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 Post subject: 240 / 480 volt plugs
PostPosted: Tue Oct 13, 2009 5:54 am 

Joined: Tue Oct 13, 2009 5:46 am
Posts: 1
Location: Minneapolis, MN
What are the rules / regulations pertaining to PPE and high voltage plugs and outlets?
When plugging in a 480 plug into an outlet (for the first time - new equipment) does NFPA or OSHA require the use of arc flash PPE in the event of a mis-wired (direct short) plug or fused disconnect?


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PostPosted: Tue Oct 13, 2009 7:36 pm 
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Joined: Sun Dec 23, 2007 1:44 pm
Posts: 348
Location: Charlotte, NC
You can test your plug carefully with a meter the first time. Don't exactly know that OSHA makes a difference, but I can say that the first time I energize a high energy device, I am always looking for someone else to do it for me. :) But it usually ends up being me.....go figure! Everyone else conviently has somethig else pressing to do!


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PostPosted: Wed Oct 14, 2009 2:02 pm 
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Joined: Sun Aug 16, 2009 8:42 am
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Location: Lawrenceburg KY
A lot of people have asked this question. This is not the answer your looking for but I'll throw in my two cents.

Normally I recommend a fused safety switch upstream a 480v 3 phase receptacle. Also, the person plugging in the device is to be trained to turn off the safety switch before plugging in.

I had a machine operator the other day get his hand lightly burned no first aid required. He did the procedure but could not get the portable equipment to work so he started twisting and pushing in the pin and sleeve plug and one phase wire came off to ground.

I am like Mr. Cobb not sure about the OSHA regs on this. If you search on this site you'll find some comments about doing this if I remember correctly from others asking a similar question.


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PostPosted: Thu Oct 15, 2009 4:40 am 

Joined: Thu Mar 19, 2009 9:40 am
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Location: Wi
We have many of these in the plant. Have not been able to find anything in OSHA either but one thing I've started doing is tag all of the plugs "do not connect or disconnect under load"


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PostPosted: Tue Oct 20, 2009 9:42 am 
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Location: Lawrenceburg KY
SPETE,
Thats a good thing. It's best to have a local disconnect switch upstream of the pin and sleeve plug or other 3 phase 480v outlet. For your worker safety you may want to look at what that would take to install some type of disconnet.


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PostPosted: Tue Oct 20, 2009 10:27 am 
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Location: Lawrenceburg KY
I have seen these and wanted you guys to know that another option is out there for your companies safety if a disconnect is not an option.
Go to this web site and they have a video of using this type of pin and sleeve connector. I believe there are more types if you search the internet.
[url="http://www.meltric.com/?gclid=CJ6L4eGQzJ0CFQEhDQodlCBGsQ"]http://www.meltric.com/?gclid=CJ6L4eGQzJ0CFQEhDQodlCBGsQ[/url]


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PostPosted: Tue Oct 20, 2009 12:46 pm 
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Joined: Tue Feb 24, 2009 7:05 am
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Don't forget that the proper PPE is needed when operating a fused disconnect.

I'm not sure if PPE is needed for the blue Meltric plugs rated for disconnection under load, or if they are considered the same as a pin and sleeve plug.


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PostPosted: Fri Oct 23, 2009 5:41 am 
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Location: Lawrenceburg KY
[url="http://www.squared.com/us/products/safety_switches.nsf/unid/C642666E4C1AD02C85256CE5006E3CC2/$file/heavydutysafetyswitchFrameset.htm"]http://www.squared.com/us/products/safety_switches.nsf/unid/C642666E4C1AD02C85256CE5006E3CC2/$file/heavydutysafetyswitchFrameset.htm[/url]

Receptacle Switches
Interlocked Receptacle Switches are furnished with a factory installed 3 Phase 4 wire Appleton POWERTITE, Crouse-Hinds Style 2 ARKTITE, or Hubbellock receptacle. The fourth wire is connected to the switch equipment ground terminal and is not a neutral termination. Interlocking linkage between the receptacle and switch mechanism prevents insertion or removal of the plug while the switch is in the "ON'' position or insertion of any plug other than specified.

Square D® MD50 Motor Disconnect Switch, Non-Fusible
The MD50 is a Pin and Sleeve Interlocked Switch Receptacle listed UL508 "Suitable For Use As A Motor Disconnect" switch and receptacle in one compact NEMA 4X enclosure. The MD50 is offered in 20, 30, 60, and 100 Amps units compatible with IEC 309-2 plug configurations.


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PostPosted: Sat Oct 24, 2009 10:34 pm 
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Joined: Thu Oct 18, 2007 7:10 pm
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Location: NW USA
I believe the Meltric brand are the only 480V receptacle UL listed as a disconnect. They seem to have a spring loaded arc break mechanism. All others should be turned off prior to connection and disconnection. Often times there is a disconnect switch local to a 480V pin and sleeve receptacle, in fact I have never seen any other kind installed. Local authorities (in NW Washington) required Meltric receptacles to be installed at fairgrounds for safety reasons, stating that they could not assure the workers would not disconnect other brands energized.

480V is not self extinguishing, and I am not aware of anyone that would consider plugging this in "hot" .


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