Wiring

[roguecutlery]

I recently purchased Acorn CNC Controller with Ethernet Connection , (2) KL-5056E Digital Stepper Driver-32 bit DSP Based drivers for x and y motors. (1) KL-8070D Digital Bipolar Stepper Motor Driver-32 bit DSP Based driver for the z motor. (2) NEMA23 570oz/in 5A 3/8” Dual Shaft Stepper Motor (KL23H2100-50-4BC) with Cable for x and y. (1) NEMA34 Stepper Motor – 906 oz in 6.1A Dual Shaft (KL34H295-43-8B) for z. (1) 48VDC/12.5A Switching CNC Power Supply, KL-600-48 power supply. And (1) 5V/3A Switching Power Supply Unit (KL-15-5) power supply. I was curious if anyone can suggest what kind of wires to use for connecting everything. Like the gauge and if i should use shielded wire or not. Any advice is much appreciated, I'm learning as i go. Everything was purchased from automation technologies inc.

[Richards]

Line power going into your enclosure needs to be the same gauge as the wire going to your outlet, which is 14 gauge in my area. Normally, your plug or wall connection runs through a disconnect switch and then to a circuit breaker or fuse. The current capacity of the breaker or fuse determines the gauge of wire that you use between the circuit breaker/fuse and your power supplies. I use a 10-amp circuit breaker so that I can use 16-gauge wire between the main circuit breaker and the power supply circuit breakers. I'm using a 4-amp 24VDC power supply, so I'm safe running 20-gague wire from that power supply to whatever is connected to it. (20-gauge wire is rated to 11-amp for chassis wiring, so there is a safety factor.) The 48VDC stepper power supply is rated at 350W (about 7-amps), so I run 16-gauge wire from that power supply to each of the stepper drivers.

You wrote that you're using a 12A 48VDC power supply. How many amps can that power supply draw? Use a wire chart to see the recommended gauge wire for the input side of that power supply. 18-gauge or larger should be used for the 48VDC side wiring. I use the chart at https://www.powerstream.com/Wire_Size.htm.

I do NOT use shielded wires except when I'm running a VFD (or anything else that has a lot of electrical noise). When I do use shielded cable, I ground the shield to the ground lug inside the cable. I do not ground the other end of the cable. Grounding both ends of a cable that exits the enclosure can cause a ground loop. (See UL electrical recommendations for electrical panels and for sub-panels to understand why using multiple ground points exterior to the enclosure not only is frowned upon, but usually violates electrical code.)

It's always good practice to talk with an electrician if you have questions about wiring. A good friend of mine burned down his commercial photo lab when he used fish-tank heaters to warm his photo chemicals. He didn't know that he should have used a fuse or circuit breaker between the fish-tank heater and the mains supply that limited the current in the wire going to the fish tank heater. The cord wire in the fish tank heaters overheated when the fish tank heaters drew excessive current. That caused a fire. The fire destroyed his business.

[roguecutlery]

Thanks Richards for your input! I've got some more things to figure out lol.

[Richards]

Half the fun of building a DIY projects is learning new things in greater depth than anticipated.

During the last year with COVID-19 restrictions, I haven't been able to just drop into my local electronics parts stores, so I've switched to buying as much as possible from AutomationDirect and other warehouse type stores that carry the odds and ends that I need. One of the unexpected pluses was buying bulk hook-up wire in 500 ft spools. The hook-up wire from AutomationDirect is good quality copper wire with better insulation that the wire that I can buy locally.

One rule-of-thumb that I use is to simply check the wiring for heat. If the wire is warmer than ambient, I start to worry. All wire acts as a resistor. Resistors "resist" current. That resistance produces heat. The wire's insulation is rated to work up to its specified temperature before burning or melting. If it burns or melts, bare wire may contact other metal and you'll have a disaster in the making. So, if I'm using good quality wire with good quality insulation and if the wire doesn't feel warm, that's a good indication that I'm using wire big enough for the job - no matter what the wire gauge chart tells me.

[roguecutlery]

This has definitely been an experience so far lol. I'm loving it though. I had also shot automation direct an email right after i made this post on here. Since they were who i bought everything from I figured I'd see what they say. They suggested I use their shielded wire, 22ga for controls and 18ga for power connections. But am now wondering if i should just do 18ga for everything? Thanks again Richards!

[slodat]

I use the 18ga MTW from Automation Direct for everything but the larger AC power stuff. I bought five colors of 18ga and a roll of 10ga and 12ga. Pretty much covers what you need in most smaller HP machines.

[Richards]

18-gauge is good for a lot of the cabinet wiring. I use 20-gauge mainly because I do a lot of work with PLCs whose terminal blocks cannot accept a wire-ferrule larger than the orange type sold by AutomationDirect. The largest gauge wire that fits those ferrules is 20-gauge. Signals to and from the PLCs are 10mA to 100mA maximum, so much smaller wire could be used. The Acorn has much larger wiring blocks, so using 18-gauge wire is not a problem the Acorn.

One change that I made is to use wire with white/blue insulation for DC ground. Black is commonly used for AC Hot or L1. The wire used with AC is usually 16-14 gauge, so its thickness should indicate its use; but, gremlins seem to follow me around, so I minimize the chance of having a mix-up by using white/blue. I also use blue for +24VDC. That's mostly a carry-over from decades of working around process control equipment. Blue was commonly used for 24VDC.

The important thing to remember is that the wire needs to be large enough to handle the current allowed through by the fuse or circuit breaker. Then, use wire colors or labels to identify the purpose of each wire. Yesterday, I decided to removed the latch circuit for the contactor in cabinet for my little Taig mill and replace it with an indicator LED to show when the 48VDC stepper motor power supply was on. It should have been a 10 minute job. I ended up stripping out the entire cabinet, moving components around and then wiring things back up. That cabinet uses a Acorn V3, so I use red wire for +5VDC, blue wire for +24VDC, orange wire for +48VDC, white/blue for ground, black for L1, white for neutral, green/yellow for earth, yellow for Acorn outputs, and gray for Acorn inputs. Things make better logical sense with the revised wiring.

[slodat]

I have a Brady label maker that does shrink tube. I use the following color codes:

Yellow +24v
Blue +5v
Red 120/240vac L1 as applicable
Black (18ga) DC common. Bigger sizes AC L2 or neutral.
Green earth ground

I use labels on almost all wires as to function or destination.

I haven’t had a problem with crossing circuits. I do only run one wire point to point at a time, working from my schematic.

In progress:

[martyscncgarage]

I use the 18ga MTW from Automation Direct for everything but the larger AC power stuff. I bought five colors of 18ga and a roll of 10ga and 12ga. Pretty much covers what you need in most smaller HP machines.

+1 for this answer!
I tend to follow Centroid schematics including wire color. Rather than different sizes, I just go with 18ga. in multiple typical colors
I also use a lot of 14 gauge. Black/Red/Blue/White/Green

Marty