What gauge wiring for limit switches?

anyone know off hand what gauge the wiring is for the limit switches? want to pick up some wire on the way home tonight to redo the wiring but cant remember what size it is

20-24 would be fine for limits.

awesome thats what i was thinking. thanks!

If you have the choice, I’d pick up shielded wiring for the limit switches. I picked some up last weekend, and that’s my next infrastructure project.

If your limit switches are isolated from the electrical noise of the motors/spindle, you should be able to enable hard limits in grbl, which would give you additional protection from your machine trying to go past its limits.

im finding it hard to find wire i need locally. the wires are 22 gauge btw. only thing i can find is like speaker wire or automotive stuff. the guy at the box store didnt understand what i was looking for. didnt realize this would be so tough. have no idea what to ask for to find shielded wire

You are not going to find shielded wire at the retail level.

Mcmasters has shielded cable two conductor, you want to search for the flexible stuff designed to go in cable guides such as this,


Not cheap but readily available.
Another source is shielded alarm cable, it 22/2 and shielded but not as flexible, search amazon for shielded cable

ahh thanks guys this helps a bunch! they have the security cable at the box store

Depends on what you mean by “retail” level. If you mean BestBuy and local hardware stores, you are probably correct.

The small town (<25,000 people) that I live in has fairly limited name-brand retail shops, but there are numerous small businesses that most people don’t think of as being “retail” stores, but that will allow the public to shop there and make purchases. The description of the grey stepper motor cable on Inventables says it is also used for intercoms, security systems and more - so try looking for shops that cater to those types of businesses.

I contacted a maintenance tech at my local sewage treatment center (believe it or not, they do a lot of computer controlled equipment work) and asked where I could get wire like that, and he pointed me to two small businesses in town that I never would have thought of - places I have driven past a 100 times or more.

Cat5 would work well

@BadWolf - This is what I have been thinking of getting. Shielded and stranded with a drain wire. Shielded keeps the signals and noise from getting in, the drain wire gives you a way to ground the shield to ground at one end (and one end only), and the stranded wire will more easily bend and resist breaking with repeated flexing.

This is what I used:

I went to Home Depot (Not Lowe’s, they don’t have it) and found some 22/2 shielded security wire. It’s very similar to the wire used in the stepper motors, same grey sheath, same shielding, same nylon string and bare ground wire inside. It’s 22ga instead of 18ga, so a little thinner, and there are only 2 wires inside. You have to ask for it and have it cut, it’s not on the shelf.

The bonus is that Home Depot also sells the 18/4 shielded security wire which IS the same as for the stepper motors. So if you want to have longer cables (for instance, if you wanted to move the power supply out of the way so it doesn’t get full of sawdust), you can get the exact same thing Inventables sends with the kit.

Also, I found some crimp connectors that are the perfect size for the limit switch spades in case you don’t want to solder them. http://www.nteinc.com/terminals-and-connectors.php?a=27 <-- that’s their website
http://www.nteinc.com/terminals/pdf/Female_Disconnects.pdf <-- that’s the product sheet.
You want the 76−NIFD22−110

I will say that despite using shielded cable on the limit switches, the DC motor seems to throw enough interference that setting Hard Limits to ON in Grbl’s $$ config makes the machine stop immediately and crashes Grbl. So if you’re thinking of using shielded cable because you want the homing switches to function as hard limit switches, there’s still some work to be done after the fact.

I think that since I am using the Dewalt DWP611 that helps with having no issues with the limit/homing switches.