NFPA 70E, Opening of doors is an arc flash risk?
NFPA 70E, Opening of doors is an arc flash risk?
(OP)
I am trying to get some opinions on the arc flash hazard identification from Table 130.7(C)(15)(A)(a) in the 2015 NFPA 70E
The task I am most interested in is: Opening voltage transformer or control power transformer compartments.
Almost everywhere on our system I consider opening a door not an action that can cause an arc flash. As soon as someone crosses the plane of the door then I will say they need to have the proper PPE. I do work for a utility so the 70E standard does not apply for most of my work.
In this case the 70E standard does apply.
The equipment in question is a 24kV/480V pad mount transformer 1000kva, no exposed conductor on the 24kV side, exposed connection pad on the 480V side where the cables bolt to.
When I look at the risk register for this it seems very unlikely that an arc flash could occur.
What has your position been on this?
If I look at this scenario and determine the risk is low do I have to wear PPE specifically for opening the cabinet door?
Thanks for your input,
The task I am most interested in is: Opening voltage transformer or control power transformer compartments.
Almost everywhere on our system I consider opening a door not an action that can cause an arc flash. As soon as someone crosses the plane of the door then I will say they need to have the proper PPE. I do work for a utility so the 70E standard does not apply for most of my work.
In this case the 70E standard does apply.
The equipment in question is a 24kV/480V pad mount transformer 1000kva, no exposed conductor on the 24kV side, exposed connection pad on the 480V side where the cables bolt to.
When I look at the risk register for this it seems very unlikely that an arc flash could occur.
What has your position been on this?
If I look at this scenario and determine the risk is low do I have to wear PPE specifically for opening the cabinet door?
Thanks for your input,






RE: NFPA 70E, Opening of doors is an arc flash risk?
RE: NFPA 70E, Opening of doors is an arc flash risk?
RE: NFPA 70E, Opening of doors is an arc flash risk?
I don't think opinions really matter as NFPA 70E is very clear on the requirement for Arc Flash PPE when opening up covers. There have been arc flash events during opening covers and that is why the requirement is there.
RE: NFPA 70E, Opening of doors is an arc flash risk?
"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington
RE: NFPA 70E, Opening of doors is an arc flash risk?
Over here we aren't governed by NFPA 70E but we take an interest in it because there isn't an equivalent IEC or EN standard, plus we're American-owned and head office do take some interest in what we do. I agree with the guys above: the only question is whether can you lower the flash hazard sufficiently to be able use PPE at all. Unless you have some sort of unit scheme - which is unusual on a small transformer - the only protection which will help you is the HV overcurrent element and that will be relatively slow to respond to an LV arcing fault.
FWIW, the heaviest arc-flash PPE we can get is 100 cal/cm². The manufacturer's sales guy described it as being 'a bag to hold all the bits together when you go through the switch-house wall'. It's comforting to know that.
RE: NFPA 70E, Opening of doors is an arc flash risk?
RE: NFPA 70E, Opening of doors is an arc flash risk?
RE: NFPA 70E, Opening of doors is an arc flash risk?