pudge565

Does a panel containing starters, both forward and reverse, for 2 75 HP motors need arc flash labeling? I believe it does but am not sure. The reason I ask is at work there are 2 such panels and the plant workers/supervisors continuously open them and leave them open because, "The blue buttons need to be reset." The blue buttons are the overloads which i still say do not trip as often as they say if ever. I close the panels when I see it but would like a very strong reason to keep them from opening them at all.

HARRY304E

See 110.16 of the 2011 NEC,also 110.27

NFPA 70 E...http://www.eswpco.com/

Jlarson

I'd say you should find the reason for the OL trips and maybe consider putting on front mounted reset buttons.

just my $.02

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drsparky

I would pose the question "would you leave the panel open if OSHA was visiting?"

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Wirenuting

Well said.
I'll use that line next time I find staff members resetting the gear.

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pudge565

Thank you I will look into them. Our safety manager is suppose to be doing the calculations but is dragging his feet.

Well I know why they trip. Because the operators have no idea how to run the machine. These two motors run a shredder for medical waste. Between the motor and the gearbox there is a clutch to prevent the motor from locking up during a jam up the clutch will kick out and throw a speed sensor fault. The problem is that the operators will continue to just reset the machine even under a jam condition and hence they trip.

That may be a good idea as well.

kaboler

I woudn't put an arc flash warning on something that didn't have an arc flash hazard.

Give us voltage. If 120, dun worry about arc flash.

pudge565

Whoops I forgot to include that in my first post. It is 480 VAC. Two 75HP motors with one each forward and reverse starters.

erics37

Maybe they should start docking their paychecks to cover repair costs until they start realizing what's up

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pudge565

Depends where that money is going.

South Jersey Sparky

Wouldn't this come under something like "Access to authorized persons only"?
Authorized being, has had training and understands safety.

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Thedroid

75 hp is a good sized starter. I think its absolutely ridiculous to leave the enclosures open. I think someone would be in big trouble if an injury occured. It doesn't sound like you have many competent co workers or management.

oliquir

some overloads have automatic reset, this may solve the problem

pudge565

Well most of them speak very little English if you catch my drift.

Does Allen-Bradley manufacture such an overload?

MDShunk

You bet. You will likely need to buy some sort of adaptor kit to mount it to your existing starter.

Allen Bradly also makes overload units that are Ethernet connectible. You can reset them over the Ethernet after a time delay from a PLC or even from your HMI touchscreen if you want to get real fancy. I put one in a month or so ago. I have pictures on my camera in the truck.

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mattsilkwood

I think this would be a bad application for those. You don't want something like a shredder to start up with no warning.

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MDShunk

I think you would. It would weed out the employees not utilizing proper lockout/tagout procedures.

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Wirenuting

The thing I find about the auto-reset is the trip/reset curve they use.
If the fault does not clear, the o/l trip quicker & quicker until you get a 10 sec run with a 1 minute rest.
Someone will sooner or later stick their hands in the way and zip those fingers right off.
Bad Idea at a company were safety has little value.

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mattsilkwood

You would definately have something to talk about at breaktime.

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MDShunk

The side benefit of the auto reset is that it takes a mechanically bound up condition, where the motor could have otherwise been saved by the overload, and cycles the motor so many times that it destroys the motor eventually too. I've seen situations where the motor was left to cycle on the self-resetting overload for weeks. Recent example was for an evaporator fan (one of 8) in a very large walk-in cooler.

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