Arc-Resistant Switchgear in Arc-Hazard Mitigation Scheme

[Sly1]

Hello All;

I was just interested in some opinions on Arc-Resistant switchgear being utilized in your facilites as part of an Arc-Hazard mitigation strategy. The basic argument being that most arc-flash incidents happen when the door to the cubical is open, so what good is an arc-resistant enclosure.

I would appreciate your thoughts.

Thanks

 

[dpc]

Maybe most, but certainly not all. I think there is a tendency to reduce the issue arc-flash safety to the single goal of reducing the level of PPE required. But the real goal should be reducing risk.

Arc-resistant switchgear will unquestionably be safer than standard switchgear. Whether it is worth the added cost probably depends on the situation.

It is true that the doors must be closed to get the full benefit of arc-resistant switchgear. But if the switchgear is located in area that frequently has people within the flash hazard boundary, I think there is merit in spending the extra money for arc-resistant gear. It also provides a safety factor if you have local control of breakers at the cubicle.

 

[waross]

I have seen arcs started in closed enclosures by moisture, dust, small animals, coil burnouts, worker errors (with the doors closed and the covers on) and mechanical failures. I don't accept your basic argument.
respectfully

 

[Zogzog]

Agreed, nealy all of the callouts we get to arc flash failures the doors (Were) closed. Switching (And racking) operations with doors closed seems to be the most common failures along with the reasons Waross listed (Saw a crispy bat last fall).

 

[ScottyUK]

waross,

I think the incidents which are officially reported tend to be the ones where injury to personnel occurs, and the evidence seems to indicate that most personnel injuries happen when doing live diagnostic testing or maintenance. In my experience the failures initiated by moisture / dust / critters / etc tend to fall in the category of 'stuff' happens , and are unlikely to make it into the official incident stats, at least in the UK. Thus the incident records which are released by officialdom tend to support the theory that most arc incidents happen with the door open.

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I don't suffer from insanity. I enjoy it...

 

[Zogzog]

Well put Scotty. The arcs caused by rats and such will usually occur when no one is around, therefore no injuries therefore nothing gets reported.

 

[RalphChristie]

In my opinion the future trend will be more towards arc-resistant switchgear - if you like or dislike it.

Certainly incidents can happen almost any time - doors opened or closed - but if it does happen, my wish would be (if I were in front of it) that the doors were closed and that the cubicle would be arc-resistant, or that something is in place to minimize the danger. If you have lost friends or co-workers in such an event, or seen a substation afterwards, you'll be in favour of it - I have seen too many times how substations look after electrical explosions.

It might be expensive, and it might seem to be totally unnecessary after service life, but if something does happen it can be worth the extra costs. A human life can't be replaced.

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[Zogzog]

There already are standards in place in Canada for arc resistance swgr

 

[dpc]

There are now ANSI standards also for arc-resistant gear, but nothing requires that it be used. The standards just establish criteria that must be met to allow manufacturer to call the gear "arc-resistant".

 

[54494060]

Additional comments to all the well stated positions above. Most arc flashes in Switch Gear are the result of improper and negligent "Pedictive/Peventive" Maintenance. Design for Bus Outage Maintenance is/has (in the past) been neglected for economic reasons "I suppose". Even if you install arc resistant Switch Gear, a consistent "Pedictive/Peventive" Maintenance program is a must. Breakers must be periodically inspected, cleaned, and tested. This is performed at most complexes without a problem, but the inspection and cleaning of the gear means "down time" which sometimes is costly and overlooked by management.
12fish
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