Question on 220V A/c outlet

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Doing some reno work in my brother-in-laws condo. Changed out the old FPE subpanel panel to a new one, worked out great. Now I am changing out the old outlets. One of them is a 220V A/C outlet that was originally connected to a 20A double polebreaker with 12 guage wire. The outlet looks like this:
http://www.levitonproducts.com/catalog/model_5029.htm?sid ÜD83CFDDBC2021DA991D8F670C60D74&pid08
My question is should I replace with the same kind? This outlet is only rated for 15A, meanwhile I have a 20A breaker. Do I need to put in a 20A outlet like this?
http://www.plumbersurplus.com/images/prod/6/Leviton-065-05821-00A-rw-163402-240797.jpg
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The outlet should be rated to at least the breaker.
What's plugged into it? While it is ok to have a 3 wire 220 outlet it is no longer ok to use the ground and neutral interchangably at the outlet. So many 220 appliances have switched to 4 wires with a 4 prong plug.
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wrote:

The outlet should be rated to at least the breaker.
What's plugged into it? While it is ok to have a 3 wire 220 outlet it is no longer ok to use the ground and neutral interchangably at the outlet. So many 220 appliances have switched to 4 wires with a 4 prong plug.
**There is no neutral on a 240 volt air conditioner outlet, and grounds and neutrals were never interchangeable on such appliances.
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In

Exactly! Only the two hots and earth ground are necessary.
HTH,
Twayne`
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On 4/1/2011 11:51 AM, Mikepier wrote:

http://www.levitonproducts.com/catalog/model_5029.htm?sid ÜD83CFDDBC2021DA991D8F670C60D74&pid08
http://www.plumbersurplus.com/images/prod/6/Leviton-065-05821-00A-rw-163402-240797.jpg
If it is the only receptacle on the circuit (and 20A breaker and #12 wire) it should be 20A.
In any case, there is no reason not to use a 20A receptacle.
--
bud--


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Thanks. It is the only outlet for a wall A/C unit.
And the wire is 12/2 BX. So the metal clad is ground. The box is steel. I am still going to put a green ground wire tail from the box to the outlet.
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On 04/01/11 02:47 pm, Mikepier wrote:

But doesn't BX already have a bare copper ground conductor? The metal sheath isn't the only ground connection -- at least, if I am remembering correctly from the last time I used it, about ten years ago.
Perce
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not OLD BX.
nate
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** MC cable has an additional copper ground conductor
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Yes, that is known as MC lite with the aluminum clad . But the old BX relied on the steel clad for a ground.
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** and the new BX (AC) lite relies on it's aluminum shield for it's ground.
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that was to be used, NOT the sheath. The new BX (plastic insulated cable instead of rubber, with "raffia" liner) virtually all had a bare copper ground.
Now, to get down to the real differences on CURRENT spiral wound metallic sheithed cable.
There are 3 basic types, MC, AC, and MC/AP
MC has an insulated green or green and yellow ground. AC has a bare copper ground. MC/AP has a full sized copper ground wire attached full length to the sheath, allowing the sheath to be used as safety ground - but that wire is cut flush with the sheath and REQUIRES special connectors where the cable enters the metal box.
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I don't know where you come up with your nonsense. For one thing, the bonding wire inside some AC cable was to assure a fault current path, and was never connected to anything . I have several coils of AC cable in my truck, none of which have a grounding conductor, copper, or otherwise, insulated or bare.
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MCAP is a relatively new standard. Look up southwire mcap. Nolan has some good info on it.
I depended on Northern cable's site for the rest of my information, which was incomplete. There are a lot more than 3 types of spiral wound metallic cable. I checked with Allied cable, one of the larger cable manufacturers. According to THEIR specs: MC-TUFF cable is steel, MC Lite is aluminum, MC Lite ig is insulated ground aluminum. all,with no integrated bond , and with the conductors taped
HCF90 is green steel with insulated ground and bare bonding connector. HSF Lite is the same but aluminum. For HEALTH CARE applications.
AC90 is steel with an integrated bond ribbon AC Lite is aluminum with an integrated bond All AC cable have the conductors wrapped with paper or raffia
And I'll be danged if I can figure out what they would call the hundreds of feet of aluminum sheathed cable with aluminum integrated bond strip AND bare ground wire I pulled last fall would be called - obviously not made by Allied.
It met the description given by Northern for their AC spec cable. (and was LIKELY Northern cable - I don't have the rolls kicking around to check
What brand is your "ac" cable that does not have an aluminum bonding strip, and is it steel (ac) or aluminum (ac lite). Sounds like MC cable rather than AC if it has no bond ribbon. Is it paper separated, or plastic "taped"?
And years ago, it was all "BX"
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On 4/1/2011 8:42 PM, snipped-for-privacy@snyder.on.ca wrote:

BX was outlawed around these parts many years ago. There is MC everywhere in buildings in this area, I use a lot of it.
TDD
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I was always told that the bond wire was not for fault current. It was to short the coils of steel so there were no induced current, but I was not able to find a cite faster than I lost interest.

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** You are exactly right. It lays across the coils of the cable to assure a straight path for any fault current

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** FYI, AC cable was invented at the turn of the century by Gus Johnson and Harry Greenfield. "BX" was never a code designation, just a name given to AC cable made by GE's Sprague division. The bonding conductor wasn't required until the 1959 Nec and was never used as a ground, only to assure a clean grounding path against the metal coils of the sheath
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over the sheath and captured by the box connector, not cut off flush with the sheath.. Inspectors were not happy if they found an end without the ribbon bent back before the anti-short was installed. The bare ground wire solved that, even though the bond strip was still there and best practice was still to bend it back under the cable connector. The "bond strip" in parallel with the coiled sheath had the effect of electrically shortening the length of the "ground" conductor and eliminating the "choke" effect of the coiled grounding conductor when ground fault current existed. This made it possible to use the sheath as a ground. Previously it was not used AS a ground, but was required to BE grounded.
Since MC cable does not have a bonding ribbon as part of it's spec, a ground wire is pretty well a requirement for most applications - virtually all MC cable I've seen over the last 20 years or so has had an insulated ground wire, while the vast majority of the AC cable I've run into (installed since the sixties) has had a bare ground.
Possibly becuase I don't get involved with wiring in the USA, and GENERALLY Canada has higher electrical safety requirements (or at least different ) than the USA.
As for the "BX" designation, WAY back in the 1800s Greenfield had their model "B" flexible conduit, and in about 1900 they brought out an experimental "B" model flex, which had the wires already installed. When it hit the market, according to the generally accepted version of the truth, it was referred to as "B Experimental", shortened on the order sheets to "BX". Might be "BS", but that's the generally accepted story.
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Grew up watching my Dad use it (was required in NYC at the time '50-'70) but may not be now. Never heard it called anything but BX cable. (-: I guess it's one of those things like Kleenex or Xerox. The tradename overtakes the common name. I can still remember moving south and seeing Romex for the first time. Oops. I mean non-metallic sheathed cable from the Rome wire company.
-- Bobby G.
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