How do you treat normal operating equipment at your facility?

[Shells]

Guys

This question may come across as a no-brainer, at least that's how it came across to me when I was asked but it has got me thinking if some companies take a more conservative approach. It has to do with 'normal operating' equipment as is defined in 70E. I'm sure in implementing your Arc Flash program someone may have voiced concerns around just being in the substation and whether or not they were at risk. I always say although its not impossible to happen with doors closed, the risk really is around intrusive work (i.e. doors open) and of course we are relying on proper maintenance etc. But what do you guys do? I saw one company requires a level of PPE based on the substation. Thoughts?
NB: We have metal enclosed gear for 600V and below and Metal Clad for 5kV and 15KV

 

[JFletcher]

Well, at Hampton Roads Sanitation District, shift operators of 10-40MGD waste water plants routinely walk around energized 480V and even some 4160V gear, no PPE. We start and run the generator(s) (1-2.5 MW ea) and switch the plant onto internal power via syncronizer. Of all the dangers there, an arc flash behind a locked door didnt register a blip to me in 6 years. ofc when high heat, high noise, trip hazards, engulfment/suffocation (confined spaces), nasty chemicals, biological hazards, moving machinery, and even nuclear (nearby power plant) are competing for your safety attention, energized electrical eqpt that isnt open isnt top priority.

I have seen one video of an arc flash training video blowing the locked door off and killing the dummy. Here it is:

https://www.youtube.com/watch?v=hA-w0QAaxRU

Scary for sure. and to think all the hours I spent in the control room running incinerators, not 6' from the furnace MCC gear.

 

[zog]

They did leave some room for interpretation in there for sure. I like to think of normal operation as the way the gear is 99% of the time, and that is static, doing nothing.

The big part people overlook is what does properly maintained mean, next rev of 70E will define that better but what that means is per the OEM recommendations which hardly anyone reads. T&I's on a normal basis are good but will not meet the OEM's requirements if you read the IB. When was the last time your breakers were completely overhauled? Every (power) breaker has a recommended interval for that based on time and/or # of operations.

 

[Shells]

They did leave some room for interpretation in there for sure. I like to think of normal operation as the way the gear is 99% of the time, and that is static, doing nothing.

The big part people overlook is what does properly maintained mean, next rev of 70E will define that better but what that means is per the OEM recommendations which hardly anyone reads. T&I's on a normal basis are good but will not meet the OEM's requirements if you read the IB. When was the last time your breakers were completely overhauled? Every (power) breaker has a recommended interval for that based on time and/or # of operations.

Hmm, food for thought. I guess if I want to avoid asking people to wear Arc Flash PPE for just being in the substation I need to start reviewing our PM strategies and align to IB. Thanks for the feedback

 

[vcrancher]

Labels only apply to energized work

Labels only apply to energized work

It is my understanding that Arc Flash labels only apply to energized work. That means doors open and covers removed.

If any piece of equipment is considered complete with doors on and closed there is no Arc Flash danger present during normal operations.

Operating an over current device in that equipment may or may not pose an Arc Flash hazard and should be addressed by company policy.

 

[GoldDigger]

It is my understanding that Arc Flash labels only apply to energized work. That means doors open and covers removed.

If any piece of equipment is considered complete with doors on and closed there is no Arc Flash danger present during normal operations.

Operating an over current device in that equipment may or may not pose an Arc Flash hazard and should be addressed by company policy.

The NEC and OSHA do not recognize that covers in place will remove any arc flash hazard. If anything the blast damage might be greater than with the cover off, and there is still the strong possibility of heat and molten metal spray when the cover blows off.

IF the equipment is specifically rated to contain arc flash when closed, you might have a valid point.
With the covers in place you may not need to wear voltage hazard PPE, but operating a breaker or other device even with the covers on or doors closed MAY trigger a need for arc flash protection.

 

[jim dungar]

The NEC and OSHA do not recognize that covers in place will remove any arc flash hazard. If anything the blast damage might be greater than with the cover off, and there is still the strong possibility of heat and molten metal spray when the cover blows off.

IF the equipment is specifically rated to contain arc flash when closed, you might have a valid point.
With the covers in place you may not need to wear voltage hazard PPE, but operating a breaker or other device even with the covers on or doors closed MAY trigger a need for arc flash protection.

You might want to look at the 'task tables' in 70E-2015. It lists quite a few tasks, including breaker operation, for which NFPA does not feel AF PPE is required at all.

Arc blast is not related to AF incident energy. If you do not stop the AF Incident Energy (AFIE) calculation at 2 secs it is very easy to have >40cal/cm^2 with very little blast force (think of an arc welder). At present there is no industry accepted way to calculate an ARC Blast.

Covers being open or closed do not impact the amount of AFIE, the hazard, but they do affect the risk, probability, of an arcing fault occurring in the first place. This is partly why NFPA70E-2015 requires that a risk analysis be performed along with determining the AFIE.

 

[GoldDigger]

One factor in bypassing the need for PPE for breaker operation is that the equipment be "properly maintained".
A breaker used frequently in day to day operations is more likely to be properly maintained compared to one which has not been opened in 15 years and is being used primarily as a disconnect.

Sent from my XT1585 using Tapatalk

 

[big john]

No OEM of non arc rated gear is going to give any information to determine reduction in IE doors open VS doors closed, but the activity tables in 70E do make a distinction between some tasks done doors closed, and reduce the PPE based on that.

I agree with Zog that maintenance is hugely important part of any arc flash risk mitigation program. Not only are you reducing the likelihood of equipment failure, but you are also reducing the IE by ensuring breakers operate as fast as possible: It's very common to find sluggish or malfunctioning breakers due to neglected maintenance.

 

[zog]

I agree with Zog that maintenance is hugely important part of any arc flash risk mitigation program. Not only are you reducing the likelihood of equipment failure, but you are also reducing the IE by ensuring breakers operate as fast as possible: It's very common to find sluggish or malfunctioning breakers due to neglected maintenance.

I like the new AC PRO II trip units that have built in sluggish breaker detection, we have installed many of them, pretty cool feature.

 

[kentirwin]

No maintenance of equipment

No maintenance of equipment

I work for a manufacturer that has bolted pressure switches dating back to the early 80's that have never been maintained in any way. In newer parts of the facility we have cb's but they date back 16 years since installation. No maintenance of any kind, no annual exercising or anything.

I've made the powers-that-be here aware that per 70E, with the available incident energy we have at the switchgear, no one can even operate a circuit breaker or bolted pressure switch unless they're wearing a 40 cal arc flash suit.

Since I didn't think they'd spring for the cost of maintenance I first approached them with a proposal for remote operators. That kind of snowballed when they learned what a catastrophic failure could do to business continuity. Now they're moving towards actually doing the required periodic maintenance.

 

[zog]

I work for a manufacturer that has bolted pressure switches dating back to the early 80's that have never been maintained in any way. In newer parts of the facility we have cb's but they date back 16 years since installation. No maintenance of any kind, no annual exercising or anything.

I've made the powers-that-be here aware that per 70E, with the available incident energy we have at the switchgear, no one can even operate a circuit breaker or bolted pressure switch unless they're wearing a 40 cal arc flash suit.

Since I didn't think they'd spring for the cost of maintenance I first approached them with a proposal for remote operators. That kind of snowballed when they learned what a catastrophic failure could do to business continuity. Now they're moving towards actually doing the required periodic maintenance.

Amazes me when I run across this, and I do often. I like to ask what it costs per hour to be down, usually the answer is accompanied by a light bulb turning on. Suddenly maintenance seems cheap.

Another one is when walking though a plant they show me their main breaker(s) for the facility, "So where is your spare?" Light bulb....