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 Post subject: 120vac control wiring question
PostPosted: Thu May 21, 2009 7:53 am 
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Howdy,
Here's something that came up recently and the outcome should be simple, but, it is still being discussed and I was wondering what you all think. Sometimes it's difficult to understand what 70E is saying (no pun intended), but the truth is out there.......

A maintenance person was working on a valve limit switch assembly with 120vac on the limit switches. The hot wire was loose and came out of the terminal strip. The maintenance person would not touch the wire to place it back into the terminal strip without the use of gloves. With gloves on it was impossible to accomplish this. So, the entire process was shut down, powered down, and the wire was replaced. Now for the question,,, is it permissable to touch the 120vac wire by holding it by the insulation to place it back into the terminal strip without gloves? Some say yes, some say no, based on the info in Table 130.2(c) and Table 130.7(c)(9)

Any thoughts?

Thanks,
BT


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PostPosted: Thu May 21, 2009 10:48 am 
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Good question. Does "avoid contact" mean don't touch the wire conductor or don't touch the wire insulation?


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PostPosted: Thu May 21, 2009 11:51 am 
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Also if I may add...what if the person uses cushion grip needlenose? Some of these assemblies are tight even without gloves.


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PostPosted: Thu May 21, 2009 1:11 pm 
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A very good question indeed. It raises two issues - working with gloves and working while energized. I can assume that he was troubleshooting when the wire came loose, else he would have needed an energized work permit. But once the wire came loose, was he still troubleshooting or was he performing energized work? If performing work, then 70E is pretty clear that the equipment should be de-energized if it is possible. Otherwise, he needs the energized work permit.

As to the gloves, since 120VAC is avoid contact, I would think that holding the insulation or, even better, using voltage rated tools to hold the insulation would be satisfactory. I've done that in the past where the voltage gloves became a hinderance to troubleshooting. I'll be curious to hear other comments.

TxEngr


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PostPosted: Thu May 21, 2009 4:55 pm 
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I would agree with most of the above. Whether or not a Live Work Permit was needed depends upon whether or not you consider this to be routine work. In my shop we permit live work without permits if it is routine. There is training on what is and isn't routine, and its reviewed annually.

The other option would have been gloves at 500V, that were on the tight side, and no leathers. This is permitted except you have to test or discard the gloves afterwards. Still cheaper than shutting down the line.

I would also say, unless there was some very unusual circumstances, that you should pull this guy aside and talk with him a little. Any electrician who is leary of a task this simple, hasn't performed much real industrial work. I am NOT saying that in a cavalier manner. Most experience electricians know and are confident in working with 120V low amperage circuits hot. Electricians are the anti-matter counterpart of ballerinas, might have been a bad hair day.


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PostPosted: Fri May 22, 2009 4:19 am 
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Howdy,

Thanks for the responses, I'm still not sure of the absolute interpretation of this. The Maintenance person involved is very competant, just didn't wish to get into any trouble by violating the sometimes foggy rules, and perhaps may have pressed the issue to get some resolution. I too have many times done work like this live without problems (before the safety program era). I'm somewhat relieved that I'm not the only one having these interpretation issues. Thanks for the responses.
B.T.


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PostPosted: Fri May 22, 2009 7:11 am 
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Haze -I'm not familiar with an exemption for energized work for routine work - only for troubleshooting (infeasibility), greater hazard, and less than 50 volts. Can you point me in the direction of this exemption?

Thompwill - sometimes it seems like the whole thing is up for interpretation, so you are not alone in your confusion - I'm right there with you.

TxEngr


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PostPosted: Fri May 22, 2009 11:39 am 
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Look at the 2009 Handbook, 130.1(B) 1 where it talks about Routine work not needing a permit (or rather a long term permit).

"...Permits that cover routine work tasks to be performed by trained and qualified employees can be written to cover a long period of time. For instance, a worker might be trained and qualified to replace a fuse that involves an exposed live part. If the worker is trained to understand the electrical hazards associated with exchanging the fuse and is wearing any necessary PPE, a permit might be issued that covers, for instance, a three month period..."

Industry in the US today can not afford to hand hold trained and qualified electricians as they perform simply tasks well within their capability. The example of changing a fuse in a MCC lineup is a perfect case. Its 'infeasible' to shut down an entire manufacturing building to replace one fuse to get one pump running again. Its equally infeasible to call three managers out of the office to sign a Live Work permit. The 'written to cover a long period of time' terminology gives rise to the concept of a 'Standing Live Work Permit'. We use the Standing Live Work Permit in lieu of the Task Specific Live Work Permit for routine work. Routine work is defined in our corporate policy. We train our in-house electricians on what is and isn't considered routine. If it is routine, then they can perform the task (with proper PPE of course) under the Standing Work Permit and not require the task work permit. Since the code uses the term 'for instance, a three month period' as an example, we determined our policy for the Standing Permit to be 'One Year' at which time we retrain and review the policy. A word like 'for instance' is not a binding obligation but rather a suggestion. Our interpretation is that the suggestion was too short and we substituted one year. But it has to be coupled with training and supervision. In-house electricians are permitted to do certain tasks under the Standing Permit, but the same task by a contractor may require a Specific Live Task permit for that one job. In that case its not the Task, but rather the person performing the task that necessitates the permit.

You have to remember that non of 130 is OSHA except for the General Duty clause. OSHA has said they won't fine you for an injury if you have an incident providing you are following 130. As long as you have a policy documented that conforms to 130, it would be hard for OSHA to say you were not 'compliant' with 130 because you substitute non binding examples. An example by its very definition is just that, an example of one of many possibilities, it is not the 'only' possibility.

We do not have an actual document that is called a Standing Permit, its just written up in our policy as being that with details outlining the training requirement. In our case 12 months is the training cycle, but we are not in violation of our policy unless we exceed 15 months between training.

Having written documentation, and then conforming to that documentation, will be the overriding judgement in defending your position. We may be pushing the envelope of the code in some areas, but only where the code doesn't make sense or treats trained professionals like incompetents.

This is just our method, but it works and gives us the liberty to continue to manufacture in the USA.


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PostPosted: Tue May 26, 2009 7:01 am 
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Howdy,
Thanks for all the information, A lot to think about. One thing for sure is, I need to order the 70E Handbook, trying to read the Standard and getting any understanding from it is difficult. Hopefully the Handbook will help.
Thanks Again,
B.T.


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PostPosted: Tue May 26, 2009 7:30 am 
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Haze,

Thanks for the detailed description. I don't have a copy of the Handbook, only the Code book so I was not aware of the recommendation to use long term permits for routine work. Your method seems like a very workable method and we may look at something similar at our plant. Again, thanks for the amount of detail you included.

It looks like I may need to order a Handbook as well.

TxEngr


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