Code Corner – Fall 2015

Can you believe that it’s “Code Change Time” again?

I hope you have completed your study and are familiar with the 2014 edition because more than 4,000 proposals have been processed to change or update the 2014 National Electric Code (NEC). These proposals come from electricians, designers, manufacturers, inspectors and the general public. The correlating committee has evaluated, listed and developed the first revisions that could possibly become the 2017 edition, and public comments were due in late September. The committee must now review all comments and decide on what will or will not be accepted, so the new, 2017 NEC is expected to be published by August 2016.

Due to the considerable amount of interest and activity in the electrical industry, I thought it might be a good idea to focus on code changes involving the generation, distribution and storage of electrical power. Therefore, we should consider looking ahead to the following three, new articles that are proposed for 2017.

Proposed article (691) will begin to set rules and guidelines for large-scale, photovoltaic (PV) supply systems with a generating capacity of 5,000 kilowatts or more.

Proposed article (706) will provide requirements to cover permanently installed systems that can be of the stand-alone type and those that could interact with other electrical power production sources.
Lastly, proposed article (712) focuses on DC microgrids. It covers such DC sources as PV, wired turbines, fuel cells, and combination or hybrid systems that can supply power directly to a private complex or to the nationwide grid. Yes, the smart grid is coming.

In addition to safety rules already in place for articles 690, 480 and 705, these new articles provide additional guidelines to help provide safety for public properties, installers, and maintenance personnel. This is necessary because some source installations are already in place but not yet covered by the code.

To view these and other proposed changes to the 2017 edition of the NEC, visit NFPA.org/70 and click on “Next Edition” for more details.

Speaking about safety and better understanding our NEC: Have you really considered the dangers that can be encountered when installing the rapid-response, disconnecting means required by section (690.12)?

It is true that the disconnecting means must be properly identified or marked to protect first responders or fire fighters. However, unless close attention is paid to section (690.17 E) – which requires a sign that reads “Warning” Electric Shock Hazard – DO NOT TOUCH Terminals – Terminals on Both the Line and Load Sides May Be Energized In the Open Position” – people can still be hurt.

When interconnecting with a public utility, the installer usually connects to the line side where the terminals are covered with an insulation material. He or she may never read that the installation includes a PV system with back-up storage, and that it can take up to five minutes for the inverter to lose power. Consequently, the blades or fuses are alive for that length of time and are really dangerous if touched.

PV systems can pose other hazards, including excessively high temperatures below the solar array, direct exposure to UV rays from the sun, direct contact with moisture, collection of debris, damage by animals or rodents, or other direct contact with the wiring methods supporting exposed cables for PV systems. Electrical workers should exercise particular care to properly protect those cables. PV wire or USE-2 wiring must be used as listed by UL 4703 and section 690.35 (D)(3). See article 338 (Service entrance cable) for support of USE-2 cables and section 334-30 for PV cable.

There are changes coming in article 425 for Fixed Resistance and Electrical Industrial Heating Process as many now range up to 480 V and to the medium-voltage class.

And remember, electrical installations must be done in a neat and workman-like manner (110.12) and must not be exposed to physical damage (300.4). There are cable management recommendations found in ANS1/NECA1-2010.

Stay Tuned! We will be hosting a Lunch & Learn in November with special guest, Gary Hoffman, Electrical Engineer. Gary will be discussing energy cost comparisons of systems. Look for more details in our e-mail communications and on the web at www.elmd.org.

Sincerely,

Gilbert Thompson
Legislative Committee Chairperson, Electric League of Maryland