View Full Version : 220V electrical connection to the control box...Need Help!

09-07-2004, 02:03 AM
Hey guys...I am right in the middle of getting my new shopbot wired to the control box and I have run into a few electrical questions I need answered...I know someone has had these situations before so if you can give some insight I would appreciate it!

My father-in-law has a 3-prong 220v 50 Amp fused receptacle in his shop that we plan on using. The problem is that it only has a black and a white (hots) and a green (ground). The power cord that came with the control box has 4 wires, a red and black (hots), a green (ground) and a white (neutral). My question is this...What do I have to do to make the 3 wire cord (from the existing 220V receptacle) work with the 4 wire cord (from the control box)? I went to home depot and the guy there said to just connect the hots and the neutral and leave the ground disconnected and to just wire nut it off?? Doesn't sound right to me...

The second question is the receptacle box for the porter cable router to plug into. The plug for the router is only a 2-prong plug with no ground. So I went and bought a 2 prong duplex receptacle (no 3rd prong) and single gang box along with about 20ft of indoor 12/2 romex and wired it without using the ground wire. Is this ok? The manual says nothing about attaching a ground for the router?

Anyways, as soon as I figure this out I will be ok...I think!

Jim Russell
Rocklin, CA
therussellhome@hotmail.com (mailto:therussellhome@hotmail.com)

09-07-2004, 09:01 AM
Hi Jim,
I just finished dealing with the same issues.
The Alpha controller takes a 220V input and splits it into two 110 V lines. One runs the router, the other runs the controller. Ignore the Home Depot information, without the neutral it wont work. Wiring for a permanent installation
will need a four wire circuit.

For the present, you can wire the controller only to a 115V 20 amp circuit, and run the router off a separate 115 20 A line. In this configutration the controller won't switch the router on and off, but the SB will work fine otherwise. Drop me an email if you have questions.

Jim Frost

09-07-2004, 09:23 AM
Depends on if you order your tool with 220V driver... Is it? If so, then you'll need a REAL 4 conductors wire (like for oven) to power both the control box and the router. If you ordered your control box with 110V driver, then a three conductors wire will be right as Jim Frost suggest. The PC router is ground using the neutral... as many hand tools are.
I got this suprise too as I got wired before receiving my tool. But then I chose to not use the control box to control the router...
Now I'm no electrician and not a SB tech. so you might want to confirm with support...

09-07-2004, 11:06 AM
Be carefull. A licensed electrician is worth the few dollars that he'll charge to set up your machine.

Like the others said, you can't split the 220-240 VAC line into 2-120VAC lines without a neutral. The RED conductor and the WHITE neutral form one 120VAC line. The BLACK conductor and the WHITE neutral form the other 120VAC line.

If the router has no ground prong, then it is double insulated; therefore it doesn't require a ground prong. I always wire all lines with a ground line so that I can plug in any piece of equipment at any time.

If things are not wired properly, not only can you fry your equipment, but you could easily be severely hurt.

09-07-2004, 12:13 PM

Your existing circuit is not wired properly for the ShopBot. You will need a 3-wire 220Volt circuit, plus ground. This means 2 hot wires (each wired to one terminal of a 2-pole, 220Volt, 30 amp breaker), one neutral wire (wired to the panel's neutral bar), and a ground wire (wired to the panel's ground bar). Do not compromise the ground either from the control box to the wall, or from the router's plug to the wall.

The ShopBot requires the control box, and in turn the frame of the machine to be grounded to your electrical panel's ground bar. If you think you can skip that, do a search of this forum for "ground" and see what kind of problems have been solved by proper grounding.

The router may not require a grounded outlet, but if you have mounted the receptacle in a metal box, the box itself is required to be grounded, as a safety to you in case of a short where the hot wire touches the box (don't scoff - it happens). Also, Romex is not approved or appropriate for exposed use, especially where it will be subject to repeated flexing and possible kinking - you should get a length of SO, SJ or equivalent (rubber-sheathed) cable.

You have spent considerable money on this machine. I strongly suggest you not take chances with the way it is wired. I am encouraged that you were skeptical of the Home Depot guy's advice (he is dead wrong), but if you don't understand this post easily the first time you read it, I respectfully recommend that you hire a qualified electrician. You are taking chances with your tool and possibly your life.

Regards and good luck,
David B.

09-07-2004, 12:52 PM
Every one are right as they suggest to hire a qualified electrician if you feel uncomfortable dealing with this electrical setup. Be careful...
You most probably orderd 110V driver since 220V diver are higher priced... and there is NO difference at your electricity bill using 220V vs 110V...

09-08-2004, 12:56 PM
Thanks guys for the information...I definately will get an electrician out there to re-wire to a 4 line outlet. I have too much money on the line to scew things up!

therussellhome@hotmail.com (mailto:therussellhome@hotmail.com)

09-09-2004, 11:16 AM
There seems to be a general misunderstanding of 110VAC that we have in North American vs 220VAC used in other parts of the world. If I've read the electrical diagrams right for equipment manufactured in Europe, their 220VAC has a single hot lead at 220-240VAC, a neutral, and a ground. In effect, it is exactly the same configuration that we have with 110VAC here in North America, with the exception that it has twice the voltage.

Because both systems use a single hot lead, a single-pole, single-throw switch can be used to open/close the circuit. However, when the North American 220-240VAC circuit is used, it requires a double-pole, single-throw switch to open/close both hot leads (Red and Black). Wiring our 220-240VAC through a single-pole, single-throw switch can be lethal.

I may be wrong, but in my conversations with Shopbot, prior to purchasing the Alpha, they indicated that the 220 driver model was built for the non-North American 220VAC, single hot lead system.


09-09-2004, 11:28 AM
Hmmmmm... interesting... and curious... is it really so in Europe?!

09-09-2004, 11:45 AM
I don't think that is true since all the 220v contactors in the control box I have switch both hot legs.

09-09-2004, 11:53 AM
Link (http://www.talkshopbot.com/forum/cgi-bin/discus/show.cgi?tpc=26&post=14783#POST14783)

09-09-2004, 03:03 PM
This is a serious subject and it is strongly recommended that you have a licensed electrician connect the power to your control box and router\spindle. It is very important that the neutral is connected as well as a ground that goes to earth. Without these you have a potentially lethal situation.

Several of you understand the importance of the neutral and how we are splitting the hot legs to power the drivers and router using seperate 110v circuits and a common neutral.

North America is one of the only countries in the world that uses a 110v single phase, 220v 2-pole and 230v 3 phase AC power. The majority of the world uses 230v single phase and 380v 3 phase AC power. The 230v drivers that we sell are only for use outside of North America and do take a 230v line, a neutral and a ground.

The main disconnect is set up to switch off/on both of the hot legs and neutral of the 220v power input for a router control box using all 3 contracts in the disconnect switch. For a 3 phase spindle box the 110v hot and all 3 three phase hots for spindle are switched off by 3 main contacts in the disconnect and an auxillary contact.

When I was a remodeling business I learned not to cut corners when it came to plumbing and electrical work. Be safe, don't take short cuts on electrical work. It could seriously hurt or kill someone one day.

Please feel free to email or call me if you have any further questions on the electrical connections for you ShopBot.

Gordon Bergfors
Product Development
ShopBot Tools, Inc.

09-09-2004, 07:49 PM
Thanks for the info. Gordon!

09-09-2004, 11:17 PM

Last time I checked, North America was not a country!

Not to detract from the seriousness of your post, of course.

David B.

09-09-2004, 11:29 PM
Electrical discussions can become convolted; however, remember, that, in reality, current flows from negative to positive; this is , from neutral to positive. We may incorrectly assume that current flows from high to low, but that is wishful thinking. In reality, current flows from low to high; therefore, if a circuit has a path, that is not totally disconnected via a disconnect( i.e. switch), the current will find a way to complete the circuit. Why is this important? Simply because we may assume that making/breaking the voltage at its highest potential is the goal; when, in effect, we need to control the voltage at its lowest potential - a much more difficult task.

Given the fact that both legs of a North American 220-240VAC circuit need to be enabled/disabled simultaniously, can a mechanical disconnect(i.e. contactor or relay) do the job? It's been my experience that relying on a mechanical component to make/break a connection in real time is hopeful, at best, and lethal at worst. Normally, when a single leg of a circuit needs to change state, a solid-state-relay is used. The advantage to a solid-state-relay is that a small controlling voltage, usually 3.5-24.0 VDC), activates the relay. Another advantage is that a solid-state-relay usually has circuitry that changes state at the cross-over or zero point of the sine wave. Changing state at the zero-voltage or cross-over voltage means that there will be no "spark" to disrupt the controlling computer. However, a solid-state-relay does not completely make/break a circut. It has leakage - shock value. It doesn't completely make/break a circuit, which requires a mechanical relay in series with the solid-state-relay to give an absolute make/break condition. Given that statement, in North America, both legs (110-120VAC each) of the circuit must act as one leg; or in other words, both legs must be controlled by the same type of solid-state-relay, controlled by the same control voltage. (Never assume that a mechanical relay will connect/disconnect with any precision. Look at the specs., most mechanical relays have a delay greater than 1/2 of a typical 60 hz sine wave.) In reality, expecting both legs of a North-American 220-240VAC circuit to engage/disengage at the same instant, with a mechanical relay-contactor, is false hope.

Given these assumptions, based on facts accumulated from years of practical experience, a good control circuit (in North America) consists of two-solid state relays(activated by the same control voltage) and a mechanical relay that can be counted on to totally engage/disengaged the entire circuit.

What does this really mean? In North America, the circuitry provided in the Shopbot control box will enable/disable, via a mechanical contactor, both legs of the 220-240VAC found in North America; however, each leg of the circuit may not engage/disengage at precisely the same time, causing an imbalance during the time that both legs are not engaged/disengaged - or electrical noise, which causes computers to act strangely. Another common name for this imbalance is voltage-spike. Irratic behavior can be attributed to mechanical relays.

The problem is grealy simplified in a typical 110-120VAC North American or 220-240VAC European circuit where only one leg of the circuit needs to be engage/disengaged.

In practical terms, what does this mean? Absolutly nothing. We work with what we have. But it does mean that a 220VAC circuit designed for the non-North American market, does not act in the same way as a 220-240VAC circuit designed for the North American market.

Tim Pugh (Unregistered Guest)
02-16-2005, 05:29 PM
It's been several years since I've had a new shop and had to wire for 220 V, single phase. I have a two pole 20A breaker and am using 12/3 w/ground. The plugs that I will be using are NEMA L6-20 - the parts I can't remember are - the red and white go to each pole, white to the neutral bar and ground to the ground bar, however the plugs only have three connectors and coming from the motor are only red, black and ground - what happens to the neutral?

02-16-2005, 06:23 PM

In a typical North American 220Volt system, there are two hots and a ground, with no neutral. (There is such a thing as a 110/220Volt system, which has 2 hots, a neutral and a ground, but if the machine plug has no neutral, you don't need one.)

You could have used 12/2 w/ground. Just hook the black and white wires to the hot leads and the green to ground. If you've already run the 12/3, just put a wire nut over the white wire at each end (who knows, you may need it for something later) and hook the black and red wires to hot, and the green to ground.

Bill Imschweiler (Unregistered Guest)
02-17-2005, 04:05 PM

David is close the black and red are hot the white is neutral and the bare wire is ground. Both White and bare wires are attached to the ground plug on the L6-20.

02-18-2005, 01:14 AM
The fun of International Cordsets (http://www.internationalconfig.com/). It is relatively easy and safe for an exporter to supply the right stuff for the destination country. It could save a heck of a lot on support calls.

02-18-2005, 05:30 PM

My understanding, having been told over the years by at least one electrician, one book, and one inspector, is that the ground and neutral systems are connected ONLY at the main breaker panel. Downstream from the main panel the neutral and grounds are never to be connected. I think it's one of those situations where it would probably never cause a problem, but if conditions were just right.... something about a ground loop, which has been covered once or twice on this forum and still eludes my ability to understand.

Disclaimer: I'm not an electrician (although I pretend to be one occasionally around the house) and I was only attempting to provide simple, general, friendly advice. Electrical work, and code compliance in particular, seems to be one of those areas where there are as many "right" ways to do it as there are people doing the work.