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Illustrated Catastrophes

Jun 1, 2010 12:00 PM, By Brian J. McPartland, NEC Consultant

As usual, never consider the following commentary associated with these photos as a formal interpretation of the National Electrical Code (NEC). Without criticizing anyone or any product, the following scenarios present us with serious safety questions.

Now That's One Hefty Grounding Electrode

This photo was taken at a shopping mall where the water service had been relocated by the local waterworks company. However, it seems clear that those involved with the project did not have any background in electrical design or installation. As a result, even though they removed the water pipe electrode, they dutifully left the water meter and the grounding electrode conductor attached to the building and street side of the water meter. It's hard to imagine what they thought this connection was all about, but it seems they felt that as long as they didn't remove it everything would be hunky-dory.

I don't believe that Code Making Panel 5, the panel responsible for overseeing the requirements of Art. 250, had such an occurrence in mind when they removed the reference to 250.52(A)(1) in 250.52(A)(2)(2) in the 2008 NEC. In fact, the concern was related to the reality that more and more city water systems are changing over to nonmetallic piping, essentially eliminating the earth connection, which is required to provide for lightning discharge and voltage stabilization.

In the 2005 edition of the NEC, 250.52(A)(2) recognized ungrounded building steel as being grounded where it was connected to a water-pipe electrode. And, where such a connection was provided, the building steel could be considered as supplementing the water-pipe electrode, which is required by 250.53(D)(2). However, the elimination of the reference in 250.52(A)(2) to 250.52(A)(1) effectively eliminates the possibility of using the water-pipe electrode to ground the ungrounded building steel and then use the now-grounded building steel to supplement the water-pipe electrode.

It should be noted that as given in 250.104(C), where ungrounded exposed building steel is likely to become energized, it must be bonded to any one of several locations in the grounding electrode system. The last location identified in this section is “one or more grounding electrodes used,” which would include the water-pipe electrode. So, for compliance with 250.104(C), it is still permissible to use the water pipe, but it's no longer permissible to supplement the water pipe by connection to ungrounded building steel.

Pure Genius

The photo on page 37 is an excellent example of the creative nature of some human beings. Although quite resourceful — and probably functional — this installation does not satisfy the rules of the NEC. Specifically, 406.6(B) would prohibit such an application. The first sentence of this rule states, “Attachment plugs shall be installed so that their prongs, blades, or pins are not energized unless inserted into an energized receptacle or cord connectors.”

Apparently, whoever did this didn't need the fan anymore, so he simply cut the internal conductors and taped them to the attachment plug to provide power to another piece of cord- and plug-connected equipment. Note how this person used adhesive tape to secure the conductors to the plug cap. Fabulous! But you have to admire his desire to provide some strain relief with the extra long support screw. I'm sure this ensures the weight of the cord doesn't pull the “connection” loose. Brilliant!

This photo should also make you think about the topic of field modifications. Does Underwriters Laboratories (UL) permit alterations of listed equipment in the field? Here's my understanding of what it has to say on the topic.

With regard to field modifications, UL states that any modification of the original configuration does not necessarily “void” the listing. However, the new configuration may or may not be capable of successfully passing the applicable testing standard. The only way to be sure your modification is acceptable is to have UL perform an on-site field evaluation of the newly configured equipment. What that means is, until such a field evaluation is completed — and the newly configured product has been empirically determined to meet the applicable standard — you have what is called an “unknown” condition.

In my opinion, if there was an accident or incident involving field-modified equipment, the person who modified the equipment could be held liable until such time the modification could be deemed “safe.” However, if the modified equipment does not meet the applicable standard, then those responsible for reconfiguring the equipment would most likely be viewed as legally responsible for any injuries or deaths. Suffice it to say, it's best to minimize any field changes in listed equipment — and where it's necessary to do so, make sure such a change is done in accordance with manufacturer's instructions and written procedures, using the parts and/or kits it identifies as acceptable.

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