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 Post subject: HRC class for troubleshooting 120v equipment
PostPosted: Mon Apr 26, 2010 8:39 pm 
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Joined: Mon Apr 19, 2010 8:07 pm
Posts: 5
As a commercial kitchen equipment servicer we have technicians working on equipment in a variety of retail and food service locations. As ‘most’ of our customers have yet to conduct Arc Flash Studies and do not have Arc Flash information available for their facility how do we protect our employee’s (service technicians) at an appropriate level?
If we mandate that in the absence of an Arc Flash Study we use the tables to determine the proper PPE is this appropriate?
I’m not sure that the tables properly account for working on 120v equipment, with the power connected for troubleshooting or while verifying a safe electrical condition after applying LOTO. NFPA 70E, table 130.7(C)(9) would classify this as requiring HRC1 PPE. HRC1 requires FRC 4 cal. long sleeve shirt, FRC 4 cal. pants, safety glasses (or goggles), in ear hearing protection, 4 cal Face Shield, and a Hard Hat. In addition to this leather gloves are also required. I’m not an electrical engineer but I can’t imagine that a 120vac circuit, protected by a 30amp or less branch circuit breaker, is capable of sustaining an arc flash.
Can 120v connected equipment be considered as HRC0 for the purposes of troubleshooting with the power on?


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PostPosted: Tue Apr 27, 2010 8:52 pm 
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Joined: Thu Jan 10, 2008 8:49 pm
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Location: New England
With no labels or calculated IE values, the Table is all you have. The 120V panelboard section is intended for distribution panels and not branch circuits. So, when you say 30A breaker, I am confused as to whether you are working at the panel, or at a receptacle. If its at the panel, then you have to follow the table. For the receptacle, well the easiest is to follow the table as if a panelboard, but, if you want a reduction to the PPE you are probably right that the IE level will be low. I have seen technicians in the elevator industry standardize on one level, like HRC0 or HRC1, as they calculated out a worse for some amperage level. You could do the same. Your obligation is to follow 70E. As a service provider you can not control the workplace of your customers. So you can have your own corporate policy of compliance. As long as your policy is based upon 70E, and is written, and employees are trained, then I would say that if there were accident you would not be cited. Remember, there is no OSHA law saying you have to comply with Art 130 of 70E, with the exception that you could be cited under the 'general duty clause'. OSHA stated that if you follow 70E you would not be cited. This does not exonerate you from civil lawsuits by an injured employee, so you want to also protect yourself and the company.

The under 240V panelboard section is HRC0 or HRC1, and you only need the HRC1 for live work. So try not to work live. If you are on the panel, the Table must be used. For a branch circuit you could try to calculate a worse case and see if it comes in under 1.2 cal to stay at HRC0.


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PostPosted: Tue Apr 27, 2010 11:03 pm 
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Thanks for the reply and the comments. As I read table 130.7(C)(9) the statement in the first section of 'Panelboards or Other Equipment rated 240v and Below' that classifies "work on energized electrical conductors and circuit parts of utilization equipment fed directly by a branch circuit of the panel board" as HRC1 raised my question. This would appear to me that any utilization equipment (appliances or devices that use electricity) fed by the panel should be treated as a HRC1 hazard in the absence of an Arc Flash study that would determine the actual Hazard Risk Class. The only 'live' work our technicians should be doing is troubleshooting. Actual repairs should be done with the equipment disconnected and rendered safe following our established LOTO procedures. Of course the equipment must be regarded as 'live' until verification has been made that the equipment has been rendered safe. While employee safety is a primary concern we are also concerned with employee comfort and compliance. To strike a balance between safety, comfort, and compliance it would seem that a policy requiring HRC0 for 120v work (non-meltable uniforms, safety glasses or goggles, hearing protection, and leather gloves) be used. For voltages 208 to 600 v we would classify the work as requiring HRC2* PPE


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PostPosted: Sun Jun 27, 2010 5:07 pm 
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Joined: Fri May 01, 2009 9:10 am
Posts: 73
Catch 22

Just curious, how can one recommend Table 130 without considering the notes that state that the available fault current and clearing times must be known before the tables can be used?!? Another Catch 22?!?


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PostPosted: Mon Jun 28, 2010 8:44 am 
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It didn't take you long to catch on to our dilema. As a servicer of commercial food equipment we're really caught between a rock and a hard place trying to provide our employee's with appropriate protection. The chanches of a restaurant having conducted an Arc Flash Study are pretty slim...


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PostPosted: Tue Aug 10, 2010 10:56 am 
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Joined: Thu Jan 07, 2010 6:42 am
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Location: Bowling Green, KY
[font="Comic Sans MS"][SIZE="3"]Along with your leather gloves, you need to have rubber gloves rated for the voltage, as the leathers are only a protector for the rubbers..probably class 00 (up to 500 volts)[/size][/font]


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