Control Panel Building

Hi

I am about to build my first small control panel at my job. I have read some of the posts with control panel building tips but I wanted to know of any tips on bundling the wires to the plc I/O cards? Some of the OEM panels we have in the panel look very good. I will be wiring up contrologix 16 point cards and running to terminals for field wiring mostly. What is the best way to bundle them neatly and fit them all in the Panduit? Also what about labeling? I was thinking of doing the finished labeling on the plc card and temp labeling on each wire before I bundle them. Then change to finished labeling once they are cut to proper length and ready to be landed

I live/love to build panels... it's fun

See these other threads about building them... it may give you some ideas

The last link is the BEST... a ton of pictures, also if you are puting in an HMI have the HMI open in, so you don't have to go to the other side of the door to make a change...

http://www.plctalk.net/qanda/showthread.php?t=18737

http://www.plctalk.net/qanda/showthread.php?t=11712

http://www.plctalk.net/qanda/showthread.php?t=8991

I normally do jobs like that by running the wires one at a time from the card to the strip, so there is less waste of wire and labels.

Make sure you use <=16awg wire if permitted...any bigger and it won't fit, unless you purchase the larger size wiring arm housings.

The controllogix wiring arms are not the easiest to work with either. Their terminals are pretty tightly packed. You will be very good with needle nose pliers after you have done one or two cards.

Also, I normally start with the bottom point on the card and work my way up. If there are jumpers from point to point on the card, it is best sometimes, to wire those first.

Make the wires long enough so that the arm can be removed from the module, and leave a little bit extra for when the time comes that a wire needs to be cut back a little and stripped again. Just don't make them too long or you may end up with a rats nest in the panduit. If you have lots of space in hte panduit, you can run the wire past the terminal point a couple of inches and then back to the terminal point to allow for extra slack that can be useful for later repairs, or "what-ifs" (like what if I need to move the whole rack over two inches to make room for an added component, or all the card need to move over one slot for an upgrade...).

When you first start out, and the wire is curly, it wont want to stay in the panduit along your path. To deal with that, I make loops of cable ties that go around the fingers of the panduit, allowing you to weave the wire behind the loops, and then you can remove those loops later.

Also, I sometimes temporarily weave the wire in and out of the panduit fingers along one edge to hold it for me, and help keep it straight until it is all done.

Once finished, you can tie them to the wiring arm with small cable ties.

Personally, I don't like excessive use of cable ties. They look great when the panel is brand new, but during repairs they are a PITA. I use as few as possible.

Before even thinking about wiring read all the applicable NEC and UL
standards and do the fault current calculations.
If you need to ask how to wire you really should get somebody that
knows what they are doing to keep you from killing someone.

One other thing that gets alot of people. When wiring inside a cabinet use MTW instead of THHN. The wire is alot more flexible and is easier to bundle. For PLC's I tend to use 20 AWG. Also when you layout your panduit try to give yourself atleast 3 inches between the bottm edge of the PLC and the top edge of the panduit. The reason I do this is as Okie mentioned you may need to get the terminal blocks off the cards. When locating the terminal strip remeber to leave room for someone's fingers. If you mount the terminal strip right at the edge of the back panel then the field wiring is going to be a pain.

Also when you are wiring the cards you need to set your labels back for the end a bit to allow the wire to bend at the terminal itself. Also try to stagger your labels on your cards so no 2 labels are side by side. This adds to the diameter of the wire and can getting them all to fit more difficult.

Note: there is no such thing as to many labels. I label my componets, there location, and my wires.

As for tempoary labels a roll of 1 inch masking tape works great. Unless somthing is on another panel I wire it directly as I do the PLC cards.

Clay B. said:

One other thing that gets alot of people. When wiring inside a cabinet use MTW instead of THHN. For PLC's I tend to use 20 AWG.

Click to expand...

Exception in the NEC I missed that allows 20awg?

Finding MTW that is not also THHN could be interesting.

Do you guys normally wire tie or bundle the wire by another method inside the Panduit or just where it leaves the Panduit? I have seen it both ways on some equipment that is why I am trying to determine which is best

As far as wire we do have mtw but it also has a second designation thwn I think? Maybe something else. I have used wire in the past that was strictly mtw but it was ordered not something we can pickup in stock at the local electrical supply house. But the wire that is just designated mtw is better than what we currently have and has less spring to it. The insulation seems to have more of a rubberized feel for lack of a better term than the dual designation type which feels more plastic like thhn.

Would buying mtw wire in 1000 foot spools be better than the 500 foot rolls less spring to it?

Derek said:

Exception in the NEC I missed that allows 20awg?

Finding MTW that is not also THHN could be interesting.

Click to expand...

Wire size is based on current. Ever noticed how a sensor wire tends to be 22AWG.

THHN or THHW is refered to as general building wire. IE if wire is to be pulled thru conduit.

MTW is wire rated for interal use. IE Insdie on a control cabinet.

As far as finding MTW wire... Got close to 50 rolls of it in my panel shop. Sizes range from 8 AWG all the way down to 24 AWG. In fact I just placed an order for some more on Friday.

Clay B. said:

Wire size is based on current. Ever noticed how a sensor wire tends to be 22AWG.

THHN or THHW is refered to as general building wire. IE if wire is to be pulled thru conduit.

MTW is wire rated for interal use. IE Insdie on a control cabinet.

As far as finding MTW wire... Got close to 50 rolls of it in my panel shop. Sizes range from 8 AWG all the way down to 24 AWG. In fact I just placed an order for some more on Friday.

Click to expand...

725 spells out wire sizes for remote signaling and control circuits.
No exceptions under 409 or 430 I can think of.
If you want to do it under conductors for general
wiring you will need to go even larger.

I would be happy if you show anywhere in the NEC
where 20 gauge is legal except class 2 or 3 power limited.

UL listed integrated assemblies can get by with using
smaller wire.

Most panel shops building one off a kind panels usually conform to the NEC as individual UL certifications are spendy.

THHN, XHHW and a few others are also rated MTW.
While finding a wire solely listed as MTW may be possible
I doubt you will find it readily available anywhere.

The Plc Kid said:

Do you guys normally wire tie or bundle the wire by another method inside the Panduit or just where it leaves the Panduit? I have seen it both ways on some equipment that is why I am trying to determine which is best

As far as wire we do have mtw but it also has a second designation thwn I think? Maybe something else. I have used wire in the past that was strictly mtw but it was ordered not something we can pickup in stock at the local electrical supply house. But the wire that is just designated mtw is better than what we currently have and has less spring to it. The insulation seems to have more of a rubberized feel for lack of a better term than the dual designation type which feels more plastic like thhn.

Would buying mtw wire in 1000 foot spools be better than the 500 foot rolls less spring to it?

Click to expand...

Panduit serves as a wire way itself so there is no reason to wire tie conductors inside it. Plus if someone needs to trace a wire the cable ties are going to make his job difficult.

MTW wire will always be labeld MTW first then if you have a special need you get the second desinator. Hince the THWN or THHN. I prefer the "just" MTW cable because it is more flxible. But it is only used inside of your control cabinet. I do not recomend pulling it thru conduit.

I have never seen lenght of roll mattor other than on your wire stand. I prefer the 500 ft rolls because I use a portable wire stand and I can have more colors on my stand. My wire vendor will sell me either at the same price per foot.

Derek said:

725.41 spells out wire sizes for remote signaling and control circuits.
No exceptions under 409 or 430 I can think of.
If you want to do it under conductors for general
wiring you will need to go larger.

I would be happy if you show anywhere in the NEC
where 20 gauge is legal except class 2 or 3 power limited.

UL listed integrated assemblies can get by with using
smaller wire.

Most panel shops building one off a kind panels usually conform to the NEC as individual UL certifications are spendy.

THHN, XHHW and a few others are also rated MTW.
While finding a wire solely listed as MTW may be possible
I doubt you will find it readily available anywhere.

Click to expand...

OK a 16 point PLC card....does that fall into a power limited catagory. Remember that was the componet he was talking about.

As far as ordering just MTW listed wire contact you vendor. Thats what we do.

FYI....All of our panels conform to NEC regs and we are UL Certified. We have our panels UL Ceertified per customers request.

Clay B. said:

Panduit serves as a wire way itself so there is no reason to wire tie conductors inside it. Plus if someone needs to trace a wire the cable ties are going to make his job difficult.
.

Click to expand...

YES.... don't tie them in the tray/wire way or conduit, I HATE when people do that.

Take a large wire tie or something similar and they work perfect in the panduit trays as a temporary holder, don't zip them just put them between the plastic

BTW I try and use MTW when ever I can, for no more reason the end product looks goods and the customer is happy

Clay B. said:

OK a 16 point PLC card....does that fall into a power limited catagory.

Click to expand...

It would fall under Class 1 power limited and still needs to comply with 725 as as I know.

Another interesting question would be if a wire classified
as MTW only would be legal for general hook up wire.
Anybody have the Green Book handy?

I would also like to get some opinions on terminal blocks

Which is best and why idc, spring cage or screw type

I am trying to see what is best in general in almost all applications as I want to standardize on a type and brand

Can See this is proving pointless

Ok, your right why don't you call up Siemens and Allen Bradley and tell them there UL approved specs are wrong and they have been wrong for the last 30 odd years. While your at it call Banner,Sick, and Turck and tell them the potted cables they sell with their sensors are incorrect and they need to take them all back.

While you at it call Beldon cable and tell them your suing because they make a 20 awg MTW cable that is not allowed to be used anywhere in your form of reality.

You can quote all the article numbers you want. That I can not refute at this time. I do not have my code book with me. Doubt I would look it up if I had it. Since I have been doing this for over a decade I really have had no reason to look it up.

But I will tell you what I do know sitting here at home. My panels have been installed in Hazardous locations and met FM approval. My panels have been UL Certified. They have met the critera of some rather large companies in this world.

But here if you want to shove 18 wires above 20 AWG that are THWN or THHN into a PLC I/O card, knock yourself out. It will be your rat nest not mine. I think I will stick with 20 AWG MTW and take my chances the NEC police won't arrest me. I know when I am done the door will close on the card and I have not destroyed the terminal strip.