Restricted Approach Boundary

[SG-1]

We have a 50KV AC dielectric test set. Many years & managers ago we installed a plexi-glass shield between the operator & the spout. There is about 24 inches of air gap between the two, because the spout comes out of the top of the unit.

Recently someone broke the barrier & it was removed. The current manager sees no reason to replace it.
It seems to me that it violates 70E restricted approach boundary of 31 inches. This machine is never used above 36KV.

Am I on firm ground with my reasoning ?

 

[WorkSafe]

There are others here that are far more knowledable in this field then I, so take what I have to say with a grain of salt.

70E (Annex C, C.1.2.) states UNQUALIFIED persons cannot cross the restricted approach boundry. Only qualified individuals wearing proper PPE can.

Has the new management even looked in 70E?

Also, I know the old plexi barrier is gone, but was that a arc rated piece of safety equipment? If it were just a typical piece of plexi, it most likely served no safety purpose at all in a real ARC flash event.

 

[jim dungar]

Was there a risk analysis performed that addressed the presence of these barriers?

Barriers are very good at reducing the chance of an electric shock. The majority of time, the barriers are in place to reduce the risk of an arc occurring, there is really no barrier that can mitigate the effects once an arc occurs. This is why NFPA 70E requires you wear the appropriate arc rated PPE whenever you are inside of the arc flash boundary.

 

[petersonra]

I am inclined to agree with the manager on this one.

The barrier was an insulating barrier that provided some protection from electric shock but none from arc flash, regardless of the HRC level.

Anyone that is close enough to the thing to be in danger of being electrocuted stills needs to wear the gloves and other PPE that protects one from electrocution regardless. That would seem to make the plastic barrier redundant and unnecessary.

 

[SG-1]

Was there a risk analysis performed that addressed the presence of these barriers?

Barriers are very good at reducing the chance of an electric shock. The majority of time, the barriers are in place to reduce the risk of an arc occurring, there is really no barrier that can mitigate the effects once an arc occurs. This is why NFPA 70E requires you wear the appropriate arc rated PPE whenever you are inside of the arc flash boundary.

This barrier was installed for the prevention of electric shock. To seperate the operator from the energized spout. No one wanted a lightning bolt between their head or hand & the spout. The barrier also prevented operation of the equipment when lowered. The barrier was henged so that it covered the control panel when the machine was not in use.

The study concluded that the test area was HRC 0. The personal are only at risk of electric shock.

No risk analysis was performed to see if the existing barrier was necessary or not.

 

[SG-1]

I am inclined to agree with the manager on this one.

The barrier was an insulating barrier that provided some protection from electric shock but none from arc flash, regardless of the HRC level.

Anyone that is close enough to the thing to be in danger of being electrocuted stills needs to wear the gloves and other PPE that protects one from electrocution regardless. That would seem to make the plastic barrier redundant and unnecessary.

The plastic barrier prevented the operator from entering the prohibited zone. I do not consider that as redundent.

 

[SG-1]

There are others here that are far more knowledable in this field then I, so take what I have to say with a grain of salt.

70E (Annex C, C.1.2.) states UNQUALIFIED persons cannot cross the restricted approach boundry. Only qualified individuals wearing proper PPE can.

Has the new management even looked in 70E?

Also, I know the old plexi barrier is gone, but was that a arc rated piece of safety equipment? If it were just a typical piece of plexi, it most likely served no safety purpose at all in a real ARC flash event.

Around here 70E is a fuse !

I just learned that concrete is a good insulator a few weeks ago.

 

[T.M.Haja Sahib]

The study concluded that the test area was HRC 0. The personal are only at risk of electric shock.

An arc flash can result from either a phase-to-phase or phase-to-ground fault caused by accidental contact with an electrical system, a buildup of dust, or an improper work procedure. It is highly unlikely that any of these can not happen in your case.

 

[petersonra]

The plastic barrier prevented the operator from entering the prohibited zone. I do not consider that as redundent.

there is no requirement for such a barrier though.

 

[zog]

A few years back I wrote OSHA for clarification of shock protection requirements when using hipots, they responded telling me that as far as shock protection requirements go, the same requirements apply for a 50kV hipot as a 50kV power system. Wish I still had that letter, lost it.

 

[SG-1]

there is no requirement for such a barrier though.

I understand what you are saying & accept it.

Thank You, because that is what I was asking.

Steve

 

[SG-1]

A few years back I wrote OSHA for clarification of shock protection requirements when using hipots, they responded telling me that as far as shock protection requirements go, the same requirements apply for a 50kV hipot as a 50kV power system. Wish I still had that letter, lost it.

A one size fits all solution.
Hipot = 100mA of fault current.
Power system = 30,000 amps +.


Are you watching the eastern morning show with Venus, Jupiter, & Aldebaran ? The best time is around 5:30.

 

[don_resqcapt19]

A one size fits all solution.
Hipot = 100mA of fault current.
Power system = 30,000 amps +.



Are you watching the eastern morning show with Venus, Jupiter, & Aldebaran ? The best time is around 5:30.

The shock hazard is the same. The 100mA is enough to kill. The arc flash hazard would not be the same.

 

[SG-1]

The shock hazard is the same. The 100mA is enough to kill. The arc flash hazard would not be the same.

Don, the PPE is the same, correct ?

 

[don_resqcapt19]

Don, the PPE is the same, correct ?

No. The votlage protection PPE would be the same. The arc flash protection PPE would not be the same. The 100mA souce may require nothing more than a long sleeve non-melting fabric and safety glasses. The high current source may require a full arc flash suit with hood.

 

[SG-1]

Thank you, Don.

 

[hawkeye23]

GE CIRCUIT BREAKERS

GE CIRCUIT BREAKERS

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