NFPA Journal - May/June 2013 - (Page 62)

— . CODES IN REVIEW . — NATIONAL ELECTRICAL CODE Green + Greener A primer on NEC changes to safeguard renewable-energy technology and other systems Like the 2011 edition of NFPA 70®, National Electrical Code®, the 2014 edition of the NEC will also feature a number of changes designed to increase safety related to a variety of green technologies. New shutdown procedures are also included for wind turbines, including a readily accessible shutdown button or switch that would either stop the turbine rotor or de-energize the turbine output circuit. hazard marking Hazard marking for alternative energy systems became an important issue this code cycle, and proposed new requirements and an “informational note” in Article 110 of the NEC will address hazard markings for all systems covered by the code. The requirements will address hazard marking signage details including legibility, color, wording, and durability, and are designed to help provide clearer, more effective hazard warnings to electrical workers, inspectors, and anyone else working in close proximity to these systems. “We’ve had warning markings in the NEC for a while,” says Mark Earley, NFPA’s chief electrical engineer, “but these new requirements provide a more standardized approach to help provide more effective signage.” electric vehicles Like the 2011 edition of the NEC, the new edition also includes important proposals aimed at electric vehicle (EV) charging technology. One proposal provides new requirements for branch circuits that supply power to EV charging equipment, specifying that these circuits should be dedicated to EV charging equipment in order to prevent circuit overload. Locking and disconnecting Another NEC-wide change with important ramifications for renewable-energy technologies is a proposed new section that would standardize requirements for “locking” and “disconnecting” the power source so that electrical equipment can’t be accidently re-energized during maintenance or repair. “The idea is to ensure that when equipment is disconnected and locked out, that you make sure it’s truly disconnected and locked,” says Earley. “These new centralized requirements will make that process clearer and easier to follow.” PV and wind turbine shutdown Related to disconnection and lockout are new requirements for the shutdown of photovoltaic (PV) systems and wind turbines. For PV systems, Earley says, the idea is to be able to shut a system down rapidly for maintenance or to fight a fire. “PV is unique in that if you disconnect it during daylight hours, it can still be energized,” he says. “This is a real concern for the fire service—they can’t just call the utility to come out and shut a PV system off, because in most circumstances the system doesn’t belong to the utility.” The new provisions would outline how to shut down such systems quickly, and how to make sure the system is no longer energized and is safe to work around. 62 NFPA JOURNAL MAY/JUNE 2013 dC and energy conversion Another set of new requirements that could affect alternative energy sources addresses direct current (DC), specifically in the conversion processes that can result in lost energy. “PV systems, for example, generate energy in DC, which is then converted to alternating current, or AC,” Earley says. “Wind power is generated in a sort of ‘dirty’ AC that’s converted to DC, then finally back to AC. Each time you do a conversion you lose a little bit of energy, and the idea with these requirements is to save that energy by eliminating some of the conversion.” energy management systems and smart grid Finally, a new section of the code, Article 750, will introduce energy management systems (EMS) into the NEC. While not specific to alternative technologies, EMS can be an important component of smart grid power management, a grid-wide approach to creating a consistent supply of power based on predicted needs. EMS tools allow a facility’s energy load to be spread over the course of a day, allowing for smaller, more economical systems. “If you have a commercial property with EV charging stations, for example, the rules require you to factor in all of the elements, including some very large equipment, into your power load, meaning you often have to design for that very large load,” Earley says. “EMS allows you to switch where that power is going over the course of the day, spreading it out, so you’re doing it much more efficiently and with a smaller system.” The new article, which will focus on EMS use in commercial and industrial campus applications, was produced by the correlating committee’s Smart Grid Task Group.

Table of Contents for the Digital Edition of NFPA Journal - May/June 2013

NFPA Journal - May/June 2013
Contents
First Word
In a Flash
Perspectives
Firewatch
Research
Heads Up
Structural Ops
In Compliance
Buzzwords
Outreach
Electrical Safety
Wildfire Watch
Treasurer's Report
Work in Progress
Amping It Up
Drill Team
Working Together
Code Process 2.0
Routine Maintenance
Here, There, Everywhere
Section Spotlight
Expo Preview: Exhibitors' Showcase
Looking Back

NFPA Journal - May/June 2013