(Electrical Distribution and Protection)
From this Article:
System downtime is reduced when overcurrent protective devices are selectively coordinated. Designers should strive to limit the outage to only that circuit which is overloaded or which has faulted in... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
Articles 409.110 and 670.3 in the National Electrical Code® require industrial control panels to be clearly marked with a Short Circuit Current Rating (SCCR). NEC® recognizes UL 508A, the... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
OSHA's 29 CFR Part 1910.132(d) states: The employer shall assess the workplace to determine if hazards are present, or are likely to be present, which necessitate the use of personal protective... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
The arc flash hazard calculation method proposed in IEEE 1584 is based on tests with the arcing electrodes in a vertical plane and the calorimeters arranged at 90° to this plane. In this paper the... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
In power electronic applications, proximity and skin effects cause an increase in the resistance of fuse elements and possible unequal sharing of the total current between multiple parallel elements.... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
As of April 26, 2006, suppliers of UL listed Industrial Control Panels (ICP) must clearly label the Short Circuit Current Rating (SCCR) of each panel so that users can properly apply them per National... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
Conventional arc flash hazard calculators use simple formulae to calculate the flash protection boundary and the incident energy density, but these methods do not represent the effects of the power... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
Based on previous statistics, it's expected that the explosive energy released during arcing faults will send more than 2,000 American workers to burn centers this year. Most of these people will not... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
Transient voltage surge suppressors (TVSSs) using MOV technology are widely used to protect power systems and components against the effects of transient overvoltages. However MOVs can fail... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
Current-limiting fuses can limit arc flash incident energy to low values provided that the arcing fault current exceeds the fuse's threshold current. Threshold current is defined as the lowest... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
Arc flash incident energies can often be significantly reduced by simply replacing UL Class RK5, Class K, and Class H fuses with A6D UL Class RK1 fuses. This is an easy and inexpensive solu¬tion,... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
Current limiting fuses can reduce both the magnitude and duration of a fault current. A UL Listed, current limiting fuse must clear a short circuit current in less than one half cycle in its current... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
This paper discusses analytical techniques and new technology that allow switchgear CBs to use sensitive instantaneous settings and maintain selectivity when using traditional electronic trips in... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
Interest in complete overcurrent device selectivity has increased due to the addition of selectivity requirements to articles 700, 701, and 708 of the National Electrical Code (NFPA70). Many users,... (View Full Article)
(Surge Suppressors)
From this Article:
Since 1985, Underwriters Laboratory (UL) 1449 standard has been providing safety guidelines for Surge Suppression, a topic found in the past to have very little structure or commonality across the... (View Full Article)
(Surge Suppressors)
From this Article:
Concerns about Surge Protective Device (SPD) failures in the field and device performance have led to some major changes in the industry in recent years. Most of the safety issues have centered on the... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
Ground-faults and ground-fault protection in solar photovoltaic (PV) arrays are discussed in this Tech Topic. Ground-faults in PV arrays could potentially result in large fault current which may... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
Line-line fault and its protection in solar photovoltaic (PV) arrays are discussed in this paper. Depending on fault locations, the magnitude of line-line faults in PV arrays could be high enough to... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
NFPA 70E is a consensus standard whose stated purpose is to provide practical electrically safe work conditions. The development of NFPA 70E was originally promoted by OSHA in 1975 and the idea was... (View Full Article)
(Surge Suppressors)
From this Article:
Specifiers and users of Surge Protective Devices (SPDs) are adjusting to new terminology and requirements. UL revised their 1449 Safety Standard for Surge Protective Devices to increase safety. The... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
Arc flash incident energy calculations are frequently above 40 cal/cm2 for equipment connected directly to the secondary of power transformers. In some cases, it may be possible to reduce energies... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
NFPA 70E is a consensus standard whose stated purpose is to provide practical electrically safe work conditions. The development of NFPA 70E was originally promoted by OSHA in 1975 and the idea was... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
http://ep-us.mersen.com/resources/media/articles/TT-PVPN5-Sizing-Fuses-of-Photovoltaic-Systems-per-NEC-Tech-Topic.pdf... (View Full Article)
(Surge Suppressors)
From this Article:
Power surges occur daily and the equipment within your own facility accounts for roughly 80% of all disturbances. As a result, Surge Protection Devices (SPD) are being used at more facilities to... (View Full Article)
(Electrical Distribution and Protection)
From this Article:
UL standard 2579, officially titled "Fuses for Photovoltaic Systems" was first released as an outline of investigation in December 2007. Since its inception, and with the help of many industry experts... (View Full Article)