sk1939Premium
join:2010-10-23
Washington, DC
kudos:9 Reviews:
 ·T-Mobile US
| Myth of the Neutral Wire »www.eetimes.com/design/industria···ral-Wire
Interesting read, but not new information to well-versed tradesmen in all likelihood. |
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 alkizmo
join:2007-06-25
Pierrefonds, QC
kudos:1 | Having skimmed this article: I know computers don't give a damn about which is hot and which is neutral. When I lived in Japan, plugs were non-polarized and non grounded (I still have a couple of power strips that are very convenient for me  ). Everything worked, whether is was a desktop PC, a laptop, printer, router, modem.
These power strips I brought home can be plugged in any direction and can accomodate 3-prong (ground prong) plugs because they don't block the ground prong when plugged at the edges. |
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harald
join:2010-10-22
Columbus, OH
kudos:1 | Computers may not care, but other kinds of equipment may. Try reversing the hot and neutral on a modern gas furnace. It won't run. |
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TexPremium
join:2012-10-20 | reply to sk1939
The most interesting part to me was:
The actual answer as to why plugs are polarized in North America is found in a ubiquitous appliance: the screw-in incandescent lamp. This appliance, standardized long ago, violates many modern safety regulations but is too common to outlaw. The power connections to the bulb involve the threaded socket and the recessed "button" at the bottom of the socket. The only reason why the prongs on the two prong plug are different sizes is to ensure that the more dangerous connection, the more accessible threaded socket, is always connected to the neutral, or safer, wire.
And, to this day you can still buy a replacement lamp plug and/or cord that is non-polarized. |
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TheMGPremium
join:2007-09-04
Canada
kudos:1 | reply to alkizmo
said by alkizmo:Having skimmed this article: I know computers don't give a damn about which is hot and which is neutral.
And most of them wouldn't give a damn whether it's AC, DC, 50Hz, 60Hz, 100Hz, 200Hz, etc. Some power supplies may have active PFC circuits that won't run properly on anything but 50/60Hz, but most power supplies just won't give a damn. |
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alkizmo
join:2007-06-25
Pierrefonds, QC
kudos:1 | reply to Tex
said by Tex:And, to this day you can still buy a replacement lamp plug and/or cord that is non-polarized.
Really? I can't recall any lamps I have that aren't polarized. In fact, I can't think of anything I have (aside from AC adapters/wall warts) that has a non-polarized plug.
Then again, I did find this oddity in my miscellaneous cable box.
So ya maybe anything dangerous can be bought. |
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 TA63ST215WPremium,MVM
join:2000-11-23
there
kudos:2 | But it is polarized, so it must be safe.
--
The talented hawk speaks French. |
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 tschmidtPremium,MVM
join:2000-11-12
Milford, NH
kudos:8
 ·G4 Communications
·Fairpoint Commun..
 ·Hollis Hosting
| reply to harald
said by harald: Try reversing the hot and neutral on a modern gas furnace. It won't run.
I find that hard to believe. Do you know why it cares and how they test for the reversal?
The only way for a device to know if hot and neutral are reversed is to compare it to safety ground (green wire). That means adding circuitry to safety ground resulting in another point of failure for no benefit.
/tom |
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harald
join:2010-10-22
Columbus, OH
kudos:1 | It has to do with ignition sensing. I don't know the theory, but a quick Google of error codes will show you that it is the case on most if not all furnaces. |
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TexPremium
join:2012-10-20 | reply to alkizmo
said by alkizmo:said by Tex:And, to this day you can still buy a replacement lamp plug and/or cord that is non-polarized.
Really? Uhh, yeah, really. |
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Reviews:
·AT&T Midwest
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alkizmo
join:2007-06-25
Pierrefonds, QC
kudos:1 | reply to Tex
said by Tex:said by alkizmo:said by Tex:And, to this day you can still buy a replacement lamp plug and/or cord that is non-polarized.
Really? Uhh, yeah, really. Like seriously? |
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TexPremium
join:2012-10-20 | Totally. |
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alkizmo
join:2007-06-25
Pierrefonds, QC
kudos:1 | no way |
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Reviews:
·AT&T Midwest
| Try this search:
"NEMA 1-15P" "non polarized" |
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tschmidtPremium,MVM
join:2000-11-12
Milford, NH
kudos:8 Reviews:
·G4 Communications
·Fairpoint Commun..
·Hollis Hosting
| reply to StillLearn
Thanks for the links - interesting.
It looks like they are using raw line voltage to sense flame relative to Safety ground. I would have thought that was illegal (NEC) but as it is only a few microamps I guess it is acceptable practice.
»www.robertshawtstats.com/spaw2/S···vB_1.pdf
They could perform the same task by using a separately derived AC voltage but that would raise cost a little.
/tom |
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alkizmo
join:2007-06-25
Pierrefonds, QC
kudos:1 | reply to StillLearn
said by StillLearn:Try this search:
"NEMA 1-15P" "non polarized"
That's not related specifically to lamps.
I see those cords often, but they can only be used to hook up stuff that aren't screw bulb lamps. |
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Reviews:
 ·AT&T U-Verse
| reply to TheMG
said by TheMG:And most of them wouldn't give a damn whether it's AC, DC, 50Hz, 60Hz, 100Hz, 200Hz, etc. Just to clarify - this applies to devices with switching power supplies ONLY. Feed an [AC] transformer with DC and you'll have sparks and smoke if the fuse doesn't blow promptly. |
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lutful... of ideasPremium
join:2005-06-16
Ottawa, ON Reviews:
·TekSavvy DSL
| reply to sk1939
said by sk1939:http://www.eetimes.com/design/industrial-control/4009524/The-Myth-of-the-Neutral-Wire
Interesting read, but not new information to well-versed tradesmen in all likelihood. Very few electricians seem to trust electrical engineers messing with their "field of expertise" ... I had some nasty arguments with forum electricians who blamed mysterious ground loops and bad ground"ed" wiring for almost any equipment problem while suggesting horrible ground"ing" solutions. |
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| said by lutful:Very few electricians seem to trust electrical engineers messing with their "field of expertise" ... And I have seen posts by so called EE's that not only didn't make sense, they weren't even close to meeting code... |
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