NFPA 70E and Category 5

[SafetyDir]

My question is about getting into Category 5 equipment and how everyone handles this.

Engineers love to state the equipment is too dangerous to open while energized. This is true, but how do you verify absence of voltage per NFPA 70E once the equipment is de-energized? No one wants to expand on this.

Since NFPA 70E doesn't even recognize Category 5, how does everyone handle verification? Don a 40CAL suit? This is in violation of NFPA 70E.

The only options I see are to:
1) Get a suit with high enough CAL rating to verify. Highest suit I've seen is 140CAL.
2) Do verification in another spot in the system where the incident energy is lower. <- I've looked in NFPA 70E for guidelines on where verification can take place and can't find anything specified.

We run into a lot of service equipment over 100CAL and no GFCI, maintenance mode switch, etc and gets difficult to figure out how to open safely.

 

[jim dungar]

You should perform a risk analysis before performing work.

For example:
If the system is on line and operating , you know there are no down stream faults.
If the cover has hinges and captive screws, you know it is not likely loose hardware will cause a fault.
If known upstream disconnecting means have been opened and locked out.
Category 4 PPE is employed and worn.
Measuring probes have extensions moving the operator further than 18" from the potentially energized parts.

The problem becomes no one is really trained in a risk analysis. Most safety departments treat arc flash risk as being equal to the hazard.

 

[SafetyDir]

You should perform a risk analysis before performing work.

For example:
If the system is on line and operating , you know there are no down stream faults.
If the cover has hinges and captive screws, you know it is not likely loose hardware will cause a fault.
If known upstream disconnecting means have been opened and locked out.
Category 4 PPE is employed and worn.
Measuring probes have extensions moving the operator further than 18" from the potentially energized parts.

The problem becomes no one is really trained in a risk analysis. Most safety departments treat arc flash risk as being equal to the hazard.

I agree. NFPA states the same.

Usually when we are opening equipment with high incident energy, the power company has come out and killed power at the transformer and we have watched them verify power is not present on the secondary.
We are getting into the main switchboard that has bolted covers, not hinged. Sometimes there is no main, and the power company fuses are very large so clearing times are great. As for the condition of the system, we don't always know if regular maintenance has been done, the state of the inside, or issues in the system. All we do know is it was operating before the shutdown.
With the situation I described, wouldn't the person opening to verify need to wear PPE rated per the sticker from the Arc Flash study? What permits someone from wearing a 12CAL suit to open a 110CAL rated switchboard?

 

[jim dungar]

I agree. NFPA states the same.

Usually when we are opening equipment with high incident energy, the power company has come out and killed power at the transformer and we have watched them verify power is not present on the secondary.
We are getting into the main switchboard that has bolted covers, not hinged. Sometimes there is no main, and the power company fuses are very large so clearing times are great. As for the condition of the system, we don't always know if regular maintenance has been done, the state of the inside, or issues in the system. All we do know is it was operating before the shutdown.
With the situation I described, wouldn't the person opening to verify need to wear PPE rated per the sticker from the Arc Flash study? What permits someone from wearing a 12CAL suit to open a 110CAL rated switchboard?

Yes they need PPE

The issue is do they really need 110CAL in order to verify deenergized?
You know your hazard, now you need to determine the risk. If you are 99.99% sure the system is deenergized you might apply a different risk probability then if you aren't sure. Is the concern the unbolting and removal of the covers or the crawling in to use the meter?

This is an analysis your safety group needs to make. My safety people may have a amount of different risk aversion than your company.

 

[SafetyDir]

Yes they need PPE

The issue is do they really need 110CAL in order to verify deenergized?
You know your hazard, now you need to determine the risk. If you are 99.99% sure the system is deenergized you might apply a different risk probability then if you aren't sure. Is the concern the unbolting and removal of the covers or the crawling in to use the meter?

This is an analysis your safety group needs to make. My safety people may have a amount of different risk aversion than your company.

The rating of the PPE we need to wear is what I'm unsure about. We have always been told more is better if you are unsure.
I'd say the doors are more of a hazard because they are slick and can be dropped easily, but checking is also a concern for us.

Sounds like it will be up to us to decide this. I'll get a meeting together with our managers to discuss.

Thanks.

 

[jim dungar]

The rating of the PPE we need to wear is what I'm unsure about. We have always been told more is better if you are unsure.
I'd say the doors are more of a hazard because they are slick and can be dropped easily, but checking is also a concern for us.

Sounds like it will be up to us to decide this. I'll get a meeting together with our managers to discuss.

Thanks.

I would follow the same OSHA standards as for your general head protection. More is not always better, we shouldn't need voltage rated gloves to plug in cell phone chargers.

 

[petersonra]

Unfortunately, way too many safety experts got their expertise by going to a few weeks of classes so they are now certified as safety experts. A lot of companies are willing to accept this as adequate. The problem is that they almost never understand the real safety problems, or the various ways you can mitigate them, or even how to determine what the risk really is.

There is a fad now at some places called safety by design. In itself it is not a terrible idea but the people implementing it often seem some clueless. I have run into such people who have a cow because of the use of a fuse block that was not finger safe that is inside of a closed cabinet. The risk from that fuse block not being finger safe is so low that it is probably close to nil.

But they are willing to accept a junction box at floor level which forces employees who might have to work in it to lay on the floor or bend over at the waist. neither is very good for the human body and is fair more of a hazard than the use of a fuse block that is not finger safe.

 

[GeorgeB]

I don't know how they determine a lineset is dead, but our POCO, after killing while working (say tree on lines) will visibly short A-B-C. I suspect that if the OP prepares suitable shorting cables that his utility will install them after killing their connection and remove them before restoring power.

Visible sorting should satisfy any safety requirement, in my ignorant opinion.

 

[jim dungar]

I don't know how they determine a lineset is dead, but our POCO, after killing while working (say tree on lines) will visibly short A-B-C. I suspect that if the OP prepares suitable shorting cables that his utility will install them after killing their connection and remove them before restoring power.

Visible sorting should satisfy any safety requirement, in my ignorant opinion.

What if the disconnecting location is not under control of the utility, such as in a customer owned campus environment or internal to a manufacturing facility?

 

[David Castor]

This issue is actually discussed in the latest versions of NFPA 70E - although it's in the FPN for Electrically Safe Work Condition. A voltage test is required and generally PPE is required to perform the test for absence of voltage. The details will vary depending on the specifics of your safety program and the risk assessment. Working distance can be increased to lower incident energy and a preliminary check with non-contact probes can be performed.

Short answer - you do the best you can to perform the test while minimizing risk. Some folks want to make this some big "gotcha" that proves this is all nonsense, but I don't agree.

And as far as I have seen, NFPA 70E never directly states that live work is prohibited over 40 cal/cm2, unless something has changed in the 2024 version.

Also, just to avoid confusion for people just reading the title - as you state in your post there is no Category 5 in NFPA 70E and hasn't been for a long time.

 

[don_resqcapt19]

You install this before it is energized for the first time.

 

[SafetyDir]

You install this before it is energized for the first time.

Yes. Would make it a lot easier. We do it on the equipment we install but existing is a different story.

Point #2 in my OP.....if shutting down a main switchboard, panelboard, etc., how far down the system can someone verify power? If killing a switchboard to do maintenance, and that switchboard feeds a panel that feeds some receptacles, can the receptacles be used to verify that power is dead at the switchboard? My thinking is it cannot and shouldn't. I have electricians that disagree with me and have done that. Can't find anything stated in NFPA 70E or other documentation that states where it should be verified.

Thoughts?

 

[don_resqcapt19]

Yes. Would make it a lot easier. We do it on the equipment we install but existing is a different story.

Point #2 in my OP.....if shutting down a main switchboard, panelboard, etc., how far down the system can someone verify power? If killing a switchboard to do maintenance, and that switchboard feeds a panel that feeds some receptacles, can the receptacles be used to verify that power is dead at the switchboard? My thinking is it cannot and shouldn't. I have electricians that disagree with me and have done that. Can't find anything stated in NFPA 70E or other documentation that states where it should be verified.

Thoughts?

In general, I think it needs to be verified in the equipment that is being worked on, however I would consider a downstream verification point if the circuit between the two locations is exposed and continuously visible.
For example the switch gear feeds a transformer and that transformer feeds a panel, with 100% of the circuit visible, I could see doing the verification in the panel.

 

[garbo]

My question is about getting into Category 5 equipment and how everyone handles this.

Engineers love to state the equipment is too dangerous to open while energized. This is true, but how do you verify absence of voltage per NFPA 70E once the equipment is de-energized? No one wants to expand on this.

Since NFPA 70E doesn't even recognize Category 5, how does everyone handle verification? Don a 40CAL suit? This is in violation of NFPA 70E.

The only options I see are to:
1) Get a suit with high enough CAL rating to verify. Highest suit I've seen is 140CAL.
2) Do verification in another spot in the system where the incident energy is lower. <- I've looked in NFPA 70E for guidelines on where verification can take place and can't find anything specified.

We run into a lot of service equipment over 100CAL and no GFCI, maintenance mode switch, etc and gets difficult to figure out how to open safely.

Side note at an IAEI class we were told told that no PPE can protect you above 60 CAL due to the intensity of arc blast would blow you backwards at least 20' killing you.

 

[jim dungar]

Side note at an IAEI class we were told told that no PPE can protect you above 60 CAL due to the intensity of arc blast would blow you backwards at least 20' killing you.

There is no industry wide accepted methodology for determining arc blast, like there is for arc flash incident energy.

Your instructor is making an unsubstantiated claim, probably because they were taught that misconception by their instructor.