Since we are all involved in the “worst case what-if� world, I have a couple what-if scenarios to throw out for discussion.

Situation: I am in the final stages of an AFH study in an existing facility. At one of the 480 volt services, the switchgear line up consists of a main section with a 1600A BPS/1600A fuse and two separate circuit breaker distribution sections. The existing IE at the bus on the load side of the main is >40 cal/sq cm.

The service is fed from a 750 kVA utility xfmr and the actual historical peak load at this service is 620 amps. As a mitigation solution, I recommended replacing the main fuses with 1000A Ferraz Shawmut A4BQ fuses. This will lower the calculated IE enough to allow HRC 4 PPE. The facility engineer agreed and is in the process of scheduling an outage with the utility to change the fuses. At that time I will complete the study and apply the labels.

Scenario 1: (actual occurrence) the facility engineer went into the electric room and discovered a couple technicians (as in non-electricians) from a conveyor contractor hastily replacing the covers on one of the distribution sections. They were contracted to relocate a conveyor system within the facility. The MCC for this system was fed by a 700’ feeder from this switchboard. The technicians took it upon themselves to extend their scope of work to include feeder conductor demo (amazing how ambitious the price of scrap copper can make some people). What if the bomb had gone off and the geniuses’ got fried? Would OSHA find that the facility engineer and I were partially responsible for the accident because we were aware of the hazard and did not have labels installed? Would the jury?

Scenario 2: (actual occurrence) while getting quotes for the fuses, the facility engineer was told by two wholesale houses that they could sell him the identical fuses from a different manufacturer for several hundred bucks less. The calculated IE with these fuses exceeded 40 cal/sq cm. What if the facility engineer hadn’t given me the opportunity to compare the fuses and used the cheaper ones. Would the standard disclaimer have kept me out of trouble if an incident were to occur? What if the facility engineer contracted this out and the EC “value engineered� the project? Would the facility engineer still be liable?

My reports are always full of disclaimers saying the results are only valid if the conditions on which they are based are unchanged. I believe you would have a defensible position, if the substituition happened outside of your control.

The 'value engineering' part of this is one reason, I tend to shy away from fuses when they are likely to be 'replaced' in the future, like those 400A and smaller. It is amazing how many people think all fuses, in a class, are identical in performance.

Contractual protections

Here's a legal answer to scenario one that is crucial for the contracts/purchasing folks to oversee for all contractors you use: ensure all contractors provide you with insurance agreements in their contracts that name your company as an additional named insured; they should name you on their workers' comp insurance, GL/products liability/completed ops insurance, and in some cases, their auto and environmental policies. There are a number of ways to do this - if your contracts folks execute this correctly (and they usually do), and if your contractor acts with negligence, and all of it or most of it is theirs, you'll receive protection from their insurance. This would usually include criminal protections if you were charged with them. Each state has different laws. The bottom line: even if you were told you have to pay something, your contractor's own insurance company would pay.

I'm now downplaying your well-intentioned question about your own responsibility. I think we all have to do what makes the most sense, but in most states, if they exceeded their scope and violated "prudent person" practices, they would probably be held almost completely liable for their own actions. There's much room for interpretation and your legal counsel might opine differently, but it's one of your best protections against contractors who are poorly trained or violate scope. The courts will not let you abuse this - that would be against the public good, but in many venues, they will let the language in the contract rule the day.

Twm22 - I appreciate your insurance related input. Proper coverages are always in place before I begin working on a project. That wasn’t the point of my questions. I carry proper life insurance too, but I’d prefer not to collect on it just yet.

Downplaying my concerns is understandable, particularly in scenario #2. I’m comfortable that my disclaimers would keep me on the fringes of litigation. I do have a lawyer friend that refers to those disclaimers as “speed bumps�, however, if I took everything he’s told me to heart, I wouldn’t leave my house.

My main concern is with scenario #1. I was aware that a dangerous hazard existed, but deferred putting labels on the equipment because mitigation action is planned. I have since put labels on the equipment and informed the facility manager that no live work, including operating any of the circuit breakers (with covers on) in the switchgear can be performed on this equipment until the mitigation action has been completed.

To simplify and rephrase my question: What is the proper way to deal with this type of situation when mitigation is imminent? Do you put labels on equipment as soon as the hazard level is identified or do you wait for the mitigation to be completed?

My preference is to install labels 'as-found' not 'as might become'. Labels are cheap and can always be replaced once the mitigation has actually taken place.