Strategies for electrical labeling and documentation

Electrical equipment must be correctly labeled and documented. Follow these strategies to achieve enhanced safety and documentation.

By Richard Vedvik, PE, IMEG Corp.; and Dan Winter, PE, Faith Technologies October 5, 2017

Learning objectives

  •  Understand codes, standards, and requirements for labeling and signage.
  • Learn best practices for documenting and labeling electrical equipment.
  • Offer solutions and tips for electrical distribution system documentation.

Consistent documentation is an important safety strategy for electrical engineers and facility operators. Operating procedures for electrical gear should be readily understood by facility staff, and methods to implement labeling should be considered by the engineers during design. Methods of documentation of arc flash data and overcurrent protection device (OCPD) settings affect the speed at which facility operators can respond to fault conditions. Additionally, electrical distribution configuration and fault data should be part of a living document that facility personnel and designers maintain as a cooperative effort.

Why electrical equipment must be labeled

Strategies for labeling and documentation are partially driven by applicable code requirements. An obvious location to look for requirements is NFPA 70E-2015: Standard for Electrical Safety in the Workplace, Article 130.5(C)(2)(D). This section specifies the type of labeling information required and includes available incident energy and personal protective equipment (PPE) categories. These requirements are echoed in NFPA 70-2017: National Electrical Code (NEC), Article 110.16. Both of these sections address the first reason to provide descriptive equipment labels: for personnel safety. Additional labeling requirements are listed in 2017 NEC Article 110.21. These requirements apply to field-applied markings and signage. ANSI Z535.4-2011: Product Safety Signs and Labels is referenced in NEC Article 110.21 and provides specific guidelines for signage. Engineers should ensure that the labeling requirements listed in the design specifications are not in conflict with those specified by the ANSI standard. ANSI distinguishes the meaning behind several common words and when it is appropriate to use them.

An example of a required “DANGER” label is in 2017 NFPA 70, Section 110.34(C), which requires rooms containing equipment with a nominal voltage greater than 1,000 V to include a sign at the entrance labeled “DANGER—HIGH VOLTAGE—KEEP OUT.” The details of this signage can be referenced in ANSI. The flow chart depicted in Figure 1 is derived from ANSI Z535.4-2011, Figure E2. This flow chart can help the designer or facility personnel to determine which signal word to choose and the color codes assigned to each hazard condition.

OSHA Standard 29 CFR 1910.144-2007, Safety color code for marking physical hazards, defines safety color codes for marking hazards. Red is specified for fire protection equipment, danger, or “stop.” Yellow is specified for caution and marking physical hazards associated with falling or tripping. OSHA Standard 29 CFR 1910.145-2013, Specifications for accident prevention signs and tags, includes specifications for signs and tags to prevent accidents and directs the facility to inform personnel about the intent of color codes and verbiage. OSHA references ANSI for color codes and adds the definition of a biohazard.

Additional signage guidelines in ANSI Z535.4-2011 include text justification and text arrangement, order of information, grammar, text font and size, letter spacing and line spacing, and multilingual arrangement. Commercial software is available for development of signage that complies with OSHA, ANSI, and ISO regulations. Table 1 references ANSI Z535.4-2011 and illustrates recommended font sizes based on viewing distance.

The guidelines for font sizing are directly related to the distance at which the message is to be considered legible. If the message is describing a hazardous condition, it should be legible from outside the hazardous area. An unfavorable reading condition may be caused by poor lighting or poor viewing angles. These are important aspects for designers and facility personnel to apply. Designers should specify lighting levels sufficient for identifying hazards and reading signage.

The second reason for labeling is informational. While the safety labels are intended to identify hazards, informational labels assist facilities in understanding how the equipment is connected and provide instructions for proper operation. Informational labels may be code-required, at the request of the facility, or as specified by the designer for enhanced understanding. A common application for informational signage is to identify the panel name and circuit number on a receptacle faceplate as required by NEC 2017 Article 517.19. The receptacle faceplate color is required to identify a connection to an emergency branch per NFPA 99-2015: Health Care Facilities Code, Article 6.4.2.2.6.2(C). Details of receptacle cover-plate labels are specified by the design engineer and should be coordinated with the naming configuration and label type desired by the facility. Additionally, the type of material used for the label should be suitable for the environment, as noted in 2017 NEC Article 110.21(B)(3). Engraved cover plates are an option when environmental conditions can cause failure of label adhesives.

Labels for panel/circuit information are not limited to receptacles. Any panel or piece of equipment should have a label to identify where power can be disconnected (see Figure 2). Lockout-tagout procedures should be considered when deciding labeling details. Equipment labeling may include voltage, source-panel name, and source-panel location (if elsewhere in the facility). Mechanical equipment labeling also should include type and location of control. Transfer switch labels should identify both sources of power (see Figure 3). Transformer labels should include panel names for both primary and secondary connections. Panelboards with feedthrough conductors should include labels identifying what other panels or loads are affected by outages. Junction boxes should include panel and circuit numbers. Labels such as these will increase safety for shutdowns and allow facility staff to quickly react to outages. Compliance with UL 969-2017: Standard for Marking and Labeling Systems should be specified for adhesive labels.

In some cases, color coding is a requirement. For instance, NEC-2017 Article 760.41 requires circuit breaker handles to be red in color when serving fire alarm panels and power supplies. The informational color codes used may conflict with the ANSI color codes to indicate hazards. OSHA 29 CFR 1910.145 supports the concept of using red color coding for fire alarm conduit and junction box covers. When used, raceway and junction box identification should combine both color and text to match a campus or facility standard. Colored conduit is an affordable way to provide quick identification of the associated system in the field. If a color-coding standard does not yet exist for a facility, designers can discuss implementing a new standard with the current projects. These discussions help build relationships between designers and facility personnel, an effort that benefits both parties.

Distribution documentation

It is important for a facility to keep accurate records of the following distribution system attributes:

  • Arc flash values.
  • Available fault-current calculations.
  • Selective coordination study results and associated OCPD settings.
  • Riser diagrams or one-line diagrams.
  • Panel locations (floor plans).

Keeping these records current is necessary to maintain safe operating conditions. NFPA 79-2015: Electrical Standard for Industrial Machinery, Article 700.5(E), requires labeling of panel short-circuit current rating (SCCR) based on OCPD settings used. Periodic review of existing OCPD settings is a good idea to maintain a safe electrical system. Arc flash and PPE labels should be updated when system changes occur due to renovation projects or every five years, whichever is first. This effort requires coordination between the design engineer and the facility for the impacted equipment. Instead of causing the facility budget to bear the cost of a study, the construction documents should include this scope in the project.

Breaker settings and the associated selective coordination study results should be considered a living document with a renewal period of no greater than every 5 years. This is easier to achieve when the engineers provide owners with electronic copies of the software files used to generate the report. Subsequent designers can modify the living document, which saves time and helps ensure that renovation projects do not have adverse impacts on existing systems. Such impacts include a change in distribution, which increases available fault-current levels above what existing panel SCCR values are, or a change in selective coordination. The latter may cause changes in existing circuit breakers from thermal magnetic to electronic trip (previously considered outside the scope of the project). Electronic trip breakers, with adjustable 

instantaneous, short-, and long-time trip settings, may not be compatible with existing panel bus arrangements or physical size. The engineer should identify these conflicts early in design, instead of relying on a coordination study by a switchgear vendor after the project is bid. To understand the impacts during design, the engineer must build an electronic model of the existing and new electrical distributions. Using software to model the existing distribution system requires extensive field take-off of all system attributes including wire sizes, wire lengths, breaker make/model, and breaker settings. Because this work will be out of the scope of a remodel project, a discussion between the engineer and owner is necessary to negotiate the scope of a study as additional services. The additional cost of a study reduces with subsequent projects when the living document is used.

In addition to updating calculations, the physical arrangement of the electrical distribution system should be updated with each project. While construction documents are required to contain all the information necessary for the bidding and installation of the electrical distribution equipment, a campus riser diagram can be simpler and provide interconnection information (see Figure 4). These diagrams should be color-coded for the various electrical branches. The arrangement of the riser diagram can identify panel location by building/wing and by floor, and these diagrams can be 2-D or 3-D isometric views. The diagrams are commonly laminated and located in main and branch electrical rooms to provide facility personnel with a quick reference during outages and fault conditions.

Another form of documentation is a floor plan that identifies the locations of electrical panels and distribution equipment. Floor plans also should contain fire ratings for walls and building separations. If possible, routes of major feeders should be identified. Designers of remodel projects will need to know what impacts their work will have on existing systems and existing distribution. When floor plans are combined with existing riser diagrams and electronic-panel schedules, the designers can accurately determine what impacts new projects will have on existing systems—and facilities can quickly access electrical distribution and have a reference for new staff.

Suggestions for improved documentation

During the design of an electrical system, equipment nomenclatures can include any combination of load name, source name, operating voltage, or equipment type. This results in a segmented set of abbreviations that only means something to the engineer that designed it, and after years of working with it, the maintenance personnel. When designing an electrical system’s nomenclature, steer the design toward simplistic. If a naming convention cannot be explained and understood in less than 5 minutes, distill it further. For example, use Main SWBD 312 instead of DSM-310-TAN-MDP.

When doing an arc flash study, it is important to precisely name each breaker. Again, simple is best. Numbering breakers and future spaces within gear is a helpful way to associate each breaker with its intended attributes. Precisely identifying specific breakers for obtaining and deploying settings remains a challenge. Instead of forcing a culture change on an unwilling or unsuspecting client, leave the naming convention intact and assign each breaker a sequential number. The reason being it is far easier to refer to Breaker 2 than DSM-310-TAN-MDP UPS-2 (see tables 2 through 5) while developing, reading, or setting breaker settings.

This breaker-numbering technique can help in developing, setting, and testing breakers during the final stages of commissioning for selective coordination or an arc flash study. These tables can be a part of a campus standard for panelboard circuit labeling, which should be part of an electronic document that the facility maintains. These tables can contain breaker settings for selective coordination, arc flash data, and PPE level.

Labeling requirements for arc flash hazards are defined in IEEE 1584-2002: IEEE Guide for Performing Arc Flash Hazard Calculations as well as NFPA 70E. These requirements include both a hazard classification as well as technical information for energy calculation and the level of PPE required. These standards also refer to UL 969 for label adhesion and durability. Examples of how IEEE 1584-compliant arc flash labels use the ANSI Z535 color and naming designations are shown in Figure 5. The description of “danger” is used when no safe PPE exists, which aligns with the flow chart suggested by ANSI.

Tips and tricks

The following suggestions can help electricians do their work:

  • Breaker setting tables usually are embedded in the report. However, no one reading the report cares what individual settings are, and no one setting the breakers cares about the report. Move the settings table to the back of the report, where it becomes an easily accessible, removable attachment.
  • Reports are 8.5×11 in., which means breaker settings tables often get crammed into the same page size. Using landscape layout makes it possible to use a larger font and still fit all the information on one standard page. Consider using an 11×17-in. size: The paper folds into a report-format footprint but still accommodates all of the information in a legible format.
  • Breaker setting tables are commonly pretty wide, as they cite quite a bit of information. Cramming them into a portrait layout forces small print. Rotate the settings table into a landscape layout so a larger font can be used. Either 11- or 12-point font is fine in a well-lit office. Use 14-point font or larger for copies used in the field where lighting may be temporary and the paper may be folded, creased, dirty, wet, or smudged.
  • The most common errors between the field and the software result from incorrect breaker frame or trip units being read or picked in the software. The breaker setting attachment should include as much information about the breaker itself. Any differences should be communicated back to the software operator and designer. Furthermore, the importance of specific settings cannot be understated. A single click of a setting dial or DIP switch could be the difference between wearing enough PPE or not.
  • Reading individual settings while simultaneously referencing between a table in your hand and a breaker at the end of your screwdriver can easily lead to referencing the wrong cell on the table. Errantly jumping cells to an adjacent breaker could drastically change the results. Adding shading to alternating columns or rows in the breaker settings table helps reduce this common error.
  • Changing a breaker setting is another opportunity for error. This can be fixed by showing the previous setting in addition to the new setting. Boldface changes help electricians focus on what is important. Tracking changes made to settings is equally important to allow confirmation and adjustment if needed.
  • Some breakers use mechanical dials instead of electronic buttons. The settings in the software do not always use the same terminology as what is printed on the breaker face. Including both the dial nomenclature and time-setting value removes a miscommunication or misinterpretation.
  • Breaker time settings can range from whole numbers to decimals. Including a leading zero helps clarify when a decimal is needed instead of a whole number. For example, .1 can easily be confused with 1; use 0.1 to avoid this error.

Implementation of documentation standards is a cooperative effort between designers and facility personnel. While code requirements are independent of design opinions, many labeling options are voluntary. Regardless of the type of facility, safety improvements are desirable. Labeling and identification methods play a key role in increasing safety and reducing downtime during a fault condition.

 

Table 1

Recommended font sizes based on viewing distance

Safe
condition

Hazardous condition

Minimum safe viewing distance

Minimum font size (points)

Recommended font size

Recommended letter height

Less than 1 ft.

8

8

0.084 in.

2 ft.

10

16

0.166 in.

3 ft.

12

19

0.252 in.

4 ft.

14

22

0.336 in.

5 ft.

16

25

0.420 in.

6 ft.

18

28

0.504 in.

7 ft.

20

31

0.588 in.

8 ft.

22

34

0.672 in.

Source: IMEG

 

Table 2

During design: common

Gear

Breaker (load)

DSM-310-TAN-MDP

Main

 

UPS-1

 

UPS-2

 

Spare

 

Fire pump ATS

 

Mechanical DP

 

Chiller 5 ATS

 

Spare

Source: IMEG

 

Table 3

During design: better

Gear

 

Breaker (load)

Main SWBD 310

1

Main

 

2

UPS-1

 

3

UPS-2

 

4

Spare

 

5

Fire pump ATS

 

6

Mechanical DP

 

7

Chiller 5 ATS

 

8

Spare

Source: IMEG

 

Table 4

During design: best

Gear

Breaker (load)

100 series

101

 

102

 

103

 

104

 

105

 

106

 

107

 

108

Source: IMEG

 

Table 5

After design

 

Gear

Breaker (load)

1

DSM-310-TAN-MDP

Main

2

 

UPS-1

3

 

UPS-2

4

 

Spare

5

 

Fire pump ATS

6

 

Mechanical DP

7

 

Chiller 5 ATS

8

 

Spare


Source: IMEG


Richard Vedvik is a senior electrical engineer and acoustics engineer at IMEG Corp. He is a member of the Consulting-Specifying Engineer editorial advisory board.

Dan Winter is a mission critical preconstruction manager at Faith Technologies.


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