Twistlock and VFD

[iceworm]

Or use the described Meltric or other pin-and-sleeve connector that can be used with FMC or LFMC instead of cord?

Maybe -

If it is money: Still put in a disconnect. But that is just a guess that a low dollar 3pole disconnect is cheaper than a pin and sleeve connector and way cheaper than the described Meltric.

If it is not the money: Still put in the disconnect.

However I do subscribe to the tenent that, "Screwing around to save a buck -- rarely ever saves a buck."

I know - screwy engineers. What are you going to do?

ice

 

[Besoeker]

In my experience, if you create a situation where Bubbah can grab a cord and pull it out when he is not supposed to, Bubbah will. If you train Bubbah not to, then Smitty will. You are setting this up for Murphy's Law to prevail. :happysad:

Nicely put.

 

[kwired]

There have been other threads about locating a disconnect in sight of the motor - in industrial plants. In my experience it is not common. They do little (or no) good. Maintenance is always under MCC LOTO.

The one notable exception is where there is regular cleaning required on a machine. There, in one operation I saw, the local operator opened (not locked out) a local disconnect, jump in and clean, jump out, close disconnect and resume operation. Maintenance by craft techs was under MCC LOTO.

Other than that - all is LOTO at the MCC.

Note to iwire: Yes I understand that in the north east, in industrial process areas, local disconnects are common.

ice

That was common and allowed in past editions of NEC to have the disconnecting means at the controller if it was lockable. They changed wording in 2005 (I think) that kind of eliminated that as a general practice and is only allowed for certain exceptions now.

Even if the NEC never changed though, you still have OSHA being a big influence on owners desiring to have disconnecting means near the equipment.

So, is it only the north east where, in industrial settings, local disconnects are common?

What say y'all? Yes, No, what area.

No this is not a poll - just minor curiousity.

ice

Kind of an addition to what is above, if NEC is adopted with no amendments, then you really don't have much choice, there may be places where maybe they don't enforce this rule all that well even though it is there, or maybe the inspectors are not even aware of it, but is a little sad if that is the case because even if you don't like or agree with the rules, the inspectors have had plenty of time to catch up with that change and you would hope would at least be aware of it.

OK.
How does the person doing the unplugging know if it is safe to do so?

You need to have the mindset of many average production employees which is "why do I care"

I can't get past:
"So, they are not doing this for 400.7.A.6 or 400.7.A.8?"

If so, flexible cord is out. Seroiusly, if they want a disconnect out by the motor, then ..........

put in a disconnect:slaphead:

ice

I think the owners goal is not about disconnects or about flexible cord, it is about what they perceive to cost the least that will still satisfy the needs. Thing is the cord, connectors/receptacle, etc. probably end up in similar price range on a 5 HP 480 volt motor as does a manual motor switch and flexible conduit. But we then have the VFD issue in this instance making it a little more complex should you want the drive to shut down before disconnection.

One thing I have always wondered with early opening contacts for shutting down the drive is if the drive is programmed to decelerate the load instead of just letting it coast - what good does the early closing contacts do, you are still going to open the motor circuit while it is decelerating?

 

[iceworm]

That was common and allowed in past editions of NEC to have the disconnecting means at the controller if it was lockable. They changed wording in 2005 (I think) that kind of eliminated that as a general practice and is only allowed for certain exceptions now. ..

I am absolutely clueless as to exactly what you are advocating and your reasoning.

In any case, the 2011 NEC is very clear

... 430.102.B.1, B.2 and following exception are perfectly clear. ...

I respectfully suggest you actually read these sections.

I know of no pressing case from OSHA nor the NEC to abolish the industry practice of NOT installing a disconnect out at the motor.

As for changes, the 1996 NEC, 430-102.(b), exception read very close to the same.

ice

 

[kwired]

I am absolutely clueless as to exactly what you are advocating and your reasoning.

In any case, the 2011 NEC is very clear

I respectfully suggest you actually read these sections.

I know of no pressing case from OSHA nor the NEC to abolish the industry practice of NOT installing a disconnect out at the motor.

As for changes, the 1996 NEC, 430-102.(b), exception read very close to the same.

ice

It is not the same, I am well aware of the differences as I used to use the exception almost exclusively and had the disconnecting means at the controller. The State of NE had a local amendment when they changed this and it basically replaced the new section with the wording of the old section. But when they adopted 2008 NEC they adopted it with no amendments and 2011 was same way, and we had to start putting disconnects at motor locations that we never used to.

from 1996 NEC 430-102(b)

A disconnecting means shall be located in sight from the motor motor location and the driven machinery location.

Execption: Where the disconnecting means provided in accordance with Section 430-102(a) is individually capable of being locked in the open position.

This exception allowed the controller disconnect to also be the motor disconnect as long as provisions are met, for any motor installation.

from 2011 NEC 430.102(B)

(B) Motor. A disconnecting means shall be provided for a motor in accordance with (B)(1) or (B)(2).

(1) Separate Motor Disconnect. A disconnecting means for the motor shall be located in sight from the motor location and the driven machinery location.


(2) Controller Disconnect. The controller disconnecting means required in accordance with 430.102(A) shall be permitted to serve as the disconnecting means for the motor if it is in sight from the motor location and the driven machinery location.


Exception to (1) and (2): The disconnecting means for the motor shall not be required under either condition (a) or condition (b), provided the controller disconnecting means required in accordance with 430.102(A) is individually capable of being locked in the open position. The provision for locking or adding a lock to the controller disconnecting means shall be installed on or at the switch or circuit breaker used as the disconnecting means and shall remain in place with or without the lock installed.
(a) Where such a location of the disconnecting means for the motor is impracticable or introduces additional or increased hazards to persons or property
(b) In industrial installations, with written safety procedures, where conditions of maintenance and supervision ensure that only qualified persons service the equipment

This version only allows the practice of using the controller disconnect as the motor disconnect in much more limited applications as opposed to all installations like the 1996 NEC allowed.

 

[iceworm]

It is not the same, I am well aware of the differences as I used to use the exception almost exclusively and had the disconnecting means at the controller. The State of NE had a local amendment when they changed this and it basically replaced the new section with the wording of the old section. But when they adopted 2008 NEC they adopted it with no amendments and 2011 was same way, and we had to start putting disconnects at motor locations that we never used to. ...

kw -
We are having two different conversations. The only instances where I have concern are industrial. I thought I was pretty clear this was my only area of discussion. Apparently not.

The changes in the code, 1996 to 2011 have not effectively changed the requirements for disconnects in industrial areas. Yes, I am aware of the addition of, "written safety procedures, where conditions of maintenance and supervision ensure ...."

ice

 

[kwired]

kw -
We are having two different conversations. The only instances where I have concern are industrial. I thought I was pretty clear this was my only area of discussion. Apparently not.

The changes in the code, 1996 to 2011 have not effectively changed the requirements for disconnects in industrial areas. Yes, I am aware of the addition of, "written safety procedures, where conditions of maintenance and supervision ensure ...."

ice

Now lets define industrial. Most AHJ's are not going to accept just calling it industrial, it needs to also have trained maintenance persons and written safety procedures etc. I do a lot of "industrial" work that doesn't even come close to having trained people that may possibly maintain the equipment or has written safety procedures. I also have places that maybe have some written safety procedures, but electrical maintenance is not included in the procedures, mostly because it is something that hasn't come up as needing addressed before, and most electrical work is done by third parties, but their own guys still will check for some simpler problems first like resetting breakers or checking fuses, but they may not realize just what hazards are being introduced by doing these tasks so they do not get included in safety policies.

I call it industrial because it is not residential and is not your typical "commercial" application either, but at same time is far from being like a Detroit automobile plant. Where is the line drawn between commercial and industrial? NEC really doesn't define either, nor does it define residential, but does define a dwelling unit. It is possible for a dwelling unit to exist in an industrial facility though.

 

[iceworm]

Now lets define industrial. Most AHJ's are not going to accept just calling it industrial, it needs to also have trained maintenance persons and written safety procedures etc. I do a lot of "industrial" work that doesn't even come close to having trained people that may possibly maintain the equipment or has written safety procedures. I also have places that maybe have some written safety procedures, but electrical maintenance is not included in the procedures, mostly because it is something that hasn't come up as needing addressed before, and most electrical work is done by third parties, but their own guys still will check for some simpler problems first like resetting breakers or checking fuses, but they may not realize just what hazards are being introduced by doing these tasks so they do not get included in safety policies.

I call it industrial because it is not residential and is not your typical "commercial" application either, but at same time is far from being like a Detroit automobile plant. Where is the line drawn between commercial and industrial? NEC really doesn't define either, nor does it define residential, but does define a dwelling unit. It is possible for a dwelling unit to exist in an industrial facility though.

Hummm .....
I understand what it takes to meet 430.102.B. The AHJ reps I work with understand. I would not look for, "the line drawn between commercial and industrial", rather the line between "industrial meeting 430.102.B" and "all others not meeting 430.102.B"

It is possible for a dwelling unit to exist in an industrial facility though.

This would be part of us having different discussions. "residential" and "dwelling" have nothing to do with my part of the discussion.

ice

 

[kwired]

Hummm .....
I understand what it takes to meet 430.102.B. The AHJ reps I work with understand. I would not look for, "the line drawn between commercial and industrial", rather the line between "industrial meeting 430.102.B" and "all others not meeting 430.102.B"


This would be part of us having different discussions. "residential" and "dwelling" have nothing to do with my part of the discussion.

ice

Very well, lets look at the last part of the exception again:

(b) In industrial installations, with written safety procedures, where conditions of maintenance and supervision ensure that only qualified persons service the equipment

It does say in industrial installations, and further qualifies it with "written safety procedures, where conditions of maintenance and supervision ensure that only qualified persons service the equipment"

If all the qualifiers are met, then you can use the exception. I don't run into many industrial settings myself where this is happening. Many small industrial places may have a maintenance staff, but not always a staff that includes trained electrical professionals, and there are also many cases where there is no true maintenance department, which kind of makes it difficult to have a true qualified person that services the equipment.

Those particular settings can not use the exception. Unless you work nearly exclusively in larger industrial facilities, I find it hard to believe you run into maintenance conditions that qualify at every installation you go to.

 

[iceworm]

... If all the qualifiers are met, then you can use the exception. ...

yes - I think that's what I have been saying - In fact I'm sure that 's what I've been saying.

... I don't run into many industrial settings myself where this is happening. Many small industrial places may have a maintenance staff, but not always a staff that includes trained electrical professionals, ...

First bummer for you, good for me.

Second: GOOOOONnnggggg Read it again. Says, "qualified".

... I find it hard to believe you run into maintenance conditions that qualify at every installation you go to.

You're not just throwing this out there for confusion are you? No, of course you're not.

Well I don't recall saying I did. Bad on me for leaving you with the impression that I did.

ice

 

[kwired]

yes - I think that's what I have been saying - In fact I'm sure that 's what I've been saying.


First bummer for you, good for me.

Second: GOOOOONnnggggg Read it again. Says, "qualified".


You're not just throwing this out there for confusion are you? No, of course you're not.

Well I don't recall saying I did. Bad on me for leaving you with the impression that I did.

ice

So every industrial place you run into no matter how big or small it is has "qualified" persons available to service equipment and you are able to use the exception for all installations?

I know what it says, but you come off leaving me the impression that all the installations you work on are eligible to use the exception, and I guess it is possible, but a little unlikely unless you only have a limited number of places you work and they are all well structured, if you are more of a contractor that takes on whatever comes up more like I am, you will get a lot of smaller clients, that don't have well trained staff - certainly not what NEC would call qualified, but rather have production people that are also maintenance people whenever the need arises, usually do limited electrical work, and when they do they often mess things up and have to call an electrician to straighten it out.:happysad:

Around here for the most part the State Electrical Division doesn't consider all than many plants to have people that are qualified to use very many of the exceptions throughout the code that allow for leniencies when qualified persons will be maintaining it, especially away from the larger cities where there is more larger industrial plants.

 

[iceworm]

So every industrial place you run into no matter how big or small it is has "qualified" persons available to service equipment and you are able to use the exception for all installations? ....

No, not all. But not very many. Other than the few installed for operational reasons I spoke of earlier, only one comes to mind. The pumphouse for the FAI airport ramp refueling system has 3 - 150HP motors. Those have disconnects right next to the motors - C1D1 disconnects in fact.

I'm sure there were others - just nothing coming to mind

 

[ptonsparky]

I suspect there is not one qualified person at any of the places I work. Well, maybe one, but i only work there every two or three years.

 

[kwired]

I suspect there is not one qualified person at any of the places I work. Well, maybe one, but i only work there every two or three years.

And that is probably because the qualified people at that place do most of the work and only call in outside help when they think it is necessary. I think in general contractors are not going to use the exceptions that relax requirements for places with qualified persons all that often except when contracting a new plant or addition to a plant that has or will have qualified persons that maintain it when it is done, or maybe if they are the regular qualified person(s) under a contract. Otherwise most other work contractors install is not going to be maintained by a regular staff of qualified individuals, it will be whoever is (or thinks they are) up to the task or whoever gets called in when there is a problem. Those that maybe are qualified but get called in on an irregular basis are not really what the NEC is talking about though when it mentions "written safety procedures, where conditions of maintenance and supervision ensure that only qualified persons service the equipment"

 

[GoldDigger]

And that is probably because the qualified people at that place do most of the work and only call in outside help when they think it is necessary. I think in general contractors are not going to use the exceptions that relax requirements for places with qualified persons all that often except when contracting a new plant or addition to a plant that has or will have qualified persons that maintain it when it is done, or maybe if they are the regular qualified person(s) under a contract. Otherwise most other work contractors install is not going to be maintained by a regular staff of qualified individuals, it will be whoever is (or thinks they are) up to the task or whoever gets called in when there is a problem. Those that maybe are qualified but get called in on an irregular basis are not really what the NEC is talking about though when it mentions "written safety procedures, where conditions of maintenance and supervision ensure that only qualified persons service the equipment"

Then there is the OSHA sense of "qualified", in which all it means is that the person knows the safety rules involved with accessing (or staying away from) different parts of the equipment, and they do not have to have any clue as to how to fix it if something is wrong .

 

[kwired]

Then there is the OSHA sense of "qualified", in which all it means is that the person knows the safety rules involved with accessing (or staying away from) different parts of the equipment, and they do not have to have any clue as to how to fix it if something is wrong .

True, but I don't run into many of those. OSHA is not a popular term in these parts that comes up all that often other than in larger organizations or government organizations, and even then it is not necessarily something that is all that thorough when it comes to all potential hazards. You see more people using safety equipment than you used to, but I'm guessing more because of insurance than OSHA. Larger businesses that have locations in other states are usually better with safety procedures, because those mandates are from higher up in the chain, but smaller businesses with only one location often only do what their insurance company makes them do when it comes to safety procedures. When some new policy/practice goes in effect in one of those companies it is because someone like insurance pointed out a problem in that area, or maybe someone was injured and it clued them in that something needs done.