DC Arc Flash

[DUnderwood]

We have a military customer who insists that our combiner boxes cannot be opened during the day without a hot work permit, because there is voltage present over 50 volts and it is an arc flash hazard. We explained that there is no current flow when the inverters are off and that the devices are current limited, but they still insist we need the hot work permit. Does anyone have any experience with calculating DC arc flash HRC?

 

[zog]

The 2012 NFPA 70E covers DC arc flash calculations in part, there is also the Bruce Hydro study and IEEE 1584 working groups recent published papers for a reference.

 

[don_resqcapt19]

I am not sure about the arc flash issue and the required PPE, but there are energized parts operating above 50 volts, so that is energized work and would require a permit.

My question would be if this energized work is even permitted under the rules in 70E or do you have to wait until it gets dark to work in the combiner box?

 

[jaggedben]

We have a military customer who insists that our combiner boxes cannot be opened during the day without a hot work permit,

The red part seems very strongly stated. I believe it makes a difference if you are actually going to perform work on the system, or if you just need to measure voltages or perform other tests.