PLC hard wiring

[brucechase]

I have on many occasions run a motor circuit with the controls not only in the same conduit, but in the same cable. I would get a 9 conductor cable (usually for TC rated systems with a remote start/stop PB) and run 3 motors leads at 480 and the controls at 120 VAC. I never had problems. I usually would not run DC with the motor leads and like everyone else, never analog signal wire without having a shield. There is no rule that says you can not do this as long as the same insulation level of the wires are maintained. This is protect the circuits in case one of the 480 VAC wires has an insulation breakdown, the other wires will have the same insulation level and therefore not be breached.

my .015 cents

 

[gary marano]

If you want to run the cinductors all in the same conduit you can

only if you color code the low voltage i/o wires. They should
not be brown,orange,yellow they are 480 volt colors. That is
nec code and electricans know this and they will be aware of
the fact that their are different voltages present in the conduit.
It is a good practice to run a seperate conduit for the i/o cables.
This way they come from the plc cabinet and the motor leads from
the mcc this way their is no confusion if you ever have to
trouble shoot the system in any way.

 

[Unregistered]

The only person making any sense in Ken Roach - all the talk about colors and insulation thickness is real worrying - the major problem is inductance and cross talk , you have have peak currents in some of these cables hitting hundreds of amps , that is bound to have an effect is it not ?

 

[rsdoran]

only if you color code the low voltage i/o wires. They should
not be brown,orange,yellow they are 480 volt colors.

This has been discussed before, NEC does not designate (BOY) those colors for 480.

The only person making any sense in Ken Roach -

Ken always makes sense but if you had fully read the thread you would see that all the talk was relevant AND that you have not said anything that has not ALREADY been said.

 

[Rick Densing]

, you have have peak currents in some of these cables hitting hundreds of amps ,

Where did you get that data?

With regard to the rest of your response, I qualified my answer regarding low horsepower motors. Did you notice I cited actual experience?

You need the same insulation rating in case your higher voltage wire is damaged. If you have a paritially exposed 480V wire lying next to a 300V insulated wire, you are going to have a breakdown. Things can go boom. Like Ron said, NEC is to prevent fire and injury, not for nice clean I/O signals.

Also, it would be nice to hear from the original poster again.

 

[snimra]

I don't remember all the Code and standards but I do remember having multiple machine shutdowns due to an AC cable (110VAC) laid across several signal cables (4-20mA, mV from TCs, mV from vibration probes, etc).
I don't care what's the reason but I'll stick to "No".

 

[gary marano]

This has been discussed before, NEC does not designate (BOY) those colors for 480.

Ken always makes sense but if you had fully read the thread you would see that all the talk was relevant AND that you have not said anything that has not ALREADY been said.

Article 210.5C ungrounded conductors. being a electrician for
over twenty years pulls are done with a color code. I cannot
find the atricle with the color code in 2006 or 02 but it was
in earlier code books. I will look into earlier years, a gray color
was also used for a four wire 460 volt system.

 

[rsdoran]

I know that BOY (brown, orange, yellow) has been used for 480vac wire color designation for many many years. The NEC Handbook example pictures even use those colors. They also use Red, Blue, Black for 240vac in an example.
BUT
They are not designated for those voltages.
Green or bare is ground
White or Gray is grounded conductor

Article 200.6 & 7 apply, also Article 310.12 Conductor Identification (C) Ungrounded Conductors. Conductors that are intended for use as ungrounded conductors, whether used as single conductor or in multiconductor cables, shall be finished to be clearly distinguishable from grounded and grounding conductors. Distinguishing markings shall not conflict in any manner with the surface markings required by 310.11(B)1.

Technically I am not an electrician but I do have a background in electrical work.

 

[Unregistered]

Mr Doran , you mention that what I said is only what is said before , I have read and reread many of the post on this site , including yours , and notice that the number of posts saying the same thing are many , but nothing is said when it is between the "gang" - I also noticed you missed the point - disturbance is not a function of insulation thickness or efficiency (though this is a factor in capacitance , but rather in inductance caused distrubance - that is why it was repeated - people kept going on about colours and thickness of insulation - it didn't seem like they were understanding some of the other factors .

To the guy that "qualified" his answer re actual experience - the original post was a generalized question , therefore the generalized answer that peak current can hit hundreds of amps was correct and justified - I mean unless of course you are working on model railways - real life and industry is a bit different.

There does seem to be rather a "bullish" clan type attitude here - if you aren't gang , then we will just talk around your comments rather than acknowledge .

Please also understand that so called good "code" work is still not good practice even if allowed by code . Electrical codes should be improved upon where possible ( particularly in this case if they allow mixing signal with high current supplies ) ?

 

[rsdoran]

Mr Unregistered

This site and mine offers answers to questions that in "most" cases have many variables involved so there may be different approaches to the answer given. The other aspect is that answers provided may also provoke other questions that may or may not be specifically relevant to the subject but can be relevant in general so it is common to see tangents form within a thread.

I am not sure what you mean by "gang". I and many members have been on this forum for some time, years for some of us. The overall atmosphere attempts to keep things informative but at the same time have some clean humor and camaraderie. You dont always have to meet, socialize etc with people to consider them friends and be comfortable conversing with them. In some cases it may seem all others are excluded from the conversation but in general I do not believe that is the intent.

I am not a highly educated person but I have years of experience involving many aspects of the industrial field. I believe by now most know I attempt to provide accurate information on the subject in question, from time to time I may misinterpret something and provide the wrong information or possible state the information inaccurately. I think by now though most people understand I can/will/do provide resources to verify my information.

I state code as the minimum necessary, anything can be improved. I will correct statements pertaining to code or any subject I believe are inaccurate. The object is to obtain "accurate" information.

As for "bullish", I was born in May and that makes me a Taurus. I am hardheaded, stubborn and have been called a drama queen (didnt care much for the queen part though). I am many other things too, some may be bad and some may be good, just depends. What you call "bullish" is what makes me take the time to provide so much information, resources, pictures etc.

Think about this. You arent registered, you made one short post basically repeating what was already said. You have not provided resources, links, website or ?, so who knows if you have a clue?

 

[CaseyK]

Should Posters Be Registered?

The only person making any sense in Ken Roach - all the talk about colors and insulation thickness is real worrying - the major problem is inductance and cross talk , you have have peak currents in some of these cables hitting hundreds of amps , that is bound to have an effect is it not ?

At some point in time, someone unfamiliar will work on the machine, and it probably will not have any documentation.

It would be nice if they followed some guidelines, if only common sense.

Insulation IS a factor, when you have your hand in there and it decides to leak through, or it cuases a machine to start up from leakage.

Back to a poll I once posted...


Should someone be registered to post?

regards, all.....casey

 

[Rick Densing]

To the guy that "qualified" his answer re actual experience - the original post was a generalized question , therefore the generalized answer that peak current can hit hundreds of amps was correct and justified -

You did not say "can" in your first post.

Like I said, it would be nice if the original poster would chime in and get more specific.

Right now, the answer to his question is "it depends". We can squabble about semantics and this situation and that, but it won't change that answer.

Mr unregistered, please register and let us get to know you. A few people here have had much rockier starts than you. Don't assume that people talking amongst themselves are doing it to exclude you. It is just that they know each other and seek a comfort level.

I have been around here a long time and sometimes I feel that people are talking around me. It is just part of an online forum.

 

[stasis]

Is it ever permissible to run I/O wiring in the same conduit as 480 volt 3 ph motor wiring? I have a dispute going right now.

the answer is yes, you can, under certain guidelines within the NEC.
As you can tell by most answers, it isn't common practice for several reasons.

And officially, there is no color code in the US other than those of grounded/grounding conductors. Most electricians use the old color code, but it's not law...again, common practice.

 

[rsdoran]

And officially, there is no color code in the US other than those of grounded/grounding conductors. Most electricians use the old color code, but it's not law...again, common practice.

That isnt totally accurate, NEC doesnt specifically state anything but green, white, and gray. NFPA 79, which applies to machinery, does state colors for certaing things, my copy seems to be getting old so anyone that has a newer copy if its changed please correct this.
Black: Ungrounded line, load, and control coductors at line voltage.
Red: Ungrounded ac control conductors at less than line voltage.
Blue: Ungrounded dc control conductors
Yellow: Ungrounded control conductors that may remain energized when the main disconnect is in the OFF position.
NOTE: European/International standard requires the use of orange.
White or Gray (use to be natural gray): grounded circuit conductors
White with blue stripe: grounded (current carrying) dc conductors.
White with yellow stripe: grounded (current carrying) ac control circuit conductors that remain energized when the disconnecting means is in the OFF position.

I am not going to debate the issue of is it "law" or not, it is an accepted standard in the US.

 

[Tark]

In case you wanted to know, there are 5 conductor colors stated in the NEC (I’m not counting bare as a color). A classic Master Electrician exam question. You have to list all 5 to get it right

Grounded conductor – White or Natural Gray
Grounding conductor – Green or Green w/ one or more yellow stripes
Delta High Leg – Orange

That’s it folks.