Can I plug my 230V compressor (NEMA 6-20P) into a dryer (NEMA 10-30R) receptacle?

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On 28 Oct 2004 22:38:22 GMT, snipped-for-privacy@ipal.net wrote:

I just talked to my dad, a licenced electrician in Ontario. The Ontario Electrical code is loosely based on the NEC, but has some differences. Some things that are forbidden by the NEC are OK according to the Ontario code, and some things accepted by the NEC are not approved in Ontario.
Anyway, according to him, there is one simple legal way to connect that 20 amp compressor to the 30 amp drier connector.
Take a 30 amp drier cord, and using an approved strain relief chassis connector connect that cord to either a breaker or a fuse block in an approved disconnect box fastened to a 2 foot square 3/4" plywood panel.
Mount a 20 amp receptacle to the panel and wire it to the protected side of the disconnect.
Plug the disconnect into the 30 amp drier receptacle, and plug the 20 amp compressor into the 20 amp receptacle.
That way you are connecting a 30 amp device to the 30 amp circuit (you effectively have a 20 amp sub panel) and plugging a 20 amp device into a 20 amp circuit. In the disconnect the neutral must go straight through, and the ground must go straight through - only hitch is the drie plug must be a 4 connector plug.
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The Ontario Electrical Code is based on CSA standard C22.1. "Based loosely on the NEC" is not really true; the CSA code was largely developed independently. Though, since the physics is the same on both sides of the border, the results are not fundamentally different. And in order to not unduly burden the far-off manufacturers of wiring devices that fill our lumberyards and home improvement stores, harmonization efforts on both sides of the border have resulted in substantial agreement.
I'd like to find a really authoritative examination of the differences between NEC and CEC.
Bill
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Canadian regulations would never allow 15 ampere devices on a 20 ampere circuit.

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| Canadian regulations would never allow 15 ampere devices on a 20 ampere | circuit.
But what is it that makes it a "15 ampere device"? Is it the maximum current rating, or the blade configuration according to NEMA?
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UL, ULC, & CSA
wrote:

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| UL, ULC, & CSA |
| wrote: |> |> | Canadian regulations would never allow 15 ampere devices on a 20 ampere |> | circuit. |> |> But what is it that makes it a "15 ampere device"? Is it the maximum |> current rating, or the blade configuration according to NEMA?
And how many words does it take for these guys to make that definition?
The answer to my question could be given in 1 or 2 answers. I'm not looking for who has authority or not to say. I'm looking for a clear well written and concise answer. Given that NEC has numerous poorly written parts, and the wordings of other standards and such can get lengthy, they are of no interest to the issue of resolving exactly what is the formal answer.
I do know the answer, but I want to see it from other people to see if they really know, and to use that for a point of debate (I'll argue the wrong answer is right to see if they are even confindent of their answer if they do get the right one).
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Exactly! There is always some info troll that will debate the stated rules for a loophole somewhere. That is why the code is stated with so many words. people that cannot read shouldn't be wiring homes or businesses where people can die in fire because of bad techniques or ignorance.
Wiring is not a hobby.
wrote:

ampere
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| Exactly! There is always some info troll that will debate the stated rules | for a loophole somewhere. That is why the code is stated with so many words. | people that cannot read shouldn't be wiring homes or businesses where people | can die in fire because of bad techniques or ignorance.
But there is wording in the NEC that if taken literally is wrong. That wording depends on one having experience as an electrician, or having at least done a lot of wiring and/or studied electricity. The problem is that people really do read the NEC (because it is the "final authority") and as a result can come away with the wrong idea. That would be the reader's fault if the wording was literally correct. But it states "rating" instead of "configuration". In this case it is the writers that have it wrong. It's not wrong to those with experience because they can draw on that experience and know what is meant. But some people who don't have that experience will be using the NEC because they have to.
| Wiring is not a hobby.
But it is something that DIY-ers are doing a lot more of, and the NEC needs to be able to guide them precisely. If that comes in the form of a separate document just for DIY usage, that might be better. But one of the existing "home wiring done easy" type books is not it because it is not, by itself in any way, authoritative. What I am referring to is a separate book that can entirely stand on its own such that being in compliance with that book is being in compliance, and the primary NEC document will never need to be consulted. It would not allow anything the NEC would not allow, but might not allow some things the NEC does.
One problem NEC does face is having to handle both extremes from DIY home wiring to industrial electricians doing major work site wiring. It's not easy. But be separating things, I think it could be made to work by relaxing the need to handle any commercial situations in the new document. I'll even suggest the name "NEC @ Home" to give it the cool modern sounding name. And again, it is not a how-to do wiring book ... it is a rule book. It supplements a wiring book (and may be licensed by NFPA, if they ever develop this, to be included in such books if they wish).
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snipped-for-privacy@ipal.net wrote:

So there are DIY people with insufficient experience to install electrical wiring/equipment properly. Imagine that! And you want to "fix" that by dividing the NEC into two portions - one for those with sufficient experience and one for those with insufficient experience?
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In misc.industry.utilities.electric snipped-for-privacy@bellatlantic.net wrote:
| So there are DIY people with insufficient experience to install electrical | wiring/equipment properly. Imagine that! And you want to "fix" that by | dividing the NEC into two portions - one for those with sufficient | experience and one for those with insufficient experience?
I didn't say that. I said they have insufficient experience to INTERPRET THE NEC as intended. Lots of people have plenty experience wiring basic things in their own home. But when they run across something a little bit different, and their "home wiring for dummies" book doesn't cover it, they might just try to get an answer from the authority ... the NEC. Of course the NEC is NOT a "how to" book. But it is often treated as a "what to" book. There needs to be such a book, written for the DIY market that will not go away no matter how much you wish it would, which ALSO is sufficiently complete that it can serve AS THE CODE for all the situations a home will have. One would simply choose whether to use the NEC or the "NEC-EZ"; the latter would not permit anything it does not cover, which generally won't been needed in 99.99% of homes.
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snipped-for-privacy@ipal.net wrote:

Your argument is specious. It nets out to them having insufficient experience to do the wiring properly, if they are forced to rely on their misinterpretation of the NEC as you stipulate in the scenario you created.
But what the hey - if you can write a book that addresses the DIY problem you have in mind, go for it!
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On Tue, 02 Nov 2004 06:27:49 GMT, snipped-for-privacy@bellatlantic.net wrote:

There are lots of guys out there who know enough about wiring and electricity to do a safe wiring job who could never, in a hundred years, understand or interpret the NEC.
They know what size wire is needed in what circumstances, and how to connect the wires. They know what receptacles and switches to use, and how many wires are allowed in a box. They know how much wire to strip, and how to bend the ends so they fit properly under the screw, and how tight to make the connection.
Some of them cannot read.Others just can't read english.
Yet they will very often do a better job of wiring a building than some highly educated electrical engineer type who can interpret the NEC day in and day out.
Some of them are even licenced electricians. Some are even union members.
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Since today was a "holiday" for us union people, I was sitting here reading this thread. I don't have ANY idea of what people do up in the NE section of the US but here in Miami,FL it would be done the usual rat way and someone would just snip of the compressor plug and put in a new plug that matched the dryer receptacle and use it until it burned up or burned the house down. The "Hialeah" way. Now, while everyone has just posted a lot of data the refers to this issue, I (personally, not to DIS anyone) have a problem with giving advice on electrical needs to anyone because it is just cutting someone (preferably a IBEW guy) out of making money doing the work. The NEC code book is NOT an instruction guide for anyone, it is the basis for which state/count/local inspectors go from. As for the dryer, older houses used 2hot/1gound plugs and new constriction is for 2hot/1nuet/1ground outlet. Did anyone ever think that the dryer has the NEUT bonded (what a word...poor choice of words) to the ground inside the dryer itself where the power cord plugs in or has anyone not ever worked on appliances before where this happens? I do new construction, some side work but not really much, and all new construction is 4wire receptacle BUT the dryers being installed in a new high rise condo I am @ do say on the back that 3wire is for OLDER and/or mobile homes only and to use a 4wire plug if NOT used in one of those situations. If your house was built in the 1960-70's, is it piped in or is it romex. If it's piped, just pull new wire (4 wire), change the dryer (un bond) the nuetral-ground, replace the power cord for that end of the circuit. Make a sub panel out of the old dryer outlet box (use X rings) and make one recept. for the dryer and one for the compressor. For me, the simple answer is usually the right answer. Just make sure the BREAKERS are turned off....you know, no one ever mentioned that. What if this guy goes and touches 2 hot wires.....? The volts will not kill you..the amps will...so he would be getting 60 AMPS...only takes 50 milliampere to stop your heart. I mean, to sum up my post on this interesting topic. He should just call a licensed electrician, preferably 3 of them, to compare quotes, and just get the job done with out trying to work with hot circuits that may or may not explode or burn up anything. 120/208 hurts...277/480 hurts a lot more. The neutral is to carry back what amps are not used by the appliance. So using a ground on 3wire as a neutral is NOT a good idea. It will carry a load. Just my 2 cents worth........it does not in anyway imply I "know it all" or I am omniscient. Just after reading all the posts over and over, all of them...hey, I wanted to jump on the band wagon too. phil
On Tue, 02 Nov 2004 15:33:18 -0500, snipped-for-privacy@sny.der.on.ca wrote:

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| The NEC code book is NOT an instruction guide for anyone, it is the | basis for which state/count/local inspectors go from.
By that logic, the law is not a guide for how to live your life, it is the basis for which police arrest you when you do break the law you didn't know about.
| The volts will not kill you..the amps will...so he would be getting 60 | AMPS...only takes 50 milliampere to stop your heart.
Move volts -> more amps ... in same impedance.
Otherwise we can all feel safe using 2400 volts as long as we keep the amps low.
| He should just call a licensed electrician, preferably 3 of them, to | compare quotes, and just get the job done with out trying to work with | hot circuits that may or may not explode or burn up anything.
With no advice, he is likely to have found a random solution. Maybe it would be safe. Maybe not. I don't think he needs an electrician until he has to deal with wiring in the walls. And some solutions do not involved that. The ideal solution is to wire up 4-wire circuits for each dedicated load. But not everyone has the money for it.
| 120/208 hurts...277/480 hurts a lot more. The neutral is to carry back | what amps are not used by the appliance. So using a ground on 3wire as | a neutral is NOT a good idea. It will carry a load.
All those dryers are unsafe, right?
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snipped-for-privacy@ipal.net wrote:

It is not a question of logic - it is a question of intent, and it is stated in the NEC in article 90-1 (c) (2002 code): "(c) Intention. This Code is not intended as a design specification nor an instruction manual for untrained persons."
<snip>

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In misc.industry.utilities.electric snipped-for-privacy@bellatlantic.net wrote:
| snipped-for-privacy@ipal.net wrote: |
|> |>| The NEC code book is NOT an instruction guide for anyone, it is the |>| basis for which state/count/local inspectors go from. |> |>By that logic, the law is not a guide for how to live your life, it |>is the basis for which police arrest you when you do break the law |>you didn't know about. |> |> | | It is not a question of logic - it is a question of intent, and it is | stated in the NEC in article 90-1 (c) (2002 code): | "(c) Intention. This Code is not intended as a design specification | nor an instruction manual for untrained persons."
And this just re-enforces my proposal. Since no instruction manual or design specification can be treated as the code (ever heard of an AHJ that adopts an instruction manual or design specification?), no one can possibly be assured that by following any instruction manual or design specification that they will be in compliance with the code. Thus they are FORCED to still consult with the code to determine that. Then what if the code APPEARS to be in conflict with the instruction manual or design specification because the wording used (for the same intention) is different, and results in different meanings? If the instruction manual or design specification differs with the code, then which do you use?
In cases where the code is poorly written (good intentions that I know and agree with, but were written wrongly) and the instruction manual or design specification were written well, someone who sees the conflict could well choose to go with what the code says (and not what the code means), just because of the fact that the CODE TRUMPS everything else.
If a homeowner installs something one way, by the book, and the book clearly says he can, but the inspector finds it not in compliance with the NEC as adopted by the AHJ, he's going to fail the work, anyway. The homeowner might dispute it, and the inspector would rightly say that only the NEC is applicable. So despite 90-1, the EFFECTIVE USE by inspectors (and there isn't any way around this) is that the code still has to be used as part of the design specification. I suspect 90-1 is there because they know the code is poorly written for such a purpose as instruction manual or design specification.
So my proposal stands. I say there needs to be something that actually *IS* an instruction manual (or design specification) that can STAND ON ITS OWN and be taken AS THE CODE (e.g. AHJ's can adopt it and allow any use of that instruction manual or design specification and inspection can then be based on it without any cross interpretation with the code).
I'm not saying this is needed for experienced electricians or for any commercial or industrial elecrical work. Experienced electricians do eventually learn what the code MEANS (despite what it says), as do most inspectors (rumor is that some, especially in large cities, just prohibit anything they don't understand). The WHOLE POINT of this is to have ONE BOOK that a DIY homeowner can use to ensure things are done right, and safe, the first time, with no hassles.
What would YOU do if a DIYer installs a receptacle device rated for 40 amps, with #8 copper wire, and protects it with a 40 amp breaker, even though the device is configured for 2 NEMA 5-20R outlets? Think such a device does not exist? I have installed one (but I did it on a 20 amp circuit because I was smart enough even before ever reading the NEC).
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I don't think that that's realistic. You could easily create a book that is instructions for doing things that will MEET code, but only if you're willing to accept limiting your possibilities to that subset of code-compliant things that are easy to to explain, understand, and get right. But your average homeowner is not equipped to cope with the sorts of things that a competent and motivated professional can do, and it's undesirable to limit the options available to EVERYONE to what any shmuck can accomplish, and no matter what you write down, there's always going to be some special case where what the book says is OK is unsafe, so there's always going to be some judgement required.
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There are at least a half dozen books that attempt to explain wiring to the novice at any decent home store. As long as they don't try anything very complex it sort of works. You do see Harry Homeowner making up his own rules for things that are not clearly explained in "wiring for Dummies" and that is how you find the plumbing elbows and sprinkler fittings on RNC runs.
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Especially one old enough to predate the U/L listing. Sell that sucker on Ebay as a depression era antique.
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snipped-for-privacy@ipal.net wrote:

You don't seem to realize what you are asking for. You want a subset of the code book that cannot possibly be misinterpreted by a DIY person.
Apparently, you do not know what people are capable of! This is not meant as an attack on you. It is simply unimaginable that a book could be written that everybody would understand identically.
In response to your hypothetical: If the DIY guy was a ball-buster, and I was the inspector, I'd bust back. If I was the inspector, and he did it the way he should, I would not. Now a question for you: In the hypothetical, what is the first thing the DIY guy needs to do specifically for the inspection?
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