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Has your company/client replaced/rebuilt electrical equipment due to poor condition of maintenance?
Yes 58%  58%  [ 42 ]
No 40%  40%  [ 29 ]
Not Sure 1%  1%  [ 1 ]
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 Post subject: Condition of Maintenance - Replace/Rebuild Equipment
PostPosted: Sun Nov 12, 2017 3:23 pm 
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One of the changes to the 2018 Edition of NFPA 70E is to change the term “Maintenance” to “Condition of Maintenance” There are many references in NFPA 70E regarding the condition of the electrical equipment and maintenance. Protective devices that have not been properly maintained may not trip as expected – sometimes taking longer and leading to the possibility a greater incident energy during an arc flash. So here is this week’s question of the week:

Has your company/client replaced/rebuilt any electrical equipment due to poor condition of maintenance?
Yes
No
Not Sure


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 Post subject: Re: Condition of Maintenance - Replace/Rebuild Equipment
PostPosted: Sun Nov 12, 2017 8:19 pm 
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The terminology is poor in my opinion. In terms of maintenance of a piece of equipment, we basically have only 5 options for what we can do with it. We can do nothing. We can perform a preventative maintenance function. We can perform a predictive maintenance function. We can perform a repair/modification, or we can scrap/replace it. A preventative maintenance activity would be something that we would do in order to preserve it's function which would otherwise allow the condition to deteriorate to the point where it no longer functions such as performing an oil change on an engine. In some ways its effectively a repair. This is as opposed to predictive maintenance functions which are all testing or checking functions intended to discern the condition of the equipment and determine if other actions such as repairs or replacement are necessary.

Condition of maintenance is at best a confusing term. It would seem to be implying quality of maintenance...how well one of the above 5 tasks is being performed. I've made plenty of repairs due to the quality of maintenance.

I believe the better term is simply the equipment condition....is it completely functional and safe to continue operation or does it require some kind of preventative or corrective maintenance, or ultimately replacement? Determining this is typically a predictive maintenance function.

The big problem as I see it with 70E in this area as it is currently written is that the terminology and concept is just too vague. No matter how good predictive maintenance is, statistically speaking and partly just because of human performance, the general assumption is that a given PM task is only going to be successful at detecting hidden defects that the test is designed to detect about 90% of the time. I'm sure we've all experienced that bad feeling right after working on a piece of equipment and then getting a report immediately after that it failed. The second problem is that conceptually how in the world are we going to define "proper" maintenance? It's impossible. Yes we have standards for this (70B, IEEE Yellow book, NETA MTS) but there are lots of things in those standards that are pretty vague and even the required timing varies quite a bit. It is also pretty well accepted in RCM circles that aside from a few cases where the equipment condition is quite predictable and follows a true bathtub curve such as contact tip wear or circuit breaker lubrication with Mobil 28 where the oil in the grease evaporates, failures with electrical equipment are truly random. All predictive maintenance activities are aimed at detecting hidden failures and with truly random failures, the frequency of predictive maintenance keeps the failure rate at a particular frequency but can't truly control it to where failures do not occur at all. Thus at best electrical equipment failure rates are dependent on predictive maintenance rates. In addition although electrical equipment is somewhat more predictable, some 60%+ of the reliability with regards to mechanical equipment is known to be caused by the external environment. The only reason electrical equipment is lower is simply because we dictate the environment in various standards set by UL and others (clean, dry, cool).

Because of this level of detail though...I submit that while it may be possible for an organization to predict their failure rates based on historical data, it is not really practical or possible for an outside organization, nor any kind of standard to control or dictate equipment condition and more specifically failure rates. Nor is it even necessary to do so in order to meet the spirit and intent of 70E.

I would instead propose that "condition of maintenance" be replaced with simply "equipment condition". Further I would propose that there are really two critical concepts here that are somewhat intertwined within 70E. The first concept is whether or not equipment is being properly maintained. This iis critical in terms of ensuring that for instance circuit breakers will trip when they are expected to trip so that for instance arc flash labels are actually valid. The second concept is related but entirely different and that is one of determining equipment condition at the time that a potentially hazardous task is being performed and for this purpose OSHA 1910.269 has an excellent list of examples in one of the annexes. For instance if you walk up to a piece of equipment and the circuit breaker is tripped, or there are big black soot marks all over it and the door is bent, or you see water pouring out from inside, or it is rusted up to the point where it is no longer structurally sound and you can put your hand in the equipment, or even something so simple as that the circuit breaker has tripped in non-Type II equipment (type II is an IEC designation for starters that are designed for no damage in the event of a fault)...those are signs that the equipment could be in a possible condition of impending failure and should be treated as such.

I also don't like simply referencing NFPA 70B and NETA MTS for another reason. Those are general maintenance standards. The places where the term "condition of maintenance" is used points out issues such as trip times being excessively long. That's a calibration problem. There is only a subset of the entire NFPA 70B or NETA MTS procedures that actually impact safety and those are the areas that should be given the greatest emphasis within 70E. Whether or not oil samples are being taken on a transformer is an issue in terms of maintaining a transformer properly but it's not going to affect the safety of the equipment compared to say failing to test circuit breaker calibration or greasing ANSI style breakers.


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 Post subject: Re: Condition of Maintenance - Replace/Rebuild Equipment
PostPosted: Wed Nov 15, 2017 7:21 pm 
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Paul, I am so glad you said this so well. It's what I've taught globally for years. It's an easy answer to quote 70B or NETA with no true evaluation of the safety aspect. I've heard so many of these "easy" attempts at an argument, but the hard work comes in doing proper evaluations of the impact of a potential failure from lack of proper electrical maintenance. This certainly goes beyond most companies' risk assesssments and requires one to really assess the issue(s) more thoroughly. As we stated, it is certainly a larger concern when a breaker has not been properly lubricated versus other important but not necessarily safety-related tasks.


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 Post subject: Re: Condition of Maintenance - Replace/Rebuild Equipment
PostPosted: Thu Nov 16, 2017 4:30 pm 
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Kenneth Sellars wrote:
Paul, I am so glad you said this so well. It's what I've taught globally for years. It's an easy answer to quote 70B or NETA with no true evaluation of the safety aspect. I've heard so many of these "easy" attempts at an argument, but the hard work comes in doing proper evaluations of the impact of a potential failure from lack of proper electrical maintenance. This certainly goes beyond most companies' risk assesssments and requires one to really assess the issue(s) more thoroughly. As we stated, it is certainly a larger concern when a breaker has not been properly lubricated versus other important but not necessarily safety-related tasks.


As I said though, there are two issues and we need to address each separately. What you are addressing is the aspect of whether or not the protection function is going to perform as expected and this is largely driven by detecting and fixing hidden failures. It is a maintenance function and "condition of maintenance" is really quality of maintenance, more specifically addressing those factors that would affect the protective function during an arcing fault and perhaps also addressing equipment conditions that can increase the likelihood of an arcing fault in the first place such as excessive buildup of contamination and/or corrosion in medium voltage gear.

The second issue is what we can do to evaluate changes in the equipment condition to the point where it is now operating abnormally. For example let's say that a circuit breaker (not the overload) tripped SEVERAL times on a pump and the operator kept resetting it before finally calling an electrician. NEMA AB-4 for molded case circuit breakers is very clear that the breaker must be inspected after EVERY trip, and OSHA (and 70E) is very clear that the cause of a circuit breaker trip must be determined and eliminated before it can be closed back in. So if I come in as the guy troubleshooting this, how do I do it safely? Is it even safe to open the door of the starter knowing that the breaker has already tripped, indicating an electrical fault has occurred? If I ohm out the motor and determine that the motor has shorted to ground internally and then replace the motor, is it safe to close the breaker back in? This is not a hypothetical. A retired electrician in this area was severely burned in an arc flash because the breaker managed to open previously but was so damaged that it arced and blew apart after said pump motor was replaced and they were just in the process of removing locks and putting everything back into service.

When we are working on equipment, we need to determine when the equipment that we are working on goes from a normal operating condition where among other things we can operate breakers, starters, disconnects, etc., with very low probabilities of failure and thus in 70E terminology it is not an arc flash hazard compared to determining that it is or could potentially be operating abnormally and thus has an unacceptably high probability of posing an arc flash hazard. This is different from whether or not we are doing the correct preventative and predictive maintenance and instead is part of the field evaluation process that is conducted during LOTO or during the energized work process.

I intend on putting my money where my mouth is. The next public input period will be this coming spring and I intend on submitting changes to clarify this. The framework is there but "condition of maintenance" just isn't the right terminology and we're mixing up field evaluation tasks with preventative and predictive maintenance tasks.


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