Reset Buttons on motor starter cabinets.

[Beenaround]

I have a question regarding the reset buttons on the front panel of Allen-Bradley motor starters. Do they have to remain on the door or can they be removed? I am asking this due motor starters being reset by general personnel without calling the maintenance. We have approximately 4000 motors, which vary in size from 1 H.P. to 1200 H.P. We have already had an arc flash due to dead short. Thankfully no one was hurt. It seems to be an easy fix to remove the button so the door has to be opened to reset. I personally do not use the reset button. It is my preference to shut off the breaker, open the door check the starter over and either OHM or MEG the motor, and check for lose screws. Then reset the overloads, close the door and turn the breaker on. Is removing the reset button violating any code or U.L. listing?
Thank you all in advance for your input.

 

[petersonra]

I have a question regarding the reset buttons on the front panel of Allen-Bradley motor starters. Do they have to remain on the door or can they be removed? I am asking this due motor starters being reset by general personnel without calling the maintenance. We have approximately 4000 motors, which vary in size from 1 H.P. to 1200 H.P. We have already had an arc flash due to dead short. Thankfully no one was hurt. It seems to be an easy fix to remove the button so the door has to be opened to reset. I personally do not use the reset button. It is my preference to shut off the breaker, open the door check the starter over and either OHM or MEG the motor, and check for lose screws. Then reset the overloads, close the door and turn the breaker on. Is removing the reset button violating any code or U.L. listing?
Thank you all in advance for your input.

Overloads are not for opening dead shorts. If the overload trips before the BC OCPD opens on the circuit, it may be that you need to reconsider the rating of the OCPD.

In general, I do not see any safety issues for allowing operating personnel to reset overloads on most motors. I would be a little hesitant to allow them to reset larger ones, as there may be some issues there that need to be reviewed before putting such a motor back into service. There also may be some motors that it is inappropriate to restart without considering what happened to the process while the motor was off.

In general, I do not see any special benefit to either "Ohming" out the motor or megging it merely because the overload tripped.

It seems to me this is not so much a turf thing as it is coming up with rational instructions for the operations personnel. If the decision is made by the appropriate personnel that a particular motor OL should not be reset by the operator, than perhaps the best answer is to just put that in the operator instructions and put a small tag next to the OL reset button to remind them. I know that is not a perfect answer, but it is a better one IMO than removing the reset buttons on 4000 starters.

ETA: I would expect that in a typical plant such as you work in that the DCS would be keeping track of motor failures. It might be instructive to determine just how many such failures there are in a year before jumping into the deep end.

 

[Besoeker]

Overloads are not for opening dead shorts. If the overload trips before the BC OCPD opens on the circuit, it may be that you need to reconsider the rating of the OCPD.

In general, I do not see any safety issues for allowing operating personnel to reset overloads on most motors. I would be a little hesitant to allow them to reset larger ones, as there may be some issues there that need to be reviewed before putting such a motor back into service. There also may be some motors that it is inappropriate to restart without considering what happened to the process while the motor was off.

In general, I do not see any special benefit to either "Ohming" out the motor or megging it merely because the overload tripped.

It seems to me this is not so much a turf thing as it is coming up with rational instructions for the operations personnel. If the decision is made by the appropriate personnel that a particular motor OL should not be reset by the operator, than perhaps the best answer is to just put that in the operator instructions and put a small tag next to the OL reset button to remind them. I know that is not a perfect answer, but it is a better one IMO than removing the reset buttons on 4000 starters.

I respectfully disagree.
Non trained personnel should not have access to electrical panels to do anything with them. Period.

 

[Jraef]

I think forcing even an electrician to open the enclosure to reset an OL is exposing personnel to more risk that having an untrained person push the button. But if you want to prevent that, there are other ways. You can install a remote reset option on the OL relay, which makes it electrically operable. Then you replace the reset button on the door with a key operated selector switch and only the electricians have the keys. You can alternatively install locking covers over the existing reset buttons so that only the electricians have the keys to those locks as well. Or you can modernize, put in Ethernet enabled OL relays and plug the reset button holes, then only allow the OLs to be reset over the network, and only after everyone knows everything is copacetic. But making an electrician suit up in his PPE just to open the door and push a reset button is going to promote your people doing stupid things.

 

[petersonra]

I respectfully disagree.
Non trained personnel should not have access to electrical panels to do anything with them. Period.

I would submit that written instructions detailing just when an overload can and cannot be reset by operations personnel via an external reset button (as I suggested in my post) is more than adequate training.

 

[Besoeker]

I would submit that written instructions detailing just when an overload can and cannot be reset by operations personnel via an external reset button (as I suggested in my post) is more than adequate training.

Yes, I again note your opinion. But I don't share it.
I suppose it might be considered rude, justifiably so, for me not to offer some explanation.

Most of the places I visit are industrial operations. Anywhere, as in the OP that has 4,000 motors is likely to be such.
Operations personnel are production workers and possibly/probably very skilled at what they do. But not (usually) electricians.

If a motor overload trips there has to be a reason for it to have done so. And that reason ought to be sought prior to the reapplication of power.
And written instructions for 4,000 motors? All the same? Not really likely. And how many of the operations personnel would you authorise to be responsible for a reset? How would you deal with the outcome resulted in serious plant failure or worse, personal injury? How would you deal with any ensuing claims?

Perhaps you can begin to understand why I think permission for operations personnel should be excluded?

 

[petersonra]

Yes, I again note your opinion. But I don't share it.
I suppose it might be considered rude, justifiably so, for me not to offer some explanation.

Most of the places I visit are industrial operations. Anywhere, as in the OP that has 4,000 motors is likely to be such.
Operations personnel are production workers and possibly/probably very skilled at what they do. But not (usually) electricians.

If a motor overload trips there has to be a reason for it to have done so. And that reason ought to be sought prior to the reapplication of power.
And written instructions for 4,000 motors? All the same? Not really likely. And how many of the operations personnel would you authorise to be responsible for a reset? How would you deal with the outcome resulted in serious plant failure or worse, personal injury? How would you deal with any ensuing claims?

Perhaps you can begin to understand why I think permission for operations personnel should be excluded?

Typical plants of this scale are able to write detailed instructions for the operators for everything else. No reason they cannot give instructions in what to do if something faults (as often as not they do include what to do in case something goes wrong). A lot of things the operators could do are likely to be far more catastrophic than resetting an OL on a motor starter. We trust them for that, but not for resetting an OL?

 

[Besoeker]

Typical plants of this scale are able to write detailed instructions for the operators for everything else. No reason they cannot give instructions in what to do if something faults (as often as not they do include what to do in case something goes wrong). A lot of things the operators could do are likely to be far more catastrophic than resetting an OL on a motor starter. We trust them for that, but not for resetting an OL?

I have been responsible for writing instructions and providing training for experienced electrical personnel. I designed these warning labels:






Fairly categorical wording I think you might agree. And in the mandatory colours, text regulation height, and mounted at the right height on the panel.
Unfortunately, a senior electrical guy didn't heed those warnings. Though not fatal, it put him in hospital months and required serious surgery, skin grafts - the whole nine yards.
It has given me much grief to think that I could have done a better job with the training and the warnings. But sometimes people get in a hurry and sh1t happens. Doesn't make me feel any better about it and I can't turn back the clock to make it unhappen.

Yes, one incident but it graphically demonstrated to me why.........well, you get the drift I'm sure.

 

[Beenaround]

I appreciate all thoughts. I would add that a lot of the motors will start running as soon the starter is reset. The screws around the coil have a tendacy to loosen. The visual inspection lets you know when a starter is getting near the end of its life (dust etc.) also these operators have taken the next step, resetting tripped breakers. Both are against company policy. They state our job is simple.
Ignorance is bliss.

 

[petersonra]

BTW, I am not necessarily opposed to the idea that after careful consideration of the problem that the plant decides to just prohibit operations from resetting motor overloads.

It seems to me though that handling it as a turf issue is not an appropriate thing, as it seems like the OP was suggesting.

 

[petersonra]

I have been responsible for writing instructions and providing training for experienced electrical personnel. I designed these warning labels:



View attachment 11865


Fairly categorical wording I think you might agree. And in the mandatory colours, text regulation height, and mounted at the right height on the panel.
Unfortunately, a senior electrical guy didn't heed those warnings. Though not fatal, it put him in hospital months and required serious surgery, skin grafts - the whole nine yards.
It has given me much grief to think that I could have done a better job with the training and the warnings. But sometimes people get in a hurry and sh1t happens. Doesn't make me feel any better about it and I can't turn back the clock to make it unhappen.

Yes, one incident but it graphically demonstrated to me why.........well, you get the drift I'm sure.

I don't recall anyone here advocating operators going into an electrical cabinet. I certainly did not.

But, the risk from resetting a motor OL via an external button is very, very low for most cases.

I suspect one of the reasons people ignore warning signs is because there are so many of them that are completely unnecessary and people know that, so they are being trained to ignore them all the time.

 

[petersonra]

I appreciate all thoughts. I would add that a lot of the motors will start running as soon the starter is reset. The screws around the coil have a tendacy to loosen. The visual inspection lets you know when a starter is getting near the end of its life (dust etc.) also these operators have taken the next step, resetting tripped breakers. Both are against company policy. They state our job is simple.
Ignorance is bliss.

I think it is a bad idea to allow operators to reset tripped breakers. Having said that, if all the electrician does when he finally shows up is reset the breaker, I can understand why the operator would take it upon himself to just do it.

I think regular maintenance is a good idea. Waiting for a motor OL to trip first to do this kind of visual check does not seem like the best approach to me.

If a motor restarts when the OL is tripped, what difference does it make if the operator resets it or an electrician does? Most times the operator has a much clearer picture of what the motor is doing then the electrician, and can make a better judgment as to whether resetting the OL will introduce a hazard beyond the electrical issues.

 

[meternerd]

At our water utility, we have hundreds of motors, small to large. Smaller motors (under 75HP) have contactors and overload heaters or solid state overloads. These motors may trip an OL for any number of reasons. We allow the operators to reset them, but we hear pretty quickly if they have to keep resetting the same motor. That's when we (electricians) do open door investigation. Larger motors have soft starts and an OL is not resettable without cycling the breaker, which operators are not allowed to touch. Seems to work for us, and since our service area is pretty spread out, driving to every tripped OL would eat up a lot of time, and often no problem is found anyway when we do amp checks. Most often it's a loss of phase or voltage sag during heavy snow or wind, not a motor problem. I think removing the reset button and requiring an open door for reset is an unnecessary risk, plus it puts added wear and tear on the breakers, which are intended to be used as switches. Opening the door requires an off breaker or defeating the interlock with a tool. The reset button does not, for a reason. It is not considered a safety issue to reset one.

 

[just the cowboy]

A little of both

A little of both

When I worked as electricial foreman in the plant, we did both, had operators reset motors and operators not allowed to reset OL's depending on the operation and size. This avoided some of the 2:00 AM callins. But on the other hand I have seen the AB melting solder pot type OL not reset permintaly because operators kept resetting the OL as soon as it cooled down. This is when we found motors burnt up when just overloaded and the OL was doing it's job.

 

[Jraef]

I don't recall anyone here advocating operators going into an electrical cabinet. I certainly did not.

But, the risk from resetting a motor OL via an external button is very, very low for most cases.

I suspect one of the reasons people ignore warning signs is because there are so many of them that are completely unnecessary and people know that, so they are being trained to ignore them all the time.

The OP mentions opening the door to reset the OL relay. The thread kind of went further afield than intended, he never asked about resetting breakers etc, just OL relays. I agree with you that the risk of resetting an OL from a closed door is very low, because as mentioned, the OL relay is not what should have tripped if it was a short circuit that might present a risk of arc flash. I also agree that "operators" often know more about how a machine is supposed to work or what lead up to an OL trip than the electrician will, so I personally would not change the situation. My comments were based on his assertion that opening the door to reset the OL relay was somehow less risky than resetting it with the external button. I think not. So if there were some sort of operational procedure violation taking place that needed to be thwarted by disallowing an OL reset without investigation, removing the reset button has alternatives that are safer.

 

[jeffegg2]

If the overload reset is on the outside of the panel it is obviously usable by the operator. Our overload resets have a secondary reset so that resetting the overload does not restart the motor. But then our overload resets are on the starter not on the panel front.

 

[iceworm]

At our water utility, we have hundreds of motors, small to large. ... These motors may trip an OL for any number of reasons. ....

Tell us about this. What are some of "any number of reasons" I only know of one - bad bearings. Maybe the ocasional foreign object stuck in a pump.

For motor overloads to be tripping regularly - I can't think of anything besides bad design. Got to be some pretty dim bulbs to intentionally design a machine to run overloaded.

For a breaker to trip and there not be fault - what can that be besides bad design?

I'm thinking that if the design were right, tripped overloads or a tripped breaker would indicate a failed device.

What am I missing here? This shouldn't be a regular enough occurance that the operators don't think anything of it.

Just my thoughts

ice

 

[kwired]

I kind of recall having to provide external reset operators years ago if voltage was over 250 volts to ground, but I see no such requirement in 2014 nor do I recall this being required in recent editions. Not sure when such requirement was removed or if we were misunderstanding a requirement at that time - but I recall it being enforced by the AHJ as well - but this was like 20 years ago or so.


Some thoughts -

I've seen operators continually reset an overload to force finishing a run of product and by time I get there the motor is so hot or even already done for, but production often gets priority and worry about maintenance later - especially for small motors in a simpler process where not much is lost but the motor, I can understand that to some extent.

Though the overload device shouldn't be interrupting a ground fault, if operators are resetting repeatedly, it may get to a point where they are resetting into a fault.

Good design maybe is to make the control circuit so that motor can not immediately start when resetting the overload - I know this gets more difficult with more complex control systems sometimes, but if the motor is a crucial part of a process tripping overload may just shut down the entire process anyway.

I still don't understand why an enclosure with external operators is allowed to be an arc flash hazard, this goes for motor controllers, safety switches, panelboards, and so forth. I understand there can be a problem operating a device with the door open, but it seems to be common sense to me that if you are going to put an external operator of any type on same device - it should be safe to operate without any PPE if the door is properly closed. If not safe then we need all this equipment in a secured area with only access from properly qualified individuals - and that only comes close to happening on larger industrial settings where there is full time maintenance, your smaller industrial or commercial may not have any electrical professional on staff at all - who can legally turn off power in an emergency in those instances, if you need to be trained to operate a simple safety switch or circuit breaker? No common sense out there for some things, and over action on others.

 

[Besoeker]

I don't recall anyone here advocating operators going into an electrical cabinet. I certainly did not.

I'm certainly not either- that would be totally irresponsible.

I suspect one of the reasons people ignore warning signs is because there are so many of them that are completely unnecessary and people know that, so they are being trained to ignore them all the time.

My notices were, in my opinion, completely necessary and as direct and succinct as I thought they could be. Just two of them. Yet still got ignored by a hugely experienced electrical guy in the case I cited.
Yet, you have suggested providing notices for operators not trained in electrical matters to make a judgement about making an electrical decision?

What the overload tripped because the motor has shorted turns?
And resetting it causes a fire that burns the place to the ground.
No, it shouldn't. But electrical fires do happen.

I just don't think plant operators should be placed in the position to make, or worse, be required to make the decision to push that button.
Overloads trip for a reason. The operators should not be called upon to be judge and jury and have to decide on what action to take.

 

[meternerd]

Tell us about this. What are some of "any number of reasons" I only know of one - bad bearings. Maybe the ocasional foreign object stuck in a pump.

For motor overloads to be tripping regularly - I can't think of anything besides bad design. Got to be some pretty dim bulbs to intentionally design a machine to run overloaded.

For a breaker to trip and there not be fault - what can that be besides bad design?

I'm thinking that if the design were right, tripped overloads or a tripped breaker would indicate a failed device.

What am I missing here? This shouldn't be a regular enough occurance that the operators don't think anything of it.

Just my thoughts

ice

Most of our OL's are solid state from Square D. They are adjustable trip and also sense phase loss. We "dim bulbs" start with the settings based on nameplate, but often it may be OK for a while, then they rearrange valving out in the field and the load on the motor goes up due to higher flow, higher backpressure, etc. Also, dirt from piping can cause excessive drag on pump impellers. We use 700ft deep wells as a source and sandy soil will allow small grains of sand through the strainers and into the piping.

Pumps are most efficient at full load, so we size 'em close to that. Any change can exceed the OL setting. But we don't want to set 'em too high initially because overheating shortens the life of the motors, which start and stop hundreds of times a day.

The single phase feature takes 'em out pretty regularly too, because we live in a forested terrain and trees in lines can cause a voltage sag on one phase until the fault clears, a fuse blows or a recloser operates to lockout. Kind of a pain, since we have phase monitors that can trip the PLC controls, but unfortunately, there's no way to disable the single phase protection. I don't recall bad bearings tripping OL's very often because the noise from the motor is enough to alert the operators that the bearings are failing. Also, with 480V 50+ HP motors, the bearing would have to be nearly seized to load the motor enough to trip, at least in my experience. Tripped breakers are another story. If that happens, it's likely a failed component.