How to Eliminate Blind Spots in Electrical Drawings

How to Eliminate Blind Spots in Electrical Drawings

The benefits of maintaining electrical documentation

The power distribution system within an industrial facility is a complex machine that requires continual maintenance, adjustment, and routine inspection. Well-designed systems are built with consideration for future expansion, reliable operation, efficiency, and safety. Capital projects, preventive maintenance improvements, and upgrades are easily accommodated by the flexibility of modern electrical distribution equipment; yet, one aspect of maintenance is often overlooked. Despite significant resources invested in these systems, documentation is often inadequate or nonexistent.

Poor electrical documentation

Operators are trained to keep this well-oiled machine running smoothly, but it is rare to have procedures in place for maintaining accurate documentation of the system and its components. Maintenance departments may be understaffed and lack time. There may be no in-house engineering support or a limited number of CAD licenses available to make changes. When a change is made, it may not be large or important enough to justify the effort required to update drawings; however, these small changes can add up over time. For these and other reasons, electrical documentation runs the gamut from slightly inaccurate to nonexistent.

Photo 1. Whether you assign someone internally to review and maintain electrical system documentation or contract with an outside firm, the time and resources will be worth the investment as your facility grows and changes.

Consider, for example, an ethanol plant that wished to expand its grains operation to add more storage. Due to understaffing and a gap in funding, over time, the maintenance department did not update plant records to note changes in the control system. The hammermills were tweaked and settings changed over the years to maximize throughput. When the contractor came to evaluate the facility for the expansion, he opened the PLC cabinet (the nerve center of the electrical system) and found a jumble of wires. Jumper wires were used to alter settings rather than pulling new wire, accurate labeling was never attached, and system documentation was never updated. Due to the sheer quantity of maintenance terminations in the PLC, wires were loose and improperly landed. The plant had to schedule a shutdown to prevent possible shock hazards during cleanup of the control wires. Before any design work or construction could begin on the proposed expansion, the client spent time and money cleaning up this mess. An engineer had to figure out the plant’s current state and document it (Photo 1). The contractor had to adjust the schedule for extra work. The plant lost revenue because expansion was completed several weeks later than planned.

The hazards of blind spots

One of the most important reasons to keep documentation current is because safety is compromised in an undocumented system. Upstream power sources may become unknown or misunderstood, or multiple sources may be installed into a single enclosure (without proper labeling of the hazard as required by NFPA 79, “Electrical Standard for Industrial Machinery”). Equipment may be overloaded unknowingly. Improper breaker settings or unchanged protocols may increase arc flash hazards. Arc flash labels can become obsolete from added loads or modified breaker settings. Updating safety reports, such as arc flash studies (required by NFPA 70E, “Standard for Electrical Safety in the Workplace,” to be updated every five years) is made more difficult.

Accurate documentation helps monitor and improve system reliability, such as protective device coordination, system harmonic effects from added non-linear loads, power factor optimization, and voltage stability. Reliability issues from undocumented changes can add up over the years if they are not evaluated as a whole. The impact of individual and combined changes on system reliability must be considered.

Finally, up-to-date records help manage future modifications and expansions in the system. Past upgrades and additions, often installed in separate contracts by different contractors, can push the system beyond its intended capabilities. Capital projects must be evaluated with consideration for the capacity of the existing system, which may be compromised by years of undocumented work.

Looking ahead with a clear view.The need for documentation will only increase over time. With continuous ongoing system improvements, notation for a new project is only as good as its most recent update. With these expected changes, it is less important to ask “what” or “why” electrical documentation needs to be kept current than asking “how” these updates will be done. How can a facility establish a process for electrical documentation, and then generate and maintain it accurately?

An outside consulting firm can provide advice and assistance to a client asking these questions. Where there is no existing electrical documentation procedure or process, the firm should be conscious of the unique qualities of the client it is serving. Factors a consultant should consider when addressing the need and procedures for updating and maintaining facility documentation include:

• Internal company structure and resources, such as availability of in-house engineering and AutoCAD licenses.

• Project sizes; for example, does the client typically perform large capital projects for system improvements, or are the majority of changes performed over time as smaller projects?

• Scope of existing relationships with contractors on-site; these contractors may be able to assist with maintaining drawing updates and have an excellent knowledge of any system modifications performed over the years.

•  Budget of capital projects.

• Frequency of maintenance and required drawing updates.

Photo 2. Current electrical system documentation is a valuable tool for your team and your electrical contracting partners as they plan their work off the site and work their plan on-site, saving facility owners valuable time and resources.

Balancing the factors above, a consultant may choose from several options to present as a path forward to the client. A recommendation may be made to have in-house engineering red-line drawings (Photo 2) periodically, or to hire a third party. If the resources are available in-house, the updates can be done in a timely manner and updated as changes are made or, if preferred, on a regular schedule. If contracted to an outside firm, internal resources are freed up, but there will be a need to communicate (and rely on) the outside firm. A farmed out assignment will likely be scheduled once or twice a year.

Whether a client chooses to perform drawing updates in-house or have an outside consultant drive the updates, it is important that a corporate document control plan be established. This plan should provide guidelines for maintaining documentation and at a minimum contain the following components:

• A responsibility matrix clarifying who has ownership of each document or type of document at the facility. This may include internal staff or external consulting firm contacts.

• A schedule for updating documentation that lists frequency and triggers for documentation updates.

• File locations for all significant documentation, listing both electronic and hard copy storage locations. Some consulting firms maintain the most up-to-date drawings for their clients off site in a central location on their own servers. This ensures consistency of drawings across multiple projects, whether they happen several years apart, within a few months of each other, or simultaneously.

• A quality control plan for documentation updates.

This document control plan can be used in bid specifications for capital projects or ongoing maintenance projects, and provides a valuable reference for all players involved. It should be reviewed every few years to evaluate if it is meeting client needs, and if industry or competitor standards justify changing any policies.

Even when drawings have been generated for a new project, they can quickly lose accuracy as the project nears completion. Ensure procedures are in place for updating electrical documentation as changes happen during construction. Identify a designated set of current drawings on the job site and a specific person who is responsible for updating them. Define departmental responsibilities in red-lining to ensure updates continue as planned. If documentation updates are not included in a job description or list of responsibilities, they likely will not happen. Add a documentation requirement to bid specifications for capital projects so contractors will include red-lines to project documentation in their price and planning. Hold up-front discussions with contractors, detailing what is expected and when they need to submit deliverables. Stipulate as-built drawings be delivered to you upon completion of the work. Review the red-line documents and talk through them. Make sure your expectations are clearly understood and agreed upon in writing.

Starting off on the right course can make all the difference for a new corporate-wide initiative to update and maintain site documentation. If no facility documentation exists, consider hiring an outside firm to perform an audit and create new CAD drawings. You might also consider hiring this firm on a retainer contract to continue drawing maintenance on an as-needed basis.

Documentation of an electrical distribution system may involve more than just CAD files. For large enough facilities, a software model of the power distribution system should be created and maintained with the drawing updates. Ensuring this model remains up-to-date can help maintain reliability, efficiency, and safety as modifications are made to the system. The model can also be used to evaluate future projects, such as effects on system voltage stability, harmonics, and power factor. The costs of building this initial power system model can be rolled into an arc flash study for the facility.

Two recent similar projects clearly demonstrated the benefits of having accurate and accessible documentation on file at a facility. An ethanol plant that wished to upgrade a process with the addition of substantial motor load to the system hired a consultant to design a new electrical service. Existing documentation of the medium-voltage power distribution system on-site, though underground and inaccessible during a site audit, was accurate and available in CAD. The engineering work was straightforward, and the electrical contractor had few questions and little difficulty installing what was shown on the design.

A similar project was undertaken at another facility where documentation of the existing electrical system was lacking. Underground utility drawings were found, but only in hard copy form — and they were not detailed. The engineering design took longer because drawings had to be created from scratch. Unknowns in the project conditions had to be communicated in the bid documents to the electrical contractors. When the work was performed on-site, an existing underground conduit to be intercepted was not located where estimated. Additional costs and time were added to the construction portion of the project. Having more accurate drawings available in CAD format would have prevented additional engineering and construction costs, variance between bids and actual installed costs, and delays during construction.

When drawings and models keep pace with system changes, documentation fulfills its purpose, enabling facility managers to make wise decisions in the present for future benefits to the company. Having such resources requires financial investment, adjustment of every day practice to align with new expectations, and time for those new or altered procedures to become routine. Sometimes, this transition can take several months or longer. For those willing to invest in the future, accurate electrical documentation helps a facility increase safety for its employees, improve system reliability, maximize operating efficiency, and wisely evaluate upgrade options. Looking to the horizon, a clear view of existing conditions can make all the difference in charting the right course and putting wind behind the sails.                          

Wyenberg, P.E., is a project engineer with Interstates Engineering, Inc., Sioux Center, Iowa. He can be reached at [email protected].


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