Arc Flash Enclosures (inside Flange enclosure)

Is anyone seeing a bump in the need for Arc flash enclosures inside electrical enclosures? Is there a change to a safety code (or upcoming change) that I'm not aware of?

Examples:
Hoffman AID1412
Saginaw SCE-60AFSD

Some of my customers are making these things standard now instead of our usual Lexan covers (which are now no longer acceptable for some reason).

Anyone used these? Advantages / disadvantages?

They are about double the cost of our lexan, but I have to believe (hope) they are a little easier to install.

Those two devices look absolutely identical, don't they ?

If you want a deep dive into the regulatory history of arc flash analysis, protection, and labeling, there's a really good article in Occupational Health and Safety Magazine:

https://ohsonline.com/articles/2014...hazard-analysis-requirements-are-not-new.aspx

In my experience, my customers are taking gripes from their maintenance crews not wanting to put on a "bomb suit" to open a 480V panel, and making segregated power disconnects a requirement, and adding requests or requirements for these kinds of inside-the-panel protective enclosures.

Hoffman's initial entry into the market was the "Sequestr" disconnect, which was bulky and expensive. I like these a lot better.

Customer requirements seem to take a very long time to catch up with regulatory changes, especially in the USA where adoption of safety standards are largely driven by insurance and litigation, not by powerful regulatory agencies.

Arc Flash has been a hot topic for 10 years now, I personally think the risks should be mitigated through engineered solutions whenever possible. Isolation of high/low voltage and these types of enclosures will become quite common.

I was working at a facility that required electrical permits, face shield, rubber gloves for simply opening a control panel that had 120VAC to supply a 24VDC power supply using finger safe terminals. Don't be surprised if you see an uptick in 120VAC separation as well, shock hazard awareness has been heightened with Arc Flash education.

Always amazes me the arc flash warning on control panels in the US.

Never seen anything of the sort in the UK, aside from when we get to voltages >1000 V Ac or 1500v DC.

Are there really that many arc flash issues in the US? Is it construction of panels problem, training of techs working on them or a bit of both?

Rob,

because I work for a Canadian-owned company, when they look at safety, we are getting asked about arc-flash risk assessments, and you are right, there is not so much over here. We normally work in panels that can have 415V AC contactors and drives running away quite happily, along with PLC equipment. The guys are aware of the live voltage issues, but maybe not so much on the Arc Flash potential.

HV - we had one company in who can modify our older 11kV switches to have strengthened front doors, but we never do local switching of these, almost in a remote room.

PPE - we do have protective trousers and jackets, but only to a low-level, and are adding polo shirts of a similar protective material, but only as a trial at the moment.

Agree, most if not all of the HV switching I do now is remote, but for some of the older OCB equipment this isn't possible.

In which case fireproof overalls are worn an a flash visor.

I've only seen one incident of an arc flash injury, an that was an apprentice sweeping up and knocked swarf onto some live bus bars, the investigation showed that guarding had been removed for maintenance and never put back.

Thankfully the poor lad only received minor surface burns to one of his hands.

Paully's5.0 said:

I was working at a facility that required electrical permits, face shield, rubber gloves for simply opening a control panel that had 120VAC to supply a 24VDC power supply using finger safe terminals. Don't be surprised if you see an uptick in 120VAC separation as well, shock hazard awareness has been heightened with Arc Flash education.

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I have taken a basic arc flash course and I get that it covers 120V, but what I don't understand is how a scenario such as this--120V in a panel with all fingersafe components--is any different than the 120V receptacle next to my desk. If I get down on the floor I can peer into the outlet and see the live contacts... certainly I could stick something in there and zap myself, or an arc fault could occur in the process of plugging something in. Why am I not required to be wearing proper PPE when plugging in my phone charger???

kolyur said:

I have taken a basic arc flash course and I get that it covers 120V, but what I don't understand is how a scenario such as this--120V in a panel with all fingersafe components--is any different than the 120V receptacle next to my desk. If I get down on the floor I can peer into the outlet and see the live contacts... certainly I could stick something in there and zap myself, or an arc fault could occur in the process of plugging something in. Why am I not required to be wearing proper PPE when plugging in my phone charger???

Click to expand...

The potential fault current could be higher in control panels?

Or is it the case of, someone has been injured an sued an now its just a blanket ruling to prevent anyone else being sued?

kolyur said:

I have taken a basic arc flash course and I get that it covers 120V, but what I don't understand is how a scenario such as this--120V in a panel with all fingersafe components--is any different than the 120V receptacle next to my desk. If I get down on the floor I can peer into the outlet and see the live contacts... certainly I could stick something in there and zap myself, or an arc fault could occur in the process of plugging something in. Why am I not required to be wearing proper PPE when plugging in my phone charger???

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I dont know NFPA regulations, but I am guessing it is because the energy (I²t) that can be let through before the current is disconnected is much greater in a control cabinet than in a 120V receptable.

IMO the requirement for arch flash protection must be valid for a certain treshold of energy. So there ought to be some rule of table specifying that in NFPA, but that uis just guessing.

kolyur said:

...--120V in a panel with all fingersafe components--is any different than the 120V receptacle next to my desk. If I get down on the floor I can peer into the outlet and see the live contacts...

Click to expand...

Completely agree.

If the safety team starts to read NFPA70E, and they read about shock hazards and PPE requirements above 50v and use that as a starting point for safety policies then you'll get into these situations of someone having to dig further to define grey areas. So a blanket policy of "Live work over 50V requires shock protection and electrical permits" begins to take shape.

True, arc flash is becoming more of an issue everywhere.
we had an engineering firm do a study on all our enclosures and classify the ppe requirements.

the issue is the older control panels built before arc flash ppe was required.
at my former jobsite before they moved north and let me go, we designed a control panel into 480,240,120, and 24 volt panels. I thought it was a waste of time to design them like that, but did it to make everyone happy.

Now that I have seen what arc flash does here at the plant, i'm all for it.
I am not allowed to post the plant pictures of the gear damaged by arc flash at this facility, I wished I could. it's truly an eye opener.

james

If anyone is interested, here is a paper that I found online talking about Low Voltage Arc Flash

View attachment low voltage arc flash.pdf