control panel building

hi guys

does anyone know of any books or websites that can help me in building control panels.

thanks for your time
stu

First, start with your local electrical codes.
Then look at (RECENT) panels that others have done.
Then look in depth, at your local eletrical codes.
Then, look at your local safety requirements.

There is no cookbook that I know of.

As rdrast said "There is no cookbook that I know of."

I've never seen anything. I have always considered it somewhat of an art. I've seen many panels that look great until I have to work on them. Layout is everything. Some shops can pump out a lot of canned panels but custom is another matter.

My company is UL 508 certified but UL doesnot say how to go about panel building. It's more like part specs., wire sizing and fuse ratings, ect.

Sorry, no real help but I do hope someone has seen a "cookbook" and lets us know.

Good luck,

I can offer some tips that may help. Go to sites like www.hoffmanonline.com and look at the technical information, data sheets and literature they provide.

Many do not realize that panels are made from different materials and use different finishes depending on the application.

One of the main issues to be aware of is HEAT (electrically generated and Solar), heat can shorten the life expectancy of electrical devices. This information is available at Hoffman and maybe others too.

As was mentioned layout is the key, be aware that space is needed between some devices...the data sheet/manual for drives, starters etc will provide that info. The worst situation I was in I had the inside panel all layed out with screw holes and wire duct etc then when the main VFD arrived I had a 9 inch deep panel with a 10 inch high drive...NOTE I did not order either and the engineer gave me a cad drawing of the layout.

If you have AutoCad most of the major companies offer cad files for their products. AB offers an abundance of programs (free) for selection and configuration using their products. http://www.ab.com/e-tools/index.shtml

Another good resource is Panduit (www.panduit.com), they actually have online training for use/installation of many of their products like wire duct, cable ties etc. http://www.panduit.com/training/index.asp?classid=1006

I could list more but you should get the idea, just get as familiar as you can with the equipment...keep the books handy.

Well, I dont know of any instruction manual on panel building, but I can offer a few tips.

1. Skinny wire duct will cut up the backs of your knuckles and hands.
2. 6" (15 cm) is a comfortable spacing between wire ducts for din-rail and terminal blocks. Make it too small and not only is it hard to work with, its hard to make it look neat, and even harder to keep it neat after installation.
3. At the panduit web site Ron refered you to, there are some recommended wire duct fill tables. Use those tables to determine the minimium size the duct. An undersized duct is a disaster looking for a place to happen.
4. Use fine toothed wiring duct - its much neater.
5. I prefer to place stand-offs under terminal din-rails to bring the terminals up to just under flush with the duct top. They are much easier to hook up and have a better appearance. I use 5/16" coupling nuts for standoffs. (Nut ID is larger than the screw used to secure the din-rail)
6. When standing din rail up off the backpan, use the 15mm deep din rail instead of the 7.5mm deep rail. It is stronger and does not flex as much. For rail bolted directly to the backpan, choose the rail that fits the application the best.
7. Buy pre-punched DIN rail.
8. Wire is cheap.
9. Attach all wires to a PLC card all at the same time. Dont attempt to wire point to point from the card. Leave the wires longer than needed (see #8). This will make it much easier to keep the wire loom from the PLC card into the duct nice and neat.
10. Some PLC cards divide IO into groups sharing a common. I don't jumper between the commons at the PLC card, but rather bring a wire out for each common to the terminal strip.
11. I used to securely bundle and wire tie the wires in the loom from the PLC card until it entered the wire duct. This results in a nice but very ridgid bundle of wires. Now I select a piece of heavy heat shrink tubing with an ID just a little larger than the diamter of the wire bundle. I cut it to length and slip it over the wires, positioning it at the wire tie down on the PLC module. I shrink only the ends of the heat shrink tubing and then put a wire tie around each end. Leave the middle of the tube un-shrunk. This keeps the loom neat, but the wires now can flex within the loom, making it much easier to remove the terminal block from the PLC card when necessary.
12. Use screw down tie downs on the backpan below the PLC to secure the lower end of the loom. Stick-on tie downs will come loose sooner or later.
13. If you are using heat shrink wire markers, dont shrink them one at a time. Wait until you have a whole row of terminals landed. Then align all the sleves and turn the numbers facing out. Be careful when shrinking the sleeves, you can warp the wire duct very easily with the heat gun. A few strips of aluminum foil can come in really handy here to protect the duct as well as reflect heat onto the back of the sleeves. Patience is a highly prized virtue here.
14. If you have a miter saw, use it to cut the duct. A hand cut with a hacksaw looks like a hand cut made by a hacksaw.
15. Don't cut the duct covers until you have the panel completed. The duct is flexible, so wait until it is full of wires, that way the duct covers can be cut so they are flush and butt up to each other.
16. Where wire ducts meet , I dont just break out the comb teeth. I use a razor knife and cut the rib away flush with the back of the duct. Wires turn the corner much easier if they dont also have to go over the hump made by the rib.
17. When screwing down the duct, I place small plastic zip-tie tie downs under the duct screws. I may or may not use them all but they are dirt cheap and they are there. It beats trying to shove a stick-on tie down into a duct half full of wires.
18. I use a disc sander to just barely radius the corners of the cut din rail.
19. Isopropyl alcohol is excellent for removing the light pencil layout marks on the backpan. Make good use of both pencil and alcohol.
20. Layout the entire backpan whenever possible, even if you have a cad drawing. A drywall square can come in really handy here.
21. A lightweight cordless screwdriver will come in really handy. I have a couple of Milwaukee 6546s - its lightweight and has an adjustalbe torque limiter, and the handle angle can be adjusted, and battery life is decent. Using a larger codless drill will get tedious when you have lots of wires. The cordless screwdriver you can buy at Walmart is not a good deal.
22. Nevertheless, a good cordless drill (or standard electric drill) is another essential tool.
23. Centerpunch the holes before drilling. Let me say that one more time. Centerpunch the holes before drilling. Oh, and also, centerpunch the holes before drilling. (is that horse dead yet?) No matter how neat the wires are, if the components aren't straight, its not going to look good.
24. I have a chuck attachment for my cordless milwaukee screwdriver. I use it on low speed to tap the holes. I use it because I have broken too many taps off in the hole trying to tap by hand. Carbide taps break off much easier than hardened steel taps, they are also much harder to extract once broken. Use tapping oil. Isopropyl alcohol also cleans it up good.
25. I place the backpanel horizontal over a couple of saw horses. That way I can move all around it. A panel builder I know has some really nice tilting tables, but he builds lots more panels than I do.
26. I have a machinist friend do my door work for buttons and openings.
27. When you have a through the door rotary disconnect, dont cut the hole until after you get the backpan assembled and the pan in the box. Then take a square shaft with a sharpened point on one end that is about 1/8" longer than what will let the door close. Place it in the disconnect switch, and smack the door gently over it with a rubber mallet. Don't whale on it, you'll break something. This will leave a faint mark where the disconnect operator should be centered.
28. I use wire ferrules. I didn't used to use them and considred them to be a royal pain in the butt. They still are, but I use them now.
29. Wire colors: Black - AC power. Red - AC Control. White - AC Neutrals. Dark Blue - DC control. White/Blue stripe - 0VDC. (This is fairly common in the US, but not a ridgid requirement and varies by location thoughout the world.)

Nfpa79

NFPA has some good books that could help with US standards. NFPA79 is the electrical standard for industrial machinery. They have some others but 79 has the most on general control panels.

Great job Aleric. I would add,
30. Keep ac voltage and dc voltages seperate, not even running in the same duct.
31. AC at the top of the panel, dc and low voltages below that.
32. Power in at the top of devices such as fuses and relays, out at the bottom, when possible.
33. It is hard to have too many fuses, especially on AC, they isolate a problem when it occurs when correctly sized.
34. All ground wires originate form a single point, Aleric's #10. More than one ground point, especially when using Servos and Inverters causes small ghost currents in the ground loops.
35. Use 30 degree standoffs for din rails where necessary.
36. Screw din rails to the backpanel, no shortcuts with double-sided tape. It will not hold up to the heat.
38. Use a good brand of terminals, such as Wago or Altech. There are lots of great brands, but decide what you want to use and stick with the brand. They can be a major investment in just the numbers and letters that go on them and one brand does not interchange with another. They can also decrease wiring time.

I think Alaric has been watching me build panels, how else could he know all my great tricks?

37. Purchase wire retainers for the wire duct. Wiring a panel without them is a pain.

Gee, the last new panel I saw had three components, and I don't remember any wire duct. The striped (that is stripes, not stripped) phone wire came directly from the sensors to the ControLogix rack, no wire markers, the 3 phase coming in was color coded, no fuses or breakers.

Guess that after they bought the Delta V and ControLogix, they couldn't afford anything else.

There is a thread on Control Panel Pictures that has some neat panels in it.

I would post Eric's nifty litle slope panel, but I am prohibited to do so until Hootie Safferticker Day.

regards.....casey

I have developed the habit of putting terminals on the side instead of at the bottom if possible, especially in a panel that is not on legs...ie no ground clearance. I hate having to sit on a floor trying to work with terminals at the bottom. If I am in a situation where I have to place it on the bottom I make sure its at least 6 inches or more above the bottom of the cabinets and no large devices (motor starters etc) are directly above it.

Another good habit is to make sure any open connections, like screw terminal transformers etc, are covered.

Avoid when possible putting small devices between larger ones...example a 5HP motor starter between 2 50HP starters.

If you place an outlet in the panel, for laptops etc, make sure its fused separate from control voltage...when possible I use a separate transformer for this.

TOOLS TOOLS TOOLS, have the right tool for the job. As mentioned, CENTER PUNCH the holes before drilling and as the old saying goes: Measure twice, cut (or drill) once. I prefer using a magnetic stand drill when possible...also be very careful when doing knock-outs for pushbuttons, switches etc...the wrong size drill bit can throw off the alignment immensely and it not look neat. One of these days I am going to build a 3 axis table that will do the drilling.

I use a regular battery powered screwdriver for assembly but actually use a torque driver on ALL the screw terminals to make sure they are tightened to specs. You can not imagine how many problems this can eliminate. ALWAYS check that ALL screws are fully tightened whether you use a torque driver or not.

I agree that ferrules can be a PITA but they can/do eliminate issues caused by "whiskers" (the strands of wire that dont go under the terminal).

They make a tool that notches the holes for switches but for the life or me I can not think what its called and I own one. The file method takes too long and does not look as neat. I will provide a picture of it and hopefully what its called as soon as I can.

Another good tool to have is a cut-out/spiral saw BUT for many devices that may be mounted on a panel there is a tool for the job...9 pin D-sub connectors and similar have knock-out punches.

If this keeps up I see a new page developing at a certain site.

rsdoran said:

I have developed the habit of putting terminals on the side instead of at the bottom if possible, especially in a panel that is not on legs...ie no ground clearance. I hate having to sit on a floor trying to work with terminals at the bottom.

Click to expand...

This is especially needed for us old geezers with bad knees and backs.

Use quality terminals. I prefer cage clamp types since they are much faster to install and change around, and you don't have to use ferrules with them, although large cores can be a problem.

Weidmuller do some great terminals - I am using their ZicZac range on a job right now.

I am incredibly impressed, Alaric.

Two suggestions:

38) Put a label with wiring color codes inside the door, and ship a set of drawings, including a point list and BOM, with every panel.
39) Use disconnect style terminal blocks for field terminals on all analog circuits - this saves a huge amount of time in field testing 4-20 mA devices and commissioning. I also use disconnect terminals wherever possible on discrete wiring - it is handy to isolate field devices, trouble shoot I/O and so on. The incremental cost is recovered after the first field problem.

Well, if the experts here continue posting thier "Tips & Tricks", You got the book you were asking for!

Related Links:

Designing Electrical Panels Not Panelbuilder

Control Panel Pictures

Ron, I whole heartedly agree with the statement about not putting terminals close to the ground. I hate it when I just about have to stand on my head to put a wire back into a terminal strip.

Dale
P.S. Already cutting and pasting all of the suggestions made here to give to one the guys in my shop. Does good work, just needs to learn how to "PLAN" things.