The answers to these questions appear at the end of this newsletter.


Reassembly During Repair
After a tense period of downtime, the repair crew puts the equipment back in service. Then someone asks, “What about these leftover parts?” You look, and there you see a missing bracket, a couple of washers, a spring, and some other mysterious parts that didn’t make it back into the equipment.

Somehow, telling people to be more careful doesn’t solve the problem of incorrect reassembly. Nor does laying out the parts exactly as they came out (assuming you can do that), if somebody accidentally kicks the parts. The solution that works is the same solution used to assemble things in the first place: Use a drawing.

The equipment service manual should have exploded view drawings and/or assembly instructions. But what should you do if it doesn’t? You could create your own drawing on the fly, during an equipment breakdown. However, a better solution is to go through your equipment documentation and contact manufacturers for what’s missing. Then, you’ll have it when you need it — and no more leftover parts.


Fuses for Motor Controls
To avoid confusion when sizing fuses for motor control circuits, refer to Table 430.72(B). This provides the maximum ratings, depending on which of three conditions apply.


Operation
NEC in the Facility
For any indoor dry-type transformer of 112.5kVA or less, ensure there aren’t any combustible materials within 12 inches of it in any direction [450.21(A)]. The only way “around” this rule is if there is a fire-resistant, heat-resistant barrier between the transformer and the combustible material.

Compliance with this rule is a constant battle in many facilities, as people try to use electrical equipment rooms as storage rooms for file boxes and fluorescent lamps. If you have this battle, make it clear to management that the insurer requires NEC compliance, and failure to comply may void coverage as well as incur operational losses.


Safety
Safety isn’t the personal decision many people think it is. One person’s unsafe act endangers others. Suppose you tape up a portable cord instead of removing it from service. Then, a coworker who isn’t even using that cord touches a surface energized by it and dies from electrocution. Or, suppose you leave wire scraps on the floor. A coworker slips, falls, and is permanently disabled.

Any unsafe act can have a devastating effect on a coworker. Don’t be the unsafe person performing unsafe acts. The flipside also applies: Don’t let a coworker be that hazardous person. Report dangerous acts to your supervisor.


Quiz Answer
Answer to Electrical Troubleshooting Quiz
This situation involves widespread failures, indicating a common cause such as a transient voltage. The problem is unlikely to have been caused by a single event such as a lightning-induced transient. You probably have an ongoing transient source, such as equipment recently put into service.

But maybe existing equipment or cabling has deteriorated and become a source of damaging transients. That includes equipment at a neighboring facility.

It might not be a transient voltage, after all. You may have bonding deficiencies, due to deterioration or human error. Or, you could have any of several types of power anomalies.

How can you find the needle in this proverbial haystack? It’s simple: Use a power monitor. Because commercial offices typically don’t have power monitoring systems in place (but the day will come), use a good power analyzer or portable power monitor.