HuskyFC450
Mechanical
- Oct 12, 2012
- 8
Has the issue with NFPA 70E – 2012; Article 130 Work Involving Electrical Hazards; Section 130.5 Arc Flash Hazard Analysis -Exception No. 1 (Revision)been resolved (or clarified)? See below:
NFPA 70E – 2009 (obsolete)
Article 130 Work Involving Electrical Hazards
Section 130.3 Arc Flash Hazard Analysis -Exception No. 1
Exception No. 1 read as follows:
“An arc flash hazard analysis shall not be required where all of the following conditions exist:
(1) The circuit is rated 240 volts or less
(2) The circuit is supplied by one transformer
(3) The transformer supplying the circuit is rated less than 125 kVA.”
The above exception was eliminated in NFPA 70E-2012 and instead the 2012 edition has the following informational note 5 in section 130.5:
NFPA 70E – 2012 (current)
Article 130 Work Involving Electrical Hazards
Section 130.5 Arc Flash Hazard Analysis -Exception No. 1 (Revision)
This exception is based on language found in Institute of Electrical and Electronics Engineers (IEEE) Std. 1584—Guide for Performing Arc-Flash Hazard Calculations. Exception 1 stated that an arc flash hazard analysis shall not be required on circuits rated 240 volts (V) or less and supplied by one transformer if the transformer is less than 125 kilovolt-amperes. This exception has been deleted. In addition, an informational note will state that an arc flash hazard analysis may not be necessary for some three-phase systems rated less than 240V. It will then reference the IEEE standard for more information.
“See IEEE 1584 for more information regarding arc flash hazards for three-phase systems rated less than 240 volts.”
There are two major reasons for the change:
1. There was an unintentional inconsistency between 70E-2009 and IEEE 1584-2002. Whereas, 70E stipulated 240 volts or less, 1584 stipulated less than 240 volts. So, if you were following 70E you would not perform an analysis for 240 three-phase systems, but you would perform an analysis for 240 volt three-phase systems if you were following 1584.
2. There is considerable disagreement over the need for an arc flash hazard analysis for systems less than 240 volts. The next revision of IEEE 1584 will address the need for an analysis and will provide new guidelines depending on test results and consensus of the committee.
I have many 3-phase 208v machine control cabinets in my facility and we are "sitting on the fence" as to what we should do in regards to Arc Flash Analysis because of the above ambiguity.
Can anyone offer clarification on this?
Tom
NFPA 70E – 2009 (obsolete)
Article 130 Work Involving Electrical Hazards
Section 130.3 Arc Flash Hazard Analysis -Exception No. 1
Exception No. 1 read as follows:
“An arc flash hazard analysis shall not be required where all of the following conditions exist:
(1) The circuit is rated 240 volts or less
(2) The circuit is supplied by one transformer
(3) The transformer supplying the circuit is rated less than 125 kVA.”
The above exception was eliminated in NFPA 70E-2012 and instead the 2012 edition has the following informational note 5 in section 130.5:
NFPA 70E – 2012 (current)
Article 130 Work Involving Electrical Hazards
Section 130.5 Arc Flash Hazard Analysis -Exception No. 1 (Revision)
This exception is based on language found in Institute of Electrical and Electronics Engineers (IEEE) Std. 1584—Guide for Performing Arc-Flash Hazard Calculations. Exception 1 stated that an arc flash hazard analysis shall not be required on circuits rated 240 volts (V) or less and supplied by one transformer if the transformer is less than 125 kilovolt-amperes. This exception has been deleted. In addition, an informational note will state that an arc flash hazard analysis may not be necessary for some three-phase systems rated less than 240V. It will then reference the IEEE standard for more information.
“See IEEE 1584 for more information regarding arc flash hazards for three-phase systems rated less than 240 volts.”
There are two major reasons for the change:
1. There was an unintentional inconsistency between 70E-2009 and IEEE 1584-2002. Whereas, 70E stipulated 240 volts or less, 1584 stipulated less than 240 volts. So, if you were following 70E you would not perform an analysis for 240 three-phase systems, but you would perform an analysis for 240 volt three-phase systems if you were following 1584.
2. There is considerable disagreement over the need for an arc flash hazard analysis for systems less than 240 volts. The next revision of IEEE 1584 will address the need for an analysis and will provide new guidelines depending on test results and consensus of the committee.
I have many 3-phase 208v machine control cabinets in my facility and we are "sitting on the fence" as to what we should do in regards to Arc Flash Analysis because of the above ambiguity.
Can anyone offer clarification on this?
Tom