[OP]
Member
So my dryer plug is connected to an old school 10-30r outlet. It has no ground wire, just two hots and a neutral. I picked up a 10-30p plug and a 6-15r receptacle to make a pigtail that matches the plug on my planer.
I guess I'm confused by the ground/neutral thing. If I wire it up hot to hot, hot to hot, and ground to neutral, what's going to happen? As I understand it, the 10-30r neutral is also the ground. Is this correct?
Contributor
This is in the off topic forum and should tell you what you are asking.
https://sawmillcreek.org/showthread....electric-range
Contributor
No, the neutral is not the ground. You have an ungrounded outlet intended for certain appliances (dryer, range) which do not require a ground. Your planer requires a ground. Your planer cannot be (safely) plugged into this receptacle.
More info: https://diy.stackexchange.com/a/161046
[OP]
Member
Originally Posted by Dan Friedrichs
Both your comment and your link seem little bit hysterical. I accept that I don't have a comprehensive understanding of what happens when the neutral wire is no longer grounded to the chassis of the dryer, but it also sounds like you don't either.
Dryers and ranges DO require a ground. Please don't reply if you have no idea what the hell you're talking about. All you're doing is muddying the waters for people who may have this question in the future and may come to this thread as a source for information.
Contributor
Not "hysterical", just the truth. Your 10-30R does not have a ground, and you want to plug a grounded appliance into it.
The 10-30R receptacle is (well, "was" - it's been obsolete for several decades) intended for appliances like dryers and ranges that are infrequently disconnected. If the neutral were to be interrupted (say, from the receptacle becoming loose, because it was not designed for frequent connecting and disconnecting), the chassis of a dryer or range (or planer) could become energized and electrocute someone who touches it.
Contributor
Well, pretty much.
Back when this was wired, the ground bare copper and the white neutral could have very likely landed on the same buss, so who cared, right? (assumes it is a home run to the panel)
A couple of questions, though. Is this fed from the main service panel or a sub panel? It makes a difference as to where the ground/neutral lands.
Is the third wire in the dryer receptacle bare copper or white?
Are there any other receptacles on this circuit?
Edit: Well, uh... yeah,...
Dan is pretty much right. The NEC acknowledges that 3-wire was allowed and has exceptions that allows 3-wire to be used in new installations if a 3-wire receptacle is present. It is 250.140 (exception)
But it has qualifiers:
- the third wire must be insulated or type SE wire connected directly to the main service panel
- the appliance must be a dryer or a range/oven
I was curious of the set-up of the wire, but in reality, it is moot. Your planer is not a dryer or a range.
You could hook it up as you suggest but it would not be code compliant.
Last edited by Charlie Velasquez; 12-26-2020 at 8:19 PM. Reason: Well, .... uh,... yeah.....
Comments made here are my own and, according to my children, do not reflect the opinions of any other person... anywhere, anytime.
[OP]
Member
That was when I stopped taking your advice seriously. Anything else you say will be seen through the lens of someone who thinks you're talking out of your ass. Maybe you're right about some stuff and maybe you're not, but I'll wait to hear from people who DIDN'T just say things that are blatantly wrong
Last edited by jamil mehdi; 12-26-2020 at 8:34 PM.
Contributor
Pretty certain for someone asking the original question. Maybe you should stop and ponder who doesn't know what they're talking about and why sharing / interchanging Neutral & Ground isn't done any more. Since you say your concerned about other's finding this thread, making the opposite argument, that doing something known to be less safe is as good as following current safety practices, isn't maybe the best position.
Contributor
See how the 10-30R is shown with a white (neutral) and not a green (ground)?
https://en.wikipedia.org/wiki/NEMA_c...ified_pins.svg
10-30R is not a grounded receptacle.1024px-NEMA_simplified_pins.svg.jpg
Contributor
How is the modern tool outlet (L6-30R) wired? Same # of conductors, going back to main panel?
Matt
Contributor
I can't believe Dan, who clearly has far more knowledge of things electrical than you do, is still offering help when you have been completely ignorant & rude. Please go join some other forum & abuse them. Or better yet, just keep your misery to yourself.
Contributor
Two hots and a ground, no neutral. The ground would be bare, green, or grounded metallic conduit/raceway. Most of the tools we would use as woodworkers at 230V 30A (5HP cabinet saw, big planer, drum sander) would not need a neutral, except maybe a CNC or something like that.
It could go back to a subpanel or the main panel, as the ground is a true ground; it isn't commingled with a neutral.
Last edited by Andrew Seemann; 12-27-2020 at 6:34 PM.
Member
The tone of this post certainly isn't what I expect to read on Saw Mill Creek.
Moderator
I'm not an electrician and I don't play one on TV, either. That said, there is only one place in a modern North American residential electrical system where Neutral (a current carrying conductor) and ground are bonded together and that is in the main panel just after the meter from the street. So that condutor that is currently being used as a neutral for an old appliance circuit really shouldn't be used as-is for a 240v (only) circuit if you want to be code compliant and also be safe. If you are going to dedicate the circuit as a 240v machine circuit and no longer use it for a dryer that is dual voltage, you "may" be able to have a licensed electrician re-purpose the conductor that's currently neutral to strictly be a ground by marking it accordingly, connecting it to the ground bus instead of the neutral bus in the panel and then replace the receptacle with current generation 240v hardware. I said "may" because I do not know for sure if that's permissible. But to use that old outlet as-is isn't a great idea.
Jamil, everyone here is trying to help by insuring things are safe. And Dan's comment about the outlet is factually correct.
--
The most expensive tool is the one you buy "cheaply" and often...
Contributor
First, check and see if you might have a true [green] ground wire in the cable to the box, or "some" metallic conduits (I'm an electrical engineer, but NOT an electrical contractor. I believe there are metal conduit that are NOT suitable for a ground.). If so, you may be able to simply replace the three-prong 220 V receptacle with a four-prong receptacle and be done with it.
There is a good reason why the neutral and ground are NOT allowed to be connected at the appliance. The neutral carries current. Current through a conductor causes a voltage to be developed across the length of the conductor -- the higher the current (such as a motor's starting current), the higher the voltage; and the higher the resistance (long wire runs, or poor connections), the higher the voltage. Therefore, if you are standing on or touching something that is grounded, you can receive a shock from the voltage at your end of the neutral. This is especially true if there happens to be a poor connection somewhere along its length which may develop over time (such as a loosened screw I found at the shared neutral tie-bar at the circuit-breaker panel, a loosened wire nut, or a mouse-chewed wire, all of which I have found in my 40 year old house). If you tie your appliance's ground to the neutral at your socket, you could be on the receiving end.
The neutrals are typically tied to ground AT THE PANEL, which is grounded through an approved grounding, e.g., a long, heavy, copper-plated stake a short distance away. Since the green ground wire doesn't carry any current, there is no voltage developed across its length from that grounding point, and it is safe for grounding cabinets, exposed metal screws, etc. of appliances.
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