway bands, the box covers and the tags under this standard and to the nameplate faces under Equipment LabelingElectrical Equipment LabelsResolves to the current adopted revision.sync/equipment-labeling. (6.1)

NOTE Red for emergency and orange for legally required standby are the colors most Owners and most specifications use, and the default states them so that a project that accepts them need write nothing; a project whose 480 V phase colors are brown, orange and yellow changes the standby color or marks the standby raceways with the words as well as the band, which is why the clause forbids a system color that duplicates a phase color. A campus with its own convention replaces the default text with the campus convention. (6.3)

NOTE White on the 120 V systems and gray on the 277 V systems is the assignment nearly every project in the United States uses and the one an electrician assumes without reading the legend, which is why it is the default; the reverse is a legacy convention of some campuses and is kept there only so that an addition matches the existing building; a stripe is used where a third system shares a raceway with the first two and neither white nor gray is left. (7.1.4)

NOTE Black, red and blue on the 208Y/120 V system and brown, orange and yellow on the 480Y/277 V system is the convention of most of the United States and the one stocked by every distributor, which is why those are the defaults; brown, purple and yellow replaces the orange of the 480 V set where the project also has a high-leg delta, whose high leg NFPA 70 reserves orange for, or where the Owner's convention says so; black, red and blue on the higher-voltage system is the convention of some utilities and industrial Owners and is kept where an existing plant uses it. The 600Y/347 V system is rare enough that no convention is the norm, so that field carries no default, and a project with that system chooses a set that does not repeat the set of its other systems. (7.2.2)

NOTE An unmarked high leg is connected to a 120 V load by the next electrician who assumes a three-phase panel has three 120 V legs, and the result is a destroyed load or a fire; the orange is the one phase color NFPA 70 reserves, and it is reserved for that reason. (7.2.5)

NOTE Phase tape is applied in the field at every point, is renewed when it ages and is the method of most projects, which is why it is the default; a heat-shrink sleeve does not unwind or slide and is specified in a hot panel, a wet location or a plant where tape has failed, at the cost of being slipped on before termination; colored insulation for the full length is the surest identification and is bought where the conductor is available in the color in the size required, which large-size colored building wire often is not without a mill run. (7.3.2)

NOTE A card in a holder is replaced when the convention is extended, and a panelboard with a directory holder commonly has room for a second card; an adhered laminated card costs the least and is read when the door is open; an engraved plate on the exterior is read without opening the door and cannot be lost, at a cost per panel and with the whole plate replaced when a system is added. No form is the norm across projects, so the field carries no default, and the form follows the directory form selected under Equipment LabelingElectrical Equipment LabelsResolves to the current adopted revision.sync/equipment-labeling so that the two cards or plates in one door match. (8.2)

NOTE A printed swatch with its name beside it is what makes a legend usable under the sodium light of a garage or by a reader who is color-deficient; a legend that names colors without showing them is read against a conductor whose brown and whose orange look alike under that light. (8.5)

NOTE A self-laminating wrap-around is printed on a desktop printer, applied after the conductor is terminated and laminates its own legend under a clear tail, and it is the marker of most power and control conductors in panels, which is why it is the default; a heat-shrink sleeve cannot slide or be lifted and is the marker of a control panel built in a shop and of a hot or oily location, at the cost of being slipped on before the lug goes on; a slip-on sleeve is re-markable and is used on small control wire where a wrap-around will not fit; a flag label stands out from the conductor and is read in a crowded gutter, and it snags. (9.1.4)

NOTE A 3/32 in character is the largest that fits two lines on a marker for a 12 AWG conductor and reads at arm's length, which is why it is the default; 1/16 in is accepted on control wire smaller than 14 AWG where the marker diameter allows nothing larger, and 1/8 in or 3/16 in is specified on feeder conductors and on markers read in a deep enclosure. (9.1.6)

NOTE An engraved plastic tag on a nylon tie is read for the life of the installation in a dry location, is made in the same shop as the nameplates and is the tag of most feeders, which is why it is the default; a printed polyester tag is produced in quantity on site and is the tag of a project with hundreds of cables, with the life of its print; a stainless steel tag is the tag of a handhole, a manhole, a wet well and a corrosive area, and of any Owner who has pulled a faded plastic tag out of a flooded handhole; a heat-shrink sleeve over the jacket cannot be lost or swapped and is the tag of a tray-rated cable, applied before the cable is pulled. (9.2.4)

NOTE Marking the special systems and the raceways NFPA 70 names is what most projects do, which is why the default is that set: the emergency, legally required standby and critical operations raceways under 700.10(A), 701.10 and 708.10, the photovoltaic raceways under 690.31(D)(2), and the raceways above 1000 V that a worker must not open. Marking normal power feeders, every exposed raceway in an equipment room, or every raceway above a ceiling is what a hospital, a laboratory or an industrial Owner with a large maintenance staff buys, and it costs a marker every interval on every run. (10.1.2)

NOTE An adhesive wrap-around marker is printed with the band and the legend in one piece, is applied in minutes at any point on a run and is the marker of most projects, which is why it is the default; a snap-on marker is applied over a painted or dirty raceway and is moved when a run is reworked, at a higher cost per marker and with a fit limited to the trade sizes the manufacturer tools; a painted band with a stencil is permanent on a plant's exposed rigid conduit and is the only marker that survives a wash-down, at the cost of masking and a second trade; a tape band with a separate legend label is the lowest cost and the first to unwind in the heat above a ceiling. (10.2.2)

NOTE Twenty-five feet is the interval NFPA 70 700.10(A) sets for an exposed emergency raceway where no boxes are encountered, and one interval for every marked raceway on the project is simpler to install and to inspect than two, which is why it is the default; a shorter interval is set in a congested ceiling where a marker must be in sight from any access panel, and a longer one is accepted on a long exposed run in a plant or a tunnel where every marker is in view from the last. (10.2.4)

NOTE A 2 in band is seen across a ceiling space on a 3/4 in or 1 in raceway and is the band width of the standard wrap-around marker, which is why it is the default; 1 in suits a crowded rack of small raceways, and 3 in or 4 in is specified on large raceways and on the exposed runs of a plant read from the floor. (10.2.6)

NOTE A machine-printed label is applied to the cover as the box is closed, is legible from the floor and is the marking of most boxes, which is why it is the default; a paint marker or stencil survives the heat and dust above a kitchen or a plant ceiling where an adhesive label lifts, and it is as legible as the hand that writes it; an engraved tag is the marking of a wet or corrosive location and of an Owner who wants the box marked for the life of the building; a cover finished in the system color with a label is the marking of the boxes of emergency and other special systems where the color is to be seen before the words are read. (11.2)

NOTE A painted cover is seen from the floor and is the convention of most hospitals and of many jurisdictions' inspectors for emergency boxes; a label in the system color keeps the cover finish and is accepted where the box is in a finished space or where the Owner's convention uses labels only. Neither is the norm across the projects this standard serves, so the field carries no default. (11.5)

NOTE The plate label is read by an occupant reporting a dead outlet and by the technician who finds the breaker from it, and both read it against the directory in the panel door; the format is the directory's for that reason, and the label is printed after the circuit is verified so that the two agree. (12.3)

NOTE Detectable tape lets a locator find a nonmetallic raceway or a direct-buried cable from the surface with an electromagnetic locator, which is the whole of the value of the tape to the next excavator, which is why it is the default; non-detectable tape is accepted above a metallic raceway, which is located by its own metal, and above a duct bank whose tracer provisions under Underground DuctbankUnderground Electrical Duct BanksResolves to the current adopted revision.sync/underground-ductbank locate it. (13.2)

NOTE A 6 in tape is wide enough to be struck by a trenching bucket crossing the run and is the width most tape manufacturers stock in detectable form, which is why it is the default; 3 in and 4 in tape is used above a single small raceway in a landscaped area, and 12 in tape above a wide duct bank or a direct-buried feeder in an open site where a wide excavation is expected. (13.4)

NOTE Twelve inches above the run is the NFPA 70 300.5(D)(3) height for service conductors and puts the tape where a bucket reaches it a full pass before the run, which is why it is the default; 6 in is used only above a shallow branch circuit in a planting bed where 12 in would put the tape at grade, and 18 in or 24 in is used above a deep duct bank so that the tape is reached near the depth an excavator expects utilities. (13.6)

NOTE A surface marker at each bend and end lets a locator start and finish a trace without a drawing, and a marker at intervals lets a crew see the run across a field; tracer wire in a nonmetallic raceway is what makes a run locatable where detectable tape has been cut or where the raceway is deep. Which of the three a site needs follows from the run lengths, the surface and the Owner's locating practice, so the field carries no default; a building whose only buried runs are short laterals under paving carries none. (13.8)

NOTE Phase identification applied after a conductor is energized is applied in an energized enclosure under an energized work permit, which is the exposure the sequence avoids; the colors go on while the conductor is dead. (14.2)

NOTE One year is the general-conditions warranty and is what an identification package commonly carries as part of the electrical warranty, which is why it is the default; a longer period is specified where the Owner has had markers fail above a hot ceiling or tags fade in a handhole and wants the second installation on the Contractor. (16.2)

NOTE A spare stock is sized to how many circuits the Owner expects to add or move in the first years and to whether the Owner's electricians carry their own markers, so no quantity is the norm and the field carries no default; zero records that the Owner stocks its own, and a plant with a maintenance shop takes the larger quantities so that the next circuit is colored and marked to the project convention from the day of turnover. (17.2)