1 or 2 dedicated 120VAC circuits for my CNC?

Wire to a receptacle on the cabinet, makes it easier to move the machine or replace the cable if it gets damaged.



Both have pro's and cons. I can't even remember how my machines are wired. I think that that are hard-wired and that's generally how conventional manual machines were wired. Often a gland into a terminal box. The problem with having a receptacle on the machine is that the machine might be shipped to a country where the matching plug is not available.

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Just had a look, both my current machines are hard-wired at the machine end. I have never had cause to wish it was otherwise.

spumco Wrote: wrote: Hardwire to the disconnect switch inside your cabinet (use a cable gland through the housing panel) and a plug on the other end.

Less to go wrong.

That is exactly what I was thinking. Thanks

andypugh Wrote:
Wire to a receptacle on the cabinet, makes it easier to move the machine or replace the cable if it gets damaged.

My plan is to have the cable come out the cabinet through a gland and then to 30A plug/outlet on the wall. The cord will only be a few feet. So to move the machine I just unplug from the wall and move it. I do see your point about if the cord gets damaged. I don't see that happening in its current location as it is against the wall that it is plugged into. There will not be any cord laying on the ground or where it could get damaged. 

Thanks guys!

I have a couple questions. As I am wiring my panel I am finding that I mis-calculated some of my circuits (wire gauge/amp/breakers, etc). I have corrected them along the way. But I have a couple things I would like to make sure I understand correctly.

1. I am feeding my cabinet with 30A 120V. I then distribute that to multiple breakers. If one of the breakers is 10A, I assume the wire feeding the breaker would need to handle the 30 Amps coming in? And then after the breaker it would need to handle 10 Amps?

2. My Router circuit (feeding an outlet for the router mounted on the side of the cabinet) is a 10A circuit because the Dewalt DWP611 is rated at 7A. I am trying to determine what wire I can use to feed the outlet. I have a 18AWG stranded silicone wire that is rated 7A Carrying Current and 20A Instantaneous Current. Would that be safe for this circuit? I usually like to have a little extra room. Especially when the router will be running for lengthy periods of time. The length of the wires in question are very short. Maybe a foot or two tops.

I know these may be dumb questions but I just like to be safe and make sure I am understanding what I am doing and why.

Thanks

There are “Ampacity calculators” online. Maybe try to find one that includes wire length.

1. Correct.  if you look way back in the thread I provided some suggestions for the 30A run to the main CB (based on your 120v system.)

2. Ditto to Andy's response.  To expand - most "NEC" wire ampacity charts don't include anything smaller than 18awg or the (more common now) 105c insulation, but you can find them if you look.

Don't forget that the standard ampacity chart is for single conductors, or up to 3 conductors in an appropriately-sized raceway (conduit).  Portable power cord (SOOW/SJOOW) has different, usually lower, ratings for the same AWG conductor.  If you're using a cut-up extension cord or SJOOW to go from the wall to the machine you'll need to search for portable power cord ampacity chart.

 

Does this image look correct? Mainly the wires between the TB's and the CB's and then the wires after the CB's. 

 

I am using mostly high strand, tinned copper, silicone wires (200c insulation) for all my cabinet wiring. They are rated at 600V. But the problem is that it is hard to find any charts that have amp ratings for these type of wires. Plus if you search for Amp charts you will find that most of them are completely different from each other. It has been challenging for sure. And unfortunately Amp ratings are not always listed in the specs. Because of this I try to give myself some extra room in the ratings. Hence the reason I asked about the 7A wire for a router circuit that will draw 7A. I ordered some 14AWG for that circuit yesterday so I should be OK now.