fraymond
Member
- Location
- Huntsville, Alabama
At what point is full arc flash PPE require for 120vac enclosure? If arc flash PPE is not required what shock protection PPE is required to troubleshoot? Not trying to talk short cuts...
PPE Requirements for 120vac Panel
- Thread starter fraymond
- Start date
- Status
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
It is not clear to me that 120V (only, i.e. not 120-0-120 for 240 line to line) can support an arc flash.
Above 50V is considered PPE territory for industrial and commercial. Howsoever there is no Arc Flash PPE requirement for residential panels!!!!
- Location
- Massachusetts
- Location
- Massachusetts
Are you on the same page as the OP?
We are not talking about AFCIs here we are talking about if you can get an dangerous arc from a panel with 120 circuits in it.
wbdvt
Senior Member
- Location
- Rutland, VT, USA
- Occupation
- Electrical Engineer, PE
The current standard for calculating incident energy (arc flash) is IEEE 1584-2002. In it, it is stated that the equations for calculation only apply to 3 phase circuits as there was no testing done and the thought is that any arc would extinguish quickly and an arc could not be maintained. Therefore, typically single phase circuits are defaulted to <1.2 cal/cm2 similar to the exemption for circuits supplied by transformers <125kVA and below 240V. This is basically non melting clothing, safety glasses, long sleeve shirt, gloves for shock hazard.
fraymond
Member
- Location
- Huntsville, Alabama
I thank you all for the response. The maintenance team already are required to wear FR shirts/jackets & britches as well as hearing protection & Z rated safety glasses. They also use the thick rubber gloves with a outer leather glove. I'll do a bit more IEEE 1584-2002 research and hopefully find shock resistance gloves. Thanks again
But are they mandated??? I am NOT saying they are not needed since the possibility exists. I am also NOT talking about working on live panel.....only operating breakers.
- Location
- Massachusetts
If I can be exposed to an arc I need to wear PPE.
The opening poster did not state that, I assume they mean when the panel is open.
Very valid answers here Iwire.
My question however re "mandatory" is a legal one rather than an electrical/technical one. I believe the flowdown begins with OSHA and maybe some legal minds might identify the hierarchical regulatory/jurisdictional flow through to the residential application.
Thank you for your great input. I realize this q may be beyond the scope of our forum but millions of homeowners for many decades have been operating their breakers. Will that change at some point????
Last edited:
fraymond
Member
- Location
- Huntsville, Alabama
Let me begin by saying my apologies to all that have responded or read this thread. I now realize the direction this thread is going was inadvertently caused by me. I should not have used the term panel. I should have said industrial enclosure with only 120VAC controls for relays and a PLC. Again my apologies :dunce:
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
OSHA does not apply to homeowners working on their own equipment, OSHA is about workplaces. But a contractor doing work at a residential installation is what makes it constitute a workplace, so for that contractor (or employee of a contractor), OSHA rules do apply.
OSHA does not get down to the nitty-gritty details, it simply states that an employer shall provide a safe work environment, AND have an electrical safety program that is reviewed regularly and that employees are trained on periodically. It SUGGESTS that the safety program might be best modeled after NFPA 70E, but even that is not mandated. Nowhere in the NFPA 70E documents does there exist a specific exception for residential systems being worked on by electricians. But what it DOES say is that a Risk Assessment must be preformed, and part of ANY risk assessment procedure will be the use of appropriate PPE for an assigned task. Not using the appropriate PPE is thereby an immediate violation of any Safety Procedure.
In the past, there used to be a "PPE Zero", meaning essentially no PPE. That is gone, the lowest level of PPE is now PPE-1, i.e. minimal (but not zero) PPE:
PPE 1
Arc-Rated* Clothing, Minimum Arc Rating of 4 cal/cm2
Arc-rated long-sleeve shirt and pants or arc-rated coverall
Arc-rated face shield or arc flash suit hood
Arc-rated jacket, parka, rainwear, or hard hat liner
Protective Equipment
Hard hat
Safety glasses or safety goggles
Hearing protection (ear canal inserts)
Heavy duty leather gloves
Leather footwear
The thing is, there are different TASKS that can be performed WITHOUT the use of PPE at all. One of those tasks is the operation of circuit breakers in 240V panels where the available fault current is less than 25kA, with the covers installed (and it is properly maintained, installed etc. etc.). So flipping breakers on and off in small residential 120/240V single phase panels does NOT need Arc Flash PPE.
Once your remove the panel and are exposed to live parts, you DO NEED arc flash PPE, and although technically a risk assessment should be done, chances are about 99% that PPE 1 will be sufficient in any residential load center.
*Note that clothing must now be ARC RATED, (AR), Flame Retardant (FR) is no longer enough.
OSHA does not get down to the nitty-gritty details, it simply states that an employer shall provide a safe work environment, AND have an electrical safety program that is reviewed regularly and that employees are trained on periodically. It SUGGESTS that the safety program might be best modeled after NFPA 70E, but even that is not mandated. Nowhere in the NFPA 70E documents does there exist a specific exception for residential systems being worked on by electricians. But what it DOES say is that a Risk Assessment must be preformed, and part of ANY risk assessment procedure will be the use of appropriate PPE for an assigned task. Not using the appropriate PPE is thereby an immediate violation of any Safety Procedure.
In the past, there used to be a "PPE Zero", meaning essentially no PPE. That is gone, the lowest level of PPE is now PPE-1, i.e. minimal (but not zero) PPE:
PPE 1
Arc-Rated* Clothing, Minimum Arc Rating of 4 cal/cm2
Arc-rated long-sleeve shirt and pants or arc-rated coverall
Arc-rated face shield or arc flash suit hood
Arc-rated jacket, parka, rainwear, or hard hat liner
Protective Equipment
Hard hat
Safety glasses or safety goggles
Hearing protection (ear canal inserts)
Heavy duty leather gloves
Leather footwear
The thing is, there are different TASKS that can be performed WITHOUT the use of PPE at all. One of those tasks is the operation of circuit breakers in 240V panels where the available fault current is less than 25kA, with the covers installed (and it is properly maintained, installed etc. etc.). So flipping breakers on and off in small residential 120/240V single phase panels does NOT need Arc Flash PPE.
Once your remove the panel and are exposed to live parts, you DO NEED arc flash PPE, and although technically a risk assessment should be done, chances are about 99% that PPE 1 will be sufficient in any residential load center.
*Note that clothing must now be ARC RATED, (AR), Flame Retardant (FR) is no longer enough.
Last edited:
Thank you Jraef for this clear description as to how you view the subject. It is very much in parallel with what I had assumed. Having read many documents one does need some interaction since I have found inconsistencies both within the same docs and between docs. That is not surprising since we are all interpreting language and content which all have ambiguity.
I hope this is helping the OP since I do not want to hijack his thread.
I hope this is helping the OP since I do not want to hijack his thread.
- Status