Installation Manuals vs. the NEC

How do you handle an installation manual when its warranty requirements violate the NEC?

You just completed a construction project, and your customer insists you redo the grounding because the distributed control system (DCS) must have an isolated ground. The manual says this means bonding to a driven electrode, but not to the plant's grounding system. The manual infers that an unbonded rod is electrically isolated from the rest of the system.

Your knowledge of Ohm's Law and soil resistance tells you this will lead to build-up of a dangerous potential on all equipment served by that rod. Because Art. 250 is clear about bonding — as in Sec. 250-24(b) — you would have no defense in a liability suit. You explain this to your customer, but he says “I hear what you are saying, but this system cost us $850,000. The manual says the warranty is void unless we do it this way.”

Now you have a decision to make. You can do the job right and risk nonpayment. Or you can do it wrong and pray nothing bad happens. Many contractors who operate on razor-thin margins choose to take the risk. But, you do have other options. You can look to formal problem-solving techniques, such as these:

Methodical approach . Break a complex problem down into individual components. This classic approach to mathematical problems works well when dealing with technical issues.
Systems approach . View the problem in relation to its inputs and outputs. This classic technique for managerial and production problems addresses interrelated issues.
Holistic approach . View the problem as a part of a larger whole. This “forest for the trees” approach ensures you are doing the right things (not just doing things right), to develop overall strategy.
Intuitive approach . Follow your instincts. This approach has more merit than many people think. It's effective when dealing with ethical issues, which are often choices between two right answers.
New technology approach . Look for a product to solve your problem. You can solve the problem by changing the constrictions that make it a problem.
Use of authority . Use a regulatory body or judge to force compliance. This is sometimes the only way to solve a problem with some parties.

Applying problem-solving techniques. The use of formal problem-solving techniques is an effective way to overcome the installation manual problem. You'll run across installation manual errors of other sorts. These techniques are valid for those, too. But now let's use each method to solve the grounding example.

Following a methodical plan allows you to manage the problem without leaving loose ends. We all have our tools for managing work (such as flow charts, decision trees, and punch lists), and you should use yours to manage this problem-solving process. But first decide whom you need to convince and what issues are important to them. Then, collect and present the information that will convince them. For example, the manufacturer wants to protect that DCS from transients and your customer wants an enforceable warranty. So analyze the situation with the other techniques and then develop your work plan.

Using the systems approach, we can view the DCS as a system within a framework of systems. First, draw boxes representing the DCS and the grounding system. While the vendor claims these are isolated, you can show this is not so. Without a bond to the service ground, undesirable currents like harmonics and surges will circulate in the DCS. Using Ohm's Law, you know these currents can build to a lethal touch potential — because of the high-resistance bond of earth between the electrodes. If that potential becomes an output to a person, that person can die from electrocution.

Ask your customer how to get rid of that potential. Connecting the DCS box to the grounding system box is your only option. A graphical representation shows the logic behind Art. 250-24(b). That handles the technical side of the argument, leaving you with the risk-management question.

Draw boxes to represent the unbonded electrode, vendor, customer, and an electrocution victim. Show the inputs and outputs and how these boxes affect each other. Now, count the costs. A wrongful death claim — not to mention criminal liability — could easily dwarf that $850,000 warranty. A simple risk assessment reveals an NEC-compliant installation is the logical choice.

The holistic approach focuses on fundamental questions. Most companies have a “safety first” mandate: If it's unsafe, you don't do it. Once your customer understands an unbonded installation is unsafe, the decision requires choosing between insubordination to upper management or insisting the vendor conform to sound engineering practices.

Using the intuitive approach, ask how your customer feels about the situation, but don't get into emotional arguments — those stop progress. The object is to get the customer to stop justifying an irrational position. Here are some questions you can ask:

“This doesn't feel right to you, does it?”
“You don't feel right about my installing an electrocution hazard, do you?”
“You don't think a high-voltage potential on that equipment is a good idea, do you?”
“Violating the Code to keep the warranty means endangering the system you're trying to protect. Do you think that could void the warranty?”

In many applications that involve this conflict between installation manuals and the NEC, new technology can fill the breech. For example, one product uses a spark gap to prevent low-level noise from crossing from one grounding subsystem to another while preventing touch potential from building up. This approach allows everyone to save face if the situation is political, and it solves the underlying technical problem.

If you refuse to obey the manual because it violates the NEC and invoke a third party to hammer the customer instead of using your own expertise to help the customer, you are in a position of weakness, and you irritate the customer.

Remember, you are on your customer's side. If the vendor refuses to budge, work with your customer to force the vendor to change its position. Point out the Code violation, but don't stop there, because you have a chance to provide a truly value-added service. Draft a short report outlining the engineering reasons the installation must conform to the NEC and the potential consequences if it doesn't. Consider the facts:

An unbonded electrode is a Code violation and an electrocution hazard.
Purposely designing an electrocution hazard means creating an illegal booby trap.
The warranty requires an unbonded electrode.
West's Law says a requirement with an underlying illegality is void.

Help your customer work with legal counsel and obtain a rewritten warranty that protects that $850,000 investment without requiring you to jeopardize people and equipment. Some engineers draft their own liability waiver that says the required installation violates the NEC and endangers human life. The waiver indemnifies all parties but the vendor, and it says the vendor will accept all liability if an accident occurs. You should consult an attorney before drafting or signing such waivers.

Forming a strategy . No single approach fits all customers or all situations. So step carefully. Use authority only if all else fails, but develop your case as you go along. This means keeping notes of all conversations, being cautious about written communication (especially e-mail), and developing a documentation trail as things develop.

Your goal is to provide a safe and reliable installation. While most vendors abide by the Code, many do not. Many people who write installation manuals lack the physics or electrical training to understand the implications of what they are writing. They assume “isolated ground” means one electrode not bonded (except via high-resistance earth) to another. The concept of isolating the grounding conductor all the way back to the service never crosses their minds.

If your customer decides the installation manual must supercede the Code, you have two final options. You could bond the electrode to the service entrance per Art. 250 and leave it up to the customer to break the connection after you are offsite. Or you could cut your losses and withdraw from the project.